Сибирский лесной журнал (Feb 2024)
The influence of feeding areas on the fall of trees in pine crops
Abstract
55-year-old crops of Scots pine (Pinus sylvestris L.) the IB productivity class (bonitet) with a completeness of 0.94 on an area of 1.9 hectares, created according to the scheme 1.82 × 1.10 m, were studied. More than 2 thousand trees were located on this area and polygons of their nutrition were built around them in the «ArcMap-ArcView» program. The territory was divided into 24 test areas, with density fluctuations at the age of 30 years 1153–2207 trees/ha, a fullness of 0.84–1.03 and an average diameter of 19.1–23.0 cm. It was found that the density affects the intensity of the fall of trees by only 22 %, and 78 % of the factors of their fall are not related to the density. Therefore, increased density within these limits is not the main reason for the fall of trees. It was also found out that in the younger class of the tree’s feeding area, the probability of its falling off after 25 years is the greatest (58 %) and gradually decreases to 5–7 % by the senior classes. At the same time, the area of nutrition increased by 2.1 times or more did not guarantee the trees their complete safety by the age of 55, and in 9.6 % of cases they died for no apparent reason. The feeding areas of falling trees turned out to be almost functionally related to the frequencies of feeding areas at the age of 30 with a correlation of R = 0.95 ± 0.03, and this leads to the fact that their small feeding area (less than average) increases the probability of falling off by only 27 %. This is confirmed by S. N. Sennov’s research (1999, 2005) that despite intensive thinning at the age of 40, over the next 40 years trees died at any diameter, and the nature of the fall did not differ from the control. Therefore, from a forestry point of view, thinning felling in middle age is no longer effective. We need a much earlier optimization of the density of the stand at the age of 10–15 years.
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