I actually wrote this last week, but I changed the date modifiers accordingly.
Last week I went out with a man whose job it is to preserve forest health in Shenandoah National Park. He's a very kind, soft spoken man with a beautiful Virginia accent, who I get the feeling really listens to what people tell him--and whose regular mission includes singlehandedly protecting as many trees in one park as he can. From what, you ask?
Well. A couple of weeks ago I wrote about the Chestnut Blight, an "accidental" from China that decided it loved our chestnut trees so much it essentially "ate" (fungi don't eat as we know it so much as digest, but you get the idea) them all to death. At 25% of the forest, that was no small feat. The chestnut story from a tree man's perspective is over and done, but the onslaught of exotic invasive bugs continues. What we did last week, what Dale does every day in the fall so long as we've had enough rain--is try to save the eastern hemlock.
There is a wooly adelgid (that's a bug in the aphid family, in case that makes it any clearer) that in my lifetime has decimated the hemlock trees of my mountains in a different fashion but similar outcome as the blight in terms of how many trees survive an infestation. (That's essentially none of them.) Scientists have determined that eastern hemlock has "no resistance", and bushwhacking through acres of forest with Dale, dead ones did abound. At only 2% of total mountain forest makeup, you don't see forest-wide effects like we did with the blight. But it is an important 2: often growing along stream banks, where the long coniferous branches shade out 95% of sunlight from falling on the water, making the streams noticeably cooler and having important consequences for temperature-sensitive aquatic ecosystems when the shade is lost.
We also saw a few scattered sick ones, and those are the ones we sought: measuring the diameter, numbering the tree in a book that will eventually go to govn't records of the use of your tax dollars--and getting out our pesticide dispenser. They tried spraying the trees with all kinds of things, with only patchy success and important consequences for the surrounding forest, but Dale assured me that this treatment works, within months.
We make holes in the ground around the tree, and pump in an ounce in each of what is essentially a synthetic nicotine. (Imidacloprid, if you care). The tree will absorb the Imidacloprid and become toxic to adelgids. We treated fifty trees that day, utilizing GPS to tramp through acres of forest that I can assure you start to look alike very quickly with no trail to guide you. I would not reccomend bushwhacking in the Appalachians unless you know what you are doing--and I didn't, but Dale did, because he wasn't the one checking the GPS, yet always led us straight back to his truck. Dale can treat thousands of trees a year, has been doing this for quite a few years, and yes, he can turn all of the data into a GIS graphic for taxpayer scrutinizing pleasure.
The hope is to learn a thing or two from the story of the chestnut, to keep pace with unhealthy and human-accelerated forest changes and keep a hemlock gene pool alive. Perhaps resistance will come with time, or else, like in the case of the gypsy moth, something will be brought in that successfully kills the adelgid without introducing it's own set of unintended consequences.
Every good farmer knows that the war with pests is never really over. The hemlocks are only a recent wave. The next big thing, so I've only recently learned, is the "asian long-horned beetle", poised to do damage to the pretty and tasty sugar maples in New England.
What's interesting about that one is that in preparation "they" have launched a massive public education campation, with TV advertisements and interactive online games! The public education angle is a largely unexplored one. We do have legally-required precautions going on in our trade: we fumegate wood products sent outside of the country to kill any hitchhikers, we have customs officers prohibiting Sally and Jim from bringing seashells from Australia into the US for their personal seashell collections. It is largely impractical to undergo any kind of intense regulation of all organic matter trade in a globally connected world, what we do helps, but it still sometimes only takes one missed shipment.
The long-horned beetle public education campaign is an interesting experiment, because simply transporting firewood is a major spreader of many of these bugs into parks and recreational areas, and the same folks who like to have campfires might feel a strong case for having the places they like to go and build their campfires continue to be conserved. Jim and Sally might not want to add Australian seashells to their collection if they understand they might be releasing the next non-native palm tree fungus into the Palmetto State. I don't know if "beetle busters" will be effective enough, but in different times, different tree species, we've sure tried many other things, so might as well give this a shot.