Forest management treatment plans should always consider wildlife.
Careful site assessment provides an inventory of habitat components, locating nesting sites and other areas of concern.
Protection of riparian areas and springs, legacy trees (the oldest trees on a site), brush islands, and patches of healthy young trees encourages forest regeneration and maintains habitat values for wildlife.
Important habitat components are discussed below, but first let’s define what habitat is and what it does. The ecosystem of a site (its location, its components, and the arrangement of those components) provides habitat, allowing a species to “persist” over the long-term. Good habitat sustains local populations of a species.
· For plants, this means they are able to survive under a site’s climatic and geographic conditions and are able to successfully reproduce. Four components of habitat for plants are: (a) water, (b) light, (c) nutrients, and (d) space to grow.
· For animals, the persistence of local populations also requires survival and successful reproduction. But unlike plants, animals can adapt to climatic and geographic conditions by moving in daily and seasonal patterns, by modifying landscapes through activity, by constructing shelter or refuge, and by using tools. Four components of habitat for animals are: (a) water, (b) food, (c) shelter, and (d) space to move.
· Three vegetation types have been associated with high species diversity: shrubs and small trees, herbaceous vegetation, and woody debris.
In southwest Oregon, fire from lightning and from cultural burning by indigenous people has shaped the landscape for ages.
When fire comes through a forest landscape, it kills some stands, thins others, and misses some all together, creating a mosaic with patches of brush, groups of young trees, and older trees more widely spaced.
Important habitat components of this forest mosaic are: (a) standing dead trees (snags), (b) fallen logs, (c) legacy trees, (d) gaps and openings, and (e) patches and clumps.
In addition to retaining or creating these components, forest management treatment plans can include the construction of “habitat piles.”
Let’s look at each component. Keep in mind these are general guidelines for dry forest landscapes, and that all sites are different.
Some sites won’t have any large old trees at all. Some won’t have shrubs. The goal is to keep these components in mind when designing a forest management plan so that wildlife habitat can be maintained and improved.
· Snags have two types: (a) foraging snags and (b) cavity nesting snags. Smaller diameter snags provide habitat for insects, which are an important forage source for birds and other animals. Larger snags provide nesting and refuge for birds and other animals, and persist longest on the landscape.
· Guideline: 6-8 forage snags and 1-2 cavity snags per acre.
· Logs provide three important services. (a) They create habitat around and beneath them that stays cool and damp, reducing soil temperatures in the summer and providing refuge from the heat for animals. (b) As they rot, they slowly release nutrients into the soil. (c) They also retain soil on steep slopes and increase water residence time, improving groundwater recharge.
· Guideline: distribute logs evenly across the treatment area. Large logs have the greatest ecological value.
· Legacy trees are the oldest trees on a site. They provide a broader range of foraging and nesting types.
· Guideline: build your treatment plan around these legacy trees. Locate openings in areas where no legacy trees exist. Clear space around legacy trees equal to 1.5-2 times the canopy diameter. E.g. if a tree canopy is 40 feet wide, clear 60-80 feet out from the canopy edge.
· Gaps and openings are treeless areas. These gaps create space for shrubs and encourage grasses and herbaceous plants. Plants suppressed by the shade will regenerate in areas opened up by thinning.
· Guideline: long, winding corridors provide more habitat value than circular or square shapes.
· Patches and clumps include shrub islands and stands of young trees. Like openings, long shapes are preferred over circular or square.
· Guideline: consider locating patches along roads to provide visual screening for animals.
· Habitat piles are constructed from logs covered with fine branches. They provide den habitat and refuge for many animals. They also provide similar ecological benefits as downed logs. Piles should have 3-5 layers of larger logs stacked in a way that is stable and creates ample interior space. After layering the logs, cover the pile with fine branches and leaves. Larger interior space means larger animals can use the pile.
· Guideline: 1-2 habitat piles per acre. Place piles away from roads and away from trees. Locate piles in areas that lack large woody debris and in spots where erosion or water runoff is a concern. Consider pile creation in your slash management plan.
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