Dynamics of environmental and biomorphological composition of a grass-shrubs layer when change of birches by culture of scots pine

Kulyasova Oksana Alekseevna, Rybachuk Oksana Vladimirovna

The dynamics of the ecological and biomorphological composition of the grass-shrub layer during the replacement of natural birch forests by ordinary pine crops was studied. It was shown that neutrophilic species dominate in birch forests and on their clear cuts, accounting for 84–86%. With an increase in the age of pine, against the background of an increase in the exchange acidity of the soil, the proportion of acidophilic plants increases (up to 47% in 60-year-old pine trees). Mesotrophic species dominate the grass-shrub layer of all communities, but due to the accumulation of coniferous litter in pine crops 30 years and older, the representation of oligotrophic species increases, reaching 27% in 60-year-old plants. Photophilous species of the longline make up more than 60% in birch forests with a crown density of 65%, increase the number to 74% in clearings, and, as the crowns close, pine crops reduce their participation in the longline to 36%. In birch forests, 53% of the species of grass cover are vegetatively mobile, among them biomorph of long-rhizome plants predominates. In pine crops, the leading position is retained by a group of vegetatively mobile plants, where with the age of the pine, the representation of biomorphs of root-laying species of grasses and shrubs increases.

Keywords:Ecological groups of plants; biomorphs; birch forests; Scots pine culture; northern forest-steppe