Muru Juurola, Pekka Ollonqvist, Heikki Pajuoja, Mikko Toropainen. (1999). Outcomes of forest improvement work in Finland. Silva Fennica vol. 33 no. 3 article id 658. https://doi.org/10.14214/sf.658

Keywords: forest policy; forest improvement work; subsidies; input-output method; allowable cut

Abstract | View details | Full text in PDF | Author Info

This paper discusses public subsidies aimed at intensifying timber production as an initial part of an evaluation of the profitability of forest investment subsidies in Finland. In many countries there are very few proper ex post evaluations of the forest policy instruments in economic terms. The scarcity of timber among users and their attempts to construct new forest policy are discussed first. The increments in annual growth and growing stock as well as its valuation are then evaluated. The final gross utility increments due to forestry investments are measured through their importance in the forest industry products. The direct and indirect changes in GDP are calculated by using the input-output method.

Juurola, The Finnish Forest Research Institute, Helsinki Research Centre, Unioninkatu 40 A, FIN-00170 Helsinki, Finland E-mail: mj@nn.fi
Ollonqvist, The Finnish Forest Research Institute, Helsinki Research Centre, Unioninkatu 40 A, FIN-00170 Helsinki, Finland E-mail: po@nn.fi
Pajuoja, The Finnish Forest Research Institute, Helsinki Research Centre, Unioninkatu 40 A, FIN-00170 Helsinki, Finland E-mail: heikki.pajuoja@metla.fi
Toropainen, The Finnish Forest Research Institute, Helsinki Research Centre, Unioninkatu 40 A, FIN-00170 Helsinki, Finland E-mail: mt@nn.fi

article id 657, category Research article

Paul C. Van Deusen. (1999). Multiple solution harvest scheduling. Silva Fennica vol. 33 no. 3 article id 657. https://doi.org/10.14214/sf.657

Keywords: simulated annealing; Metropolis algorithm; Gibb’s sampler

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Application of the Metropolis algorithm for forest harvest scheduling is extended by automating the relative weighting of objective function components. Previous applications of the Metropolis algorithm require the user to specify these weights, which demands substantial trial and error in practice. This modification allows for general incorporation of objective function components that are either periodic or spatial in nature. A generic set of objective function components is developed to facilitate harvest scheduling for a wide range of problems. The resulting algorithm generates multiple feasible solutions rather than a single optimal solution.

Van Deusen, Principal Research Scientist, NCASI, Northeast Regional Center, Tufts University, 1 Anderson Hall, Medford, Massachusetts 02155, USA E-mail: pvandeus@tufts.edu

article id 656, category Research article

Klaus Silfverberg, Markus Hartman. (1999). Effects of different phosphorus fertilisers on the nutrient status and growth of Scots pine stands on drained peatlands. Silva Fennica vol. 33 no. 3 article id 656. https://doi.org/10.14214/sf.656

Keywords: needles; Scots pine; stand growth; drainage; phosphorus; peat; fertilisation

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The aim of the study was to compare the effects of phosphorus fertilisers of different solubility and different phosphorus doses. The material was collected from 8 field experiments situated on drained peatlands in southern and central Finland (60°–65°N). The sites were drained, oligotrophic pine fens and pine bogs, which had been fertilised between 1961 and 1977 with different combinations of N, K and P. In 1991–94 stand measurements and foliar and peat sampling were carried out on 162 sample plots. Apatite, rock phosphate and superphosphate affected basal area growth to a rather similar extent. However, apatite slightly surpassed superphosphate and rock phosphate at the end of the study period in two hollow-rich S. fuscum bogs. Higher doses of phosphorus did not significantly increase the basal area growth. The foliar phosphorus concentrations clearly reflected the effect of the P fertilisation. Especially on the pine bogs basic fertilisation with 66 kg P/ha maintained the needle phosphorus concentrations at a satisfactory level for more than 25 years after fertilisation. The amount of phosphorus in the 0–20 cm peat layer was not significantly increased either by basic fertilisation or refertilisation. The phosphorus reserves in the peat in the individual experiments were between 88 and 327 kg/ha. There was a strong correlation between the amounts of phosphorus and iron in the peat. Large amounts of iron in peat may reduce the solubility and availability of phosphorus. According to the foliar phosphorus concentrations in the basic-fertilised plots, the need for refertilisation seems to be unnecessary during the 25-year postfertilisation period at least. None of the basic fertilisation treatments seriously retarded the basal area growth compared to the refertilised treatments. There seems to be a greater shortage of potassium than of phosphorus, because the foliar potassium concentrations and the amounts of potassium in the 0–20 cm peat layer were very low in several of the experiments.

