Regional risks of artificial forestation in the steppe zone of Kazakhstan (case study of the green belt of Astana)

Abstract

This article deals with results of research on artificial forest in a green zone around the city of Astana. The authors of the article established temporary sample plots where condition, capacity for survival, and growth of trees were observed by standard techniques adapted to conditions of the forest-steppe subzone of Northern Kazakhstan. The reasons for the unsatisfactory condition of the planted forest were found and recommendations on improvement were made. The conclusion was drawn that to establish forest plantations it is necessary to select such species of trees and shrubs that will be resistant in specific conditions to the negative factors of urban lands. A possibility of replanting adult trees to intensify reforestation was also studied. The authors analyzed the dynamics of Silver birch preservation in 2011-2017. The Mann-Whitney-Wilcoxon U test was used to prove the presence of differences between the types of trees’ average preservations. Based on the data thus obtained, it was concluded that the forest plantations created by the different methods differed significantly in terms of the preservation rate, as well as in the heights and diameters of the trees. Forecasts of tree preservations in 2018 were made using moving average and linear regression methods. The best forecasts were chosen in terms of the mean relative absolute error of approximation. The results confirmed an initial hypothesis predicting significant differences between the methods used for artificial reforestation: the non-replanted trees are expected to have the highest rate of preservation, whereas the trees replanted to a low location, the lowest preservation rate. The prediction of the preservation rate of forest plantations of Silver birch created by the different methods will allow reducing the risks when conducting forestry activities on artificial reforestation. Regional features must be taken into account in the development of recommendations for a comprehensive system of measures which are based on the scientific forestry techniques to ensure optimum reforestation.