The role of planted forests in improving the productive capacity and ecological potential of Scots pine boreal forests in the Middle Volga Region

Abstract

Russia’s boreal forests are a major source of timber as well as being a large terrestrial sink for carbon. Planted forests have played an important role in increasing the overall area of the Russian boreal forest. The total area of planted stands in republics and oblasts of the Middle Volga Region is about 3.2 million ha. Scots pine (Pinus sylvestris L.) is the most widespread species in planted forests of the Middle Volga Region. As a result of its mass planting since the 1950s, the proportion of pine forests increased from 21 to 29 %. In order to justify the continued use of artificial regeneration to re-establish forests after harvest, more information is required on the growth and yield of planted and natural Scots pine forests. Therefore, the main objective of this study was to quantify and compare the productivity of planted Scots pine forests with that of natural forests in the Middle Volga Region. Data were obtained from seven representative forests in the republics and oblasts of the Middle Volga Region spanning the period between 1961 and 2007. The relationship between total standing volume and stand age was modelled for both planted and natural stands of Scots pine using the nonlinear Mitscherlich equation. Planted Scots pine forests generally have a higher relative stand density than natural forests, due to the presence of natural regeneration in planted stands. Mean annual volume increment of planted Scots pine forests was 5.6–9.2 m3/ha, which is approximately 15 % greater than the volume increment of natural Scots pine forests. Artificial stands are of high importance for maintenance of resource potential of Russian boreal forests. Mathematical and statistic calculations show benefits of planted Scots pine in comparison with natural pines in height, volume, density, productivity and growing stock increment. The achieved results suggest that wood can be obtained at an earlier age from planted forests thus preserving natural boreal forests.