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Conservation In Mind – In praise of trees

By Frances Lamberts

The Arbor Day Foundation, which Theodore Roosevelt found in existence and “now observed in every state of our Union,” in 1907, recently launched a new “Time for Trees” initiative.

With the goal of planting 100 million trees in forests and communities by 2022, it seeks more strongly to advance protection of water resources and to mitigate the worsening ill effects from climate change, such as extreme heat and flooding.

For their cleansing the atmosphere of greenhouse gases which threaten planetary health, we could rightly link Arbor Day with Earth Day, both celebrated in April. Daily measurements by the U.S. Weather Service, from a mountain in Hawaii since 1958, have shown a large and steady increase in carbon dioxide in the air, in line with growth in fossil-fuel burning.

But this “Keeling curve” – after the scientist who initiated the measurements – also finds every year a low point in the carbon density, thanks to trees’ work: their seasonal greening and photosynthesis withdraws the gas for food to build their tissue.

By far the greatest carbon-sequestration benefit, as a botany researcher reported in the Science journal, comes to us from old forests, as tree longevity rather than their early faster growth controls the forests’ carbon storage.

In line with this, a German Federal Agency for Nature Conservation stated similarly superior air-cleansing benefits from old urban trees. For space reasons in fast-growing metropolises, these often are supplanted with smaller, “designer-flora” species. Yet it would take more than a thousand of those, the agency suggested, to replace the air-cleansing value – some 40 pounds of greenhouse gases withdrawn and nearly 30 pounds of oxygen released during a summer day – of centenarian linden, beach or oak trees.

As the author of the Science article on tree longevity and carbon sequestration suggests, the best practice to retain the climate-mitigation benefits of trees is to “protect carbon-rich, old-growth forests.”

Additionally to its many other treasures – abundant water generation, majestic trees and mountain scenery, shelter and nourishment for astounding numbers and varieties of plants and animals – Unicoi’s Rocky Fork forest is a gift to all of us in aiding the fight for a climate-benign future planet.

As the spice bush, red maple and pussy willow, pawpaw and other trees and shrubs were unfurling their flowers and foliage, it seemed a reflection of Roosevelt’s sentiment about “the importance of trees to our nation, and what they yield in adornment, comfort and useful products in the communities in which [we] live.”