New Grant: Gypsy Moth, Carbon Storage, and Tree Mortality

A Harvard Forest-led research team has received a $99,000 Rapid Response Research grant from the National Science Foundation to study the factors underlying widespread oak tree mortality across southern New England in the wake of an ongoing, multi-year outbreak of invasive gypsy moth. 

It has been more than thirty years since gypsy moth has caused such a high level of tree defoliation and mortality in eastern North America. Not all trees have succumbed during the 4-year outbreak, however, leading the research team to question what actually controls tree mortality during a major defoliation event.

In spring, trees create new leaves by drawing on stored starches and sugars. When caterpillars defoliate a tree several years in a row, the research team posits, the tree may become resource-starved. Their research proposasl asks: is there a critical threshold of resource (carbon) starvation beyond which a tree cannot recover?

To answer this question, the researchers established a network of plots in oak forests that experienced differing severities of gypsy moth activity in 2018. This year, they are collecting small wood samples from the stems and roots of oak trees in those plots, to study the relationship between stored carbon resources and tree mortality.

The research team is made up of several Harvard Forest senior scientists - Jonathan Thompson, Audrey Barker Plotkin, and David Orwig - with HF research assisant Danelle LaFlower, Harvard University graduate student Meghan Blumstein, and UMass-Amherst professor Joseph Elkinton.