APPROACHES TO DEVELOPING THE MIXTURE PATTERNS FOR MANAGED FORESTS WITH CRIMEAN PINE IN THE FOREST-STEPPE ZONE OF EUROPEAN RUSSIA (VORONEZH OBLAST)

Abstract

Crimean pine (Pinus nigra subsp. pallasiana (Lamb.) Holmboe (1914)) is different from Scots pine (Pinus sylvestris L.) in its ecological characteristics, which becomes evident under the conditions of the forest-steppe zone of European Russia, where it is being in troduced. So far, the patterns of growth and development of Crimean pine stands mixed with Scots pine have not yet been thoroughly studied. The main goal of this research is to study the interrelations between Crimean pine and Scots pine in the forest-steppe zone of European Russia (in Voronezh Oblast), to develop a methodology and prepare proposals for the creation of such forest plantations. The results have brought us to the following conclusions: 1) the illumination factor linked to the geographic latitude implies that stands should be created with view to high canopy density, early canopy closure, and formation of a multi-storeyed forest. In the forest-steppe zone, Scots pine should be mixed with Crimean pine at an initial density of 6.7 thousand seedlings per hectare (2×0.75 m) and 2 rows of Crimean pine should be alternating with one row of Scots pine (planting direction – west to east); 2) in non-forest areas in the forest-steppe zone it is also advisable to use an arrangement where species alternate within rows in groups of several trees, while retaining the initial density; 3) in areas south of the forest-steppe zone, in order to increase the biological stability of coniferous forests, 2 rows of Crimean pine can be placed closer, up to 1.5 m, while retaining the distance of 3 m from the Scots pine row.