The devastation of Hurricane Katrina has focused attention on the Gulf Coast wetlands and the need for its protection. But for many of us who live hundreds of miles from the Gulf Coast, it’s difficult to see what we can do individually to help. The National Wildlife Federation reports that one simple way for us to have an impact is to choose our garden mulch wisely.
Even before Katrina, the Gulf Coast’s wetlands and their swampy cypress forests were disappearing at an alarming rate. More than one million acres have disappeared into open water between 1930 and 2005. A report by the U.S. Geological Survey estimates that another 64,000 acres were lost in the hurricane. Some scientists assert that Katrina was able to hit with such deadly force because of the destruction of the coastal wetlands?- due mostly to the construction of levees and canals – left the coast without a protective barrier.
Cypress trees grow in the wildlife-rich wetlands in the southern United States and are a critical part of the coastal ecosystem and its wildlife habitat. Gulf Coast cypress trees, however, have long been prized for mulch because of their resistance to insects and rot. Cypress bark mulch has also been favored by gardeners for its rich color, earthy smell and durability.?
Historically, Florida cypress trees were most often harvested for mulch, but as mature cypress in that state become harder to find, Louisiana cypress trees are increasingly logged, chipped and sold as mulch in large retail stores. Cypress trees take as much as a century to reach maturity, cannot reproduce in standing water and seedlings require a short period of dryness each year to survive. When a coastal cypress tree is harvested, it is very unlikely it will be replaced by a new, healthy tree. Because mature cypress trees have been logged at unsustainable levels, cypress mulch now most often comes from immature trees and has wood mixed in.
New research indicates that immature trees have not yet developed the rot and insect-repellent qualities valued by gardeners. This means that most cypress mulch is simply wood chips that do not contain the rot and insect-repellent or durability that gardeners want. Further, beneficial garden mulch should contain an even mix of carbon-rich and nitrogen-rich materials. Because wood chips and bark are virtually all carbon, they tie up the available nitrogen in the soil as they decompose, leaving plants without the nutrients they need to grow.
The National Wildlife Federation reports that the most nutritious garden mulch is something most gardeners already have on hand: yard waste. Researchers at the Ohio Agricultural Research Center found that composted yard waste increased the number of flowers on rhododendron plants by 300 percent over plants grown without mulch. Wood mulch gave no such benefit.
Compost, a mix of kitchen scraps and yard trimmings, is one of the best and cheapest mulches around. Another good alternative to cypress mulch is fall leaves. Composted, they make a wonderful component in fertilizer. Even when they are simply shredded and spread around the yard, they make an inexpensive and effective mulch. Well chosen bark mulch from plantation grown – and therefore renewable – pine or other conifer trees makes a good, long-lasting mulch.
When you or your landscaper are buying mulch, read the packaging carefully to see what material it is made from, and resist buying any products made from cypress. You’ll be helping to protect our nation’s wildlife heritage.
NWF’s mission is to inspire Americans to protect wildlife for our children’s future.