7. Coarse woody Debris – Animals / Endangered Species
227. The question is this - Looked for shrews – “specifically where”
“how” “when” “how many times”?
228. Symplastless trees, especially with soil contact act as a storehouse
for moisture providing moisture for plants and animals during dry times such
as summer so called drought (Page-Dumroese, Harvey, Jurgensen and Graham,
229. Preservation of a threatened or endangered species involves preservation
of its habitat and the diversity that habitat entails. When such becomes
a goal of forest management, managers need information not only on owls or
small mammals, but also on the mycorrhizal fungi that form the base of the
food web. Removal of ectomycorrhizal tree hosts removes the energy
source of ectomycorrhizal fungi, which will not fruit without their host
plants (Amaranthus, Trappe and Bednar, 1994).
230. Many insects and animals eat fungi and disperse the spores and
probably occur through all decay stages of a tree. The fungal grazers
are food for predators, so the animal-plant interactions are a prelude to
animal-animal interactions (Maser and Trappe, 1984, pg 29-par 2)
231. ...dying and symplastless wood provides one of the two or three greatest
resources for animal species in a natural forest. ..if fallen timber and
slightly decayed trees are removed the whole system is gravely impoverished
of perhaps more than a fifth of its fauna (Maser and Trappe, 1984, pg1-par1).
( The USFS practicing foresters call removal (killing) - “reforestation”).
232. Certainly our knowledge of biological processes and their interactions
within forest is incomplete, and we know too little about the cumulative
effect of a wide range of stresses on the ecosystem. But integrative research
at the ecosystem level shows clearly that the many processes operating within
forest inter-connect in important ways. Further, diversity of microscopic
and macroscopic plant and animal species is a key factor in maintaining these
processes (Maser, Tarrant, Trappe and Franklin, 1988, pg1-par2).
Maser et al. (1979) reported that 178 vertebrates use logs in the Blue Mountains
14 amphibians and reptiles, 115 birds, and 49 mammals; they tabulated use
by log decay classes for each species. Logs are considered important
in early successional stages as well as in old- growth forests. The
persistence of large logs has special importance in providing wildlife with
habitat continuity over long periods and through major disturbances (Franklin,
Cromack, Kermit, et al. others, 1981).
233. Logs become habitat for a variety of invertebrate species shortly
after falling. CWD is used by invertebrates as a source of food, for nesting
and brooding sites, for protection from predators and Environmental extremes,
as a source of construction material, and as overwintering and hibernating
sites (Samuelsson et al. 1994) (Voller and Harrison, 1998).
234. Debris has many functions ranging from soil protection to wildlife
and microbial habitat. The management of coarse woody debris is critical
for maintaining functioning ecosystems (Graham, Harvey, Jurgensen, Jain,
Tonn and Page-Dumroese, 1994).
235. Coarse woody debris plays numerous roles in providing habitat
for organisms in ecosystems (Voller and Harrison, 1998).
236. Many invertebrates use or require particular species, and different
communities of invertebrates occupy and use different decay stages
(Harmon al. 1986; Samuelsson et al. 1994) (Voller and Harrison, 1998).
237. Insectivorous species such as woodpeckers, small mammals and bears
forage on insects dwelling in CWD (Maser et al. 1979; Maser and Trappe 1984;
Samuelsson et al. 1994) (Tables 7.3 Id 7.4). Coarse woody debris has been
found to provide thermal and security cover for a variety of small mammals
in British Columbia (Voller and Harrison, 1998).
238. Forest floor diversity is partly maintained by windthrown trees
that create a pit-and-mound topography as they are uprooted (Maser, Tarrant,
Trappe and Franklin, 1988, pg34-par2).
239. About 140 years are needed for essential elements to cycle in
large, fallen trees and more than 400 years for such trees to become incorporated
into the forest floor; they therefore interact with the plants and animals
of the forest floor and soil over a long period of forest and plant successional
history (Maser, Tarrant, Trappe and Franklin, 1988, pg37-par2).
240. Symplastless trees are structural components of great importance
for forest dynamics and forest biodiversity. The decomposition of trees
provides an important link in cycling of nutrients and essential elements
in ecosystems. In addition, many species of plants, fungi, and animals
are dependent on symplastless trees for nutrients, essential elements, habitat
or substrate and nesting (Kruys and Jonsson, 1999).
