Norway spruce cultivation in conditions of drained sedge-sphagnum birch stands' reconstruction

Significant shortage of spruce timber for Karelian pulp industry manifested itself in the second half of the XX century. Considering the above mentioned an experimental plot for Norway spruce cultivation was established in southern Karelia (61°50' N, 33°30' E) in 1982. The experimental plot was developed during restoration of a low-value sedge-sphagnum birch stands formed on a peatland drained in 1970. The soil of the site was rich with mesotrophic peat-gley with deposits lying 0,4-0,6 m deep. Five-year-old spruce saplings were planted in strips of 3 and 7 meters wide. The growth of spruce crops was studied by repeated regular measurements using forest management survey practices. Obtained results of the study proved that the actions have been very effective. Productivity of the crops corresponds to the quality class II. No more than 10 % of growing spruce trees have been frost-damaged. After 15 years of growth and onwards the rate of spruce growth in the narrow strips has decreased due to light deficit. Release treatments have yielded a positive effect. The resultant surplus annual volume increment has amounted up to 3 m 3/ha. Statistical treatment of the data shows that in spite of specific site conditions the diameter distribution in the young stands was nearly normal. The coefficient of diameter variation in 30 years old trees was within 30 %.