Identifying Restoration Opportunities for Northern White Cedar by Contrasting Historical and Modern Inventories in an Ecological Classification System Context

Abstract

We propose an approach toward identifying restoration opportunities on the landscape using historical Public Land Survey (PLS) data and modern Forest Inventory and Analysis (FIA) data within an ecological classification system (ECS) context, and demonstrate this approach for northern white cedar (Thuja occidentalis) in Minnesota, U.S.A. Concern over long-term declines in the abundance of northern white cedar, particularly in younger (<40 yr) upland stands, has spurred interest in northern white cedar restoration in the Lake States region. Comparing historical PLS and modern FIA data revealed a decline in long-term northern white cedar area by 45% due to land use conversion and species shifts in extant forests in Minnesota. Changes in extent and relative abundance varied by ECS land type association (LTA): decreases occurred predominantly in mixed species stands and upland northern white cedar communities, while increases occurred in monotypic stands and lowland northern white cedar communities. We suggest that this landscape variation can guide adaptive management and restoration by focusing adaptive management on LTAs in which northern white cedar has fared well, and restoration on LTAs in which northern white cedar has dramatically declined. Where the data are available, this ECS_PLS-FIA approach could facilitate the prioritization of potential restoration candidate areas by revealing population dynamics in a temporal context that match the life span of the species of interest.