COMPREHENSIVE RAPID ASSESSMENT OF THE TECHNOLOGIES FOR FOREST REGENERATION IN THE FORESTS OF GREEN BELT

Abstract

Introduction. To save the pine gene resources of the green belt (suburb of Kazan), foresters of the Republic of Tatarstan introduced various technologies for forest restoration. The goal of the research is to assess the technologies for forest restoration in the green belt by number and live condition of undergrowth and forest plantations under forest crown cover. The considered undergrowth and forest plantations were diagnosed on morphometric and bioelectric indices. Objects and methods of research. Uneven-aged (70–150 years) wild stand of Scots pine with no natural regeneration and with a number of weakened, doted, and overmature trees was studied. At that, the share of weakened, doted, and overmature trees is constantly growing. After selection assessment, researchers of East-European Forest Experiment Station and Suburban forestry farm conducted single tree selective felling and group selective cutting in order to  promote the natural regeneration with  soil mineralization. To get quick assessment of the efficiency of the technology, morphometric and bioelectric indices of mother trees, undergrowth, and forest plantations under forest crown cover were specified. Results. High value of bioelectric potentials ( 185–230 mV) are typical for 70–80-year old stands with quick substance exchange. Overmature and weakened trees have low value of bioelectric potentials (66–100 mV). The undergrowth on the plots of group selection is of better physiological state in comparison with the undergrowth on the plots of single tree selection. In the case of group selection, regeneration with the undergrowth of the best and medium physiological state takes 70,5 %. On the plots of single tree selection, the general share of pine undergrowth of the best and medium physiological state is 33,5 %. The trees of the best state had 180–230 mV bioelectric potential, weakened trees - 60–80 mV. The impedance of precambial complex of tissues of pine undergrowth is better (29,1 ± 0,83 kiloohm) than the impedance of precambial complex of tissues of physiologically weakened trees ( 80–300 kiloohm). Conclusion. A comprehensive assessment of physiological state when selecting mother trees and their undergrowth made it possible to consider the system of group-selective felling with the preliminary selection of mother trees to be better technology for developing the plantations of the local undergrowth and for saving the gene resources and ecological functions of forests in the green belt of the city.