The current health of spruce forests was assessed on experimental sites of the Mountain Research Department, which was organized in 1996 as a basic forestry department for conducting scientific studies of the Ukrainian Research Institute of Mountain Forestry and for implementing a full range of forest management activities. The forest area of the department belongs to the forests of the Ukrainian Carpathians and is located on both sides along the Khripelivets River at altitudes of 600–1,300 m above sea level. The forest cover in the area of the Department’s activity is 48.9 % and the total forest area is 560 hectares. The Norway spruce represents 73 % and common beech, 16 % of the species composition of the forests.
Materials and methods
The health of spruce forests was investigated on permanent research plots of rectangular shape, by carrying out detailed forest pathological studies. The laying of such objects was carried out with the generally accepted methods of forest inventory. According to the developed methods, on a six-point scale, the category of a particular tree was determined by position, relative size, economic value, and condition.
The first experimental object revealed uneven spacing, both single and group (up to 6 specimens), of 138 trees of the following four wood species: mountain ash (1), silver fir (2), Scots pine (21), and Norway spruce (114). Five types of damage of spruce were found for 39 from 114 trees. Bark beetles damaged only old dead standing trees (i. e. the trees of 6th health category). The number of holes was up to 160 pcs per 1 dm2 and the average value amounted to 7.6 pcs per 1 dm2. The distribution of the average value of the health condition of spruce showed its gradual deterioration with the change of tree categories. It is a characteristic feature of the health that it sharply deteriorated with the size of the trees, starting from the third category, with the economic value, from the fourth category and with the position, from the fifth category of trees.
The second experimental site had an uneven single and group (up to 5 specimens) spacing of 149 trees of the following three species: silver fir (6), Scots pine (8), and Norway spruce (135). The spruces damages caused by bark beetles were found only at the old dead standing trees. The maximal number of the holes per 1 dm2 was 99 pcs; the average value amounted to 4.1 pcs per 1 dm2. There was a sharp deterioration of the health according to the size of the trees, starting with the fifth health category, in terms of economic significance, only in the sixth one, and for the position, from the third category of trees.
The tendency to health deterioration of spruce was found as a result of the more suppressed position, the smaller size and the lower economic significance of trees in two experimental plots. Despite the lower altitude above sea level, the worse health and lower economic significance of trees at the second experimental site with the greater share of spruce were associated with a large number of trees in the same area and smaller shares of other tree species in the stand. Therefore, to increase the productivity of such stands, a wider cultivation of, for example, silver fir, common beech, European larch is advisable. Growing Scots pine should be limited because it was the least resistant.
4 Figs., 6 Tables, 12 Refs.