SHI iHSOWIftM IH&miniOM LIBRARItb P.O BOX 37012 NHB 25 M?C 154 UV^HINCVOW DC 2001 : 7012 " ■>» si* armndia Volume 63 • Number 1 • 2004 Arnoldia (ISSN 0004-2633; USPS 866-100) is published quarterly by the Arnold Arboretum of Harvard University. Periodicals postage paid at Boston, Massachusetts. Subscriptions are $20.00 per calendar year domestic, $25.00 foreign, payable in advance. Single copies of most issues are $5.00; the exceptions are 58/4-59/1 (Metasequoia After Fifty Years) and 54/4 (A Source- book of Cultivai Names), which are $10.00. Remit- tances may be made in U.S. dollars, by check drawn on a U.S. bank; by international money order,- or by Visa or Mastercard. Send orders, remittances, change- of-address notices, and all other subscription-related communications to Circulation Manager, Arnoldia, Arnold Arboretum, 125 Arborway, Jamaica Plain, Massachusetts 02130'-3500. Telephone 617.524.1718; facsimile 617.524.1418; e-mail arnoldia@arnarb.harvard.edu. Postmasters Send address changes to Arnoldia Circulation Manager The Arnold Arboretum 125 Arborway Jamaica Plain, MA 02130-3500 Karen Madsen, Editor Mary fane Kaplan, Copyeditor Andy Winther, Designer Editorial Committee Phyllis Andersen Robert E. Cook Peter Del Tredici Jianhua Li Richard Schulhof Stephen A. Spongberg Kim E. Tripp Copyright © 2004. The President and Fellows of Harvard College Page 2 In Memoriam: Richard Alden Howard 1917-2003 8 Horticulture and the Development of American Identity Philip f. Pauly 18 Lingonberry: Dainty Looks, Sturdy Disposition, and Tasty Berries Lee Reich 26 Herbarium Specimens as a Novel Tool for Climate Change Research Abraham J. Miller-Rushing, Daniel Piimack, Richard B. Primack, Caroline Imbres, and Peter Del Tredici 33 Finding a Replacement for the Eastern Hemlock: Research at the Arnold Arboretum Peter Del Tredici and Alice Kitajima 40 Arnold Arboretum Weather Station Data — 2003 Front cover: Cinnamomum sp. photographed by Peter Del Tredici on LuShan (Mountain) in the LuShan Nature Preserve, Jiangxi .Province, China. Inside front and back covers: Chatsworth Bakewell, Derbyshire. Photographs by Alan Ward from his series Portraits of Trees. Back cover: The Concord grape as illustrated in U. P. Hedrick's 1908 The Grapes of New York. From the Library of the Arnold Arboretum. In Memoriam RICHARD ALDEN HOWARD 1917-2003 T WO forces of nature hit Massachusetts in September 1938. The Great Hurricane sv/ept through on the 22nd, dramatically altering Nem^ England's landscape. Richard Alden Howard arrived in Cambridge that same week to make his own, far more positive, impact on Harvard's landscape and, later, on the 265 acres at the Arnold Arboretum in Jamaica Plain, Massachusetts. Howard was born in Stamford, Connecticut, and reared in Warren, Ohio. He graduated from the Botany Department at Miami University in Ohio in 1938. Afterward, unable to afford graduate school, he accepted a position as a technician at Harvard University under Irving W. Bailey. Bailey put him to work on a little- known group of tropical flowering plants, the Icacinaceae. Howard also attended classes, and in 1939 the Society of Fellows awarded him a Junior Fellowship that supported his postgraduate training. As a graduate student, he had the opportunity to visit Harvard's Atkins Garden at Soledad, near Cienfuegos, Cuba. The experi- ence inspired both his life-long interest in tropical plants and his relationship with the scientists in the Caribbean. It was also where he met one of the great plant explorers, David Fairchild. After travel to Cuba became restricted, Howard contin- ued his tropical research and teaching efforts at the Fairchild Tropical Garden in Miami and visited Fairchild's estate, the "Kampong," in Coral Gables, Florida. Howard continued the work he had started under Bailey on the Icacinaceae and completed his doctorate in 1942. His thesis, entitled "Studies of the Icacinaceae: A monograph of the New World species," was later published in a series of papers. The country was at war. Howard wanted to enlist in the United States Navy but was rejected because his height of six-feet-five-inches exceeded U.S. Navy limits. Instead, he entered the Army Air Corps where his combination of leadership and teaching skills and practical knowledge of tropical plants led to his assignment Clockv/ise from top left: On a field trip in the Lesser Antilles, Richard Alden Howard holds specimens of a plant so rare it defied identification. He located it on a spur of St. Vincent’s original volcano, north of the then-active crater lake. Dr. Howard, Harvard botanist Lily M. Perry, and Yin Hung-chang, director of the Shanghai Plant Physiology Institute, photographed during the 1979 visit to the Arboretum of a delegation of botanists from the People’s Republic of China. Colleagues Carroll E. Wood, Jr., and Howard with plant specimens in Professor Howard’s office in the Harvard University Herbaria. Howard, at left, as a graduate student in Cuba. Director Howard takes his turn with a spade at the 1961 groundbreaking ceremonies for the Arboretum’s Dana Greenhouses. At bis left are George Taylor, director of the Royal Botanic Gardens, Kew; Bradford Washburn, director of Boston’s Science Museum; and Nathan Pusey, president of Harvard University. All photographs are from the Archives of the Arnold Arboretum. 4 Arnoldia 6312 with the newly established Research and Rescue Program of the Air Force. He was appointed its first director and devoted the rest of his time in service to teach- ing airmen how to survive adrift on desolate oceans, in freezing snow, scorching sands, and sweltering jungles. He wrote survival manuals (some published by the Arctic, Desert, Tropic Information Center (ADTIC). When he left the service, he was a captain, and he continued as a consultant to ADTIC for several years. The Air Force recognized his contributions by presenting him with the Legion of Merit award in 1947. Howard continued not only to write but also to collect survival manuals, and amassed a unique collection that he donated to Harvard's Houghton Library in 1998. Following the war, Howard and his bride, Elizabeth "Betty" Solie, moved to New York, where Howard worked as a curatorial assistant at the New York Botanical Garden. In 1948 he was called back to Harvard as an assistant professor responsible for the botanical semester of the large introductory biology course. He proved to be a popular and innovative lecturer who often provided generous supplies of edible plants to demonstrate his belief that the best way to a student's mind was through his stomach. At the same time, he published papers on the floristics of the West Indies and New England. In 1953 the University of Connecticut appointed Howard professor of botany and department chair. His stay in Connecticut was short-lived since he was recruited hack to Harvard in 1954 as director of the Arnold Arboretum and the Arnold Professor of Botany. Howard's new challenge was to guide the Arnold Arboretum through a period of tremendous change and turmoil. Controversy surrounded Harvard's decision to move portions of the Arboretum's herbarium and library from Jamaica Plain to a new facility in Cambridge. Despite an atmosphere charged with tension, Howard forged ahead. He possessed the stamina, integrity, and sense of humor to carry him through a contentious decade. Critics were won over by his zealous promotion of the Arnold Arboretum and all things botanical and horticultural. He gave count- less lectures at garden clubs and cultural organizations and presented his lecture "A Botanist in Your Grocery Store" more times than he could recall. Among his other favorite talks were "Botany in Boston Restaurants," "Jungle Housekeeping," and "South to the Antilles." He was in such demand that he often joked about "living out of a suitcase for weeks on end," but he knew that he was rebuilding a support network and he channeled all of the honoraria back into the Arboretum's public education programs. Howard encouraged the Arnold Arboretum staff to become active in local, national, and international botanical and horticultural organizations. He and staff members were soon involved in the Horticultural Club of Boston, the Mas- sachusetts Horticultural Society, the New England Botanical Club, the American Association of Botanical Gardens and Arboreta, the American Society of Plant Taxonomists, the Botanical Society of America, the International Association of Botanical Gardens, and the International Society of Plant Taxonomists. Howard served as an officer for many of these organizations. He also encouraged the library Richard Alden Howard 5 staff to join the newly organized Council on Botanical and Horticultural Libraries when it held its first meeting in Boston in 1968. During his twenty-four years as director, Howard assembled a capable team to advance the mission of the Arnold Arboretum. He was interested in every aspect of the operation and made himself available to his staff when decisions were needed. He acknowledged both personal and professional achievements and milestones of the staff and volunteers in the Arboretum Newsletter and in his annual Director’s Report. He restored the botanical and horticultural reputation of the institution, improved the grounds, and built greenhouses. While cultivating mutually beneficial relationships with the City of Boston and its Parks Depart- ment, at the same time he thwarted attempts by the city to reclaim portions of the Arboretum for other purposes. Computerization of botanical records was in its infancy, and Howard was among the first to introduce this new record- keeping system to the Arboretum. He bolstered the Arboretum's public educa- tion program, introduced innovative uses for the Arboretum's Case Estates in Weston, Massachusetts, and promoted major research projects like the Generic Flora of the Southeastern United States in the Journal of the Arnold Arboretum. Howard shuttled from his home at the Case Estates to famaica Plain and then on to Cambridge nearly every day for almost twenty-four years. He maintained two offices and supervised staff on both sides of the river. His motivation was clear, his energy boundless. He considered his success at the Arnold Arboretum to be his greatest professional achievement. Howard was not content to limit the Arnold Arboretum's research program to his own sphere of interests. In the early 1970s he took every opportunity to rebuild relations with botanical institutions in China. By the mid-1970s he had succeeded in renewing the exchange of specimens, and in 1978 he was able to visit colleagues there as a member of the Botanical Society of America's delegation. In 1980 the Arnold Arboretum resumed its botanical work in China by sending a new team of botanical explorers and hosting a stream of Chinese botanists in Cambridge to collaborate on the Flora of China project. Professor Howard continued to teach in Cambridge and to lead Harvard stu- dents on field trips to Cuba until the formal relationship with the Atkins Garden ended in 1961. From then on, he conducted his field studies in the Everglades and elsewhere in subtropical Florida but continued to correspond and exchange materials with his Cuban colleagues. Howard also devoted time to collecting on islands throughout the Caribbean, frequently traveling with colleagues and family members. He joked about the wisdom of choosing to explore the tropics, but the work was often dangerous. He and his team worked in remote locales, trekked over rough terrain, and scaled slick volcanic mountainsides. Howard's extensive knowledge of tropical vegetation was put to practical use. Aluminum companies sought his help in the revegetation of strip-mining sites in Jamaica and later in Hawaii. A grant from the National Science Foundation permitted him to study the montane elfin forests at Pico del Oeste in the Luquillo 6 Arnoldia 63/2 Mountains of eastern Puerto Rico, a project that resulted in seventeen papers. The Boston Poison Information Center relied on his advice about poisonous plants, and he was "on call" to them for many years. The work that represents the culmination of Howard's research in the West Indies is the six-volume Flora of the Lesser Antilles (1974-1989). In the foreword to Volume One, Howard wrote, "Since the time of the voyages of Columhus much botanical data has been assembled from the various islands of the Lesser Antilles. Yet, after almost five hundred years, a unified and comprehensive account of the specific components of the vegetation that flourishes on that chain of islands is still wanting. The launching of the publication ... is aimed to fill this gap just before the last steadfasts of our natural vegetation succumb to the recklessness of man and his civilization . . . The undertaking of the preparation of a definitive flora dates back to some twenty years involving both extensive field work, com- bined with exploration, and intensive research in herbaria." The series was com- pleted in 1989 and it is still a standard reference work on Lesser Antilles flora. Professor Howard asked to be relieved of his administrative duties in 1978. He continued his teaching and research as professor of dendrology in Cambridge. His courses ranged from introductory botany to graduate level classes in advanced plant anatomy and the phylogeny of flowering plant families, and he was proud to have supervised three graduate students. In 1988, when he reached mandatory retirement age, he taught his last course at Harvard: "Plants and Human Affairs." He was asked to substitute at the last minute but did not hesitate to accept since it was a course that he had always wanted to teach. His research during this period focused on his extensive survey of the nodal and petiolar structure of the vascular conducting system through which plants move materials between leaf blade and stem. Howard left Cambridge briefly from July 1989 until September 1990 to serve