Analysis of Relations between the Landscape Morphometric Characteristics and Forest Productivity (Using the Example of Leningrad Oblast)

Abstract

An algorithm for determining the correlations between the structural characteristics and productivity of forests and the morphometric characteristics of terrain has been shown using the example of 12 model plots related to 11 different types of landscapes in Leningrad oblast. Geoinformation forestry databases, data from ASTER GDEM survey, and landscape maps have been used for the research. Geoinformation systems have been used to form the spatial datasets, create a grid with a 1-km pitch, and determine the generalized structural and productivity characteristics of the forests (mean stand growing stock, quality classes, rates of the dominating species, and area covered by different forest types and by the dominating species). Automatic landscape classification based on data from the ASTER global digital altitudinal model has been performed using the Iwahashi–Pike method. During the classification, each pixel of the altitudinal model was allotted to one of the eight classes, based on the calculated values of the morphometric characteristics of terrain relief: slope steepness, texture, and convexity. Principal components analysis has been used to determine a set of form classes that explain most of the landscape diversity in model plots. Correlations between the representation of the determined set of landscape classes and some of the productivity and structural characteristics of the forests have been revealed using the rank correlation analysis. A possible explanation for the landscape impact on the formation conditions of forest ecotopes has been provided. Morphometric characteristics used for classification (slope steepness, texture, and convexity) can specify the draining conditions in forest ecotopes and, as a result, influence the productivity and structural characteristics of the forests. The regression correlations between the landform classes and the productivity and structural characteristics of the forests for different landscape levels and landscape types of Leningrad oblast have been revealed. Thus, the results allow one to value the perspectives of further studies in this direction and regard geomorphometry methods as a possible instrument for forest inventory.