Edge Effect in Pine Stands in the Northern Taiga

The studies are carried out in pine stands situated on the forest boundaries, which are in between the open space locations and forest growth areas. The investigations were made on the territory of the Kholmogorskiy and Primorskiy districts in the Arkhangelsk region. The purpose of the research is to identify the characteristics of meteorological factors at different distances from the edge of phytocenosis as well as their influence on the undergrowth and ground vegetation in the ecotone zone. For this purpose, the vegetation, which grew on the transects at different distances from the edge of the phytocenosis, is described in layers. The transects were positioned perpendicular to the forest boundary. The following parameters were described and measured, such as undergrowth, ground vegetation, luminance, air temperature, wind speed, air humidity. The taxation of the stand was accomplished by using relascopic circular platforms. It is found that luminance, air temperature, and wind speed naturally decrease with distance from the edge of the phytocenosis deeper into the forest. The decrease in luminance can be revealed to 8 m, temperature to 8-15 m, wind speed to 30 m. However, air humidity increases up to 8 m. A correlation between meteorological factors and the distance from the edge of the phytocenosis is determined. The distribution of the undergrowth according to the edges of phytocenosis has a consistent pattern. The undergrowth of heliophytes of pine, birch, and aspen is most abundant at the edge of phytocenoses, and their numbers decrease with distance from the edge. The undergrowth of sciophytes either increases or its quantity does not change. Such distributions are confirmed by correlation analysis. The resulting figures are rated as significant or high. They are reliable at the significance level of 0.05. The number of plants in the grass-shrub tier decreases with the distance deep into the forest. Any define conclusion can't be made regarding the moss-lichen tier. In general, it can be concluded that the size of the ecotone zone in terms of meteorological factors and indicators of vegetation is 12-14 m.