THE ECOLOGICAL CONDITIONALITY OF TREE VITALITY INDICATORS AND DENDROMETRIC PARAMETERS OF THE WOODY PLANTS COMMUNITY GROWING NATURALLY ON THE DEVASTATED LANDS IN IRON WASTE ROCK DUMP

Abstract

Introduction. Numerous researchers have сonvincingly proven that iron waste rock dumps have a strong and negative impact on the environment in industrial areas. While the tree revegetation is the most efficient, effective and widely accepted way for environmental stabilization of the said post-mining landforms. That’s why the knowledge on relationships between the current state of woody plants community and the harsh environmental conditions on iron waste rock dumps play an important role in pollution control, ecological protection, and safe-guarding human health. Aim. The object of this study was to analyze from the standpoint of an ecosystem approach the ecological conditionality of the current state, tree vitality and dendrometric parameters) of the community of woody plants growing naturally on the devastated lands in iron waste rock dump. Material and Methods. Petrovsky waste rock dump areas at Kryvyi Rih Iron Ore Mining & Metallurgical District (central part of Ukraine) were chosen for the present research. During 2017–2021, the 5 research plots (40*50 m) were established in the dump’s ecosystems and the field data (tree species, tree vitality, mean diameter and height of trees, volume, basal area) were collected through direct enumeration and measurement of all trees in each plot. Pearson and Spearman correlative analysisbetween the indices of the current state of the woody plants community and the parameters of the dump’s environmental conditions (the content of heavy metals in the soil, the time of the community formation, air temperature and soil moisture)was applied. Results. It is shown that in Petrovsky waste rock dump the woody plant species are usually affected by adverse environmental factors and are in the state of stress. Therefore, they lose their ecological stability and phytomeliorative (reclamative/restorative) efficiency. Our calculations confirm that there is a correlation between the content of heavy metals in the dump’s initial soil and indicators of the currentstate of the woody plants community. In this case, 45.5–92.7% Pearson correlation coefficients are significant p < 0.05 (from the theoretically possible ones). The feedback has a slight prevalence – 54.9–66.7% from the number of significant coefficients. The weak and medium relationship prevails – 70–100% from the number of significant coefficients. It is established that there is a correlation between the ecological conditions of the devastated land on the dump and characteristics of the current state of the woody plants community. It should also be noted that 66.7–83.3% Spearman correlation coefficients are significant p < 0.05 (from the theoretically possible ones). The feedback also has a slight prevalence – 55.6–80.0% from the number of significant coefficients. As in the previous case the weak and medium relationship predomanated – 30–70% from the number of significant coefficients. Conclusion. The taxonomic structure, tree vitality and dendrometric parameters of the community of woody plants that grow naturally on in iron waste rock dump have a clear ecological determinism. The most strong correlations were observed betweenthe concentrations of Pb, Zn, Cd, Fe in the dump’s soils, as well as the duration of vegetation formation, the additional soil moisture and indicators of the current state of the woody plants community.