Sanitary state of water-protection pine plantations in the interfluve of Dnieper and Desna

Abstract

The purpose of the study was to establish the sanitary state of pine plantations, identify the causes of the development and spread of diseases and pathogens, develop recommendations for improving the condition and increase the biological stability of pine plantations between the Dnieper and Desna rivers. The studies were carried out in middle-aged, mature and over-mature pine plantations of the Ukrainian interfluve of Dnieper and Desna. The sanitary state of the stands was determined on 52 circular trial plots laid in the forest growing conditions of fresh poor site and fresh rich site. On each trial plot, the index of the sanitary state was calculated according to the generally methodology accepted in forestry. Calculations of the sanitary state index showed that middle-aged plantations are more resistant to biotic and abiotic factors, the dominant number of trees is classified as weakened. In general, the sanitary state index of middle-aged pine forests of fresh poor site and fresh rich site is 2.04 and 1.79, respectively. The mature plantings of fresh poor site with sanitary state index 2.86 are highly weakened, and fresh rich site are weakened, due to the more fertile rich site soil conditions enriched by the biodiversity of the living ground cover. Pine plantations of ІХ and XI age classes, in which the sanitary state index varies between 2.30–2.33, and the percentage of drying and dead trees reaches 10 %, are weakened. It has been established that the most influential factors of a significant deterioration in the sanitary state of mature and over-mature water-protection pine plantations are changes in the hydrological regime of floodplain territories, which leads to tree damage by the mistletoe Austrian and root sponge. In order to prevent the development of these pathogens, it is recommended to create mixed plantations of Scots pine with the introduction of 20–40 % deciduous species, which will simultaneously serve as a fire barrier to the spread of ground fires. Key words: biological stability, state categories, indicator of sanitary state, Austrian mistletoe, roots sponge, dry wood.