Structural Canopy Recovery of an Urban Woodlot Following Pulse Disturbance Events

We examined the novel vegetative assemblage trajectory of a woodlot within a 235-acre urban brownfield. As our previous work documented the stochastic trajectory of the site’s vegetative guild since 1969 and demonstrated the strong influence of soil metals on forest development, we questioned whether the combined effect of soil stress and the increase in pulse event occurrence and intensity had altered the site’s vegetative assemblage trajectory. Using orthomosaic images, digital elevation mapping, and normalized data vegetation indices, our research assesses shifts in forest productivity and structural changes. These ecological characteristics are then compared to the long-term effects of the site’s total soil metal load and the impact of two pulse events. The decrease in the relationship between soil metal load and canopy productivity was 38% over the course of the study. Canopy surface area and volume increased between 2003 and 2011, then decreased between 2011 and 2014 (volume change above 2 m of 3.14%) due to the pulse events, and then recovered and increased by 2023 (volume change above 2 m of 47.9%). The observed decline in the NDVI–TML association suggests that the apparent influence of the abiotic filter imposed by the soil metals has decreased over time.