Jansons, A., Matisons, R.*, Krisans, O., Puriņa, L., Dzēriņa, B. and Neimane, U. 2014. Height of the Mass Point and Some Properties of Crown of 26 Year Old Scots Pine and Lodgepole Pine as Potential Parameters for Wind Damage in Zvirgzde, Latvia. 2014. Ba

Experimental plantation of exotic species and provenances of trees have been established to assess possibilities to increase productivity of stands. However, risks related with various hazards must be evaluated before commercial use of novel (introduced or exotic) tree provenances or species. One of such risks is wind damage, which can be related with crown properties and physical stability of trees. Lodgepole pine (Pinus contorta var. latifolia) from three provenances and local Scots pine (Pinus sylvestris) at the age of 26 years from experimental trial in central part of Latvia in Zvirgzde were sampled. Mass of branches in four quarters of crown, mass of stem and parameters of branches were measured. Height of the mass point of aboveground part of trees and distribution of crown biomass was determined and compared between provenances of lodgepole pine (LP) and Scots pine (SP). Similarity of distribution of crown biomass was determined by cluster analysis and the relationship between crown biomass and properties of stems and crowns were determined.

Height of mass point correlated with height of the tree, which was significantly higher for Summit Lake provenance of LP. However, the relative height of mass point was similar for LP and SP, ranging from 31.8 to 43.6% of tree height. The properties of crowns and trees differed between species; aboveground biomass was higher, branches were longer and thicker for SP. LP had higher ratios of branch mass-tree height, and branch mass-branch length. Only several parameters such as ratio of branch-stem mass, height of lowest living branch and diameter of the thickest branch in first two meters differed between provenances of LP. Four groups of trees established according to cluster analysis of crown biomass distribution consisted of trees from different provenances and species of trees and had different patterns of crown biomass distribution. Biomass of upper half of crown, length of crown, and branch length differed between groups of trees distinguished according to the distribution of crown mass.

Key words: tree provenances, crown properties, mass point of tree