Evaluation of disturbance and spatial attribute on regeneration using structural equation modeling (Case study: Khyrud forest- Nowshahr)

Abstract

Effects of anthropogenic disturbances through livestock grazing, wood harvesting, and direct utilization by local people plus spatial heterogeneity on the regeneration of forest tree species and forest health have been recognized worldwide. In this research, effects of disturbances and site features (Aspect, slope percent, altitude, and soil) were investigated on tree species regeneration in Khyrud forest-Nowshahr, north of Iran. Indicators pertaining to saplings, large sapling and trees were measured in 100 plots, 10 m2 each, for disturbance and spatial constructs of Structural Equation Modeling- Partial Least Squares method. Results showed disturbance has a significant (α = 0.01) effect on regeneration. Effects of sapling on large sapling and large sapling on tree constructs were significant (α = 0.01), too. The moderating effect of spatial construct on disturbance to sapling path (α = 0.01) and disturbance to large sapling path (α = 0.05) was significant. We conclude that disturbance and spatial attributes have high influence on sapling and large sapling in the study area, respectively which affect trees indirectly.

Keywords

• Disturbance construct
• forest health
• large sapling
• sapling
• spatial construct