Methodology for Estimating Deer Browsing Impact

Because there were no reliable indicators of deer browsing on tree seedling regeneration, we developed methodology that can be used to measure deer browsing impact. We compared 11 years (2002 to 2012) of annual estimates of deer density with coarse (percent-plots-no-regeneration, percent-plots-no-impact) and fine (3 levels of impact on 6 indicator seedling species) indicators within a 29,642-ha study area in northwestern Pennsylvania. Coarse and fine measures met established criteria for indicators of environmental stress (e.g., high deer density); they were predictive of stresses that can be: avoided by management; integrative with causes of stress; responsive to disturbances and changes over time; and of sufficiently low variability to be significantly responsive to changes in stressors. Time spent and equipment required to collect indicator data were minimal. Data were collected at the same time and on the same plots as deer density data, producing a significant savings of time and capital. Indicators tested had potential as proxies for deer impact on other forest resources.