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Tuesday, August 21, 2012

America's Long Lost Trees

   We Americans, speaking generally, are a clever collection of people. We've accomplished so much. Yet wisdom, unlike ingenuity, seems to be a bit harder to come by. There aren't many things we can't do when we set our collective minds to the task. But sometimes, frustratingly, we tend to make the same kinds of mistakes repeatedly.

When it comes to stewardship of our natural environment, we often mean well, yet we can't seem to put the brakes on our tendency to "manage" it to the point where "the operation was a success, but the patient died." Like Charlie Swindell, the mythical financial advisor who "helps people with their money till there's none left", we keep trying to undo one biological disaster by introducing another potential one in the hope that it will fix the problem.

1 - American Chestnut Leaves
What am I referring to? Well, what I have in mind is the fact that we purposely or inadvertently introduce non-native species and pathogens into our surroundings that have an unexpected devastating effect on species that do "belong here."  Or, we alter an environment to our advantage, only to learn that our actions were a mistake; sometimes the cure is worse than the ill, and we must make greater and greater efforts to undo the cascade of harm.

This scenario is all too common. We introduce a plant or animal to control or eradicate another. Or we import a species for its benefits, often to discover, to our dismay, that it has pernicious characteristics.

But there's an effort underway now that does show promise, and hopefully will have a happy ending in reversing previous damage, without causing any further harm. Specifically, I'm talking in this instance about the American Chestnut tree, and the attempt to bring it back from virtual mass extinction.

What happened:

More than a century ago, around 1900, we unknowingly imported a fungus from China or Japan. It arrived here on Chestnut lumber or trees, and was discovered on Long Island. The Asian Chestnut trees were resistant to the fungus, having evolved with it, but our American Chestnut was not; it was completely and utterly vulnerable. In a mere three decades or so, the tree that had comprised up to 25% of our eastern hardwood forests was essentially gone! What had been an unimaginable population of some 4 billion trees was almost entirely devastated by the quickly spreading disease. Above-ground growth is killed, but the root systems persist (luckily), at least for a while.

The American Chestnut had been the predominant hardwood tree species in the eastern forest, particularly in the Appalachians. It reportedly attained trunk diameters in the 12-foot range and beyond, and heights of 150 feet; typical diameters and heights were well below those numbers. It has been largely replaced over time by various oak species (which may now be facing a threat of their own... Sudden Oak Death disease). Nut crops were huge, providing food for man and animal. The lumber it supplied was legendary in the building of America; for hundreds of years, house and barn frames were typically built of chestnut timbers. So were railroads.
2 - Chestnut Blight Blisters

The fungus enters the bark through wounds or other openings, and grows into the cambium layer, which finally kills the tree's above-ground tissues. A canker infection can be seen on the bark of infected trees; the first visible signs will be orange-colored blisters (photo 2).

 The root system often has a little more resistance to the fungus, so it repeatedly sends up new shoots around the stump. However, those quickly die off as well. Sometimes they grow long enough to produce a few nuts, but that's rare. The root systems gradually lose vigor due to the lack of above-ground growth (which, through photosynthesis, produces food for the tree's growth), and eventually die off.

3 - Dead Chestnut Stem w/ New Sprout




The Chestnut in Today's Forests: 


A walk in the forest where Chestnuts historically occurred will very often reveal clumps of Chestnut struggling to hang on. Typically, at least here in New England, you will see a small diameter, short, dead trunk, surrounded by several whips of new root sprouts. The dead trunk will usually be about 1 to 4 inches in diameter (occasionally up to 7 inches), perhaps 12 feet tall. It will be a silvery gray color, without bark.

Photo 4 shows a typical Chestnut clump of today; a dead main shoot or two, with one or more new young ones sprouting from the rootstock. Chestnut wood is very rot resistant, so the dead snags persist for many years. The new shoots will have typical Chestnut foliage, which usually stays attached to the stem through the winter; that's probably the easiest time of year to locate Chestnuts... just look for the brown leaves still on the twigs (they can be confused with American Beech trees, which also retain some of their leaves in winter).
4 - Typical Chestnut of Today

Because of Chestnut's highly rot resistant wood, dead giants of the past stood for a long time. When they did eventually fall over, they persisted on the forest floor for decades, very slowly fading to dust. Today, I still find their remnant hulks on the forest floor. Although they died nearly a century ago, to the experienced eye they can often be immediately recognizable. The wood weathers in a particular way, leaving long, parallel fissures along the length of the silver-gray trunk and limbs. Sections that are still elevated off the ground are especially long lasting.

