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Abstract
Introduction
The trees resin productivity along with genetic conditionality of this feature in considerable degree is determined by the ecological and forest inventory conditions of trees growth. For the plant-breeding selection of trees by the resin productivity it is necessary to take into account regularities of height and spatial structure of a pine stand that is of both scientific and practical interest.
Materials and Methods
For evaluation of the Scots pine (Pinus sylvestris L.) resin productivity following the analysis of forest inventory indices and spatial structure, the author studied pure pine stands at the age of 78 years in fresh fairly infertile pine site type conditions (State Enterprise “Radekhivske Forest Economy”). The trees in tapped stand were divided into 5 categories by the resin productivity: 1 - low resin productivity (the soft resin yield does not exceed 40 % of average one for this stand; 2 - lower (41-80 %); 3 - medium (81-120 %); 4 - higher (121-160 %); 5 - high (161 and more). To establish the spatial structure of the stand, the field GIS Field-Map (IFER-Monitoring and Mapping Solutions. S.r.o.) was used.
Results
The results of calculation of trees placing indicate an artificial origin of stands on sample plots. Higher density stand at the group type of placing has the lowest resin productivity (33.7 gs are from bark-chipped streak) and, alternatively, in stand with the lowest density of trees at the casual placing of trees the soft resin yield was the greatest. Most of trees of the lowest 1 and 2 categories of resin productivity are exactly in biogroups and dense groups. Trees with higher and high resin productivity of 5 and 6 categories are evenly concentrated on all over the sample plot mainly on forest margins.
All indices of morphometric and spatial structure of trees on sample plots have a tendency to increase with an increase in category of resin productivity. Such indexes as diameter of tree and area of crown projection are characterized by considerable difference. In particular, on a sample plot with the casual placing of trees, a difference between the diameters of pine trees of extreme categories of resin productivity reaches 50%, and by the area of crowns projections it is 90 % correspondingly. However, the average biometrical indices of trees on sample plots with the different type of placing of trees had insignificant differences. The research results show little straight-line correlation of resin productivity with the diameter of trunk, parameters of crown and distance between trees. It has to be noticed that the factors of spatial structure of stand have certain tendencies of influence on trees resin productivity.
Conclusions
High differentiation by resin productivity typical to the Scots pine trees is predefined, in some degree, by the spatial structure of stand that gives an opportunity for a spatial stochastic design of a pine stand by this characteristic.
Research of spatial structure and its relations to resin productivity assists the decision of the problem of increasing of forests productivity and resistance, improvement of their qualitative composition. Creating favorable conditions for a diameter and crown development increment can increase the resin productivity of pine stands considerably.