The present study investigates some sampling strategies for the estimation of abundance and canopy cover of trees outside forest (TOF) over large areas. A collection of about 53 000 TOF units in Central Italy was acquired by visual, on-screen interpretation of aerial orthophotos and was taken as the reference population with the purpose of investigating: (i) one-phase inventories withsample points located bymeans of the tessellation stratiﬁedsampling (TSS), which involves covering the study region by a grid of regular polygons of equal sizes and randomly and independently selecting a point in each of them; (ii) two-phase inventories with the one-per-stratum stratiﬁed sampling adopted in the second phase to select a sample of polygonsfrom the grid and then visit only the points contained in those polygons.Uniformrandomsampling is also considered in the ﬁrst phase as a benchmark for tessellation stratiﬁed sampling. The sampling schemes adopted to select TOF units at the sample points are as follows: (i) pointsampling, (ii) centroid-based plotsampling with plot radius of 50m (CPLS50) or 100m, and (iii) plot intersect sampling with plot radius of 50 or 100 m. CPLS50 under single-phase TSS proves to be a promising strategy to large-scale TOF inventories.
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1139/cjfr-2016-0013|
|Codice identificativo ISI:||WOS:000386675600002|
|Codice identificativo Scopus:||2-s2.0-84992323193|
|Titolo:||Checking the performance of point and plot sampling on aerial photoimagery of a large-scale population of trees outside forests|
|Appare nelle tipologie:||1.1 Articolo in rivista|