The success of reforestation after experimental strip-shelterwood felling in the pine stands of the Eastern Polissia of Ukraine

The article presents the results of experimental strip-shelterwood felling in mature pine stands of the Eastern Polissia of Ukraine, carried out in 2013-2019. The experimental strip-shelterwood felling was carried out in two or three cuts. In the first cut, all the trees within the strip to be cut were designated for felling. The width of the strip with removed trees was equal to the average height of the parent stand (25-30 m). The next strip with removed trees was laid out at a distance equal to 1 or 2 widths of the cut strip. The strips were laid out in meridian or latitudinal directions. Trees growing in the adjacent strip were used for the subsequent following cut of strip-shelterwood felling. After felling carried out in the autumn or spring, natural regeneration was promoted by loosening the soil with disk cultivators or by making furrows with ploughs. During the accounting by the selective statistical method, individuals of natural regeneration of tree species were divided into self-sowing: 1 and 2 years old, advance growth: 3 years old, 4-8 years old, 9-15 years old. Within 3-4 years after the first cut of felling and measures to promote natural forest regeneration, depending on the type of forest, from 5.4 to 32.0 thousand pieces per hectare of Scots pine, from 0.7 to 9.4 thousand pieces per hectare of European oak and other valuable tree species were regenerated. In the latitudinal orientation strips, 1.2–2.5 times more pine advance growth is regenerated compared to the meridional direction of the strips. After felling without the use of promotion measures for natural regeneration, the density of natural pine regeneration is 1.8-7.2 times lower than with soil mineralization. After carrying out the second cut of strip-shelterwood felling with a cutting cycle of 4-5 years and measures to promote natural regeneration for 2-4 years, the density of advance growth and self-sowing of pine in the age group of 4-8 years was 4.2-15.4 thousand pcs. .ha-1 (regeneration success is good and satisfactory). Natural renewal is supplemented by other tree species: by European oak, weeping birch, aspen. A sufficient amount of viable advance growth of Scots pine and other valuable species provides grounds for conducting the third (final) of cut of felling. The cutting cycle period between the second and third cuts of strip-shelterwood felling will be 4-5 years. Mature pine stands with a tree crown length less than 1/3 of their height, with undergrowth density of more than 0.3, with the presence of expansive plants in the living above-ground cover, in which successful natural regeneration of pine does not take place after carrying out of uniform-shelterwood and group-shelterwood felling, should be designated for strip-shelterwood felling. It is expedient to carry out strip-shelterwood felling to reproduce natural stands and conduct Close-to-Nature forestry measures. Strip-shelterwood fellings are carried out in three cuts with the width of removed strips identical to the height of stands (25-30 m). To ensure more successful natural regeneration, the latitudinal direction of the strips should be chosen. Each cut of strip-shelterwood felling and measures to promote the natural regeneration of Scots pine and other species should be carried out in the seed year before the beginning of the opening of the cones. The best way to promote natural regeneration is to make ploughed furrows. The share of soil mineralization should be more than 60% of the plot area. The period of cutting cycles is 4-6 years. In the final cut of felling, it is necessary to ensure the preservation of seed sources, advance growth, mineralization of the soil to promote the natural regeneration of Scots pine and other valuable species.