as the vice president for science at the New York Botanical Garden. Howard was an international goodwill ambassador for the botanical and horti- cultural sciences. In 1963 he made a world tour, visiting gardens and herbaria at every stop, collecting whenever he could, and photographing plants and people to add to his already voluminous collection of Kodachrome slides. He served on hoards and consulted at established or new botanical and horticultural organiza- tions like the Pacific Tropical Garden based in Kauai, Hawaii (now the National Tropical Botanical garden), the Acton (Massachusetts) Arboretum, the Coastal Maine Botanical Garden, the Fairchild Botanical Garden, and the beloved Kam- pong. He was thrilled to return to Cuba and the garden at Soledad in 1999 with a delegation sponsored by Harvard's David Rockefeller Center for Latin American Studies. In a surprise finale to the conference, the Cuban delegation planted two new palm trees in his honor. Over a sixty-year period Howard published thirteen books and more than three hundred papers. Their depth and breadth reflect his eclectic interests. He wrote on plant anatomy and morphology, fioristics, cultivated plants, economic botany, tropical ecology, biogeography, the social and economic history of the West Indies, the lives of botanists, and botanical trivia. Even in his later years, when Richard Alden Howard 1 his eyesight and general health began to fail him, he spent his good days working in the library on various projects and manuscripts. During his long career Howard received many awards. The Jamaica National History Society, the Montserrat Natural History Society, and the Montserrat National Trust acknowledged his botanical contributions to their islands. The American Association of Botanical Gardens and Arboreta, the American Herb Society, the American Horticultural Society, the Garden Club of America, the City of Boston, the Massachusetts Horticultural Society, and the National Coun- cil of State Gardens bestowed horticultural awards upon him. He was named an honorary fellow of the Danish Royal Academy of Arts and Sciences and received the Distinguished Citizen Award from his hometown of Warren, Ohio. He was named an honorary Doctor of Science at Framingham State University in 1977 . In 1999 the National Tropical Botanical Garden awarded him the Allerton Award in recognition of his decades of service in the advancement of tropical horticulture and the understanding of tropical plants. Howard was a member of the New England Botanical Club from 1940 until his death. He served as president in 1953 and held the record of most-often-featured speaker at the Club's milestone meetings — the 700th, the 800th, and the Centen- nial. At the centennial meeting Howard was not content merely to summarize the highlights of one hundred years of the organization,- he commissioned noted author Maurice Sagoff to compose a poem about the NEBC, which he read at the end of his speech. The Howards reared four children, Jean, Barbara, Bruce, and Philip, and the family shared many botanical adventures. Betty co-authored several papers with her husband and edited many more. She co-hosted open houses, exotic botanical- theme dinners for international dignitaries, impoverished students, and prospec- tive faculty and staff. She was a true partner in Howard's life, traveling the world with him and managing their family and home when he was off on his own. They were proud of their children and eight grandchildren and in later years looked forward to annual family reunions in Florida. (Of course, Howard timed the reunions to coincide with his work on the inventory of plants at the Kampong.) Richard Alden Howard's legacy to Harvard and to the fields of botany and hor- ticulture are as large as his life. The citation presented to him by Framingham State College in 1977 is an apt tribute. It reads, "Scholar, interpreter of the world of plants to people of all ages, botanical explorer of the world's remote corners, entrusted with the care of our botanical treasures, he has taught us survival in the wilderness and the beauty of civilized nature." — Judith A. Warnement, Librarian, Harvard University Herbaria, and Carroll E. Wood, Jr., Professor of Biology emeritus. Harvard University. Acknowledgments Special thanks are due to Bruce Howard and staff of the Arnold Arboretum and the Harvard University Herbaria for contributions and corrections. The memorial was previously published in Rbodoia (2004) 106(926): 178-184. Horticulture and the Development of American Identity Philip J. Pauly C ulture was not the same in nineteenth- century America as it is today. This statement is so obvious as to he banal, whether the subject is painting, clothing, sport, or slang. One difference, however, stands as prominent yet unexplored: the word culture itself. In the Century Dictionary and Cyclo- pedia, a massive scholarly compendium of the 1880 s, the primary meanings of culture in- volved "tillage," controlled breeding, and tech- niques used in the new science of bacteriology. Only with apologies did the editors extend their definitions of the word to describe, on the one hand, the individual and collective improve- ment of the mind, and, on the other, the ethno- graphic whole.' This essay sketches aspects of a world where culture was a verb that referred primarily to activities that are now considered parts of bio- technology. Well into the nineteenth century, Americans could speak unselfconsciously about strawberry culture, pear culture, and arboricul- ture. More tellingly, high culture meant, not sweetness and light, hut manure, hand weeding, and controlled pollination. The primary sites of culture were rural pastures and suburban gar- dens, not opera houses or Polynesian villages. This is not to say that the meaning of cul- ture then was either completely different from now, or that it was more precise. Horticultur- ists in particular were aware that they stood hip deep in a linguistic compost redolent with metaphors that sprouted like mushrooms and with meanings that hybridized uncontrollably. Even if they did not read Virgil or Alexander Pope, they knew that gardening was as much about culturing themselves as their shrubs, and “Elms at Yale College,” ca. 1840, engraving by William Henry Bartlett (1809-1854), from Nathaniel Parker Willis’ American Scenery, or. Land, Lake, and River Illustrations of Transatlantic Nature, 1857. Horticulture 9 that a man's pears, pines, and peonies were indi- ces of his taste. I take advantage of these many connotations of culture hut hold to the idea that its primary meaning in nineteenth-century America was the use of intelligence to improve living things. Some elements of culture were universal, while others were geographically and histori- cally specific. One way to understand the par- ticular is to focus on certain exemplary plants. This essay focuses on two characteristic but contrasting New England types — American elms (found objects that were used as street ornaments) and the Concord grape (a construct- ed variety with horticultural uses). Comparing the histories of these two Yankee plants gives 1 Horticulture 9 Horticulture and the Development of American Identity Philip f. Pauly that a man's pears, pines, and peonies were indi- ces of his taste. I take advantage of these many connotations of culture but hold to the idea that its primary meaning in nineteenth-century America was the use of intelligence to improve living things. Some elements of culture were universal, while others were geographically and histori- cally specific. One way to understand the par- ticular is to focus on certain exemplary plants. This essay focuses on two characteristic but contrasting New England types — American elms (found objects that were used as street ornaments) and the Concord grape (a construct- ed variety with horticultural uses). Comparing the histories of these two Yankee plants gives C ulture was not the same in nineteenth- century America as it is today. This statement is so obvious as to be banal, whether the subject is painting, clothing, sport, or slang. One difference, however, stands as prominent yet unexplored: the word culture itself. In the Century Dictionary and Cyclo- pedia, a massive scholarly compendium of the 1880s, the primary meanings of culture in- volved "tillage," controlled breeding, and tech- niques used in the new science of bacteriology. Only with apologies did the editors extend their definitions of the word to describe, on the one hand, the individual and collective improve- ment of the mind, and, on the other, the ethno- graphic whole.' This essay sketches aspects of a world where culture was a verb that referred primarily to activities that are now considered parts of bio- technology. Well into the nineteenth century, Americans could speak unselfconsciously about strawberry culture, pear culture, and arboricul- ture. More tellingly, high culture meant, not sweetness and light, but manure, hand weeding, and controlled pollination. The primary sites of culture were rural pastures and suburban gar- dens, not opera houses or Polynesian villages. This is not to say that the meaning of cul- ture then was either completely different from now, or that it was more precise. Horticultur- ists in particular were aware that they stood hip deep in a linguistic compost redolent with metaphors that sprouted like mushrooms and with meanings that hybridized uncontrollably. Even if they did not read Virgil or Alexander Pope, they knew that gardening was as much about culturing themselves as their shrubs, and "Elms at Yale College, " ca. 1840, engraving by William Henry Bartlett (1809-1854), from Nathaniel Parker Willis’ American Scenery, or. Land, Lake, and River Illustrations of Transatlantic Nature, 1857. AfjjgHSR MILSTEIN DIVISION OF UNII ED STATES HISTORY. LOCAL HISTORY AND GENEALOGY, THE NEW YORK PUBLIC LIBRARY, ASTOR, LENOX AND ULDEN FOUNDAUDNS PHOTOGRAPH COURTESY OF PEABODY ESSEX MUSEUM 10 Arnoldia 63/2 "Salem Common on Training Day” by George Ropes, fr. 1808. fresh shape to an old and hramhly theme — the role of New England culture in forming Ameri- can national identity. Political independence separated the citi- zens of the new United States of America from their European roots. They were no longer ordi- nary memhers of transatlantic British imperial networks, and their ad hoc alliance with the French grew tortured after 1789. The possibil- ity of a national future of drift and degenera- tion loomed in Americans' increasing tendency to disperse across the countryside to isolated farmsteads and barren frontier settlements; in the new nation's vast swamps and increas- ingly virulent fevers (yellow fever struck New York and Philadelphia heavily in the 1790s); in many Americans' unrefined diets of corn and potatoes; and in the surplus of cheap and crude whiskey, punch, and cider, and shortage of good wine to he drunk in moderation. Within this context, American leaders sought to reaffirm that the development of the United States was linked to both European traditions and to the progress of civilization. In New York, Washington, and elsewhere, they designed pub- lic buildings in classical styles to proclaim that Americans had taste. Gentlemen such as Thomas Jefferson in Virginia, William Ham- ilton in Pennsylvania, and Christopher Gore in Massachusetts built villas that advertised classical values. Landscaping and planting were integral to these displays: Hamilton initiated a broad movement when he planted the drive leading to his Philadelphia estate. The Wood- lands, with Lombardy poplars he imported from Europe. The pioneering Prince family nursery on Long Island soon marketed these columnar exotics widely; by the 1810s symmetrical rows of poplars marked dozens of cities, displaying, more visibly than any pillared stone building, the affiliation between the United States and both the Roman and Florentine republics. Fruits were surprisingly significant elements within this complex of anxieties and desires. Horticulture 1 1 North American "fruits of nature" — huckleber- ries, cranberries, crabapples, and strawberries — were either small, puckery, or only fleetingly productive; they provided little stimulus to sophisticated tastes. The introduction of Old World "fruits of culture" had been an integral part of early colonization. Apples were par- ticularly successful immigrants, but the vast majority of trees were undistinguished cider- producing varieties. In the late 1700s British, French, and Dutch fruit growers were making major improvements in pears, peaches, plums, grapes, and strawberries through a combination of selection, hybridization, and grafting. The few Americans who traveled to Europe could experience these products of modern high cul- ture, but such people were too preoccupied to raise American horticulture to the European level. In the 1820s, gentlemen and nurserymen in New York, Pennsylvania, and (most conse- quentially) Massachusetts organized to collect and distribute the fruits of European culture as well as to identify and improve American plants. They imported scions, selected vigor- ous varieties, compared fruits, and encouraged emulation. The American elm (Ulmus americana) became iconic within this cultural landscape. In the early nineteenth century this previously unremarked swamp dweller became a special tree in New England, transforming village and city streets into cool gothic archways. Because the elm could survive in places as diverse as Maine, Texas, Virginia, and Oregon, its appearance, identified with the New England village, could be replicated throughout the nation. Elm culture thus became part of the construction, both real and ideal, of a common American experience.