Наукові праці Лісівничої академії наук України (Nov 2023)
Forestry and ecological features of distribution and improvement of biotic stability of pine forests in the conditions of Lviv region
Abstract
In the context of climate change and growing anthropogenic pressure, identified were the features of the distribution and silvicultural indicators of the functioning of pine stands in Lviv region, taking into account various types of forest site conditions. Measures have been developed on silvicultural and ecological principles to increase biotic stability and to preserve Scots pine stands. The total area of forest land in the region where pine is common is 151,246.5 ha, of which 94,648.8 ha (62.5%) are occupied by stands of artificial origin, 48,898.3 ha (32.3%) are of natural origin, 7,681.3 ha (5.19%) – open forest crops, 149.4 ha (0.1%) – sparse forests. It should be also noted that pine forest stands in Lviv region are distributed in all four trophotopes – A, B, C, and D, and in dry, fresh, moist, wet, and very wet hygrotopes. They are most common in fresh and moist fairly infertile pine site types (42.1%) as well as in fresh and moist fairly fertile site types (49.0%). In general, Scots pine in the region grows in appropriate climatic-edaphic and phytocoenotic conditions, in which it occupies an area of 137,467.6 ha or 90.9% of the total area of pine forest stands and acts as a type-forming species or a climatic type-forming admixture. At the same time, over an area of 13,778.9 ha (9.1%), Scots pine is distributed in forest growth conditions that are not typical for it, in particular in fertile site types (5,268.5 ha), fairly fertile site types (8,498.2 ha), fairly infertile pine site types (12.2 ha). The largest area in all types of forest growth conditions is occupied by pure pine stands (10 units – 71,592.6 ha (47.3%). Forest stands with a share of pine in the composition of 6, 7, 8 and 9 units are also common – 64,032.6 ha (42.4%), and only in a small area (170.6 ha; 0.1%), there are stands in which pine is represented by one or two units. In terms of age, in Lviv region middle-aged pine forest stands are predominant (69,723 ha; 46.1%). A significant area is also occupied by maturing stands - 32,711.3 ha (21.6%) and young growth – 31,284.4 ha (20.7%). More than 64% of pine-involved stands are characterized by medium relative density (0.51-0.80), and 25.7% are high-density stands (0.81 and more). Pine forests in the region are highly productive and reach site classes І, Іа, Іb and even site classes Ic, Id . They occupy an area of 12,548.1 ha (82.3%). Low-quality pine-involved stands (site classes ІІІ-Va) are spread over a small area (4,185.5 ha or 2.7%). The growing stock of the pine stands already at a maturing stage reaches more than 300 m³/ha. The largest growing stock is, of course, in fairly fertile site type and fertile site type which is not typical for pine. However, even in infertile pine site types, the growing stock in the pine stands in Lviv region reaches 160-260 m³/ha at the middle-aged stage and the age of pre-maturity. The largest annual increment of pine stands in terms of stemwood in all types of forest growth conditions is observed in the mid-aged period – 4.5-5.8 m³/ha. To ensure high vitality and preservation of pine stands, it is necessary to regularly carry out a number of forestry activities, including: conducting pathological examinations and health-improving activities; timely conducting tending, main, and sanitary fellings; increasing the biodiversity of forest stands; creation of forest cultures in accordance with edapho-climatic conditions of the territory of the region and forest-seed zoning; selection of biologically stable genotypes of Scots pine; introduction of selection-system, close-to-nature forestry based on natural renewal. In general, in pine forest management units, it is necessary to practice the cultivation of mixed pine stands with the participation of broad-leaved tree species. At the same time, it is necessary to make maximum use of natural regeneration and, if necessary, to supplement it with the creation of mixed pine cultures.
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