Some of the most important trees in your woodlot are the ones that are no longer alive. Large, standing dead or dying trees—called snags—are an important component of healthy forests and a critical habitat feature for wildlife. They provide places for many birds and mammals to forage, den, nest, perch, and roost. Snags are particularly important for cavity nesting birds like woodpeckers, nuthatches, and chickadees; for bats that roost within cavities, crevices, and flaky bark; and for countless species that rely on the abundant insects, fungi, and lichens as a food source.
As long as they aren’t in a hazardous location such as near a road or building, consider leaving snags for wildlife. In woodlands where snags are sparse or absent, it’s possible to create a few by topping, girdling, or simply leaving several mature trees as legacy trees that may become snags in the future. Biologists recommend having at least three large snags (>12” diameter) per acre to benefit wildlife. These stately spires also add structural complexity, provide an element of visual interest, store carbon, reflect a forest stand’s past, and will enrich soils in the future.
Photo at top: A dead tree or “snag.” Photo by Katherine Yard. Photo courtesy of the NYS DEC.
I have many 50+ year-old white pines that are dying off because of a water table that has been rising over the last 50 years. Fewer wells, closure of a water bottling plant, and a new municipal water system drawing water from Lake Champlain instead of wells/springs has drastically altered groundwater. These trees were in marginal soil when young. So I have a nice assortment of downed trunks 50 + years-old, and standing snags 20+ years old.
This moist understory used to be home to various species of thrushes and warblers, but the last 10 years has shown a fairly dramatic decrease on my tiny woodlot. I believe this is mainly due to overbrowsing by increasing numbers of deer. Initially I suspected predation by cats and other predators, but my trail cams placed along my brook don’t really bear this out. My brook is an active deer trail and deer families are seen almost twice daily. I keep seeing more deer and fewer predators of any sort. I do see fisher, mink, raccoons, cats, red and grey fox, coyote, turkey, and squirrels, so there is a good assortment of predators on ground breeders, but not in large numbers. Squirrels and fox are the most numerous stars in my photos, but nothing that seriously predates on deer. They are seriously damaging understory where they cannot be actively hunted. These birds need understory to survive.
I am sorry but I miss the point here. There are a gazillion trees in protected state forest land all in various degrees of health. So why am I being encouraged to leave dead trees upright on my property ? I think we are approaching the point where we are not seeing the forest, just only the tree.
Removing dead trees removes food and shelter that many organisms depend on. It also removes biomass that was destined to build soil feeding future forest species.
“I think we are approaching the point where we are not seeing the forest, just only the tree.”
It seems you are focusing on the tree and not the forest.
I just looked up the % forested land in NYS that is privately owned. 74%, so only 26% is state owned. I believe the encouragement of private property owners to leave snags standing to help increase biodiversity is a positive thing to do.