^ Puritans imported the English elm (Ulmus procera, a continental species probably brought to Britain by the Celts or Romans) to Massachu- setts as part of their colonization toolkit. These familiar trees shaded yards and produced a split- resistant timber that was used for specialized purposes such as wagon hubs. Scattered speci- mens of the related North American species grew in wet areas. Because these trees seemed inferior to English elms in growing less straight, because they did not occur in large stands acces- The Washington Elm, Ulmus americana, photographed in 1893 showing the trunk cavity after dressing and an application of coal-tar. sible to cutters, and because isolated specimens were innocuous — casting only light shadows that did not hamper surrounding crops — they were almost the only trees not systematically lumbered in the New England lowlands in the 1600s. By default elms became a prominent and therefore characteristic element of rural nature in the Connecticut River Valley and in other settled parts of New England. In towns and villages, particularly as sur- rounding forests disappeared in the 1700s, indi- vidual trees became community pets. Certain magnificent specimens of great size and pre- sumably great age (such as the Great Elm on Boston Common or the elms named for Pitts- ARCHIVES OF THE ARNOLD ARBORETUM ARCHIVES OF THE ARNOLD ARBORETUM 12 Arnoldia 63/2 An allee of elms in Sandwich, Massachusetts, photographed by E. H. Wilson in September 1929. Horticulture 13 field, Sheffield, or Weathersfield) were revered as living relics of presettlement times. During the Revolution, particular trees also became semi-pagan symbols of liberty (and were some- times cut down by royal troops for that rea- son). Finally, trees could become markers for remembered or imagined historic events: Cam- bridge residents revered the elm under which George Washington supposedly accepted his commission as head of the revolutionary army, and other towns preserved elms associated with Washington, Franklin, and Lafayette. (Farther west, in my hometown of Cincinnati, we had to be satisfied with the General "Mad Anthony" Wayne Elm.) Not all these special trees were elms: Marylanders celebrated the large and old Wye Oak, and Hartford claimed the Char- ter Oak, associated from the late 1600s with the preservation of Connecticut autonomy.^ Local people often went to great lengths to pre- serve these specimens. With the short-lived, top-heavy elm, these struggles were predictably tragic. Illustrations of Cambridge Common in 1839, 1861, and 1908 show the Washington Elm increasingly contorted and cut back, hemmed in by streets; it toppled in 1923 while undergo- ing surgery following a rainstorm. Elms were easy to move in quantity from swamps to roadsides,- sometimes — as in Litch- field, where thirteen sycamores planted to cel- ebrate the new republic soon died — they were a second choice. The realization that double rows of American elms produced a particularly impressive effect emerged gradually. Only after 1820 did travel writers (including the generally disdainful Charles Dickens) begin to emphasize that elms in quantity transformed some other- wise ordinary New England towns into distinc- tively beautiful blends of country and city. The apotheosis of the American elm occurred in the 1840s. Emersonian Transcendentalism elevated communion with trees to a religious experience. Nationalistic garden writers argued that planting and experiencing common Ameri- can, rather than rare Eurasian, trees and shrubs would advance American identity and promote democratic values. On a more practical level, the Lombardy poplars planted in the Federal- ist period were becoming tatty from age and diseases that killed the tops. For the influential landscape theorist Andrew Jackson Downing, the vase-shaped American elm, with its pen- dulous branches and dappled shade, expressed the truth that the Gothic was the aesthetic appropriate for modern America. And as Yan- kees began to worry about their region's decline relative to the Midwest, rows of elms expressed their towns' supposed organic traditions, dis- tinctive cultural maturity, and appeal as sum- mer residences for prosperous Manhattanites and Southerners. Elms thus shifted from being trees that grew in New England to the trees that, to a substan- tial degree, defined New England. After mid- century, village improvement societies, aided by nurseries, initiated elm-planting programs that soon made the region's villages look as if they had been cloned. Elm monocultures spread, along with copies of Downing's books, along streets in the Midwest and beyond. In his journals, Henry Thoreau expressed the implications of these movements. On the one hand, he imagined that New England was its elms: his idea of a village included "more of the elm than of the human being." On the other, he understood that New England, like the elm, could reproduce itself and migrate: that "Free Soil" principles, like elms, would spread across the continent, outcompeting the decaying slave South. The importance of questions regarding different plants' American identities, and the difficulty in providing answers, become evi- dent if we turn from shade trees to the domes- ticated species that provided people with food and fiber. Cultivars (named varieties of cultured plants) were products of particular places, his- tories, and values. Choice of a cultivar could be a major practical issue: the economic survival of a plum grower, for example, could depend on the hardiness, productivity, and taste of the stick-like slips planted years before. No plants that had evolved in temperate North America were cultured prior to 1800. Angloamerican colonists grew either cultivars from such New World tropical regions as Mex- ico (corn) and Brazil (tobacco), or some frac- tion of the grains, beans, and fruit trees that Old World farmers had developed over previ- ous millenia. The degree to which Eurasian 14 Arnoldia 6312 and African cultivars could be "naturalized," or grown successfully, in North America varied greatly. The apple, originally from central Asia, was a paradigm of effortless naturalization. Recent books by Michael Pollan and Sue Hub- bell both describe how this highly variable spe- cies evolved rapidly into forms that flourished in New England and beyond.'* Pears, although closely related to apples, seldom grew well in the Northeast. Maintaining wheat culture was a continual struggle. The most fraught situa- tion symbolically — one element in my ongoing research on the history of American horticul- ture — involved grapes. The European wine grape, Vitis vinifera, was hy far the most "cultured" plant in the world in the 1800s. Domesticated in the Near East four to six thousand years ago, it had been altered through selection by generations of vinegrowers into a plant that could only live and bear fruit with constant and careful attention. Its quali- ties were the result of tastes that changed in unrecorded ways from the times of Hesiod and Pliny up to the emergence of the great Bordeaux chateaus in the 1700s. The English, while avid consumers of wine, were unable to participate in viticulture for lack of summer heat. As a consequence, the early promoters of Virginia and New England, who (like the Vinlanders six hundred years earlier) learned that grapevines grew rampantly along North American shorelines and riverbanks, anticipated that Vitus vinifera could be made to prosper there and that wine would soon be flowing from America to England. Colonists, however, failed repeatedly in their efforts to establish viticulture. Thomas Pinney explains that imported vinifera vines would readily take root and grow vigorously but would fruit for only a few years before fading away.^ The reason for these failures, not understood until the late nineteenth century, was that American grape species supported bacteria (black rot), fungi (downy and powdery mildews), and root aphids (Phylloxera) that reliably destroyed the evolutionarily defense- less vinifera vines. Prior to the 1870s, local and English commentators debated whether the difficulty in growing vinifera lay in the particu- lar soils chosen, problematie loeal climates, the lack of vineyard experience of Anglo-American growers, or the lack of American experience with French or Italian viticulturists imported for the purpose. The more ominous argument, in retrospect understandable and close to the truth, was that eastern North America was somehow inherently inhospitable to the high culture of winemaking. In the early 1800s, scattered American wine enthusiasts gave up on vinifera and sought instead to culture the vines already growing wild in North America. The common north- eastern species, Vitis labrusca, produced good yields of large fruits but it was singularly unpromising from the standpoint of taste. Its common name, the "fox grape," referred to a distinctive odor that was linked with varying degrees of specificity to anal secretions. Cultur- ing vinifera had taken millenia; the idea that a grape as rank as labrusca could in a few years be sufficiently tamed to serve to ladies was only imaginable among men who believed in the heroic potential of horticulture. Such men existed in Massachusetts in the 1840s. With symbolism so weighty it could split an elm, the birthplaee of the great Ameri- can grape was Concord — the reputed birthplace also of American freedom, American philoso- phy, American environmentalism, and, in some interpretations, American fiction. Ephraim Wales Bull (1806-1895), the devel- oper of the Concord grape, was a fine craftsman from Boston with liberal religious leanings, good social connections, and a longstanding interest in gardening. At the age of thirty he moved to a hobby farm just east of Concord where his acquaintances included Thoreau, the vegetarian Transcendentalist Bronson Alcott (and his teenaged daughter Louisa Mae), agri- cultural editor Simon Brown, and Nathaniel Hawthorne. Bull was an avid reader of nursery catalogs and annually purchased a diverse lot of material from the Prince nurseries, the leading supplier of new and exotic plants. The Concord, however, began mythically, with a seed dropped in a corner of Bull's garden around 1840 by a passing bird or local boys. Fol- lowing theories articulated most prominently by Belgian medical scientist and pear cultur- ist Jean Baptist Van Mons, Bull believed that Horticulture 1 5 Alfred W. Hosmer photographed Ephraim Wales Bull in the 1890s standing next to the original ‘Concord’ grapevine in Concord, Massachusetts. culture involved a combination of gentleness, selectivity, and patience. He moved his volun- teer seedling to a comfortable bed in the center of his garden, tended it carefully, and planted the seeds it produced. The crucial step was to select the offspring most susceptible to culture. The quickest-sprouting seedlings were rejected as close in type to their wild parent; those that were slower to germinate, or more "feeble," were considered more likely to put their energy into the production of fine fruit. One of these plants rewarded Bull's efforts by producing, at the end of the 1840s, grapes that were early, large, and. Bull claimed, tasty. He shared the news of his new fruit with neighbors such as Thoreau and, naming the vine for his adopted village, arranged to market cuttings through Charles Hovey, the leading plant pro- moter in Massachusetts. The variety gained national prominence thanks to favorable press coverage by Alcott's former commune compan- ion Horace Greeley, who was editor of the New York Tribune and a weekend farmer in Chap- paqua, New York. The identities of Bull, his grape, his village, and his nation fused rapidly in the mid 1850s. Bull advertised the Concord as a "native grape" with a decidedly Yankee character — it was early, versatile, did not wilt, and had "good shoulders" (that is, the bunches were neither small nor spindly). This hardy "American" fruit was contrasted to its "too tender Syrian broth- ers" (a coded reference to Semitic/Jewish degen- eracy). Bull's reputation as a hero of American horticulture enabled him to gain election to the Massachusetts legislature under the auspices of the nativist American Party (the so-called Know-Nothings) and then appointment to the State Board of Agriculture. There he became an archetypical village Yankee, noted for blunt attacks on sharp businessmen who controlled the distribution of new varieties and who unfairly captured profits that should go to farmers and local innovators. After the Civil War, increasingly sophis- ticated tastemakers like Horace Greeley rejected the still-foxy and highly tannic Con- cord as crude. But the variety continued to solidify its position as the standard American grape. Provincial backyard growers appreci- ated its reliability and good looks, and rapidly expanding commercial producers in upstate ARCHIVES OF THE ARNOLD ARBORETUM LIBRARY OF THE ARNOLD ARBORETUM 1 6 Ainoldia 6312 turned to readily available Concords. Making this leathery liquid palatable required the addition of large quanti- ties of sugar; the consequence was that a beverage sold originally in drug stores as "Dr. Welch's" tonic for the el- derly succeeded because it appealed to the naive tastes of children. While Welch's was not, as one ad claimed, "the national drink," it was nationally specific. Imagining an Angloameri- can family around 1900, sitting on a porch and sipping Welch's grape juice while looking out onto an elm-shaded street in a suburban town — whether in Connecticut, Illinois, or Oregon — is a remarkably easy exercise.