Influence of Highly Active Compounds on Mechanical Properties of Wood of Two-Year-Old Scots Pine Seedlings in Forest Nurseries

Abstract

Scots pine (Pinus sylvestris L.) has the leading environment-forming function. Also, the pine is an economically valuable tree species in the Ural region. The long-term use of the pesticide complex in forest nurseries has led to the pesticide pollution of the arable soil, which causes disruption in the pine seedlings growth, weakening their ability to overcome the difficult period of transportation into the forest environment. The use of biostimulants created from extracts of fir and spruce needles, as well as organic ameliorant (forest litter from pinebirch plantations), is considered as a way to reduce the negative impact of pesticides on pine seedlings. At the same time, biologically active preparations and substrates can lead to shifts in the metabolic processes of young plants, which affect the formation of physical characteristics of the stems. The research aims at assessing how wood density changes under the influence of highly active substances of different nature in two-year-old Scots pine seedlings grown in forest nurseries of the Middle Urals. The study objects were two-years-old pine seedlings dug out in autumn from sylvicultural fields and experimental sites in different forest nurseries. Morphometric parameters of seedlings were determined in the laboratory conditions. The basic wood density of stems in the 1st and 2nd years of growth was determined by the method of maximum humidity. It was found that the metabolic activity of pesticides and biostimulants leads to changes in the formation of physical properties of stems at the initial stages of pine growth: when growing seedlings in pesticide-polluted soil, the height of seedlings is lower, and the basic density of stem wood is higher, compared to control group. Forest litter from mixed plantations (birch-pine), when introduced to the forest nursery soil, produces seedlings of greater height and has no significant effect on the formation of physical and mechanical properties of wood. The seed treatment by biostimulants leads to a rapid increase in the stems size, but the wood density decreases, relative to the control option. Corrective measures and the development of balanced agronomic machinery for production of pine with the required physical qualities of wood are needed in the future. The study of the qualitative characteristics formation features of trees, when using intensive technologies in nurseries, is necessary for the development of target models for the subsequent use of such seedlings in forest management.