On a ridge southwest of our little spot on the planet there is a tremendous beech grove. The ridge has relatively thin soils, save two large areas where the bedrock dips far beneath the dirt on the surface and where this wonderful member of the tree family Fagacea has found a perfect place to dwell. It is a difficult place to access; the climb to the site is steep, without trails, and fraught with debris left behind by the great ice storm of 2008. Speaking of which, about half of the beech trees in this local were either moderately or severely damaged by the record layer of frozen water whose weight was too great to bear for even the strong limbs of these wonderful trees. Despite the damage, a good number of trees are still surviving, still somewhat healthy, and still producing heavy crops of beech nuts every couple of years.
The reason I say that this large grove of beech trees is “somewhat healthy” is that almost all of the trees have contracted beech bark scale disease. This disease is prevalent throughout the northeast United States and eastern Canada and has made a real dent in the overall health of our American beech tree population. The disease was first found in the maritime provinces of Canada in the 1920′s. It is presumed to have been introduced by the importation of European beeches for landscaping. The disease is fatal to many native beech trees: a long drawn out process that may eventually leave the tree without a solid protective layer of bark. This beech bark scale disease is complicated. It is a cascading set of events started by the introduction of a very small beech scale insect carrying a fungus known as Nectria coccinea. The scale insect and the fungus has a commensalistic association where one organism is benefited by the relationship but the other organism is not. In this case the insect is simply a mode of transportation for the fungus who reaps the benefit of a new host once introduced to the unsuspecting beech tree.
The adult scale insects aren’t capable of mobility on their own. They have no wings and effective distribution would happen too slowly by crawling through the dense forest duff found on the surface of most woodlands. Rather they are carried by wind. These tiny insects can travel significant distances on windy days introducing them to new territory where fresh populations have the resources to propogate and introduce the Nectria fungus to a new beech grove. The adults typically move in the autumn, hide in the bark through the winter where a cotton-like blanket protects them to minus thirty degrees Fahrenheit. Late the next spring, or in the beginning of summer, the adults lay eggs on the bark. These insects mature by autumn. Some move on, others remain in their present habitats.
The scale insects, so small that they cannot be seen with the naked eye without aid of magnification, feed on the sap of the beech. These minute critters have a specialized mouth parts that help them to pierce the bark. These tiny wounds may introduce the Nectria fungus. The fungus alters typical bark growth resulting in abnormalities that appear as pits, splits, and discoloration. The weakened bark leaves the entire tree vulnerable. Bark is the first defense for these magnificent trees against invading insects, other fungi, and climatic elements.
Over the years, and this disease has been prevalent in these parts for a few decades, the cascading impact of scale insects, Nectria fungus, other invading insects like carpenter ants and termites, and other fungi that decays the wood, especially the heart wood, leaves the tree open to a phenomenon know as beech snap. Beech snap results in the tree breaking off about 20 feet up the trunk from the root crown.
But beech trees have a uncanny will to survive. When stressed the roots produce sprouts that emerge from the forest floor as a new thicket of beech saplings. These saplings are an exact genetic copy of the tree that is about to survive. This is both good news and bad news. Perhaps a little explanation is necessary.
Recent studies in Vermont have brought about encouragement for the native beech populations. It appears that some trees are somewhat disease resistant to the Nectria fungus. These trees only suffer minor damage from Nectria. The exact reason for this resistance is not fully understood. Is it a natural genetic resistance to the fungus found in the DNA of some beech trees? Or is it an adaptation that some trees are developing, the production of a chemical that kills the invading fungus? Only time will tell why this happens in some beech trees. The important and critical issue is that some trees appear to be somewhat resistant to the fungus, meaning it is not seriously impacted by the cascading set of events that so often occurs when the scale insect introduces Nectria to a beech tree.
The current thought is that by encouraging the trees that seem to be resistant to the disease and by culling the trees that have no resistance to the disease we may be able to stem the tide to the end of a healthy beech forest as we know it. New management techniques are being actively pursued. And the initial results of these management methods are promising.
Still, there are remnant populations of healthy beech trees that have not been exposed to Beech bark scale disease. High ridge tops where winds have not introduced the scale insect and have been isolated from other infected beech groves. Winds are not as likely to carry this forest pest to high altitudes, although it is certainly not outside the realm of possibility. The lower temperatures on northern high ridges where beech are found is also a major discouragement for Nectria.
Since the loss of the mighty American chestnut in the beginning half of the 20th century oaks and beech have had to provide the hard mast so critical to not only the own survival but as a forage crop for an abundant number of wildlife species. Although nothing can ever replace the American chestnut, a tree lost to a disease introduced by importing foreign chestnuts from the far east. Native chestnuts, a part of the northeastern climatic forest, produced huge hard mast crops. The loss of these steady and plentiful sources of food has been hard felt by forest critters for generations. The forage gap was filled by the oaks and beeches. Not only did these trees physically fill the voids left in the forest but they brought new, but less plentiful, hard mast to the woods. Beech nuts, in particular, are a very nutritious source of proteing, carbohydrates, fats, and essential minerals. They are the preferred food for many of our wildlife species including black bears, wild turkeys, ruffed grouse, and white tailed deer, not to mention all of the rodents that enjoy this wonderful forage supply.
On this day I am simply on this ridge to enjoy this grove of beeches. I look for old claw scars left behind where black bears climb the trees to harvest the premium crop before it falls to the forest floor to be consumed by the other wildlife. These scars are deep and will stay for years. The look like four vertical and parallel stripes, usually formed as the heavy bear descends the tree its claws tearing the bark under the heft of the bruin. I often see parallel dots in beech trees as well. Remaining clues where the bear climbed up the tree using its claws to hold it in place as it got a new grip. Only once have I watched a bear climb a beech tree. I was in a tree stand while hunting deer. The bear climbed a massive beech tree downwind and about a hundred yards away. It was shocking how agile the large black bear was in ascending the tree. Both athletic and powerful the bear managed to maneuver its way to the top of the tree and out onto a sturdy branch where it used the large claws on its paws while raking in beech nuts. When the bear descended a couple of hours later it did so quickly and efficiently. Clearly this bear was an expert tree climber with a tremendous amount of experience.
I have noticed over the years that the majority of bear climbing scars left behind by black bears are on relatively few trees. They seem to gravitate towards the same trees every year when there is a good beech crop. I’m guessing these trees produce larger yields and sweeter nuts. And given I’ve never really had the opportunity to quiz a black bear about its foraging habits this conclusion will have to remain with some doubt.
The few trees in this grove that have not been heavily impacted by the beech fungus are remarkable. Their smooth gray bark and towering stature is awe inspiring. One beech even has a carving of some love lost hiker or hunter. The scars from this carving are now black and contrast sharply with the slate gray bark. Presumably these are the initials of the carver and that of an equally unknown love interest. Normally I would object to this type of vandalism and I certainly would not encourage these activities in the future. But somehow I am struck by this romantic proclamation. I wonder if their love lasted. There is nothing quite so sweet as lasting love.
As I turn to the east and head towards our homestead I hear the whisper of the wind. Music-like notes that can be deciphered in the soft breeze seems to be telling me something. My imagination interprets the message and I smile. Long after I’m gone this forest will remain. Both the forest’s will to survive and its valuable contribution to our ecosystem will endure.
And with that I descend this steep and rugged hill happily knowing that I am a child of these woods. My journey home will be with a warm feeling in my heart and a renewed and ever lasting love for these hills through which I wander.
Life is good.
Originally written for the Heath Herald in May of 2013.