Silfverberg, The Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: klaus.silfverberg@metla.fi
Hartman, The Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: mh@nn.fi

article id 655, category Research article

Raija-Liisa Petäistö. (1999). Growth phase of bare-root Scots pine seedlings and their susceptibility to Gremmeniella abietina. Silva Fennica vol. 33 no. 3 article id 655. https://doi.org/10.14214/sf.655

Keywords: Pinus; nursery; age; Scleroderris

Abstract | View details | Full text in PDF | Author Info

Bare-root row-sown seedlings of Scots pine (Pinus sylvestris L.) in a forest nursery were inoculated with Gremmeniella abietina conidia at different times during their first and second growing seasons. The following spring, the proportion of diseased seedlings was different in various inoculation time treatments according to the age of the seedlings. The first year seedlings were susceptible to infection until late summer, whereas the second year seedlings were not. It is thought that this difference is due to the different growth rhythms of the first and second year seedlings. The difference in the susceptibility of bare-root seedlings to the disease in various growth corresponded to that reported earlier for container seedlings.

Petäistö, Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland E-mail: raija-liisa.petaisto@metla.fi

article id 654, category Research article

Margus Pensa, Risto Jalkanen. (1999). Needle chronologies on Pinus sylvestris in northern Estonia and southern Finland. Silva Fennica vol. 33 no. 3 article id 654. https://doi.org/10.14214/sf.654

Keywords: needle age; needle trace method; needle retention; crown thinning; needle loss; shedding

Abstract | View details | Full text in PDF | Author Info

A needle trace method was used to reveal the chronology of needle retention on Scots pine (Pinus sylvestris L.) in southern Finland (two stands) and northern Estonia (two stands). The average annual summer needle retention along the main stem varied from 2.2 to 3.1 in Estonian stands and between 3.4 and 4.2 in Finnish stands during the period 1966–1990. The 23-year-mean needle age was 3.0 and 2.1 years in Finland and Estonia, respectively. In all stands, the mean needle age decreased sharply in 1980s.

Pensa, Institute of Ecology, Department of Northeast Estonia, Pargi 15, EE-41537 Jõhvi, Estonia E-mail: margus@ecoviro.johvi.ee
Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN-96301 Rovaniemi, Finland E-mail: rj@nn.fi

Category : Research note

article id 659, category Research note

Anneli Viherä-Aarnio, Pirkko Velling. (1999). Growth and stem quality of mature birches in a combined species and progeny trial. Silva Fennica vol. 33 no. 3 article id 659. https://doi.org/10.14214/sf.659

Keywords: stem quality; growth; Betula pendula Roth; Betula pubescens Ehrh.; Betula papyrifera Marsh.; progeny; timber production

Abstract | View details | Full text in PDF | Author Info

The growth and stem quality of silver birch (Betula pendula), downy birch (B. pubescens) and paper birch (B. papyrifera) were compared in a 32-year-old field trial in southern Finland. The material consisted of different unselected stand origins and progenies of phenotypically selected plus trees of silver and downy birch from southern Finland and differing stand origins of paper birch from the North-West Territories, Canada. Growth, yield and a number of stem quality traits, including taper, sweep, stem defects, heights of different crown limits and length of the veneer timber part of the stem were measured or observed. The native Finnish silver and downy birches were superior to paper birch in terms of both yield and stem quality, silver birch being the best. Progenies of silver birch plus trees were better than the stand origin, indicating that the former are able to reach high quality veneer log size in a shorter time than unselected material. The cultivation of paper birch can not be considered viable in Finland.

Viherä-Aarnio, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: anneli.vihera-aarnio@metla.fi
Velling, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: pv@nn.fi

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