5 - Rotting Chestnut Log

6 - Chestnut Upper Trunk
Photo 5 shows such a log, looking from the butt end toward the upper branches. That long mound of brown material is what's left of the rotted trunk. But notice that at the far end, some limbs remain, because they've not been in contact with the soil as long; while the trunk was still intact, it kept them elevated. Now that it's gone, the limbs are on the ground and will rot more quickly.

Here in western Massachusetts, these old relics tend to be found on drier hillsides and ridges. I'm sure most people pass by them totally unaware of what they are.

8 - Parallel Weathered Furrows
9 - Limb Crotch Section
10 - Trunk, Branch and Collar
7 - Limb and Trunk Intersection

Still Graceful and Beautiful:

Click on the photos to enlarge.

While the small, resprouting shoots are very commonly found, the resting remains of larger fallen specimens are not all that easy to find in New England.

Photos 6 through 10 are what to look for if you'd like to find some Chestnut. Notice in particular how the weathered wood is deeply eroded longitudinally, leaving parallel ridges of gray wood. That's very characteristic of Chestnut.

Usually, these remains are hollow, so there's no significant amount of usable wood left (at least in the acidic New England forests), just thin shells of trunk and limb. On occasion though, I've found pieces large enough to make rustic vases. Since these trees were killed off some 80 or more years ago, their remains have persisted that long. Quite often, only a small amount of limb material is left, and may not earn a second glance. But sometimes you'll find a long section of trunk, invariably hollowed,  and typically collapsed down on itself.

I find many of these hulks to be quite beautiful in their final glory, seemingly pleading with eloquence and grace to be remembered...

The Chestnut is Not Forgotten:

Fortunately, there are a lot of Americans who feel as strongly about the loss of Chestnuts as I do, and they're actually doing something about it.

The American Chestnut Foundation (TACF) is an organization that is working to restore the American Chestnut to its former status in our forests.

Through a program of hybridization, volunteers across the country are succeeding in breeding blight resistance into the trees. The time-consuming process begins by crossing blight resistant Chinese Chestnuts with American Chestnuts. The goal is to introduce the blight resistance genes of the Chinese trees into the American. But they also don't want to lose the genetic makeup that defines the American version, so they back-cross generations of resultant trees to remove Chinese traits, except the blight resistance. It's a very time-consuming process, taking years to produce a resistant tree that's almost entirely American Chestnut.

After 28 years of effort, TACF now has some potentially blight-resistant Chestnut seeds that you can buy (with membership in TACF) and plant, to become part of the experiment.

Once you find some of these beautiful old relics in the woods, and you take the time to give them a close look to appreciate their lasting beauty, you may be moved to plant one of your own.

In Conclusion: 

This story is not over. It remains to be seen whether or not the American Chestnut will be restored. Probably no one reading this today will live long enough to see a mature specimen. But there's hope, and things look promising. A lot of dedicated and knowledgeable people are working hard on the project. Thank you to all who are.

What's still disturbing is that so many of our tree species (not to mention animal and other plant species) are facing the same possible and actual decline.

Elms are falling rapidly to Dutch Elm disease, and are largely gone.

Hemlocks are disappearing due to the Wooly Adelgid insect.

 Ash trees are facing the Emerald Ash borer disaster.

 The Asian longhorned beetle is causing massive problems (the city of Worcester, MA, had to cut down and destroy thousands of trees to try to contain the spread of the beetle).

Oak species (and a long list of other plants, including rhododendrons, azaleas, maples, Sequoia, blueberry, beech, etc, etc, etc) are susceptible to Sudden Oak Death. First found in California, it's already been trucked to the east coast. Northern Red Oak, a hugely important species that largely replaced Chestnut, is potentially threatened.

That's just a partial list, a very shortened list. Many municipalities have banned the transport of wood into their jurisdictions, in an attempt to prevent the spread of destructive organisms. In some areas, boaters must wash their boats before putting them in certain bodies of water, to remove insidious organisms. We keep hearing of biological pests being introduced to this country from cargo ships, pallets, etc.

So, while we've become much more aware of these problems, they continue. Our globalized commerce is accelerating the spread of exotic organisms, and is already having major ecological effects. Pythons in the Everglades. Zebra mussels in the Great Lakes. Killer bees in the South. Kudzu vine. And so much more.

My hope is that the efforts to restore the American Chestnut tree will be a success. Not just in the sense that the trees will be out there again, but also in the sense that there won't be unintended ill effects.

I wish I could live long enough to take a snooze on a glorious autumn day, in a western Massachusetts forest, under the wide canopy of a grand American Chestnut.

~~~  **  ~~~


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