On the HJ Andrews Experimental Forest, OR, studies on paired small watersheds compared site productivity for locations with diverse environmental attributes. For study code TP115, Watershed 8 and Watershed 9 were measured in 2003 with a series of 17.82 m radius plots on multiple transects in each watershed. Watershed 8 is an unmanaged small watershed (median elevation 3600 feet) with a dynamic and varied history of fire disturbance. Watershed 9 is lower (median elevation 1750 feet) unmanaged small watershed and has less disturbance apparent in the extant forest. Trees, shrubs, and herbal vegetation were measured. The understory vegetative cover by species and species-specific structural characters were measured in 4 m square quadrats, while the all trees = 5.0 cm DBH were tagged and measured for diameter. Tree crown closure in each plot was measured by ocular estimate. Biomass estimates for each watershed was generated from the plots with equations in Biopak (Means, et al., 1994).
Frederick J. Swanson, Kari B. O'Connell, Mark E. Harmon, Robert J. Pabst
On the HJ Andrews Experimental Forest, OR, studies on paired small watersheds compared site productivity for locations with diverse environmental attributes. For study ID TP115, Watershed 8 and Watershed 9 were measured in 2003 with a series of 17.82 m radius plots on multiple transects in each watershed. Watershed 8 is an unmanaged small watershed (median elevation 3600 feet) with a dynamic and varied history of fire disturbance. Watershed 9 is lower (median elevation 1750 feet) unmanaged small watershed and has less disturbance apparent in the extant forest. Trees, shrubs, and herbal vegetation were measured. The understory vegetative cover by species and species-specific structural characters were measured in 4 m square quadrats, while the all trees = 5.0 cm DBH were tagged and measured for diameter. Tree crown closure in each plot was measured by ocular estimate. Biomass estimates for each watershed was generated from the plots with equations in Biopak (Means, et al., 1994).