|Nuttall's woodpeckers are among the many species that nest in dead trees. Photo by Tom Grey|
Gillian Martin would like everyone to know just how important a dead tree can be.
Martin, a volunteer naturalist, is spreading the word about the benefits of keeping dying trees, called snags, in place. Instead of reaching for a chain saw, we should consider the benefits of saving them, she says.
“Dead trees and tree limbs provide vital habitat for cavity-nesting birds and other wildlife,” said Martin, of Laguna Niguel.
About 84 species of birds in North America depend on dead trees for nesting, she said. About 40 of these rely on woodpeckers, a family of birds known as primary excavators, to make holes in these rotting trees. In Southern California such primary excavators include Nuttall’s, downy and hairy woodpeckers and the northern flicker. When woodpeckers abandon their nest sites, secondary cavity nesters such as tree swallows, Western bluebirds, mountain chickadees and oak titmice inherit them.
“The removal of too many snags results in competition among the species and fewer breeding opportunities for these cavity nesters,” Martin said.
Snags also provide benefits beyond nesting. Unlike live trees, snags provide unobstructed views for birds of prey when hunting. Other species use them during displays of courtship and for defending their territories. A dead tree also returns nutrients to the soil when allowed to die in place.
To promote the preservation of dead tree limbs and snags, Martin developed the Cavity Conservation Initiative, a program established in conjunction with the Southern California Bluebird Club. As part of the program, she brings the message to local schools and community organizations. As an environmental activist, she has also been educating land managers and officials from golf courses, county and state parks and the Forest Service on the value of snag retention.
“A securely rooted dead tree can often be safely retained by reducing its height and weakest branches,” she said. Cutting the tree down to as low as 6 feet and shortening the limbs to 18 inches is enough to provide valuable habitat. Dead limbs need to be at least 8 inches in diameter to be useful to cavity nesters.
“The project requires perseverance,” she said. “But the word is definitely spreading.”
Martin recently returned from the International Woodpecker Conference in Spain, where the scientific studies presented underscored the repercussions of lost habitat.
“I learned that whether one is managing a forest, woodland or urban park the issues are the same,” she said.
For more information, go to cavityconservation.com.