Forest ecotone survey by line intersect sampling

Abstract

Given their ecological relevance, the survey of ecotones is of considerable interest in forest multiresource inventory. To this end, it is useful to set up survey procedures to provide efficient and reliable information about the length of such elements within the landscape mosaic. This note demonstrates a procedure based upon line intersect sampling on remotely sensed imagery. The estimate of ecotone length per unit area is obtained by visual interpretation of the changes from forest to other land use classes along each sampling line. The experimentation carried out in two test areas within forest landscapes of central Italy proves the operative soundness of the proposed procedure, which is more efficient than the classical approach by forest polygon delineation and perimeter mensuration in a GIS environment. Under the examined conditions, samples based on a moderately high number of lines characterized by relatively long length prove to be more efficient than those based on shorter survey units.