Monday, August 27, 2012

Adirondack Ecology: Wildlife, Wilderness and Dead Wood

Discussions regarding the ecological value of wilderness compared to an actively managed forest often centers around the health and well being of specific members of the wildlife community. While the flora and fauna that a tract of wilderness supports may be strikingly similar to that which occurs in periodically logged woodlands, the relative abundance of the various plants and animals contained in each is often quite different.In wilderness regions, there eventually develops a much higher concentration of those organisms whose lives are connected either directly or indirectly to the presence of dead wood.

Forests that are protected from timber harvesting operations contain substantially more dead wood on the ground and on the stump. While some trees that succumb to a disease or insect infestation may remain upright for only a few years after they die, many remain standing for decades before they eventually fall. Standing dead trees, especially ones that are larger than a foot in diameter, harbor numerous living entities and provide many animals with shelter.

Forest dwelling invertebrates are particularly attracted to dead timber as their bark is often loosely connected to the trunk which allows space for placing eggs, or permitting nymphs, larvae and adults to reside there during the winter months. Pulling a partially rotted section of bark from a dead tree in summer typically reveals dozens of critters ranging in size from pin-head spiders to inch long centipedes. The grubs of wood boring beetles, along with small colonies of carpenter ants, are frequently encountered when chopping out a chunk of wood from a trunk that has just started to decay. Larger creatures, like woodpeckers, chickadees, nuthatches and the brown creeper occasionally scour such standing wooden columns for the invertebrate matter which they harbor.

Many birds also rely on the cavities that develop in such dead trees for roosting sites during winter and nesting locations in spring and early summer. Birds as large as the wood duck, merganser, and screech owl have a much easier time locating a nesting cavity in a parcel of wilderness than in an area in which trees have been removed for firewood or lumber.

Mice and flying squirrels also rely heavily on cavities in dead trees for their nests. Even though these creatures cease breeding and no longer have young in their care during the latter part of autumn and throughout the winter, they still maintain a nest in which they take shelter when they want to rest when the weather is cold.

Large rotting logs on the ground create a haven for many small organisms, as such massive objects form a favorable microhabitat that is most attractive to those members of the wildlife community that are all too often overlooked. As wood rots, it develops a sponge-like quality that better enables it to retain moisture. This allows the soil beneath a large dead log to remain moist during prolonged periods of dry weather, which lures moisture-sensitive animals like salamanders, wood frogs and toads to these spots.As cold weather sets in during late autumn, the soil fails to freeze as quickly beneath such massive objects, and when it eventually does, the frost line never goes down as deep below a log carpeted with moss as it does on a section of soil that has been temporarily cleared of trees.

Unquestionably, there are numerous species of wildlife that do much better in a forest that is periodically thinned. There is no denying that the white-tailed deer thrives in woodlands in which timber is routinely harvested. This is why big game sportsmen prefer to hunt in places where logging has taken place. Creatures that depend on deer, like the coyote also tend to have higher populations in areas that have been worked by foresters and lumberjacks.

A tract of land that is cared for by a responsible timber company can have a clean and orderly appearance. This stands in sharp contrast to the unkempt look of a wilderness forest which is littered with rotting logs, fallen limbs, diseased trees, and patches of dense underbrush creating impassable obstacles in many scattered spots. Yet appearances are often deceiving, as the wilderness woodland typically has a more diverse and vibrant ecology. From mushrooms to salamanders to woodpeckers, a wilderness woodland is able to support a greater abundance of life than a managed forest.

I fully realize that economic issues come into play when discussing the value of wilderness, however, I know far less about economics than I know about ecology.

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Tom Kalinowski is an avid outdoor enthusiast who taught field biology and ecology at Saranac Lake High School for 33 years. He has written numerous articles on natural history for Adirondack Life, The Conservationist, and Adirondack Explorer magazines and a weekly nature column for the Lake Placid News. In addition, Tom’s books, An Adirondack Almanac, and his most recent work entitled Adirondack Nature Notes, focuses on various events that occur among the region’s flora and fauna during very specific times of the calendar year. He also spends time photographing wildlife. Tom’s pictures have appeared in various publications across the New York State.

4 Responses

  1. Peter H says:

    Tom, this is a great article.

    One of the very first things that Gould Hoyt taught forestry students, was to always leave some dead snags for wildlife. It’s the simple things like this that are the essence of stewardship.

  2. catharus says:

    Very good article summarizing wildlife and biodiversity value of unmanaged forests. Thank-you!

  3. William Deuel,Jr says:

    I had written a response to another article last night in reference to dead woods. I do agree with what you have written in your article as these dead woods certainly have their place and I am all for it. An area logged in the correct way also has it’s place and all I would like to see is a balance between the two. It has been done and can still be done if we are willing to put in the effort. I have seen this balance on the Finch lands for many years. Rather than all the sniping that has been going on in regards to the land deal in the park I am looking for some common sense solutions that can benefit all parties involved.

  4. Great article and a great debate in the Adirondacks that has gone on as long as I remember. Just to add to the mix, I found that breeding songbirds didn’t care so much about whether they were living in wilderness or resource management in the Adirondacks (Glennon and Porter 2005), but I found more small mammals in old growth woods than I did in managed woods (Glennon and Porter 2007). I agree with the above commenter that my experience on Finch lands was that they did a great job of retaining some of those features we know to be so important. No simple answers in ecology, but thank you for highlighting the diversity of critters that benefit from all parts of the forest environment.

    Michale Glennon