Monitoring change in the spatial heterogeneity of vegetation cover in an African savanna

Potential utility of the spectral red-edge region of SumbandilaSat imagery for assessing indigenous forest structure and health

“…The variogram analyses of SumbandilaSat and SPOT NDVIs have shown variability in the range values in areas with different levels of forest fragmentation. The range parameter increases with forest fragmentation, corroborating results of other studies (Garrigues et al, 2006;Murwira and Skidmore, 2006). The variograms for the intact forest patches increased promptly and reached the sills at shorter ranges when compared to the variograms for the disturbed forest patches for both the SumbandilaSat and SPOT.…”

Mapping beech (Fagus sylvatica L.) forest structure with airborne hyperspectral imagery

“…Spatial heterogeneity of a given surface property (mean DBH in our case) can be described using the spatial variability of the surface property over the observed scene (Garrigues et al, 2006). Several statistical tools have been used to explore image spatial variation including semivariogram and wavelet transform (Garrigues et al, 2006;Murwira and Skidmore, 2006). The characterisation of spatial heterogeneity using semivariograms involves hypothesis of stationarity (Jongman et al, 1995;Garrigues et al, 2006).…”

Assessment of SPOT 5 and QuickBird remotely sensed imagery for mapping tree cover in savannas

“…These studies have generally used vegetation indices, such as leaf area index (LAI) or the normalised difference vegetation index (NDVI) to examine broad patterns in landscape heterogeneity (Riera et al, 1998). These sensors, with the added advantage of relatively high return periods and lower cost, are also commonly used to examine temporal patterns in vegetation (Murwira and Skidmore, 2006;Archibald and Scholes, 2007). However, these sensors can only provide proportional estimates of woody cover and cannot be used for analyzing tree cluster patterns.…”