Estimation of the relation of NDVI steppe vegetation and radial growth of pine belt forests in arid conditions of the south of Western Siberia

Abstract

This article presents a spatial-temporal analysis of the NDVI vegetation series (based on the MODIS satellite data) and dendrochronological data obtained for the steppe regions of the Altai Territory. NDVI series are built for five polygons of natural and natural-anthropogenic steppe landscapes for the period 2000–2018. Experimental areas of natural landscapes are located in coastal and specially protected natural areas, natural and anthropogenic arable lands. Most of the points are located in the dry-steppe sub-provinces of the steppe zonal area, a smaller part is in the arid-steppe (including the dendrochronological area). The chronology of the tree ring width is built for the Scots pine in the steppe part of extrazonal belt pine forests. A positive trend in vegetation indices change and a weak positive trend for the tree-ring chronology of the pine were found for the NDVI series of almost all polygons for the study period. A more pronounced positive trend is characteristic of the area with the lowest average NDVI values, while a negative trend is characteristic of the area with the highest average values of the vegetation index. The correlation of the NDVI series averaged over polygons with each other ranged from 0.54 to 0.64 (significant at p < 0.05). The dependence of the analyzed series on the dynamics of moistening of the territory was revealed. The correlation coefficients of the Selyaninov hydrothermal coefficient with the NDVI series ranged from 0.51 to 0.76, and with the tree-ring chronology was 0.63 (significant at p < 0.05). A statistically significant relationship was established for some points between the chronology of the pine and the NDVI series, mostly related to dry steppe vegetation.