A Followup on Beech and other Threatened Native Trees

Having grown despondent about the devastating toll beech leaf disease will likely take on Princeton's beech trees, I was surprised and somewhat heartened by what I found on the Princeton University campus. 

A friend from childhood was visiting me for the first time, and as I showed him and his wife around campus, I began to feel as if we had somehow been transported back to an era before introduced pathogens and insects had marginalized many of our native trees.

An American white ash towered over us, healthy as can be. American elms, too, grew as if Dutch elm disease had never arrived.

Unlike the ailing beech trees up along the Princeton ridge, the beeches on campus appeared unfazed by beech leaf disease.

I looked for signs that these trees had been injected with chemicals to ward off invasion, but found none. Surely, though, this improbable survival depends heavily on medicinal intervention.

Since I first alerting the community to the presence of beech leaf disease in Princeton in a blog post and letter to the editor, some articles have been written in the local press--one in TapInto Princeton and one in Town Topics. 

Both mention phosphites as the primary treatment available thus far. Applied to the soil, phosphites are a biostimulant that improves the tree's immune system response. I was skeptical that this could make much of a difference, but the University appears to be having good results. Grounds supervisor EJ May said they started seeing signs of beech leaf disease two years ago. Speaking generally about efforts to save native trees, he acknowledged some losses but some success as well.  

Another lead I had checked out was a kind of beech mentioned in a list of special campus trees.  Called a fern-leaved beech (Fagus sylvatica 'Asplenifolia')--a variety of European beech with unusual foliage--the university had gone to great lengths to save this extraordinary specimen during construction of the new chemistry building. The tree's described online as having "no serious insect or disease problems." Was the text written before beech leaf disease was discovered in 2012, or might this variety have some sort of natural immunity? I stopped by to take a look, and could find no visible symptoms. 

There remains, too, an uncertainty as to the origin of the nematode that causes beech leaf disease. It is most similar to a species found in Japan, but differs in some ways.