Kuliešis, A.A., Kuliešis, A. 2006. Edge Effect on Forest Stand Growth and Development. Baltic Forestry, 12 (2): 158-169

Edge, pre-edge and interior zones were distinguished in the forest compartments of Scotch pine, Norway spruce, Common birch and Common alder stands. The edge zone is located at 10-12 m, pre-edge at 12-27 m distance from the borderline. The most favourable growth conditions for trees at the stage of stand formation are in the pre-edge zone. In the beginning trees are characterized by a faster growth, however, later it approaches the growth of trees in the interior zone. In the edge zone, during stand formation plants suffer from additional competition for sunlight and nutrients on account of the adjacent stand, leading to the formation of sparsely stocked stands with lower and thicker trees. Growing more sparsely, trees later attain higher yield than trees growing in the interior part. The edge zone trees of lower diameter and height ratio form a buffer zone of the stand and increase its stability. The highest differences in the growing stock volume of stands growing in the edge zone and comprising 38-47 m3/ ha at maturity, as compared to the volume of stands growing in the interior part of compartments, were found in Scotch pine and Common alder stands, while the least - 8 m3/ha - in Norway spruce stands. Volumes of trees growing in the pre-edge zone, as compared to the volumes of stands growing in the interior part, remain higher up to maturity in Scotch pine by 3-4, Norway spruce by 1-2, Common birch by 9-10 and in Common alder stands by 1-3 %. Stand yield formation in the edge zone of a compartment is closer to the normal or slowed types, while in the interior and pre-edge parts - to the accelerated or normal types.

Key words:stand zones, differences in tree height, diameter, yield and its formation