Spatial dynamics of radial growth and growth efficiency in residual Pinus resinosa following aggregated retention harvesting

Variable retention harvest systems are encouraged to promote complexity in managed forests, and aggregated retention has been suggested as a means of reducing moisture stress in residual trees. We studied the impacts of within-aggregate position on growth and foliar physiology to better understand the spatial dynamics of residual-tree responses to aggregated retention harvests in even-aged Pinus resinosa Ait. stands. Distance from edge and edge aspect influenced radial growth, volume increment, and growth efficiency, but only edge aspect affected foliar nitrogen content. Spatial variables had no significant relationships with foliar carbon isotope ratios (δ13C). Increases in radial growth, volume increment, and growth efficiency following harvesting were greatest near edges and in the northeastern quadrants of aggregates that received mechanical understory release treatments, and lowest in the southeastern quadrant of aggregates and near aggregate centers. Foliar nitrogen content was highest in the southwestern quadrants of aggregates that received understory release treatments, and lowest in the northwestern quadrants of aggregates. Our results suggest spatial relationships are important determinants of residual-tree responses to aggregated retention harvests.