Stand Dynamics and Structure of Two Primary Champlain Valley Clayplain Forests, Vermont

Understanding natural forest dynamics is critical for informing forest restoration and conservation efforts. However, such information is often difficult to generate for areas that have a long history of intense land use, such as the Champlain Valley of Vermont. We used dendroecological methods and assessments of forest structural conditions to describe the tree recruitment history and structural dynamics of 2 examples of valley clayplain forest, a rare natural community that has been drastically reduced in extent by agricultural land use in the Champlain Valley. Although historic selective harvesting had occurred in the areas sampled, these sites represent the best remaining examples of semi-natural valley clayplain forests in the region, thus providing an opportunity to document long-term patterns of structural and compositional conditions and tree recruitment in areas with limited land-use. Age structures in these 2 areas were strongly uneven-aged, with older cohorts composed of Quercus alba (White Oak), including an individual dating to the 1640s, and recruitment over the past 2 centuries dominated by Tsuga canadensis (Eastern Hemlock). Size distributions of live trees also reflected these patterns of recruitment, with White Oak occurring exclusively in larger diameter classes (>35 cm) and Eastern Hemlock predominating across all smaller size classes. We observed sparse regeneration of Quercus spp. (oaks) in these areas, suggesting that this historically important component of valley clayplain forests may disappear over time in the absence of large, stand-scale natural disturbances or management activities focused on the perpetuation of this species group.