Formation and growth of shelterbelt plantings of Voronezh region
Shelterbelt plantings in the Voronezh region occupy an area of ​​approximately 60 thousand hectares. They were created at different times with tree species: poplars, silver birch, English oak, common and green ash, locust, elm, English field maple and Bosnian maple, little-leaved linden; bushes – Elaeagnus angustifolia, yellow acacia, Tatarian honeysuckle, fly honeysuckle, alder buckthorn and other pure and mixed in composition. Width of the bands, row spacing, and planting density determine their growth and condition. It was found that in artificial linear stands with the main species of silver birch with an increase of double width, there is average decrease of the growth parameters to 12 %. Mixed cultures of birch are more productive and in them by the age of 25 years conservation, average diameter, height is greater for 4, 8…16, 3 % as compared to pure composition forest belts. Silver birch is in a dominant position in the stands with green ash, locust, Norway maple and forest apple trees. European ash has higher inventory indices in cocultivation with English oak and Norway maple than with elm and silver birch. Similar laws are identified also for green ash. For all the considered species active growth period in height and diameter up to the age of 10…15 years is observed. At the same time at middle-aged stands on the main soil types, there are differences in the growth of marginal tree belt and central belts. During this period of growth convex transverse profile is usually formed.