Dead Wood Is Still Good Wood

 “Ideally, your forest should have four to six snags per acre,” says Kristi Sullivan, who hails from Cornell’s Department of Natural Resources and the Environment.  This was news to me.  Anyone who works with computers, has a boss, or tries to organize anything is annoyed by snags.  I’ve hit snags when paddling my kayak and even snagged my jeans on a barbed wire fence.  But snags in the woods?  Kristi’s snags, in forestry parlance, turn out to dead, but standing, trees.  Once I’d gotten around that snafu, it all started to make sense. 

What looks like rotting timber to us is a multi-use opportunity for the wild things.  According to the Washington Department of Fish and Wildlife, “birds, small mammals, and other wildlife use snags for nests, nurseries, storage areas, foraging, roosting, and perching. Live trees with snag-like features, such as hollow trunks, excavated cavities, and dead branches can provide similar wildlife value. Snags occurring along streams and shorelines eventually may fall into the water, adding important woody debris to aquatic habitat. Dead branches are often used as perches; snags that lack limbs are often more decayed and may have more and larger cavities for shelter and nesting. Snags enhance local natural areas by attracting wildlife species that may not otherwise be found there.” 

Any tree species, including hardwoods and conifers, can become a valuable snag.  The process begins with a hard snag, or a tree which is partially or totally dead but still has its bark and inner tissues largely intact.  Woodpeckers are especially attracted to such real estate and start their excavating activities, earning themselves the moniker of primary cavity nesters.  Since woodpeckers become bored easily and don’t nest in the same hole twice, they move on and carve out new homes elsewhere.  Then avians including bluebirds, swallows, chickadees, nuthatches, house wrens, wood ducks and owls, who cannot excavate cavities themselves, move in next.  Meanwhile, the tree continues to decay, with fungi advancing and weakening the wood fibers, creating a soft snag.  Soft snags don’t have limbs and often lose their tops.  As the forces of weather, animals and fungi continue, the remaining hulk eventually falls over, but still provides food and shelter on the forest floor.  I’m sure foresters have a technical term for a dead tree lying on the ground, but I don’t know it.

This discussion sprouts two ideas in my gardener’s mind.  First, we are often much too neat.  Nature would benefit if we left more rotting stumps and standing snags.  When gardening friends raise an eyebrow over our apparent sloppiness, we could grasp the moment as an educational opportunity.  Secondly, snags could be a way to positively end my relationship with some Norway maples.  These invasives are growing on the edge of our woods, and while I know they should come down, that seems a daunting task.  By removing a four inch band of bark to girdle them, they’ll turn into useful snags, then eventually fall quite harmlessly (I hope) to earth.  That’s my plan, unless I hit a you-know-what.