Plotnikova O. The tree improvement aspects of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franko) introduction in the Forest-Steppe of Ukraine.

The object of research is the introduction and the tree improvement of Douglas-fir in the Forest-Steppe of Ukraine. The subject of research is the peculiarities of growth and acclimatization of Douglas-fir in the conditions of the Forest-Steppe of Ukraine. For the first time, the level of intraspecific polymorphism of Douglas-fir was determined for the conditions of the study region according to the morphological and anatomical structure of the needles; individual variability in the colour of microstrobiles and pollen viability were assessed; features of growth of geographical origins of Douglas-fir in the conditions of introduction are established; a method of complex assessment was introduced to determine the prospects of using Douglas-fir to create forest plantations. The method of Douglas-fir pollen germination and approaches to the use of morphological and anatomical indicators of needles as additional characteristics for predicting the growth and condition of trees have been improved. The obtained results have scientific and practical significance for solving silvicultural and selection problems, in particular with the introduction of Douglas-fir in forest plantations and expansion of its forest seed base in the Forest-Steppe of Ukraine.