Chad Hanson, a University of California-Davis researcher and Sierra Club board member observes, “We are trapped by an outdated cultural idea that a healthy forest is one with nothing but green trees. An ecologically healthy forest has dead trees, broken tops, and down logs.”
Over the last several years, you may have noticed an increase in dead and dying trees in our watershed, particularly oaks. There are a number of factors at play, including soil compaction from development, old trunk wounds, storm damage, environmental stressors such as heat and drought, opportunistic diseases and insects, and just plain old age. If you think the only response to a dead tree is to cut it down, think again!
It has been estimated that dead trees, called snags when they are still upright, and trees with decaying wood provide important habitat for about 25 percent of the forest wildlife species in the northeastern United States. Add aquatic species and that number climbs even higher.
Did you know that more than eighty birds in North America are cavity-nesters, include 10 species of owls, 7 ducks, 2 falcons, all 21 woodpeckers, and about 40 songbirds? They raise their young in hollowed out sections of dead and dying trees. In addition to providing a place for birds to nest, cavities also protect birds from predators and offer shelter from the elements. Dead branches serve as a perch from which birds can survey their surroundings, hunt, eat, and dry their wings and rest. If that weren’t enough, a dead tree offers a smorgasbord to insect-eating birds and other animals, with holes, depressions and cracks that double as places to store seeds, nuts and other food.
Logs on the ground also provide a bounty of food and shelter for a range of critters. Hollow logs provide cover and protection for small mammals like foxes, rabbits, skunks and raccoons. The wood itself may be home to ants, beetles, and carpenter bees that tunnel into it, while bark beetles build extensive chambers under the bark. These insect residents are, in turn, a good source of protein for turtles, toads and lizards. No walk in the woods is complete without flipping over a log to see what lies beneath –
beetles, worms, centipedes and, if you’re lucky, a salamander. Don’t forget to roll the log back over gently, lest you destroy someone’s happy home. Continue reading