By JASON REYNOLDS
If I would ask the question, “what are living trees good for,” I would probably get a large response.
Some people may say that trees provide us with shade, oxygen and lumber to build our homes. They also provide habitat to wildlife, prevent soil erosion by slowing down rainwater and provide us with food. But if I asked what are dead or dying trees good for, I would probably get one common response, firewood.
But these trees are actually very important wildlife habitat. Standing dead trees are called snags and living trees with a cavity in the trunk or limb are called den trees. These snags and den trees provide quality habitat for birds, amphibians, mammals, reptiles and invertebrates.
Some of these animal species are snag- dependent; they use snags for shelter, nesting habitat and food in order to survive. In some forests as much as 45 percent of the bird species are cavity nesters.
Our forests in Ohio have two types of snags: hard and soft. Hard snags consist of trees that have recently died and the wood is still solid. It is difficult for birds and mammals to excavate cavities in these snags, but they provide excellent perching and roosting sites for many bird species. Bald eagles, red-tailed hawks and owls will use these large snags to hunt from and as nesting sites. They also provide a food source for birds and mammals in the form of insects that occupy these dead trees.
As these hard snags deteriorate and break down, the wood becomes soft and a soft snag is created. Birds such as woodpeckers and other species that excavate their own cavities will use these soft snags as nesting sites. Other bird and mammal species that cannot excavate their own cavities will find natural cavities or cavities made by woodpeckers or a similar species to nest in. These species include black-capped chickadees, bluebirds, kestrels, screech owls, wood ducks and raccoons.
As these trees deteriorate further, large limbs may break off and fall to the ground or the whole tree may fall over. These large limbs and logs provide many other uses to birds, mammals, amphibians, reptiles and invertebrates. For example, ruffed grouse will use these logs for drumming and courtship displays. Salamanders will seek refuge in the damp soil beneath a rotting log.
These rotting logs will also provide the perfect soil conditions for young developing trees. The wildlife value of a den tree or snag depends on the species, size, level of decay and location of the tree. Deciduous trees are more likely to create larger cavities than conifers.
Deciduous trees such as sycamore, beech, black locust, maple and hickory provide some of the best den and snag trees. Large animals such as the pileated woodpecker and raccoon need trees 15 inches in diameter or greater with a height of 6 feet or more.
Smaller animals can use trees or limbs down to 4 inches in diameter. Remember that larger, hardwood trees will take longer to decay than smaller, softwood trees. But it is important to retain a variety of different sizes and species of den trees and snags.
It is important to have these wildlife trees spread over 60 percent of the forest area. Research has shown that maintaining at least two-four wildlife trees per acre will greatly benefit wildlife. Having more than two-four wildlife trees per acre will reduce the competition for these nesting, foraging and roosting sites.
So as you can see, den trees and snags provide a unique habitat for a variety of wildlife and even plants. Having and increasing the number of wildlife trees in your forest area should increase the biological diversity of your area.
Dead or dying trees are not a sign of an unkempt forest, but a sign of an area that provides a unique habitat for wildlife. So the next time you are out in the woods cutting firewood, be sure to leave a couple of den trees, snags and logs for those animals that depend on them for survival.
(Jason Reynolds is a Wildlife/Forestry Specialist with the Columbiana Soil and Water Conservation District. He is a Columbiana County native and a 2010 graduate of Kent State University with a bachelor’s degree in conservation.)