Monday, December 21, 2015

Hemlocks--still here but under assault

Holiday preparations clearly are affecting both my writing and photographic time this week.  I love Christmas, but I am ready for the event itself and for the preparations for the event to end.  I hope that once the holiday is over, my days will return to normal, so I can spend more time writing and taking photos again.
The photo today was not taken at my cabin but in Michaux State Forest.  This is, I believe, a little feeder stream into Tom’s Run.  It’s already been a week since I was there and I’m only now downloading the photos.  One thing I noticed on my walk that day was that live hemlocks, Pennsylvania’s state tree, can still be found in abundance.
The state’s trees are under assault by something called the wooly adelgid, which sucks fluid from the base of the hemlock needles, eventually killing the tree.  They look a lot like wooly aphids that can infect houseplants.  Like so many other devastating pests, this one is not native to North America.  It came from Japan, and our native hemlocks have no immunity against it.  And like wooly aphids, the pest can be killed with a soap/oil mixture.  Unfortunately, the preventative needs to be applied at least once a year, not to mention just how does one spray all the hemlock trees in a forest? 
Currently, the pest is found in 56 of Pennsylvania’s 67 counties.  They can kill a tree in 4-10 years without treatment.  The state is moving ahead with the soap/oil treatment and is apparently thinking about introducing a beetle that can kill the adelgid.  This worries me, as I can only hope the beetle doesn’t end up causing other problems, as so often happens.  The beetles are expensive, too, I’m told.
The hemlock is a foundation tree in our forests. A healthy tree supports many other animal and insect species.  Clearly, a forest without hemlocks would not support the same species as a forest with hemlocks.  A forest without hemlocks would be an entirely different ecosystem. 
On my walk, I did see some dead hemlocks—most looked to have been dead for years and may well not have died from this pest.  The other hemlocks I saw still appeared healthy, at least for the moment. I hope they stay healthy.  I can’t imagine a Pennsylvania forest without them. 


Pablo said...

chestnuts, elms, now hemlocks. Bananas soon. Dogwoods under threat.

Holiday cheer!

Scott said...

We have some high-and-dry hemlocks planted near our parking lot. They had adelgids, and we treated them many years ago with a systemic insecticide via a soil soak. The adelgids disappeared, the trees are healthy, and the insects have not returned.

Carolyn H said...

Scott: I think the local forest people are trying to stay with a natural hemlock insecticide for the adelgids--the soap mixture--but also one that is cost effective for the whole forest. I'm glad to hear the bugs haven't returned to your trees, and I sure hope it stays that way!

Carolyn H said...

Pablo: I guess the changes wrought by man and modern transportation just never end. I sure hope we can win the war against hemlocks and dogwood. I'd miss bananas, too. I keep hoping they find a strain of disease resistant chestnut and elms. A few years ago there was some promise with the chestnuts, but I haven't heard anything since, so perhaps that didn't pan out, after all.