Wednesday, April 26, 2017

Sustainability and the Hidden Life of Trees

Beech tree forest, central Europe. Courtesy Wikimedia Commons
   By now many readers of this blog will have sat down with Peter Wollheben’s remarkable best-seller, The Hidden Life of Trees. Wollheben, a German forester, writes about forest sustainability, but there are takeaways for musical and cultural sustainability as well. Indeed, one of his major points is that trees have a kind of social and cultural life together. The author anthropomorphizes trees to an extent that bothers me; he attributes emotions and feelings to them, for example, as well as intentions and agency in ways that are striking. Nevertheless, he makes a convincing case that trees in a forest comprise an interactive community.
    In his first career, Wollheben was a professional forester, and managed a forest for commercial interests. In central Europe, as in many parts of the US, planned forests are planted (or replanted) with trees evenly spaced (or thinned to give them space) so they will grow fast for a quick harvest by large, efficient machines. Although he doesn’t specify, we infer that the forests he worked in were coniferous, with spruce trees the favored commercial species. At some point, he stopped managing commercial enterprises and instead began to manage an old-growth forest chiefly of beech trees, not for harvest but for preservation for the community nearby.
    When he began doing so, he observed that the beech forest (which had been growing for many decades without much human interference) was much different than the commercial forests he managed. The trees were much closer together—too close, in terms of the forestry management practices he’d learned—and yet they grew better, straighter trunks, and they grew more slowly and to a ripe old age: hundreds of years. It took them far longer to come into maturity, and they lasted many times longer than the trees in the commercial forest of conifers. They were well adapted to the soil, unlike many of the conifer forests that had been planted in unlikely places. He began to wonder if, for the health of the trees and the forest, it wasn’t better to manage as nature did, rather than to adopt the practices of forestry management—even so-called selective cutting and thinning and harvesting. Although he does not reference Thoreau, 150 years ago Thoreau came to the same conclusion, on reading an English book about planting walnut trees.
    Searching for an explanation about why this beech forest that seemed to violate all the principles of forestry management was able to maintain itself better than the managed one, he read reports by scientists. What most intrigued him was a paper published in 1997 by Susan Simard as lead author. Simard and her group observed that in the forest soil, fungi attach to tree roots and that, when trees grow close to each other, the roots and fungi of different trees intertwine, even among different species, and transmit carbon and other chemicals (glucose, for example) from one tree to another. In effect, the trees were feeding one another. Afterwards, Wollheben began to read of other experiments in which trees seemed to “help” each other, for example by sending out scents signaling the presence of a pest, that would cause other trees in the forest to erect chemical defenses against the pest. It was not a big step for him to conclude that the trees in a forest constituted a kind of symbiotic community, even though they were also in competition with one another for sunlight and water.
    One of the corollaries of this research, he concluded, was that trees closer to each other can help each other more—they are better off that way. Not only are their entwined roots better able to reach each other and exchange food, but the stronger trees often “feed” the weaker ones because it is beneficial to keep them all alive so they can “help” each other. When I walk out in the un-managed spruce forest behind my own house, I hear tree branches and sometimes the trunks, high up, rubbing against each other when there is a strong wind. I used to think that was unfortunate, that the trees were too close together. Now, after reading Wollheben, I realize that they are propping each other up against the possibility of breaking off or toppling over completely.
    In early October, 2014, a snowstorm with high winds occurred where I live on East Penobscot Bay. It toppled many trees, also snapping off branches. The earth was wet from recent rains, making it easier for the top-heavy trees to become uprooted if they had no nearby tree to prop them up. I noticed there were more snapped and toppled trees at the edges of clearings. Also, four apple trees in an old, planted orchard had been uprooted completely. I was able to save two of them with the help of a neighbor, and get them back upright after pruning them back heavily; they are growing again, but the other two were beyond help.
    Consider, then, the advice given by professional foresters for planning an apple orchard: plant the trees at some distance from one another so they avoid their branches touching. For a full-sized tree, that should be forty feet apart in all directions; but such a tree will not be able to extend its roots to entwine with its neighbor, for the roots spread about as far under the ground as the branches do above. Those trees will also be more susceptible to damage from wind and insect pests. Of course, for easier harvest they are planted at that distance; but it would not be that much more difficult to harvest apple trees planted closer together. The apples might be more numerous, but they would be smaller, and many would not fully ripen unless the branches were pruned so that in a heavy wind they would not prop each other up.
    In nineteenth-century New England, when a house was built, a small home orchard usually was planted out behind the house, the tree trunks about fifteen feet from each other. You can find these commonly with the older houses still standing, and even when the houses are gone and only the cellar holes remain, and the surrounding area has grown up into forest, a home apple orchard is likely to found within seventy-five feet of the cellar hole. The full-sized trees that grew up were able to live long as their roots and branches entwined, and the apples they produced--for cider, baking, and fresh eating--were easily enough harvested, by climbing the trees or using pole harvesters for the best specimens, while the cider apples were gotten off the trees by shaking the branches. Such an orchard stands in back of my own house, and these trees were not damaged in the 2014 snowstorm the way those planted in a field nearby, according to proper orchard practice, were damaged.
    In short, the trees in a natural forest, according to Wollheben, comprise a community, a kind of mutual aid society while at the same time they are competing with each other. By means of mutual aid they are able to sustain the forest far better, and for far longer, than a forest planted or managed according to the principles of contemporary good forestry practice. The same principle might be applied to the management of music cultures. Indeed, I have embraced it in earlier blog posts here: feed the cultural soil, do not target the individual plant. In other words, encourage the music culture, not individual musical genres. If the cultural soil is nurtured, the musical genres will develop and thrive. An endangered music will not thrive if the cultural soil is not working in its favor, no matter how much it is aided.