Density optimisation of pine plantations in the Left-Bank Steppe in ukraine

Abstract

The paper presents the results of long-term research on different cultivation regimes for planted Scots pine (Pinus sylvestris L.) stands in the experiment initiated by B. Gavrylov in 1932 in the Left-Bank Steppe in Ukraine. The aim of the study is to identify the optimal density of planted pine stands that provides the largest growing stock at the age of 95 years. The study shows that it is possible to form highly productive pine stands by regulating their density within certain limits through their thinning. The results suggest that the intensity of thinning in young pine plantations in the Left-Bank Steppe conditions in Ukraine can vary within a wide range (30–70% of the growing stock). With the increase in the intensity of thinning of pine plantations, the growing stocks do not change significantly, but other stand characteristics, such as average height and average diameter, increase significantly. In young stands, high-intensity thinning creates favourable conditions for the growth of the remaining trees. As the intensity of thinning increases, the number of tending operations in the stand decreases and the operation costs are reduced. Accordingly, the number of interventions in the forest ecosystem decreases. The efficiency of wood mass use increases by decreasing losses from natural decline. The impact of machinery on the environment in such pine stands during harvesting is significantly reduced. Such stands are more resistant to man-caused load as well as to forest pests and diseases. The most rational was the cultivation regime, under which about 1,000 stems·ha−1 were left to the age of 30 for further growth after thinning. At the age of 95, such stands had the largest growing stock and basal area as well as the best health condition.