*^ Concord grapes as illustrated in Les Vignes Americaines, 1876. New York saw the value of marketing a sin- gle named product that could be identified by urban consumers. In addition, the Concord became the basis for a technologically grounded, clear-head- ed grape culture different from any that had existed since the pre-Sumerian development of controlled fermentation. In 1869 the New Jersey Methodist dentist, Thomas Welch, used the new technology of pasteurization to make a non-alcoholic church wine. When his son Charles decided to target a larger market, he What happened to this idyllic picture? Elm culture declined dramatically in the decades after 1930. The most vis- ible reason was the introduction of an Asian fungus misleadingly named Dutch elm disease. But in contrast to the almost complete disappearance of the mature American chestnut due to another Asian fungus, elms were not completely at the mercy of their new parasite. In particular, a cultivar sold widely by New Jersey's Princeton Nurseries prior to the 1930s happened to be particularly resistant. As a conse- quence, scattered sites — including the quadrangle at Rutgers University in New Brunswick, New Jersey, where my office is located — are still filled with plantings of mature American elms. The appeal of such groves in the twenty-first century derives, to a significant degree, from their uncommonness. More than a century ago, tastemaking Americans who chafed under elm monoculture were promot- ing alternatives. The Arnold Arboretum was established in the 1870s explicitly to test any tree that could grow in Massachusetts. These included both southern and western North American species (such as sequoia and various magnolias) and, especially after 1890, plants from China (including the dove tree and dawn redwood). The renewed interest in exotic Horticulture 1 7 plants may have directly impacted elms. The cosmopolitan horticulturist David Fairchild re-imagined the nation's capital in the early 1910s by planting flowering cherries around the newly built Tidal Basin in place of a grove of elms. These contorted Japanese cultivars, dripping with both imperial tradition and ori- entalist romanticism, played a role in freeing the cultural landscape of the United States from the bland symmetries of nineteenth-century New England. Similar but more complex transformations occurred in American grape culture. Ephraim Bull had achieved fame and influence by iden- tifying both himself and his grape as Yankee natives, as that term was understood in the 1850s. The constraints of this identification became evident to Bull after the Civil War. Concord evolved from a rural center with an overlay of authors and bohemians to a suburb of Boston with historic weekend homes. The house next to Bull's, previously occupied by Alcott and Hawthorne, became the part-time residence of Harriet Lothrop, the wealthy writer who sentimentalized antebellum village pov- erty in The Five Little Peppers and How They Grew. Bull, however, did not change with the neighborhood. He grew his hair and beard long, tended his garden, tinkered with his grapes, and railed at the businessmen who, he believed, had taken advantage of him. His socially proper wife, unable to abide his eccentricities, left him around 1870. When, at age 87, he fell while trying to patch his leaky roof, he was put into a rest home, and the plants he had nurtured during the past fifty years soon died. The cranky epitaph on his tombstone was, "He sowed, others reaped." The Concord, like Bull, was native only in a historically constrained sense. Bull classified it as a variety of labrusca because, like its wild relatives and unlike vinifera, it was self- infertile. But as culturists understood by the 1850s, species of Vitis hybridized readily. Bull believed that one parent of the Concord was a Catawba, a variety believed then to he native but in fact a Euro- American hybrid. He asserted that the original bird-dropped seed was wild; but since he and probably other Concord gardeners were enthusiastic planters of grape varieties imported from Europe by the Prince family, there is considerable likelihood that his unusually early and sweet volunteer was also hybrid. The original Concord, in sum, was prob- ably the result of at least two generations of mixed breeding. This revision of the Concord's genealogy provides a congenial avenue for reinterpreting its identity in the twentieth century. Tradition- alist Jewish immigrants to New York needed a ceremonial wine that would be both kosher and inexpensive; to produce it, they turned to the grapes that were available on the Lower East Side — Concords — and, like Welch, added sugar to make the product drinkable. Schapiro's Kosher Wines, forthrightly advertised their syrupy beverage as "wine so thick you can cut it with a knife." The nativist Bull would likely turn farther in his grave were he to know that his grape was identified as much with Schap- iro and Manischewitz as with Welch. But cul- tural hybridization has been a characteristic phenomenon in the history of North America during the last four hundred years; it would be surprising if grapes were different. Notes Adapted from "The Interpretation of Horticulture," Raritan 23 (2004); 111-124; reprinted with permission. * W. D. Whitney, ed., The Century Dictionary: An Encyclopedic Lexicon of the English Language, 9 vols. (New York: The Century Co., 1889) 2: 1393. ^ My discussion of elms is drawn largely from Thomas J. Campanella, Republic of Shade: New England and the American Elm (New Haven: Yale University Press, 2003). ^ For more information, see "The Charter Oak" by Gayle Barndow Samuels in Arnoldia (1999-2000) 59(4): 2-9. “ Michael Pollan, The Botany of Desire (New York: Random House, 2001), 1-58; Sue Hubhell, Shrinking the Cat (Boston: Houghton Mifflin, 2001), 121-154. * Thomas Pinney, A History of Wine in America (Berkeley; University of California Press, 1989). ^ For more information on the Concord grape and the man who developed it, see "He Sowed; Others Reaped": Ephraim Wales Bull and the Origins of the 'Concord' Grape" by Edmund A. Schofield in Arnoldia (1988) 48(4): 4-15. Philip J. Pauly is a historian of science at Rutgers University, New Brunswick, New Jersey. He is completing Fruits and Plains: Horticulture and the Meaning of America. Lingonberry: Dainty Looks, Sturdy Disposition, and Tasty Berries Lee Reich L ong popular in other parts of the world, the lingonherry (Vaccinium vitis-idaea) is only now being recog- nized in the U.S. for its lovely appearance and good taste. Those qualities should come as no surprise since lingonberry is a member of the heath family (Ericaceae), a close relative of such beauties as rho- dodendron, pieris, and, of course, heath (Erica) and heather (Calluna) as well as to the delectable blueberry and our Thanks- giving cranberry. Vaccinium vitis-idaea is separated into two botanical varieties with natural hybrids occurring in Scandinavia. The larger of the two, V. vitis-idaea var. vitis- idaea, is a spreading subshrub that grows to about two feet high and has inch-long, pointed leaves. The more diminutive lingonberry, V. vitis-idaea var. minus, stays under eight inches in height and has commensurately smaller leaves, one- third by one-sixth of an inch, oval, and rounded at the tips. Although fragile in appearance, leaves of both varieties are evergreen, with a green gloss similar to that of holly leaves. The larger lingon- herry, hardy to USDA zone 4, is native to the lowlands of Europe and northern Asia. Variety minus grows wild in the moun- tains of Scandinavia and extends west- ward to Iceland, Greenland, and northern portions of North America; it is hardy to zone 2. Both botanical varieties can be grown as far south as USDA zone 7 provided summers are not too hot for too long; nonetheless, they are at their best in cooler areas. In fact, as an ornamental plant in cold climates lingonherry stands in well for low-growing boxwood parterres, for example, a use first suggested in A Swiss Army pocketknife takes the measure of a flowering lingonberry plant. 1651 by Andre Mollet, the French gardener to Queen Christina of Sweden. Lingonherry can be enjoyed in one way or another year-round. Let's start in spring, when small, urn-shaped blossoms dangle singly or in in clusters near the ends of the thin, semiwoody stems. The urns hang upside down and are ALL PHOTOGRAPHS BY THE AUTHOR Lingonberry 19 white with a pink blush. They're not going to stop traffic from the street, so the plants should be grown where they can be looked at up close. Don't worry if you miss the spring floral show because lingonberries blossom twice each sea- son. The second show, appearing in mid to late summer on young stems, is absent at far north- ern latitudes. The pea-sized fruits that follow the flowers are a show in themselves. The bright red — or, rarely, white — berries hang on the plants for a long time, well into winter, making a perfect Christmas decoration in situ. Fruit yields are greater from the second flowering than from the first, and although cold and time will eventu- ally darken and shrivel the berries, I find them tasty at whatever season I find them. Vitamin C concentration in the fruits, at 25 milligrams per 100 grams, is moderately high. Attempts have been made to hybridize ling- onberry with cranberry (Vaccinium macrocar- pon) in order to combine the taste of the small lingonberry fruits with the large size of cran- berries. Thus far, success has been achieved only when cranberry was the pollen parent, and the resulting plants showed characteristics intermediate between the two parents (except that none produced underground runners). But like mules, the hybrids have all been sterile and therefore bear no fruit. THE FRUIT Lingonberry may be a pomological upstart in the U.S., but this is not the case elsewhere in the world. Merely utter its name to Scandina- vians and watch for a smile on their lips and a dreamy look in their eyes. Each year, thousands and thousands of tons of lingonberries are har- A bed of lingonberries in fruit. 20 Arnoldia 6312 vested from the wild throughout Scandinavia, destined for sauce, juice, jam, wine, and haked goods. And of course, a fair numher of these berries are just popped posthaste into apprecia- tive mouths. Lingonherry has long been a favorite not only of Scandinavians hut of northern peoples throughout the world. It grows in climates so rigorous that any palatable fruit is appreci- ated, making the delicious lingonherries all the more cherished. So important was the fruit in thirteenth-century Iceland that laws limited berry-picking on other people's lands to what could be eaten on the spot. This fruit is the Preiselbeere of the Germans, the kokemomo of the Japanese, the puolukka of the Finns, the wisakimin of the Cree, the airelle rouge of the French, the keepmingyuk of the limit — and the lingon of the Swedes. In English, the plant has a number of monikers, including partridge- berry (Newfoundland), cowberry (Britain), fox- berry (Nova Scotia), mountain cranberry, and rock cranberry. I don't wish to seem unpatriotic, but the cosmopolitan lingonherry outshines our native cranberry in a number of respects. A lingon- berry couples just enough sweetness with a rich, unique aroma so that the fruits — if picked dead ripe — are delicious eaten right off the plants or mixed with morning cereal. A cranberry, in contrast, is never palatable until doctored up with plenty of sugar and cooked. Lingonherry also heats the cranberry as an ornamental, its leaves retaining their lush, green color through winter — long after the cranberry's leaves turn a muddy purple. Along the front of my home, a rock retaining wall anchors a bed of lingon- berries whose glossy greenness is enlivened in autumn by the red leaves of interplanted low- bush blueberries, and then, in winter, by the red stems. CULTIVATION Lingonherries grow naturally on raised bogs, rocky barrens, lichen woodlands of boreal taiga, dry heaths, tundra, mountaintops, and other cold, sometimes exposed habitats — that is to say, among the harshest conditions in the world, especially for an evergreen. One reason the plants tolerate such conditions is that they hug the ground, where they are sheltered from wind and close to the earth's warmth, and often further protected by snow cover. All the soils that lingonherry inhabits are extremely rich in humus, thus providing good drainage and at the same time holding moisture. In addition to having good drainage and abundant organic matter, the soil must be very acidic, with a pH ideally between 4.5 and 5.5. These condi- tions — similar to those needed by blueberry, cranberry, mountain laurel, rhododendron, and other lingonherry relatives — must be met for lingonherry to thrive. Adapting site conditions to suit lingonherry is not at all difficult on the scale of a garden, or even a small farm, as long as natural condi- tions are not too far off the mark. After ridding an area of weeds, against which lingonherries are poor competitors, a bucketful of acidic peat moss mixed into each planting hole provides the needed humus and helps acidify the soil. Peat moss, being poor in nutrients, is especially suitable for lingonherries,- rich soils can burn their delicate roots and promote more vigorous weeds. The soil behind the rock wall where I planted my lingonherries and lowbush blueber- ries was nothing more than a great quantity of old potting soil that was almost fifty percent peat moss. Where soil pH is not low enough — that is, below about 6.5 — elemental sulfur should be applied before or when planting. Three- quarters of a pound of sulfur per hundred square feet in sandy soils, or two pounds per hundred square feet in loams, will change the pH by one unit. Where soils are naturally very alkaline (pH higher than 8), such as in many parts of the western U.S., native soil should be excavated from the planting site and replaced with a fifty- fifty mix of peat moss and sand. If the planting site has poor drainage, mounds of soil and peat can be built up to keep the lingonherries' shal- low roots above water level. Lingonherries can thrive in full sun but as a plant of northern climes, it will appreciate the coolness of some shade or — like the lingon- berries on the east side of my house — a site shielded from hot afternoon sun. Too much shade, on the other hand, will produce lusty stem growth at the expense of yield. Lingonberry 21 