Still majestic, still imperiled


Trees: Words from years ago on the need to preserve Maryland's forests ring just as true today.

September 17, 2004|By Tom Horton | Tom Horton,SUN STAFF

THIS WEEK, members of the Bay Ridge community south of Annapolis gathered to toast a remarkable tree preservation effort that has spanned 15 years.

To preserve the area's magnificent mature forests - 150 acres that were faced with imminent development - residents raised $4 million.

More than a decade ago, when that still seemed an almost insurmountable task, L. Eugene Cronin, a leading bay scientist, asked if I could write something on the value of forests to help his community's effort.

I did, and members of the Bay Ridge Trust said this week it had been helpful. I'm excerpting from that essay - with updates, where appropriate - in hopes of helping a few more trees.

What's a Forest Worth - Observations on Bay Ridge and Beyond

To the modern logger, oaks of the type found around Bay Ridge reach maximum value at 60-80 years. Beyond then, the tree is no longer adding wood as rapidly, and delaying its harvest only risks disease, or injury from lightning or wind.

If such a tree is exceptionally straight and knot-free, it may even be "veneer quality" - fit for slicing into paper-thin swatches to cover the walls of executive boardrooms and fine furniture.

To the squirrel or deer that feeds on the oak's acorns, the same tree will not even come into its own until it has lived a century or more, when its acorn production begins to peak. The oak may sustain that level of food production for wildlife for another century.

To woodland birds, vireos, warblers and the like, a forest studded with oaks two, three and even four centuries old is living at its finest. The remarkable habitat afforded by the canopy and structure of such an old-growth forest maximizes niches for nesting and feeding.

As the tree ages, decays, begins to rot from within, its value to animals only increases. More than 49 species of North American mammals and 85 species of birds find prime habitat in the cavities of deteriorating forest giants.

The forest itself might say the most productive oak is the old giant that has spanned half a millennium, nourished generations of squirrels, cradled millions of songbirds, died, rotted in place and, at long last, crashed to the ground.

A sizable pit created by the oak's uprooting, along with the bulk of the fallen tree, creates unevenness on the forest floor, damming up leaves that will rot into rich piles of compost, regenerating forest soils.

The "dead" carcass of the oak bristles with new communities - mosses, fungi, lichens, beetles, ants, microbes, new oak seedlings sprouting. A whole new ecosystem has been created, further enriching the diversity of life in the forest and ensuring its perpetual health.

All this only starts to account for the values of undisturbed forest. Walk into the woods when it is raining hard. Watch how the water flows through the forest to streams and the bay. The deep, absorbent leaf duff of the forest floor acts like a giant organic filter, removing pollutants carried by air pollution and in runoff from surrounding pavements, gutters and construction sites.

We spend tens of millions of dollars annually around the Chesapeake on storm water detention basins, sediment fences, agricultural terracing and a host of other techniques to control polluted runoff. Nothing yet devised, or likely to be devised, works better than leaving the forest intact.

Yet across the bay's 64,000-square-mile watershed, the trend has been to degrade the great, green filter - even as we spend billions to restore water quality.

The six-state bay watershed has lost nearly 50 percent of its forests. That understates the problem. The third or so of the watershed nearest the bay, where a forest buffer is needed most to maintain water quality, is where forest loss has been greatest - around 70 percent.

This only hints at the worth of trees. Acid rain appears to be detoxified after filtering through the floor of forests. The forest is a bank for carbon dioxide, the key contributor to global warming. As important as forest acreage are forest patterns. More rapidly than they are being cleared, forests are being "fragmented," crisscrossed and isolated by roads, power line corridors, interstate highway fencing, housing development - even by wildlife management in some cases.

Many species of songbirds need unbroken forest interior for successful breeding. If they are too close to a forest edge, their nests are easier prey to raccoons, blue jays, possums and cowbirds.

All these "ecosystem" values above say little about why most of us love forests - for the rich palette of autumn colors and the crunch of dry leaves underfoot on a winter's walk; for the spring blizzards of dogwood blossoms floating in the sun-spangled understory; for all the different tunes trees pluck from the wind; for the smells and sounds and shade, and the graceful way bare branches frame sections of the winter sky; for the age-old kinship between us and trees.

The forest at Bay Ridge is nearing 90 years old. Population in Anne Arundel County is booming, and undeveloped waterfront is scarcer every year.

For the logger and developer, the forest's time has come. But for those who value birds and plants and animals, who value clean air and the bay, and the glory of nature allowed to create one of its fullest expressions - a mature, sustainable forest - the time is not yet, not ever.

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