You are here
Harvard Forest REU Symposium Abstract 2022
- Title: Digging out the Root of the Problem: Understanding Hemlock Tree Mortality through Root Resource Allocation
- Author: Lorelei M Wolf (Harvard University)
- Abstract:
Hemlock woolly adelgid (Adelges tsugae) is a sap-sucking aphid species invasive to the northeastern United States and is decimating the ecologically important late-successional species eastern hemlock (Tsuga canadensis). The range and abundance of non-native herbivores are increasing in response to climate change, and native plants often lack the physiological defenses to survive infestation. Research on the aboveground tree response of eastern hemlock is abundant, but there is a lack of standardized study on belowground root response to infestation. Such research is necessary to document whole tree dynamics and to ultimately understand the mechanisms of tree death due to infestation. This study developed and tested protocols to collect and measure the roots of hemlock saplings and mature trees. We extracted whole saplings and collected square soil cores from four transects around mature trees. In the lab, we separated fine absorptive roots from thicker transport roots. Using the absorptive roots, we measured specific root length (m/g), carbon/nitrogen concentration, fungal colonization density, and starch concentration, comparing measurements across a range of adelgid infestation severity and between saplings and mature trees. We expect that root resource allocation will scale with infestation severity, and that mature trees will be more resource deficient than saplings due to length of infestation. Future studies should consider the use of these protocols to increase replicability and comparability across scales in more comprehensive whole-tree hemlock studies.
- Research Category: Invasive Plants, Pests & Pathogens; Physiological Ecology, Population Dynamics, and Species Interactions; Regional Studies