The shiny leaves of the evergreen lingonberries set off the bright fall red of Vaccinium angustifolia, and vice versa. If you grub beneath lingonberry plants, you will find a dense mat of fine roots growing just beneath the soil surface. Aboveground shoots originate from buds near the ends of rhizomes; they are responsible for the plant's spread. Plants that are raised from seed, in contrast to those propagated from rooted cuttings or run- ners, also have taproots. Lingonberry looks and feels at home in a rock garden. It also makes an attractive, edible groundcover if plants are placed equidistant in all directions to eventually fill a bed with a uniform mat of stems. Vaccinium vitis-idaea var. vitis-idaea, being more vigorous, can fill an initial spacing of eighteen inches within three to five years; plants of V. vitis-idaea var. minus need to be set about ten inches apart. When farmed, lingonberries are planted in rows four to five feet apart, then — like strawberries — main- tained as solid ribbons thirty inches wide. Lingonberry plants are partially self- fertilizing, though cross-pollination results in increased yield and herry size. Pollination occurs best at about sixty degrees Fahrenheit; very little takes place at temperatures below fifty degrees, which are common during the early bloom period in spring. Fortunately, when the plants bloom for the second time in a season, conditions are more conducive to good pollination. The plants benefit from annual applications of mulch, the ideal being a two-inch layer of finely divided, organic material that is not too rich in nutrients: sawdust, woodchips, chopped straw, or shredded leaves, for example. Such mulches sift down through the leaves and stems, keeping the ground cool and moist, pre- venting frost from heaving plants in winter, and decomposing to maintain high humus levels in the soil while at the same time providing 22 Arnoldia 63/2 limited nutrients and buffering changes in soil acidity — all of which translates into larger ber- ries and more of them. New roots, which form mostly in spring and autumn, will eventually form along covered portions of stems. Sand can also he used as an annual mulch, as it is for cranberries, but it has the drawbacks — espe- cially in a backyard garden — of being heavy to move and providing no nutrition or buffering of changes in soil acidity. Plants need care their first season if they are to thrive, perhaps even to survive. Most of that care can be summed up in one word: water. One-half gallon per week per square foot of planted area, the equivalent of an inch depth of water, keeps plants happy whether it comes from the sky, a sprinkler, or drip irrigation. Except in drought conditions high levels of soil humus from initial additions of peat moss and maintenance applications of organic mulches should eliminate the need for further watering once plants are established. Just because lingonberries thrive in lean soils does not mean that they never get hungry. Annual additions of organic materials help sup- ply many nutrients, however, so nitrogen may be the only additional nutrient needed, if any. One indicator of nitrogen deficiency is yellow- ing of the oldest leaves. Soybean meal, available at feed stores, is an ideal source of nitrogen for lingonberry: it is inexpensive and doles out its nutriment slowly and in synch with growing conditions because these are the same condi- tions — heat and moisture — that stimulate soil microbes to work on the soybean meal. In acidic soils, the nitrogen from soybean meal ends up as ammonium ion, which is the form of nitrogen that suits lingonberry and other acid- Heathers and lingonberries make good neighbors. Lingonbeny 23 loving heath plants. As a general rule, a pound of soybean meal per hundred square feet per year, spread sometime between late fall and spring, will fulfill the plant's nitrogen needs. Avoid overfertilization because lingonherries' fine roots are especially susceptible to fertilizer burn and because it encourages the growth of weeds. Soils that are not sufficiently acidic require periodic adjustments to keep acidity in lingon- herry's preferred range. Every few years I spread elemental sulfur over the ground. Yellowing of the youngest leaves while their veins remain green is a sign of iron deficiency, the result of insufficient acidity among other things. Lingonberry bears flowers and fruits on its youngest shoots, so pruning will stimulate the growth of young, fecund stems, as it does for lowbush blueberries. Plants are slow to estab- lish themselves and need no pruning for the first five or six years. Then, while the plants are dormant, mow or cut a portion of the planting down to within an inch of the ground (leaving an unpruned portion so that you can still har- vest that year). Current recommendations for the frequency of this drastic pruning range from every three or four years for the slower-growing minus — every two to three years for the more vigorous idaea — to as long as every fifteen years for either variety. Being evergreens, lingonber- ries will not bounce back from drastic pruning with as much enthusiasm as do their deciduous relatives the lowbush blueberries. Except for needing annual mulching, occasional pruning, and perhaps additions of fertilizer and sulfur, lingonberry is a carefree plant. Problems with insects or diseases are rarely significant. PROPAGATION A number of techniques can be used to prop- agate lingonherries, each with its advantages and disadvantages. Sowing seed can produce many plants, but the seeds do have their quirks. Fresh seeds are best, averaging about eighty-percent germina- tion. To extract seeds in quantity, crush the fruits in water and let the mix ferment for a few days. Then wash away the pulp and skins. Sound seeds sink. A one-to-one mixture of sand and peat moss, equal parts sand, peat, and soil, or one-hundred- percent milled sphagnum moss are all good sowing media. Barely cover the seeds because they need light to germinate. A period of about three months of cool, moist stratification seems to improve germination, although fresh seeds may sprout without it. Seeds sprout within a few weeks, after which the seedlings grow slowly and begin fruiting, on average, within three years. It is probably because of that three- year juvenile period — when all of a plant's energy is directed to growth and none to fruit- ing — that seed-propagated plants spread faster than plants grown by other methods. Cuttings have several advantages over seeds: they are easy to root, bear fruit a year after root- ing, and replicate genetically the plant they orig- inate from. Cuttings of succulent new shoots or just ripened, mature shoots (the younger the better) are the most successful. Two-inch lengths treated with rooting hormone and kept in a humid atmosphere, preferably with bottom heat, root in about two months. Rhizomes tend to develop slowly on rooted stem cuttings. Pieces of rhizomes two to four inches long can also be used to grow new plants. The best times to propagate from rhizomes are spring and fall, probably because these are peak peri- ods for new root growth. If you want to create just a few new plants, you can dig up older plants in spring or late summer and divide them just like any peren- nial. Take clumps having both roots and shoots for replanting. The same technique can be used to move plants or parts of plants from the wild, success being largely a function of the soil in which they are growing; damage to the thin, fragile roots can most easily be minimized when the plants are taken from soil rich in humus. Micropropagation — cloning — is the creation of new plants from just a few cells of a mother plant. When used with lingonberry, it produces more plants in less time than any other tech- nique, but it requires specialized equipment and sterile conditions. Small plants, whether seedlings, cuttings, or micropropagated plants, do best if grown for a year or two in a nursery bed enriched 24 Ainoldia 6312 A berry -hungry author. with abundant humus. Spread mulch over the plants in the dead of winter and, perhaps, cover- ings of glass or plastic to help them keep their still-fragile roots in the ground as it freezes and thaws. HARVEST AND USE Three to six years is needed before a reason- able crop can be expected and even then yields vary considerably depending on growing con- ditions. Under suhoptimal condi- tions — in fertilized forest stands, for example — yields might be five to ten pounds per hundred square feet (one to two tons per acre). Skillful cultivation and the use of better cultivars can yield twenty- five pounds or more per hundred square feet (five tons per acre). A berry comb like that used for lowhush blueberries speeds the task of picking fruit, but the resultant harvest needs to he cleaned of leaves and unripe fruits. A berry-hungry Scandinavian can rake about five pounds of fruit in an hour. But there's no need to rush the picking or eating of lingonber- ries. They keep well on or off the hush, in part because they contain benzoic acid, a natural preserva- tive. Refrigerated, they can be enjoyed for at least eight weeks, longer for the variety idaea than for minus. In nineteenth- century Sweden, lingonberries were kept from one year to the next as "water lingon," made by simply filling a jar with berries, then pouring water over them. There seems to be no end to the uses for lingonberries. In Fin- land, for example, the berries are the traditional accompaniment to blood sausage or blood pancakes. They also find their way into meat stews, sauces, juice, and wine. They make excellent jam alone and an even better one when combined with rosehips. The juice is delightfully refreshing mixed with that of other berries. A refreshing, albeit potent, drink can be made from lingonberries and vodka. One recipe calls for soaking a quart of berries in a quart of vodka for two months, then pouring off the liquid into a bottle and adding two cups of sugar to the berries. Let the berries and sugar sit for about a week while the sugar draws out more liquid. Lingonbeiiy 25 then add it to the vodka. Let that mix age for a month before tippling. Lingonberries also find their way into the dispensary. Arbutin, the hydroquinone glyco- side, in a tea made from the leaves is reputedly good for intestinal and bladder disorders, and the fruits are said to combat bladder and kidney infections, lower cholesterol levels, and treat rheumatic diseases. I have never used lingon- berries for curative purposes, nor have I tasted them in all their culinary incarnations. But I do have great affection for the berries plucked right from the plants — at their peak of ripeness — into my eagerly waiting mouth. CULTIVARS OF VACCINIUM IDEAE VAR. VITIS-IDEAE 'Ammerland', introduced from Germany, spreads at only a moderate rate and is produc- tive if given suitable soil; stems are upright and bushy, reaching twelve inches in height; berries are bright red and small to medium sized, ripen- ing midseason. 'Erntedank', also from Germany, introduced by Zillmer in 1975, has relatively pale leaves and poor growth. It produces very heavy yields of small- to medium-sized berries. 'Erntekrone', yet another introduction from Ger- many, also introduced by Zillmer — in 1978 — is vigorous and stiffly upright with roundish, dark green leaves. It produces high yields of large, dark red fruits. 'Erntesegen', likewise from Germany and another 1978 introduction by Zillmer, won a Gold Medal in the 1981 German Garden Show. It is a very vigorous plant with large leaves, growing sixteen inches tall; productive, with profuse second bloom and late-ripening berries that are bright red and very large. 'Koralle', introduced from Holland in 1969 by H. van der Smit, represents a seedling population of thirty-five plants that produces some variation depending on the clone a plant was propagated from. It is Europe's most popular lingonberry and winner of a prestigious award of merit in 1976. In growth and yield it is very similar to 'Ammer- land', with slightly smaller berries. 'Masovia', a 1985 selection from Poland, is vigorous with heavy yields. 'Red Pearl', a 1981 selection from Holland, is not the most productive cultivar, but it spreads rapidly and gives consistent yields. Stems are upright, reaching sixteen inches; the dark red fruits are medium sized and have excellent flavor. 'Sanna', a 1988 Swedish introduction, spreads moderately fast, with erect stems that grow eight to twelve inches high. Its productivity is excellent, perhaps the highest of any variety to date. It bears attractive crops of bright red ber- ries in both the summer and the fall. 'Scarlet', a Norwegian selection, grows twelve to eighteen inches high. CULTIVARS OF VACCINIUM VITIS-IDEAE VAR. MINUS 'Ida', a Swedish selection introduced in 1977, stands out for its beautiful leaves and abundant and repeated bloom. It is a vigorous, compact plant of about eight inches in height with a pre- cocious first bloom and a profuse second bloom,- its large fruits ripen early. 'Regal' was selected in Wisconsin in 1990 from Finnish seeds. Plants spread moderately fast with stems growing eight inches high; it is precocious and produces a low yield of small red fruits. 'Splendor' was also selected in Wisconsin in 1990 from Finnish seeds and is also moder- ately fast spreading. The stems grow six to eight inches high; it is precocious, with a low yield of medium-sized carmine berries. 