Upcoming Earth Day, April 22, is a time for us to celebrate the beauty and benefits we receive from Earth and its ecosystems. Whether you hike, ride, fish, hunt, or just enjoy magnificent views, Earth Day is a good time to ponder the effects of our actions on the ecological networks which support our lives in New Mexico.

In 2008, the Santa Fe National Forest released its Travel Management proposed action. Its purpose: To regulate forest-damaging off-road vehicles, including motorcycles and all-terrain vehicles. The April 12 My View, "Do the math: OHVers not asking for much" by Joanne Spivak gave an entirely false impression of the impact of 600 miles of proposed motorcycle-only trails.

Contrary to Ms. Spivak's math, those 600 miles of trails do not affect only 220 acres. Instead, motorized trails impact forest health and function, as well as the enjoyment of recreationists who seek nature's peace and tranquility.

Let's look at specific examples, and "do the math" in a realistic way.

For instance, in the broader case of all motorized trails 'proposed open' on the west side of the Santa Fe National Forest, the New Mexico Department of Game and Fish determined that, using Forest Service definitions, a 200-meter zone on either side of each motorized route resulted in a loss of roughly 264,000 acres of effective habitat for mule deer and elk.

Applying this 200-meter zone to the 600 miles of motorcycle routes: 200m = 656 feet; x2 for both sides of the trail; gives us a "loss of effective habitat" section across a motorcycle trail of 1,312 feet. Times 5,280 feet per mile, that yields 6.9 million square feet, or 158 acres, of effective habitat lost for each mile of motorcycle trail (43,560 sq. feet per acre). The loss of effective habitat for 600 miles of motorcycle trail is therefore almost 95,000 acres — not the "absurdly tiny" 220 acres Ms. Spivak erroneously claims.

The issue looms larger when calculating the noise impact of 600 miles of motorcycle trails. Research documented in the official SJM40 report found that ORV noise can travel more than a mile, disrupting wildlife and everyone seeking forest quiet. Using less than one-third of a mile on either side of the trail (500 meters, 1,640 feet), we get a "noise cross section" for a motorcycle trail of 3,280 feet. For one mile of trail (5,280 feet), the math shows us that at least 398 acres are disturbed by the "noise footprint: of a single mile of motorcycle trail.

The sounds of motorcycle engines over the requested 600 miles of trail, therefore, disturb game and hunters, birds and birdwatchers, hikers and horseback riders across at least 239,000 acres. That's 15 percent of the Santa Fe National Forest — a far cry from Ms. Spivak's estimate of "0.000142 of the land."

We are all free to enjoy the beauty and majesty of our national forests, wilderness, and wildlife. But with that freedom comes a direct responsibility — to reality-based management of our forests so that we, and future New Mexicans, can continue to enjoy their quiet beauty.

Valerie Gremillion, Ph.D, is a Research Assistant Professor at UNM Albuquerque and a co-author of the SJM40 report, found at http://www.emnrd.state.nm.us/main/sjm40/SJM40report-01-07-09.pdf.