# Hemlock Blight



## Prof (Jun 27, 2012)

Here in PA the hemlock blight (Woolly Adelgid) is destroying hemlocks by the acre. My wife and I are planning on building a house on 15 acres that is primarily located in a hemlock forest. The Woolly Adelgid has no natural predators outside of Asia and the northeast, sprays and the like are not suited for woodland application, and the only reasonable option seems to be a predator beetle from Japan that is currently not available to private landowners. It has been in the past, but private labs have been closed and the government/university labs only release beetles on state lands. So as you can imagine, I'm in quite a bind. Though it would seem that I have a vast supply of potential firewood, I'd rather not see my property go from being a beautiful hemlock forest to scrubby open land. Any ideas?


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## semipro (Jun 28, 2012)

That's a shame.  I love hemlocks.  We're having the same problems with the blight in VA. 
Could you contact one of the universities doing beetle research to see if they'd like to use your property as a test site? 
In many cases researchers are looking for good, well defined properties like yours where they can apply their treatments and gauge results without confounding influences from outside factors.


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## billb3 (Jun 28, 2012)

I have about 30  45 year old planted hemlocks (privacy hedges along the road ) that were infested pretty bad. Treated with the Bayer stuff you pour in the ground around them. I'm impressed with how well it worked and I tried one half the recommended rate. (2 years ago) . Weird thing - the ones that grow wild in the woods  and some of those that were planted 50 years ago as a hedge but are now in the woods  don't appear to be infected at all. 

There was about a half acre here that was all hemlock and under them (they were old) would be the coolest place in the woods on a hot Summer day. Lost every single one of them in the drought of 66/67.


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## firebroad (Jul 2, 2012)

Forgive my ignorance, as I am not familiar with this one, but can you replace them with a species that is immune?  You could plant seedlings (very cheap from ArborDay Foundtation) as the hemlocks are removed.  I know it is not a perfect solution,  just a thought.


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## sesmith (Jul 5, 2012)

Prof said:


> Here in PA the hemlock blight (Woolly Adelgid) is destroying hemlocks by the acre. My wife and I are planning on building a house on 15 acres that is primarily located in a hemlock forest. The Woolly Adelgid has no natural predators outside of Asia and the northeast, sprays and the like are not suited for woodland application, and the only reasonable option seems to be a predator beetle from Japan that is currently not available to private landowners. It has been in the past, but private labs have been closed and the government/university labs only release beetles on state lands. So as you can imagine, I'm in quite a bind. Though it would seem that I have a vast supply of potential firewood, I'd rather not see my property go from being a beautiful hemlock forest to scrubby open land. Any ideas?


 

Unfortunately, I'm afraid that you will have to develop some sort of management plan that assumes that the hemlocks will be lost. You may want to contact an independent consulting forester (ie, not a lumber mill) and work out a long term management plan for the property. This might include cutting out some of the hemlock, if there is any market for it in your area, before it is lost and trying to regenerate something to replace it. It's a pretty depressing scenario where this bug has taken hold. FWIW, the dead trees have wildlife value, and something else will grow in time, but this may take more time than you want or have. Is there anything of value in the understory that can be released if some of the hemlock is cut out to give it light? You might want to do some selective cutting to encourage other things to grow.  You could also treat some of the hemlocks that are most important to you with insecticide even though it's not possible to do the whole wood lot.


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## Wood Duck (Jul 6, 2012)

I would try an approach that includes treating some of the most important hemlocks, while also planning on losing many of the hemlocks. There is a treatment that goes on the ground that works, but it would be very expensive to treat a large area. I'd plan to treat the best trees around the house, and maybe a few of the really large ones throughout the property, but not try to treat everything unless you have lots of money. In every hemlock forest I have seen there are other trees in the forest that will fill in the space left when hemlocks die. Often these other trees are actually quite tall but hard to see among the hemlocks. Hopefully you have enough large trees of other species that your forest will recover quickly. I think some of the hemlocks will survive the adelgid - at least here in central PA it seems like some make it through the initial die-off. I would be very careful about having a commercial logger harvest any trees. Commercial loggers can really trash the woods and do more damage than you would want in the forest surrounding your house. If you have lots of trees to fell maybe find a small outfit that will fell the trees for a fee without using too much heavy equipment to remove the wood. Maybe you can just have the trees felled and move the wood yourself using small equipment like a four-wheeler and a trailer; you'll do a lot less damage than a bulldozer would.

There really aren't a lot of native alternatives to Eastern Hemlock, and I would not want to plant my woods with non-native trees. Invasive plants are as big a problem as invasive insects like the Hemlock Wooly Adelgid. Don't count on the Arbor Day Foundation to provide responsible recommendations for tree species, since they seem to sell every invasive species I can think of (except Ailanthus). If you want to plant a replacement for Hemlock, maybe a spruce like Red Spruce or White Spruce would grow well on your site. Non-native Norway Spruce is easy to find and doesn't seem to be invasive in western PA.

I hope that like the Gypsy Moth the Hemlock Wooly Adelgid invasion will eventually peak and begin to wane, and when that happens not all of the Eastern Hemlocks will be gone. If hemlocks can survive  long enough eventually predators for the adelgid will become established here, or disease will develop, or whatever other natural control controls them in Asia will eventually control them here. There is no doubt that lots of beautiful hemlock forests will be destroyed by this bug, but hopefully the Hemlock will survive as a species and eventually begin to re-establish itself. I am trying to think of an example of an invasive insect that has passes its peak abundance, and I cannot think of one right now, but the Dutch Elm Disease has reached most areas and although it has killed and is still killing a lot of Elms there are still many nice big elms in most areas where elm historically grew. unfortunately Elms Yellows disease is not killing a lot of the trees that were left behind, but that is a different disease than Dutch Elm. You'd think that eventually we will stop introducing new diseases and insects. I hope the Eastern Hemlock doesn't end up like the American Chestnut tree, which is almost extinct.


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## Prof (Jul 6, 2012)

Thanks for the replies--over the past week or so I've come up with a strategy. I'm working to get the ball rolling on a forest management plan--may even be able to get some federal money to help with the plan and managing the timber stand. Still considering introducing a predatory beetle. Probably going to stay away from chemical treatment--I eat a lot of stuff that grows/lives in the woods. In general, I'm going to plan for the worst and hope for something other than the worst (I'm too much of a realist to hope for the best).


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## osagebow (Jul 15, 2012)

Good luck, keep us posted.


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