photo by Sandy Loucks
Here’s an article from 2009 that seems timely this year:
Home & Garden: Maine’s Forest Sponge
from the MidCoast Free Press
by Georgeanne Davis mailto:calendar@freepressonline.com
After all the precipitation Maine has had over the past two months, water isn’t a topic of any urgency: we’ve had more than the gardens can soak up, and the need for any watersaving devices or sprinkling and soaking systems is obviated at this point. But I’ve been saving the following information from “Fresh from the Woods,” a newsletter produced by Forests for Maine’s Future, which is a partnership of the Maine Forest Service, University of Maine Center for Research on Sustainable Forests, Maine TREE Foundation and Small Woodland Owners Association of Maine. The lack of clean potable water is an increasingly serious problem in many parts of the world, including the western and southwestern areas of the U.S., but lucky us – Maine has some of the cleanest water in the nation, and forests are the reason why.
The Maine Department of Conservation puts it this way: “The Maine forest – with its vegetation, streams, lakes, wetlands and groundwater aquifers – functions like a huge sponge that collects, cleans and stores water. The forest’s water system is the foundation for wildlife habitats and recreational uses of the forest. It evens out lake levels, [the] flows of streams and rivers, and groundwater levels, throughout wet and dry periods. And it provides Maine people with their drinking and household water.”
A staggering amount of water is filtered through the forest “sponge” each year – about 24 trillion gallons, or enough to fill 40 million Olympic-size swimming pools. About half of the precipitation runs off in streams and rivers and collects in ponds and lakes before flowing back to the sea. Some of that surface water is used by Maine utilities to provide “city water” to about 60 percent of state residents.
For example, Sebago Lake is the water source for about 200,000 people in Greater Portland and clean enough to be exempt from the expensive filtration process required of most surface water sources. The lake covers 30,000 acres, and the extent of forest cover in its watershed is one of the chief reasons that Sebago Lake is so clean. Forests remove sediments and capture pollutants before they can reach water bodies.
Forest-to-Faucet, a partnership of the USDA Forest Service Northeastern Area and the University of Massachusetts at Amherst, says that “People are a forest-dependent species. … In virtually every [water] system, large or small, the faucet is ultimately connected to a forest.” Maine is the most heavily forested state in the nation. Although its population almost doubled from 1900 to 2000, the abandonment of small farms also caused the amount of forestland in Maine to nearly double. That means there is just about as much forestland per person now (35 acres) as there was 100 years earlier (36.2 acres), according to Forest-to-Faucet.
In forests, rain tumbles through the mature tree canopy, understory trees and shrubs, and herbaceous plants such as ferns before reaching the litter layer, which is a natural mulch that limits evaporation, a shock absorber that protects soil pores, an insulator that inhibits soil freezing, and a slow-release source of nutrients to foster more plant growth and site protection. That’s not the case in developed areas, where roofs, driveways, parking lots and roads convert rain directly to storm water. The conversion of forest land to developed areas replaces a storm water and pollutant sink with a storm water and pollutant source. This is the two-edged sword of suburban sprawl and forest fragmentation, and the reason why a comprehensive approach to forest conservation and the revitalization of urban areas is at least as important today as it was a century ago. When one reads about the efforts to plant green roofs in cities and the utilization of permeable hardscapes for parking lots in urban areas, it seems both miraculous that in Maine we have such an abundant supply of water, and forgivable if once in a while it becomes overabundant – “once in a while” being the key phrase here.
