Gypsy Moth Damage

An old, specimen White Oak killed by Gypsy Moths, June 2019. Cat for scale at base of tree. Note the stacks of firewood in the background from trees that died last summer. 

Eastern Connecticut and adjacent areas have been suffering from a severe Gypsy Moth outbreak for the past few years. The worst of it probably happened in 2017 for a lot of places, but my local area in Mansfield Center experienced patches of total defoliation in the summer of 2018, and now, a year later, it's clear that a lot of trees are goners. Most of these trees had leafed out again after the caterpillars had finished feeding in July 2018, but many trees were apparently weakened, and became infested by wood-boring beetles and probably fungal pests. An unusually hot, humid late summer probably did not help. The foliage on the weakest trees then started turning brown from the top of the crown downwards; trees with these symptoms seem to be mostly dead in 2019, with just a few of them leafing out weakly from lower branches, with dead tops, this summer.

Severe tree mortality, mainly among White Oaks, on a dry gravelly ridge on state park land in Mansfield Center Ct.

Gypsy Moths defoliate just about everything, including pines, during a bad infestation, but they prefer oaks, especially White Oak (Quercus alba). White Oaks account for the majority of the tree deaths in my area, with just a few scattered red oaks and trees of other species having expired. The greatest number of dead trees seem to be on drier, warmer, more exposed sites; I'm not sure if this is just a function of where the densest stands of White Oak were, or if diseases and predators of Gypsy Moths perform better in damper, shadier places.

The view from Coney Rock looking south to Mansfield Center; grey areas are all dead trees. 

Across the region, tens of thousands of acres of forest have suffered significant tree loss during the Gypsy Moth outbreak of recent years. In addition to the immediate and easily quantifiable losses from the cost of dealing with dead trees that are going to become hazards to life and property as they decay, I suspect that there will be essentially permanent ecological effects. The oaks and all of the insects and larger wildlife that depend on them are likely to become less abundant, while Red Maple (Acer rubrum) is going to be much more dominant in the decades to come. Woodpeckers are going to have a very good couple of years with all of the insect-infested standing timber around, but might decline when those dead trees start to disappear, and aren't replaced as they would have been in a normally functioning mature forest.

The ancient "wolf tree" White Oak at Coney Rock in Mansfield: still perfectly healthy this summer.

The Great Gypsy Moth Outbreak of 2016-2018 is, I hope, now finished. The caterpillars are still around here and there in fairly high numbers, but there don't seem to be enough of them anywhere to actually defoliate trees this summer. What is left of the moth population is clearly suffering from a fungal disease (Entomophaga maimaiga) that turns the caterpillars to black mush, and any Gypsy Moth  egg masses that manage to get produced next month are going to be hit hard by a minute parasitoid wasp (Ooencyrtus kuvanae?) that started showing up in large numbers last summer and autumn. I'll be keeping my fingers crossed.