Forest management with wildlife in mind

Often, I get questions from landowners about managing their forests, and about forest stewardship. Typically, one of the most important concerns and values landowners have been wildlife. I am often asked what can I do to promote wildlife habitat, while at the same time managing other things such as wildfire? We wanted to share some things that you can do while managing your forest to promote a diversity of wildlife, while still managing your fire-adapted Swan Valley forest.

Snags

Snags are standing dead trees, either full height or broken off at some point up the tree. Trees can die from things such as insects, diseases, wind breakage, or fire damage, which are all natural processes. As far as wildlife habitat goes, snags are a great thing to promote in your forest.  Woodpeckers, including pileated, hairy, downy, three-toed, and northern flickers to name a few, will all utilize snags in some fashion. These birds forage on insects living in the snags, such as bark beetles and wood boring beetles and pileated woodpeckers can excavate even further into a snag to get carpenter ants. Woodpeckers also utilize snags by excavating cavities for nests. In subsequent years, other cavity-nesting bird species, such as blue birds and nuthatches, as well as other species, will utilize those old holes for homes themselves. Small mammals such as squirrels, flying squirrels, and chipmunks will use hollowed out snags for caching cones for winter.  Bats will roost under the loose bark of larch and ponderosa pine snags, or in cavities or hollowed out snags.  As far as snags go, the bigger the better, and the more the better.  Trees that are broken off by wind make great snags for wildlife, because they tend to stand longer than full-height snags, as they are no longer as vulnerable to windthrow.  I don’t recommend having tall snags near structures, as just as any tree, there is always the possibility of them falling. But out in the woods, they are just part of a healthy, functioning forest.

There are a few techniques for creating snags intentionally. Some logging equipment have a cutting head on a boom that can be extended to different heights. During a logging or thinning project, equipment operators for certain trees can reach up with the boom as high as they can (for example 30-40’ up) and cut the tree off at that point instead of at ground level. This leaves the bottom part of the tree as a standing snag, while the upper part of the tree is still utilized for wood products for the thinning project. Another technique called girdling is simply using a chainsaw or axe to cut around at the base of the tree, just enough to sever the cambium layer (just inside the bark) but leaving the tree standing.  Doing this will cause the tree to slowly die and become a snag.  This technique works well, though sometimes the tree can break off at the girdled location, as rot will usually form at that point.  Regardless of how snags are created, they do provide good quality habitat for a diversity of species.  So, the next time a wind event breaks off trees on your property, or you are having a thinning project done, consider leaving some of the broken-off snags for the wildlife.

Wildlife patches, hiding cover

Many landowners we work with are concerned about wildfire and are planning on wildfire risk reduction thinning or logging projects, or are utilizing our cost-share fuels reduction program. The Swan Valley is a fire-adapted ecosystem. Fire is natural here and historically was much more common than currently due to our management practices. So, thinning and fuels reduction, especially around structures, infrastructure, and access roads, is critical to firefighter safety and improving the likelihood of structures surviving a wildfire. For general thinning the recommendation is a 10-foot-average crown spacing and the removal of small trees (known as ladder fuels) to reduce the risk of crown fire through a forest. Sometimes it’s good to leave small patches of un-thinned areas. These patches provide hiding cover for small mammals, such as squirrels and rodents, as well as grouse, songbirds, bears, deer, and elk.  The recommendation for untreated patches left in a thinning project is that they should be less than 1/10th of an acre in size, have a 20-foot crown spacing around the perimeter of the patch, and be located at least 300 feet from structures.  This type of variable tree spacing will help with mitigating fire risk without losing important wildlife hiding cover.

Downed wood, debris piles

Leaving some dead wood, such as large-diameter logs or isolated piles of sticks and branches out in your forest can provide a surprisingly high value habitat for small mammals such as squirrels, mice, voles, shrews, and the like.  These animals utilize complex structures of downed logs or brush piles for both nesting and foraging. These rodents are the basis of the food chain and owls, foxes, coyotes, bobcats, and pine marten hunt these small mammals and depend on them.  In winter I often see animals checking out logging slash piles or other natural downed woody debris piles as they hunt for small mammals.  If a large tree snaps off in a wind event, and I’m not going to use the wood for firewood, I burn most of the branches to reduce the fire risk and leave most of the bole of the tree on the ground to decompose back into the soil, as well as leave the standing snag. Doing this leaves the downed wood and the snag for wildlife, while removing most of the fire risk that is the needles and branches. In our fire risk reduction out in our forests and away from structures, sometimes leaving some dead logs and small piles of brush and sticks here and there can go a long way in providing habitat for a diversity of wildlife. 

 

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