Наукові праці Лісівничої академії наук України (Dec 2019)
Forecast of the Norway spruce forests’ decline at the Ukrainian Carpathians according to forest types
Abstract
The most negative result of the mass decline of the spruce forests in the Ukrainian Carpathians is the loss of most of the spruce wood stock, which is practically uncontested for many industries. The decline forecast gives a chance for forestry enterprises to respond appropriately in good time. The studies of the decline intensity of the Norway spruce stands were in 2010-2019 at 21 stationary objects in the main forest types of the region. The research methodology provided for the assessment of spruce wood stock in the context of health conditions of this tree species. The results made it possible to identify the interrelations of the decline intensity of spruce forests according to the stand indicators that mainly determine its: forest type, age groups, basal area, and species composition. For example, the next interrelations have been established for forest types: with increasing of the forest types humidity, decline intensity of spruce forests decreases, and with humidity decreasing, intensity increases; with increasing of the forest types fertility, decline intensity of spruce forests decreases, and with fertility decreasing, intensity increases; in mixed forest types, decline intensity of spruce forests is less than in pure (one species) forest types; in non-spruce forest types, decline intensity of spruce forests is higher than in spruce ones; and in forest types outside the spruce areal it is even higher. In accordance with the established intensity and trends of the spruce forests decline, a forecast scheme was developed, which is based on the distribution of the area and wood stock of the Norway spruce according to the forecast ’s criteria and calculated according to forest inventory data. Results of the forecast indicate that the loss of spruce wood volume in the spruce forest types of the Ukrainian Carpathians in the next 20 years will fluctuate from 48 to 95 percent depending on site conditions, age, basal area, and proportion of spruce in the species composition of stands, and the average loss will be 80%. A significant fluctuation of these percent is explained by the high variability of site conditions in the regional spruce forest types – from wet suboligotrophic to raw megatrophic. For Common beech forest types, these fluctuations will be from 77 to 97 percent and average losses – 92%, and for Silver fir forest types – suitably 71-89 and 80%. Decline intensity of spruce forests in the spruce and fir forest types is the same and less than for beech forest types, and that confirm forestry correctness of the prediction results. The average losses in the area of spruce forests are smaller than spruce wood volume: in spruce forest types – 28 percent to 2040, in beech – 63, in fir – 53%. Note, that the loss of spruce forests area is closer for beech and fir forest types than for spruce ones, where for it is much less. It is because when the secondary spruce stands decline – the main species changes (for example, from Norway spruce on Common beech), but when the native spruce stands decline – it is not. The spruce forests’ decline in the Ukrainian Carpathians in the next 20 years will be significant for state forestry enterprises and its result will be decreasing in the area of spruce forests from 425.6 to 328.9 thousand hectares, and of the spruce wood volume – from 145.6 to 32.1 million m3. The individual enterprises’ losses depend on the forest types, age, basal area and the spruce part in the species composition of their spruce forest. These predictions confirm a necessity to develop a regional program for the spruce forests restoration in the Ukrainian Carpathians.
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