'Sussi', introduced from Sweden in 1985, is a low-growing variety with stems of only four to eight inches high. It spreads rapidly; production of the dark red, medium- to large-sized berries is moderate. Lee Reich was formerly a fruit researcher with the U.S. Department of Agriculture and Cornell University. He is currently a garden writer and consultant (www.leereich. com). This article is adapted from his book Uncommon Fruits for Every Garden (Timber Press, 2004). Herbarium Specimens as a Novel Tool for Climate Change Research Abraham J. Miller- Rushing, Daniel Primack, Richard B. Primack, Caroline Imbres, and Peter Del Tredici M any changes in plant and animal behavior point to the effects of global climate change. In recent years, biologists have observed birds migrat- ing earlier in the spring, tropical frog popula- tions declining, and insects relocating to higher altitudes on mountain slopes. Yet the most convincing evidence that living organisms are responding to global warming comes from flow- ering plants, which are especially responsive to warm weather in the spring. The data on plant flowering times is particularly compelling because there is so much of it. Thanks to the professional and amateur botanists who have kept annual records for a variety of plant species and locations, there exists more long-term data on first flowering dates than on other biological phenomena. As described in a 2003 article in Arnoldia, analyses of these records show con- clusively that both wild and cultivated species are flowering earlier than in the past because of warmer growing conditions. Although these data sets have proven valuable for understand- ing how certain plants in certain places have already been affected by global climate change, there are too few long-term data sets available to predict future impacts worldwide. To build a more geographically complete picture, scien- tists must seek new sources of data. Botanical gardens and museums might be those sources. In the spring of 2002, we decided to investigate whether the extensive collection of herbarium specimens at the Arnold Arboretum could be used in conjunction with the Arboretum's liv- ing eollections to determine how plants in Bos- ton are responding to global warming. If so, our study would show that herbarium collections throughout the world could be valuable tools for studying plants' responses to climate change. Boston, like other large cities, is an especially good place to study climate change because its average annual temperatures have risen over the last hundred years by 1.5 degrees centigrade (2.7 degrees Fahrenheit) — more than in less urbanized parts of the world. Only half of Boston's increase corresponds to the increase in the average global temperature. The other half is related to urbanization — more paved surfaces to absorb sunlight and radiate it as heat, less plant cover to remove heat through transpiration, and more sources of greenhouse gas emissions, such as buildings and cars — a phenomenon collectively labeled as the "urban heat island effect." As a result, the increase in Boston's average temperatures has already reached the magnitude expected for the entire planet later in this century. Thus, Boston provides a preview of the warming that will occur elsewhere in the world. Prior to 2002, the Arnold Arboretum did not systematically collect phenological data — that is, records of the dates of seasonal biological events such as flowering or fruiting, which have been used in previous studies of climate change. However, the Arboretum does possess an alter- native source of phenological data extending well over a hundred years: the Arnold Arbo- retum Herbarium, a collection of 80,000 dried plant specimens, most of which were taken from the woody plants of the living collections as part of the Arboretum's standard documen- tation process. The record that accompanies each dried and pressed specimen includes the name of the species, the identification num- ber of the plant, the date of collection, and — importantly — the phenological state of the plant on that date, such as flowering, past flow- ering, or in fruit. Many of the plants from which Climate Change Research 27 the specimens were taken are still among the 15,000 plants growing on the grounds of the Arboretum. Together with the 80,000 herbarium specimens, of which a large number were col- lected while the plant was in flower, the Arbo- retum's living collections provided a potential sample size large enough to compensate for any species-specific phenological changes unrelated to temperature change. Thus, we could detect general patterns of response common to most of the species despite occasional anomalies. Studies published by other researchers have typically tracked the date of first flowering within a certain population to measure a spe- cies' response to climate change. This method is potentially sensitive to changes in population size: if the population is growing over time, or the plants getting larger and producing more flowers, first flowering dates might come earlier even without a warming trend and even though the average flowering time within the popula- tion remains constant. (Increasing population sizes and larger individual plants tend to cause the first flower to appear earlier and the popu- lation to flower for a longer duration.) Herbar- ium specimens, however, are generally taken when the flowers are most visible and interest- ing to collectors — that is, when the plant is in full flower. As a result, a herbarium specimen reflects more accurately the date of peak flower- ing, a measurement that is not affected by the size of the population or the individual plants. Another advantage of using the plants at the Arboretum for climate research derives from the controlled environment found there. Indi- vidual plants are well spaced and grown under conditions considered ideal for their species, with the grounds being carefully mulched, weeded, fertilized, and kept free of pests. This level of care probably reduces the possibility of unrepresentative flowering times that might result elsewhere from crowding, scarcity of nutrients or light, or other suboptimal condi- tions. Finally, one would expect the relatively high temperature increase in metropolitan Bos- ton to have produced a greater magnitude of phenological change at the Arboretum than in rural areas, making it easier to detect changes in flowering times. HOW WE WENT ABOUT IT In 2003, using a computerized list of all plant- ings currently in the living collections and of all specimens in the herbarium, we selected her- barium specimens and corresponding plants on the Arboretum grounds for our study sample. We chose only living plants that are represented in the Arboretum's herbarium by at least one preserved specimen taken between 1880 and 2002 when the plant was in peak flowering con- dition — that is, with most of its flowers open and in good condition. Our second criterion was that the plants had to have flowers that were easy to recognize, observe, and census,- we typically chose plants with large, dramatic flowers, such as cherries and magnolias, and usually avoided plants with small flowers lacking petals, such as birches 25 April 2004 30 April 2004 7 May 2004 Almost flowering Full flowering Past flowering Weekly monitoring of a pear tree (Pyrus) progressing through its seasonal stages demonstrates that it has a short flowering period that peaked on April 30. Monitoring once a week appears to be sufficient to determine flowering phenology. DANIEL PRIMACK ANICA MILLER-RUSHING 28 Arnoldia 63/2 Researchers at the Arnold Arboretum standing in front of Rhododendron vaseyi on May 11, 2004, holding a herbarium specimen collected from the same plant on May 19, 1938. Both living plant and specimen were captured in full flower. This is a visual demonstration that plants are now flowering earlier than they did in the past. and oaks. Third, we selected primarily spring- blooming species; these were likely to show greater response to increases in spring tempera- tures than later-blooming plants because their flower buds are preformed the season before. Fourth, we selected plants known to have short flowering cycles, which would permit us to more accurately estimate a single date of full flowering by calculating the average between the dates on which the plant was observed in full flower. We could be reason- ably confident that herbarium specimens taken from plants that flower for less than three weeks — azaleas and apple trees, for example — had been collected within a week of the time of peak flowering. Specimens taken from spe- cies with longer flowering times, on the other hand — spring-flowering witch hazel, for exam- ple, which flowers for a month or more — could have been collected up to two or three weeks from the plant's peak flowering date. Finally, in order to minimize possible phenological effects caused by unknown alterations to plant physi- ology, we selected plants that are representative of wild species, whether native to the New Eng- land region or introduced, rather than cultivars or hybrid plants. Using these criteria, we selected 229 liv- ing plants encompassing 35 different genera. Major genera (represented by ten or more indi- viduals) were Amelanchier (shadbush), Connis (dogwood), Corylopsis, Enkianthus, Halesia (silverbells). Magnolia, Malus (apple). Primus (cherry). Rhododendron (including azalea), and Syringa (lilac). Because multiple herbari- um specimens were often collected from the same plant, we found 372 herbarium specimens taken from these 229 plants. (A complete list of climate Change Research 29 specimens and species is available online at the Arboretum's website, http://www.arboretum. harvard.edu/). We readily located the 229 selected plants using the Arboretum's computer-generated map of the living collections. Then, during the spring and summer of 2003 two people observed the individually numbered plants weekly between April 13 and July 14. Plants were recorded as being in one of four stages: not flowering, almost in full flower, full flower, or past full flower. (A plant in full flower was defined as having at least fifty percent of its buds in full bloom and being suitable for herbarium speci- mens.) Once a plant was recorded as past full flower it was no longer observed because the plants in our sample flower only once a year. These weekly observations enabled the observ- ers to determine the peak flowering date and duration of flowering for each plant in 2003. We also determined a single Julian date (day numbers that run from 1 to 365 over a year) of full flower for each plant, although this date could have missed the true flowering peak by several days because of sampling only once a week. For example, if a plant reached its highest number of flowers on day 110 but was sampled on days 108 (when it had lots of flowers) and 115 (when it retained only a few flowers), then the day of peak flowering would be listed as day 108 rather than the true peak flowering day of 1 10. In cases where full flowering was observed on multiple dates, the mean of the Julian dates for those days was used. If a plant was recorded as being in peak flower on days 121 and 129, its date of full flowering would be calculated as day 125. Once the Julian date of full flow- ering in 2003 was determined for each plant, we subtracted it from that of the correspond- ing herbarium specimen to estimate a change in flowering time. If a plant was observed in peak flower on day 120 in 2003 and flowered on day 110 in 1990 according to the herbarium specimen, then it flowered 10 days earlier (-10) in the past than it did in 2003. We then inves- tigated how changes in spring flowering times correlated with the temperature differences between individual years as recorded at the Boston weather station. WHAT WE FOUND The spring of 2003 (February through May) was colder than in any previous year since 1967, with temperatures typical of the early twenti- eth century. As a result, the 229 plants exam- ined in this study flowered at about the same time in 2003 as they had between 1900 and 1920. In contrast, typical plant flowering times between 1980 and 2002 were about eight days earlier than in 2003, and eight days earlier than between 1900 and 1920, thereby showing a sig- nificant trend toward earlier flowering over the last one hundred years (Figures 1 St 2). While the data showed wide variations in historical plant flowering times, it is clear that plants have been flowering earlier in recent years than they did in the past because of warm- ing temperatures in Boston. Eight days may not seem like much, but it constitutes a major change. For plants that flower for three weeks, it represents more than one third of the entire flowering season. Changes of this magnitude can significantly affect relationships between plants and the animals that pollinate their flowers, eat their leaves and seeds, and disperse their fruits. In many cases these relationships rely on a synchrony between the phenology of the plant and that of the animal — for instance, between the flowering of a plant and the activ- ity of a pollinator — which may be disrupted if the timing of events shifts too quickly. Evidence from elsewhere in the world shows that some of these relationships are already changing. CAVEATS AND STATISTICAL CONSIDERATIONS Although we found a significant correlation between changes in temperature and flowering times, the use of herbarium specimens raised several questions. First, as noted earlier, we could not be certain that the herbarium speci- mens were all collected on the exact day of peak flowering. Specimens identified as "flowering" may have been collected when the plant first started to flower or when it had just finished flowering. In the case of short-flowering plants, the error would be small: if the collector took a sample from a plant with a one-week flowering period, for example, the collection date would 30 Arnoldia 6312 Figure 1. Boston temperatures from 1885 to 2003 as reported by the National Oceanic and Atmospheric Administration in 2004. The top series (diamonds) represents mean annual temperatures. The bottom series (squares) represents mean temperatures in February, March, April, and May. Boston temperatures are clearly increasing over time. The two horizontal lines represent the long-term mean temperatures for each series (annual = 10.3 degrees centigrade or 50.5 degrees Fahrenheit; February through May =6.1 degrees centigrade or 43 degrees Fahrenheit; °F = (°C x 1.8) + 32). Figure 2. This graph tracks changes in flowering times of plants at the Arnold Arboretum over time: The dots indicate the number of days plants flowered earlier or later in the past than they did in 2003 calculated as the fulian date the herbarium specimen was collected subtracted from the peak flowering date in 2003. Negative values indicate that a plant flowered on an earlier date than it did in 2003. Note that 2003 was a relatively cool year; plants from the cool 1900 to 1920 period flowered about the same time that they did in 2003. In contrast, plants flowering in the warm period of 1980 to 2002 flowered about 8 days earlier than they did in the cool year of 2003. The line is the best fit line for the series. Climate Change Research 31 be only 3.5 days away from the actual date of peak flowering. In the case of a plant with a 20-day flowering period, on the other hand, the amount of error would he 10 days. However, our statistical tests found no evidence of this type of hias; data were no more variable over time for long-flowering plants than for short- flowering plants. A second concern was that trends would he obscured by outlying data points resulting from plants that had flowered many weeks earlier or later in the year that they were collected for the herbarium than they did in 2003. Exam- ples of outlying data points include a dogwood (Cornus mas) that flowered 27 days later in 1965 than in 2003 and a cherry tree (Primus apetela) that flowered 24 days later in 1987 than in 2003. These apparent anomalies may have been caused by someone collecting the specimen at the very end or very beginning of an unusually long flowering season in those years. But again, thanks to our large sample size the few outlying data points did not have a statistically significant effect on the results. Finally, we were concerned about the uneven collection of herbarium samples: in dif- ferent years, different numbers of herbarium specimens were collected, creating gaps in the period between 1940 and 1960 that could give disproportionate weight to certain years in our analysis. We resolved this problem by dividing the data into two subsets, one on either side of the 1940-1960 gap, and separately analyzing each subset using the same methods that were used for the entire group. In each subset, we found the same significant trend toward earlier flowering times, indicating that the irregularity in specimen collection (i.e., the gap in collec- tion) did not affect the outcome. Given these concerns about the quality of data from herbarium specimens, our results are quite striking and show clearly that plant flowering times are highly responsive to changes in average temperatures in the four months before and during flowering. (For the spring- flowering species we studied, we used the mean temperature for February, March, April, and May to calculate changes. See Figure 3.) In general, flowering times advance 3.9 days per one degree centigrade increase in mean spring temperature, as calculated using a statistical technique known as multiple regression that considers the flowering time of plants in warm years and cold years. This rate falls within the Figure 3. This graph demonstrates changes in flowering times of plants at the Arnold Arboretum as temperatures increase, showing the number of days plants flowered earlier or later in the past than they did in 2003 in relation to the average temperatures in the February through May preceding flowering. Plants flower earlier in warm years, and later in cool years. Years with many specimens or with extreme temperatures are noted. The line is the best fit line for the series. 32 Arnoldia 6312 range of findings of other published studies from the U.S. and Europe, which record flower- ing times occurring from two to ten days earlier for each degree centigrade of increase in tem- perature. Since Boston's temperatures in Febru- ary through May have warmed approximately 1.5 degrees centigrade over the past hundred years, the recorded temperature increase can account for nearly six (5.85) of the eight days that flowering time has advanced over the past hundred years. Factors other than the tempera- ture increase recorded at the Boston weather station must account for the other three days of increase. These other factors might include tempera- tures during other months of the year or other climatic variables such as rainfall and humid- ity. Focal conditions within and around the Arboretum may also he affecting flowering times. Construction of roads and buildings on adjacent land, for example, may have led to a very localized increase in temperature that was not registered at the Boston weather station. Finally, if plants were flowering over a longer period as they increased in size and age and were consistently collected for the herbarium at the beginning of their flowering periods — while our baseline observations in 2003 were made at peak flowering — there could be a false trend toward earlier flowering over time. Further investigations are needed in order to determine the relative importance of these factors. WHERE WE GO FROM HERE We have shown that herbarium collections and data collected by botanical gardens can be used to measure the effects of climate change on phonological events, and we know that many large collections of herbarium specimens exist at other institutions. Even more col- lections probably exist in dispersed form as samples collected at different times by many individuals from a single location and now held at multiple storage sites. In the past, biolo- gists have collected intensively in places with unusual concentrations of endemic or rare species, especially mountain peaks, islands, swamps, lake shores, and dunes; examples include the top of Mount Washington in New Hampshire, the Florida Everglades, the north- ern tip of Newfoundland, and Cape Cod in Mas- sachusetts. If information on flowering times from one of these locations could be gathered into one data set, an analysis could assess the responses of native species to local climate change and improve our capacity to predict the effects of future climate change on biological communities. We believe that many data sets of this sort could be assembled from around the world, covering the last one hundred to one hundred fifty years. Botanical gardens are an especially promising source for these dispersed specimens. We hope that our own study will contribute to the ongoing discussion of global climate change and encourage others to take advantage of this novel methodology of docu- menting biological response to climate change. For Further Reading on Climate Change Jensen, M. N. 2004. Climate warming shakes up species. BioScience 54(8): 711-719. Ledneva, A., A. J. Miller-Rushing, R. B. Primack, and C. Imbres. Climate change as reflected in a naturalist's diary, Middleborough, Massachusetts. Wilson [Oinitbological Society] Bulletin, in press. Miller-Rushing, A. J., and R. B. Primack. 2004. Climate change and plant conservation: plant conservation strategies need to anticipate climate change. Plant Talk 35: 34-38. Parmesan, C., and G. Yohe. 2003. A globally coherent fingerprint of climate change impacts across natural systems. Nature 421: 37-42. Primack, D., C. Imbres, R. B. Primack, A. J. Miller- Rushing, and P. Del Tredici. 2004. Herbarium specimens demonstrate earlier flowering time in response to warming in Boston. American lournal of Botany 91: 1260-1264. Primack, R. 2003. The special role of historical plant records in monitoring the impact of climate change. Arnoldia 62(3): 12-15 Root, T. L., J. T. Price, K. R. Hall, S. H. Schneider, C. Rosenzweig, and J. A. Pounds. 2003. Fingerprints of global warming on wild animals and plants. Nature 421: 57-60. Walther, G., E. Post, P. Convey, A. Menzel, C. Parmesan, T. J. C. Beebee, J. Fromentin, O. Hoegh-Guldberg, and F. Bairlein. 2002. Ecological responses to recent climate change. Nature 416: 389-395. Abe Miller-Rushing, Dan Primack, Richard Primack, and Carolyn Imbres are all at Boston University. Peter Del Tredici is a senior research scientist at the Arnold Arboretum. Finding a Replacement for the Eastern Hemlock: Research at the Arnold Arboretum Peter Del Tredici and Alice Kitajima T he hemlock woolly adelgid [Adelges tsugae, hereafter HWA) is an introduced insect from Asia that was first discovered feeding on eastern (or Canadian) hemlock (Tsuga canadensis) in Virginia in the 1950s.' It did not become a seri- ous problem on the East Coast until the 1980s, when it started killing entire populations of both wild and cultivated trees in the mid- Atlantic region. HWA is now well established in the eastern portion of the range of eastern hemlock, from New Hampshire south to North Carolina,^ as well as in most of the range of Carolina hemlock (T. caroliniana). While considerable research has been directed toward developing chemical and biological controls for HWA on eastern and Carolina hemlock,^ relatively little work has been done to determine the resistance of other hemlock spe- cies. In one experiment, McClure"* found that one Japanese species, T. diversifolia (northern Japa- nese hemlock), and two species from western North America, T. heterophylla and T. mertensiana (western hemlock and mountain hemlock) showed more resistance to HWA than Carolina and east- ern hemlock when all five species were cul- tivated outdoors in Connecticut for one year. Subsequent fieldwork on native hemlock popu- lations in Asia has shown that HWA occurs This specimen o/ Tsuga chinensis was collected by E. H. Wilson in Hubei Province, China in 1910. It is now growing at the Arnold Arboretum. only infrequently in natural populations of T. diversifolia and T. sieboldii in Japan® and in a subspecies of T. chinensis (Chinese hemlock), in China.® These results have been attributed to PETER DEL TREDICI 34 Arnoldia 6312 a combination of host resistance and the pres- ence of natural predators. Bentz et al.^ reported that cultivated specimens of northern Japanese hemlock and Chinese hemlock growing in close proximity to infected eastern hemlock in Washington, D.C., and in Philadelphia, Penn- sylvania, showed strong resistance to HWA over an eight-year period of exposure, while a second Japanese species, T. sieboldii (southern Japanese hemlock), showed variable levels of damage. The existing literature on HWA resis- tance of various hemlock species is summa- rized in Table 1 . At the Arnold Arboretum we have been study- ing the Chinese hemlock as a possible replace- ment for eastern hemlock in landscape settings. Species Range Shade tolerance Relative growth rate Hardiness to USDA zone 6 HWA resistance Tsuga canadensis Eastern North America Yes Fast Yes No Tsuga caroliniana Southern Appalachian Mountains Yes Moderate Yes No Tsuga chinensis Central and western China Yes Fast Yes Yes Tsuga diversifolia Central and nonhem Honshu, Japan Yes Slow Yes Yes Tsuga heterophylla Nonhwestem North America Yes Fast Questionable Questionable Tsuga merlensiana Nonhwestem North America Unknown Slow Yes Unknown Tsuga sieboldii Central and southern Honshu, Japan Yes Moderate Yes Questionable Table 1. Comparison of the environmental tolerance' factors of various Tsuga species cultivated at the Arnold Arboretum. Source Collection no. and (date) Collection location Altitude (m) Arnold Arboretum accession no. No. living plants (2004) Veitch China Exp. (1899-1902) EHW #952 (1901) Xing Shan, Hubei Province 2,130 6851 (Nov. 1907) 0(died 1921) Arnold Arboretum Exp. (1910-1911) EHW#4453 (1910) Fang Xian, Hubei Province 2,300-3,000 17569 (= 6851-1) (Feb. 1911) 1 (grounds) Botanic Garden. Sun Yat-Sen Memorial Park (Nanjing) (1932, 1934) Sichuan Province 394-32; 534-34 0 Chinese Academy of Forestry (1979, 1980) Sichuan Province (3rN;103'E) 1,000-1,300 1291-79; 481-80 0 Shanghai Botanical Garden (1980) Zhejiang Province — 664-81 0 Quarryhill Botanical Garden (1991, 1992) Sichuan Province 2,070-2,500 466-95;92-93 0 U.S. National Arboretum (1992) Wild source — 233-2003 5 (nursery) Sheffield Seed Co. China Natl. Tree Seed Co. (1992) Wild source — 100-94 75 (grounds) Xian Botanical Garden (1994, 1996) Ningshaan, Shaanxi Province 1,600-1,900 503-94; 65-96 10 (grounds) NACPEC Exp. (Qingling Mts.) QLG-013, 188, 190, 193 216,217(1996) Ningxi Reserve; Shaanxi Province 1,800-2,200 20-99; 21-99; 227 to 232-2003 13 (grounds); 26 (nursery) Cui and Ma (Xian Botanical Garden) CU! 97-053; 97-054 (1997) Shaanxi Province 242, 243-2000; 307, 308-2000; 225, 226-2003 28 (grounds); 14 (nursery) USDA Forest Service (2002) Wenbishan; Yunnan Province 2,650 439-2003 Greenhouse USDA Forest Service (2002) Ningshan Co.; Shaanxi Province 1,800 440-2003 Greenhouse Table 2. This list o/ Tsuga chinensis accessions received by Arnold Arboretum and originating in China between 1901 and 2002 documents the Arboretum’s persistence in introducing specimens from diverse parts of T. chinensis's native range. See text for details. Hemlock 35 Our ten-year research project has focused on three primary goals: reconstructing the history of the introduction of Chinese hemlock into cultivation in North America; documenting its resistance to HWA; and delineating its environ- mental tolerances. CHINESE HEMLOCK IN CULTIVATION IN NORTH AMERICA Chinese hemlock is widely distributed at eleva- tions between 3,282 and 11,487 feet (1,000 and 3,500 m) in mountainous regions of eastern, central, and southwestern China.* E. H. Wilson is credited with introducing the species into cultivation in North America with seed he collected in Xing Shan, Hubei Province (col- lection #952), in October 1901, while working for the Veitch Nursery Company of Chelsea, England.