INFLUENCE SEEDS ORIGIN OF DOUGLAS FIR ON ITS CULTIVATION SUCCESS IN KYIV POLISSYA
Douglas Fir (Pseudotsuga menziesii (Mirb.) Franco) -one of the most promising species of exotic tree plants in Ukraine. The aim of the research was to study the influence of geographical origin of Douglas seed on its size, soil germination, seedlings biennial morphometric characteristics and peculiarities of growth they created the plantation in soil condition of fresh “sudubrava” in the Kyiv Polissya. It is established that the provenances, formed in harsh climate conditions, have smaller seeds. Bige seeds are sizes noted from seeds the Pacific Northwest of USA. Control seed batch of seed plantations in Kharkiv and Ivano-Frankivsk region had a longer average length of 6,8 ± 0,19 mm and 7.3± 0,14 mm and an average width of 3,3 ± 0,10 mm and 3,8 ± 0,08 mm respectively. This fact may confirm the view of many scientists about higher adaptability of introduced trees grown in Ukraine, to local soil and climatic conditions comparing with planting material received from other countries. This larger seeds size was noted from in case of Ivano-Frankivsk plantations where conditions for the growth of Pseudotsuga menziesii (less continental climate and higher rainfall) are more favorable. The greatest height and length of root seedlings were in case of local seeds (Kharkiv and Ivano-Frankivsk region), indicating their high adaptability to soil and climatic conditions of Ukraine. Among North American origins highest morphometric parameters were in case of seedlings from seeds and medium coastal areas of Washington. This indicates that the soil conditions and rainfall in these regions and contributes to the preservation of this fast-growing forms of Douglas Fir, which transmit these traits to offspring. The least height by seedlings from seeds obtained from the Idaho and Montana states - 13,90± 0,37 cm, but they had a well-developed root system length 30,8 ± 0,52 cm. The natural conditions of the region tougher type climate over dry, which led to a number of forms of Douglas Fir, with less rapid growth, but with higher adaptive capacity to these conditions. These forms can be used for planting in Ukraine due to climate change towards more. After the first and second years of growing, plantation from seeds of Idaho and Montana, origin as well as New Mexico and Arizona had higher survival rate. Where the seedlings had the lowest height, due to the optimum ratio of the latter to the root system and greater adaptability to adverse conditions. In the second year of forest crops growth there was a significant mortality of most trees from proveniences Washington, due to their lower genetic ability to grow in hot and dry climate. In the group with insignificant mortality of trees except origins №№ 40-47, were proveniences of Idaho and Montana (№№ 1-5) and British Columbia (№№ 64-77). The high performance of medium height of two-years-crops (50,0 ± 3,66 cm), Kharkiv origin different, which in 2016 significantly exceeded the annual growth of the plant in Ivano-Frankivsk region, which can be explained by a higher adaptation of the Kharkiv plant origin to the dry and hot weather, studies observed in the Kyiv Polissya in recent years.