Silva Fennica vol. 6 no. 2 | 1972
Category : Article
Male and female flowering, cone crop, and some vegetative characteristics were studied in grafts 10 to 16 years of age in a clonal seed orchard of Scots pine (Pinus sylvestris L.). Genetic variation was found between clones in flowering as well as in cone production. Clone evaluation resulted in similar classifications of clones in different years. A regression analysis showed that crown size clearly increased but previous height growth slightly decreased flowering and cone production. The percentage of pollinated female strobili did not differ between clones.
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Tormilainen,
E-mail:
mt@mm.unknown
The paper deals with the concepts of time consumption and output in forest work science. When output is defined as the inverse of time consumption and vice versa, it is possible to show the important consequences in probability functions. For instance, it is not the same if the dependent variable in a regression analysis is output or time consumption. Also, the average differ depending on if they are based on the time consumption figures or on the average output.
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Kärkkäinen,
E-mail:
mk@mm.unknown
The study was an attempt to assess, from a theoretical viewpoint and with the techniques of measurement in mind, the usability respiration and cumulative respiration in the observation of the progress of seed germination in Norway spruce (Picea abies (L.) H. Karst.), as well as the influence of air temperature substrate moisture and the stage of physiological development of seeds on respiration. Furthermore, the reserve nutrient consumption and the possible uptake of mineral nutrients were kept under observation during the 9–11 days after seeding.
The results showed that the stage of physiological development of the seeds can be rather well described by the means of cumulative CO2 release. There was a strong interaction in the CO2 release between the moisture of the substrate and the air temperature. It seems to be to great extent due to differences in the rate of development in the early phases of germination. The CO2 release from seeds showed a close correlation with percentage germinated seeds.
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Hari,
E-mail:
ph@mm.unknown
- Lehtiniemi, E-mail: tl@mm.unknown
A growing stand of Norway spruce (Picea abies (L.) H. Karst.) marked for cutting was investigated in the winter of 1971–72 in Helsinki in Southern Finland in order to determine the economic loss caused by decay. Taking a sample from growing spruce trees with increment borer is not a reliable method of determining the frequency of decay. The decayed stems were twice measured for assortment cutting into lengths; the first time disregarding the decay and the second time doing the actual assortment cutting according to the grade of timber. The direct economic loss caused by decay was 13% of the price for standing timber. The indirect loss may be as great as the direct loss.
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Kallio,
E-mail:
tk@mm.unknown
The material comprised 12 Norway spruces (Picea abies (L.) H. Karst.) from Central Finland, with 2,118 branches. The exact location of the branches on the stems, their diameter at the thick end, their length, and the green weight of all the branches was measured on two-metre lengths of the stem.
According to the results, the diameter of a branch can be estimated very accurately from its length. The variation of branch diameter along the stem was also very regular, although there were considerable differences from one tree to another. The greatest work requirement for trimming was in the middle and upper parts of the green crown. Branch variables per tree, such as the number and cross-section area o the branches, could be satisfactorily estimated from the volume or breast-height diameter of the stem.
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Kärkkäinen,
E-mail:
mk@mm.unknown
In the literature review the current status of information on the genetic variation of CO2 exchange and some reviews and investigations on this subject are listed. Photorespiration is separately discussed and unpublished data of an electron microscope study of poplar leaf microbodies are presented.
Considerable genetic inter- and intraspecific variation is found in several characteristics that affect CO2 exchange in trees. Photosynthesis in young trees does not correlate well with growth through the whole rotation cycle. A special interest has been shown to marginal environmental conditions (e.g. water deficit, low temperature, and low light intensity), as opposed to optimal conditions often employed in laboratory studies of CO2 exchange in trees.
In an unpublished poplar studies by the author et.al. a preliminary experiment with poplar clones showed variation in the CO2 competition point. This variation was negatively correlated with the photosynthesis efficiency of these clones.
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Luukkanen,
E-mail:
ol@mm.unknown