VARIETY OF FORMS AND VITALITY OF THE LARCH IN THE STANDS OF WESTERN POLISSIA
It was not possible to distinguish forms for Larix decidua Mill., Larix kaempferi Carr., Larix eurolepis Henry by the angle of branching due to the high variability of this feature at different heights of the trunk during the life cycle of individuals. Also the attempt to identify forms of the studied larch varieties by the thickness of knots failed due to the strong dependence of this characteristic on the age and density of stands, the distribution pattern of individual trees in the forest. The density of the crown, in contrast to the angle of branching, is more stable attribute of the form, which gives grounds for distinguishing on the territory of Western Polissia the forms of Larix decidua with open and medium density canopy; the forms of Larix kaempferi with dense and medium density canopy; the forms of Larix eurolepis with dense crown. In terms of clean-boled trees, there are three forms of Larix decidua with satisfactory, good and very good cleaning; in other varieties of larch, in view of the limited age of investigated stands, no forms with such characteristics have been found. Six forms by the type of bark were identified for Larix decidua - thick-barked, alder-like, thin-barked, pine-like platy bark, broad-scaled bark, narrow-ridged bark.; the last two types of bark are the most common. For Larix kaempferi there are three forms - alder-like bark, narrow-ridged bark, and narrow-scaled bark, the last of which is the most common; Larix eurolepis -only two forms are distinguished according to the type of bark - broad-scaled and narrow-scaled. The vitality of larch varieties such as European, Japanese and hybrid in the young stands up to 20 years of age is determined by the degree of differentiation of trees in stands, it is fairly active in this age range with the result that in the plantations there are individuals in different categories of vitality. The European larch, as light-demanding species, is characterized by somewhat lower vitality compared to other types of larch. In middle-aged, maturing and mature stands of European larch, the predominant categories are completely healthy and relatively healthy individuals (about 90%). The most productive stands with participation of Larix decidua in Western Polissia have a medium-density crown with a thin or middle-thickness knots, clean trunks and narrow-ridged bark. Highly-productive stands with participation of Larix kaempferi are characterized by trees with dense canopy, knots of medium thickness, satisfactorily cleaned trunks and narrow-scaled type of bark. Highly-productive stands with participation of Larix eurolepis have a dense crown, thin knots, satisfactorily cleaned trunks with broad-scaled bark.