COS 127-2 - Linking forest change to landscape-scale drivers in the Southeastern U.S.

Abstract: Forest managers and planners are tasked with fostering resilient, adaptive ecosystems, yet they are challenged with accounting for how land use and climate change (landscape context) may affect internal forest conditions. The Landscape Drivers of Forest Change (LDFC) project was co-developed by a working group of forest managers, planners, and researchers from the USDA Forest Service and external tribal and non-profit partners in the Southeastern U.S. (SE) to address these stakeholder needs. The LDFC project takes an all-forest-lands approach to provide understanding of the relationships between land use and climate context, forest dynamics, and forest conditions to advance monitoring, planning, and management of forests and their sustainability across the SE. We aim to address: How are forest conditions and forest canopy phenology dynamics related to the variability and change in climate and surrounding land use context?

Our project integrates new and existing remote sensing-based datasets of land use patterns and forest canopy phenology dynamics (using the Landscape Dynamics Assessment tool, LanDAT), with gridded climate data and Forest Inventory and Analysis (FIA) forest condition field data to study 20 years of change. Land use change was quantified as the percentage change in density of forest, natural, agricultural, and developed land use classifications of 39x39 pixel neighborhoods (~1.4km²) for 10 year moving windows. We calculated trends and anomalies in climate variables for 4km² pixels also for 10-year intervals. These landscape context variables were paired with plot level FIA forest condition variables (e.g. stand structure, tree mortality, forest composition) and forest canopy phenology metrics of dynamics (e.g. rate of inter-annual change). We used a multilevel modeling approach to disentangle relationships between landscape context change and variability on forest canopy phenology and plot-level forest conditions. Data were summarized to describe spatial and temporal variability in landscape context and forest dynamics over 20 years at the regional, state, and National Forest (NF) level. Preliminary results show that between 2001 and 2016 forested areas across the SE region experienced a 22% increase in the dominance of developed land. Lands surrounding National Forests within a 3km buffer experienced greater change in land use than within the NF boundary. This change in landscape context corresponded with stronger forest canopy phenology dynamics in the lands surrounding NF than in their interiors. With a focus on science-management integration the LDFC team continues to produce new spatial data products linking forest change to landscape-scale drivers, to support SE forest managers.