^ Despite this early introduction, Chi- nese hemlock remains poorly represented in North American botanical gardens. One of the very few specimens of known provenance was collected by Wilson as a seedling in Fang Xian, Hubei Province, China, in September 1910. He sent it to the Arnold Arboretum, where it arrived in February 1911.'° As of the winter of 2004, Wilson's tree was growing under acces- sion #17569 and was 49.2 feet (15 m) in height with a diameter at breast height of 14.4 inches (37 cm) and a branch spread of 39.4 feet (12 m). It showed no sign of HWA infestation. Over the years, the Arboretum's staff has propagated both seedlings and cuttings from the Wilson tree and distributed them to vari- ous botanical gardens and nurseries throughout the United States; records show at least sixteen separate distributions involving twenty-eight plants between 1915 and 1945. Many of the older Chinese hemlocks now growing in botani- cal collections in the United States are direct descendants of Wilson's Hubei seedling. Apart from Wilson's collections in 1901 and 1911, wild-collected germplasm of Chinese hemlock appears not to have entered North America again until 1979 and 1980, when vis- iting delegations of Chinese botanists presented their hosts with seed from the Chinese Acad- emy of Forestry. Since then, numerous Ameri- can and European expeditions to China have Year sampled Excellent* Good Fair Poor Dead or removed 1998 249 1,406 163 87 — 2002 10 68 422 1,142 263 * Excellent = outstanding specimen; good = healthy specimen, no evidence of disease or physical damage; fair = specimen in decline, evidence of disease or physical damage; poor = specimen in poor condition, more dead branches than living Table 3. Changes in the condition ratings of the 1,905 eastern hemlocks (i.e., those with dhh’s greater than 2 inches [5 cm]) growing on Hemlock Hill at the Arnold Arboretum between 1998 and 2002. Plant condition was rated both years by the same staff members. collected and distributed seeds from wild popu- lations growing at altitudes between 3,282 and 8,697 feet (1,000 and 2,650 m) in the provinces of Sichuan, Hubei, Shaanxi, Fujian, Zhejiang, and Yunnan (Table 2). THE ARBORETUM'S RESEARCH PROJECT The north-facing slope called Hemlock Hill consists of approximately 22 acres (10 ha) cov- ered with a nearly pure stand of eastern hem- lock. Bedrock is close to the surface on much of the hill, and the soils that overlay it are well drained but poor in nutrients. When HWA was first discovered there in April of 1997, the hem- lock population numbered 1,905 individuals with diameters at breast height greater than two inches (five cm). Since then the pest has spread rapidly. The entire population was labeled, mapped, and qualitatively assessed for condition and HWA damage during the win- ter of 1997-1998. The trees along the base of Hemlock Hill have been sprayed annually in the fall with dormant oil since 1997, which has effectively protected them from HWA, but those in the out-of-reach interior portions have been left untreated and are now in a serious state of decline. By the winter of 2002-2003, when the entire population was recensused, 263 trees had been removed (all were either dead or nearly dead), and those remaining had lost foliage and were in poor health." Table 3 shows the dra- matic decline in the hemlocks' condition that occurred between 1998 and 2002 as a result of the HWA infestation. For our study of Chinese hemlock's resis- tance to HWA, we used seedlings that were raised from a seed lot purchased in February 36 Arnoldia 6312 No. seedlings Mean plant Exposure Mean shoot Mean no. HWA Mean % shoots Mean % shoots Species sampled height (cm) Sun Gap Shade length (cm)* egg sacs per shoot w/new growth w/mite damage Tsuga chinensis 38 169.0 ± 38.0 (range = 84 to 240 cm) 8 18 12 10.3 ±3.5 (range = 5.5 to 17.2) 0 100 8.7 ±24.7 (range = 0 to 92) Tsuga canadensis 33 182.6 ±94.5 (range = 45 to 380 cm) 2 31 4.9 ± 1.2 (range = 2.7 to 8) 3.8 ±4 (range = 0 to 14.7) 45.4 ± 38.8 (range = 0 to 100) 20.9 ±27.6 (range = 0 to 100) •Based on samples of 12 shoots per tree. Table 4. Performance o/Tsuga chinensis versus T. canadensis in the Arnold Arboretum study. 1994 and known to have been collected in China in the wild (AA accession #100-94). After a three-month period of cold stratification, seed was sown in a warm greenhouse. In April 1999, when the five-year-old seedlings were between 23.4 and 42.9 inches (60 and 110 cm) tall, we planted 42 of them in scattered light gaps of the interior portions of Hemlock Hill, in groups of three to six individuals. The canopy for all the seedlings consisted of eastern hemlocks that were badly infected with HWA. At the same time, we established a control group by tagging 33 seedlings of eastern hemlock that were grow- ing spontaneously on the north-facing slope of Hemlock Hill, adjacent to the newly planted Chinese hemlocks. Unlike the majority (68 per- cent) of the Chinese hemlock seedlings, which were growing in light gaps with at least some direct sunlight during the day, the majority of eastern hemlock seedlings (94 percent) were in understory positions that received no direct sunlight at all. Four years later, on June 25 and 26, 2003, we evaluated the growth and extent of HWA infestation of the control group and of 38 of the 42 Chinese hemlocks that had been planted in 1999. By this time the Chinese hemlock seed- lings had had four years of exposure to HWA and the eastern hemlock seedlings six years. We measured the heights of all the seedlings in both groups and rated their canopy positions as "sun" (growing in a large canopy gap with mod- erate amounts of direct sun), "gap" (growing in a small canopy gap with minimal amounts of direct sun), or "shade" (growing in complete shade). To assess the level of HWA infestation, we selected at random two branches on oppo- site sides of each tree, taking for evaluation the six topmost shoots on each branch (consisting of growth from both 2002 and 2003). The fol- lowing was then recorded for all the shoots: (1) shoot length to the nearest millimeter; (2) the number of HWA egg sacs found on the undersides of the 2002 shoots; (3) the presence or absence of new (2003) growth; and (4) the presence or absence of spider mite damage, assessed by looking for the characteristic leaf stippling on the upper sides of the 2002 shoots. The 38 Chinese hemlock seedlings were recensused on March 9, 2004, to obtain final height measurements for the 2003 growing sea- son and to learn how many had survived after an unusually cold winter that saw the tempera- ture at the Arboretum reaching a low of -8.5 degrees Fahrenheit (-22.5 degrees centigrade) on January 16. RESULTS OF THE STUDY Results of the study are summarized in Table 4. The most dramatic finding was the total absence of HWA egg sacs on all of the 38 Chinese hem- lock seedlings, in contrast to a mean of 45.9 egg sacs per 12-shoot sample for eastern hemlock. Another indicator of Chinese hemlock's resis- tance to HWA was found in the measurement of new growth: 100 percent of the terminal buds on the sampled shoots of Chinese hemlock had produced new growth in 2003, compared with only 45 percent for eastern hemlock. Finally, the mean shoot length for Chinese hemlock was 4 inches (10.3 cm), more than twice the 1.9 inches (4.9 cm) recorded for eastern hem- lock. These results clearly show that Chinese hemlock possesses a high degree of resistance to HWA when growing in conditions that are optimal for infestation of eastern hemlock. Hemlock 37 Hemlock Hill as photographed in 1 905 by T. E. Man. ARCHIVES OF THE ARNOLD ARBORETUM PETER DEL TREDICI 38 Arnoldia 63/2 One of the Tsuga chinensis seedlings (AA #100-94) growing in a canopy gap on Hemlock Hill at the Arnold Arboretum, photographed in summer 2003. Hemlock 39 The remeasurement of the 38 Chinese hem- locks on March 9, 2004, showed them to be 17 percent taller than they had been the previous summer when their shoot tips were drooping, with an average height of 77.1 inches (197.8 cm) within a range of 57.3 to 96.9 inches (147.1 to 248.5 cm). The seedlings had averaged between 31.2 and 35.1 inches (80 and 90 cm) in height when they were planted out in April 1999; their average growth over four growing seasons was therefore more than a meter. This is a remark- able figure, considering the stressful conditions on Hemlock Hill and the minimal aftercare the plants received. It should also be noted that the plants showed very little winter damage at the time of the March resurvey, despite the low temperatures recorded in January 2004. These results show that Chinese hemlock is fully hardy in USDA Zone 6 and is a suitable replacement for eastern hemlock in landscape situations thanks to its relatively rapid growth rate, its tolerance of shade, and its resistance to HWA. Endnotes ' R. J. Gouger. 1971. Control of Adelges tsugae on hemlock in Pennsylvania. Sci. Tree Topics 3 1-9. ^ M. S. McClure. 1990. Role of wind, birds, deer, and humans in the dispersal of hemlock woolly adelgid (Homoptera: Adelgidae). Environ. Entomol. 20: 258- 264; D. A. Orwig, D. R. Foster, and D. L. Mausel. 2002. Landscape patterns of hemlock decline in New England due to the introduced hemlock woolly adelgid. Journal of Biogeogiaphy 29:1475-1488. ^ McClure. 1995. Managing hemlock woolly adelgid in ornamental landscapes. Bulletin of the Connecticut Agriculture Experiment Station # 925. New Haven, CT; McClure, C. A. Cheah, and T. C. Tigner. 2000. Is Pseudoscymnus tsugae the solution to the hemlock woolly adelgid problem? An early perspective, pp 89-96. In K. A. McManus, K. S. Shields, and D. R. Souto, eds. Proceedings: Symposium on Sustainable Management of Hemlock Ecosystems in Eastern North America, 22-24 June 1999, Durham, NH. GTR- NE-267. USDA Forest Service, Northeastern Research Station, Newtown Square, PA. “ McClure. 1992. Hemlock woolly adelgid. American Nurseryman 175(6): 82-89. ^ McClure et al. 2000. * M. E. Montgomery, D. Yao, and H. Wang. 2000. Chinese Coccinellidae for biological control of the hemlock woolly adelgid: Description of native habitat, pp 97-02. In K. A. McManus et al. 1999. ^ S. E. Bentz, L. G. H. Riedel, M. R. Pooler, and A. M. Townsend. 2002. Hybridization and self-compatibility in controlled pollinations of eastern North American and Asian hemlock (Tsuga) species. Journal of Arboriculture 28(4): 200-205. ® Z.-Y. Wu and P. H. Raven, eds. 1999. Flora of China, Vol. 4. Science Press, Beijing, China, and Missouri Botanical Garden Press, St. Louis, MO. ’ C. S. Sargent, ed. 1913-1917. Plantae Wilsonianae. An Enumeration of the Woody Plants Collected in Western China for the Arnold Arboretum of Harvard University During the Years 1907, 1908, and 1910 by E. H. Wilson. Cambridge University Press, Cambridge, MA; A. Rehder. 1940. Manual of Cultivated Trees and Shrubs, 2nd ed. Macmillan, New York, NY; K. S. Clausen and S. Y. Hu. 1980. Mapping the collecting localities of E. H. Wilson in China. Arnoldia 40(3): 139-145; R. A. Howard. 1980. E. H. Wilson as a botanist (part I). Arnoldia 40(3): 102-138. >0 Sargent 1913-1917, 3:446; Howard 1980. " P. Del Tredici, T. Akin, J. Coop, J. DelRosso, R. Ervin, S. Kelley, A. Kitajima, J. Papargiris, and K. Port. 2003. Proposed Hemlock Hill Management Plant. Arnold Arboretum Living Collections Department, internal report. Jamaica Plain, MA. M. E. Montgomery. 2003. Research scientist, USDA Forest Service, Camden, CT. Personal communication. Acknowledgments The authors would like to thank Arnold Arboretum staff members Tom Akin, Julie Coop, John DelRosso, Bob Ervin, Susan Kelley, Jim Papargiris, and Kyle Port, whose work on the Hemlock Hill project made this study possible,- Mike Montgomery of the USDA Forest Service, Northeast Region, for providing details on protocols for counting HWA; and Nathan Havill for his helpful comments on a draft of the manuscript. Peter Del Tredici is a senior research scientist at the Arnold Arboretum. Alice Kitijama now coordinates plant records at Descanso Gardens in La Canada Flintridge, California. This article is adapted from "Introduction and Cultivation of Chinese Hemlock (Tsuga chinensis) and Its Resistance to Hemlock Woolly Adelgid (Adelges tsugae)," published in Journal of Arboriculture (2004) 30(5): 282-287. 40 Arnoldia 6312 Arnold Arboretum Weather Station Data ■ — ^ 2003 Avg. Max. Temp. (°F) Avg. Min. Temp. (°F) Avg. Temp. (°F) Max. Temp. (°F) Min. Temp. (°F) Precipi- tation (in.) Snow- fall (in.) JAN 31 13 22 42 -3 3.36 5.7 FEB 36 16 26 61 -6 6.13 42.4 MAR 49 25 37 78 2 4.47 7.2 APRIL 55 35 45 89 25 5.08 3.5 MAY 67 46 57 97 32 4.12 0 JUNE 78 57 68 99 46 5.77 0 JULY 89 65 77 98 58 2.32 0 AUG 83 66 75 92 53 4.45 0 SEPT 73 57 65 82 43 2.51 0 OCT 60 41 51 72 28 5.38 0 NOV 52 36 44 75 21 3.11 0 DEC 42 26 34 60 15 5.89 21.4 Average Maximum Temperature Average Minimum Temperature Average Temperature Total Precipitation Total Snowfall Warmest Temperature Coldest Temperature Date of Last Spring Frost Date of First Fall Frost Growing Season 60° 40° 50° 52.59 inches 80.2 inches 99° on June 27 and 28 -6° on February 14 32° on May 18 29° on October 20 163 days Note: According to state climatologist R. Lautzenheiser, 2003 was quite sunny although colder than normal with above-normal levels of precipitation. The temperature averaged 50.2 degrees Fahrenheit for the year, 1.4 degrees below normal. This was 2.7 degrees colder then 2002 and the coldest year since 1992. The total precipita- tion of 52.59 inches was 9.76 inches above normal, which is 42.53 inches a year. Our snowfall total of 80.2 inches was 38.2 inches more than the past average of 42 inches. The snowiest month was February with a record-breaking storm that came on the 17th and 18th and dropped 27.6 inches. The coldest month was January when the state recorded 308 hours of continuous temperatures below freezing. Nonetheless, the growing season at the Arnold Arboretum was a very good one. Cooler summer temperatures and consistent levels of precipitation allowed the plants to put on above-average amounts of new growth.