241. Fallen trees that are oriented along the contours of a slope seem
to be used more by vertebrates than are trees oriented across contours, especially
on steep slopes. Large, stable trees lying along contours help reduce erosion
by forming "a barrier to creeping and raveling soils.” Soil, nutrients
and essential elements deposited along the up slope side of fallen trees
reduce loss of nutrients and essential elements from the site. Such spots
are excellent for the establishment and growth of vegetation, including tree
seedlings. Vegetation becomes established on and helps stabilize this
"new soil", and as invertebrates and small vertebrates begin to burrow into
the new soil, they not only nutritionally enrich it with their feces and
urine but also constantly mix it by their burrowing activities (Maser and
Trappe, 1984 pg 4-par1&2).
242. As a log decomposes, many organisms such as plant roots, mites,
collembolans, amphibians, and small mammals, must await the creations of
the inner space before they can enter. The flow of plant and animal
populations, air, water, and nutrients as well as essential elements between
fallen tree and its surrounding increases as long as aging process continues
(Maser and Trappe, 1984, pg 12-par1).
243. The logs being removed would otherwise serve a key role as erosion
control and animal activity (Page-Dumroese, Harvey, Jurgensen and Graham,
244. Besides nitrogen, Calcium , Magnesium , Potassium, Phosphorus
and other essential elements play key roles in soil, plant and tree health
as well as the health of the other associated living organisms (Page-Dumroese,
Harvey, Jurgensen and Graham, 1991).
245. The interactions of fallen trees with soil are directly affected
by steepness of slope and ruggedness of terrain; a fallen tree on flat ground,
for example, is much more likely to contact the soil over its entire length
than is one oriented either across or along contours on steep or rough terrain.
The proportion of a tree in contact with the soil affects the water-holding
capacity of the wood (Graham 1925). In our studies of fallen trees in old-growth
Douglas-fir forests, the moisture retention through the summer drought was
best in the side of trees in contact with the soil. The moisture-holding
capacity of the wood affects in turn its internal processes and therefore
the succession of plants and animals. In addition, the orientation of a fallen
tree to aspect and compass direction and the amount and duration of sunlight
it receives, drastically affect its internal processes and biotic community
(Maser and Trappe, 1984 pg 4-par3).
246. Various mites, insects, slugs, and snails feed on higher plants
that become established on so called rotten wood. These plants also
provide cover for animals, as do the lichens, mosses, and liverworts that
colonize fallen trees in decay class IV. Wood-boring beetles, termites,
and carpenter ants produce channels in heartwood (heartwood forming trees)
that provide passageways for roots. The fruiting bodies of the mycorrhizal
fungi, produced from energy supplied by the host plant, can also be a major
source of food for insects, arthropods, and small mammals such as the California
red-backed vole (Maser and Trappe, 1984, pg 29-par 4).
247. As the bark becomes loose on a late class II fallen tree, lungless
salamanders (Family Plethodontidae) join the internal community. Three species
of salamanders are associated, as predators. with rotten 'wood in western
Oregon: Oregon slender salamander, Oregon salamander, and clouded salamander
(Maser and Trappe, 1984, pg34-par1).
248. Decayed heartwood, i.e., of heartwood
forming tree species, splits into chunks; roots grow down the resulting
cracks as well as along insect channels. Invertebrates – from minute
mites to centipedes, millipedes, slugs, and snails – find shelter in these
openings and passage along them. Vertebrates such as salamanders, shrews,
shrew moles, and voles, find cover under debris of sloughed bark and so called
rotten wood alongside the class IV tree; they also find the so called rotten
wood on the underside of the tree crumbly enough for digging tunnels or burrows.
Fungi and other microorganisms abound on the wood itself as well as on the
new substrates offered by the feces of animals (Maser and Trappe, 1984, pg
249. Colonization of decomposing wood by animals helps microbes to
enter interior surfaces of the wood and creates additional openings for entry
of water and essential elements; and penetration of the wood by roots of
trees, such as western hemlock, facilitates entry by mycorrhizal fungi (Which
is the base of the food web) (Maser and Trappe, 1984, pg19-par4).
250. One salamander, the clouded salamander, frequents so-called rotten
wood, particularly Douglas fir in late classes II through IV. These
salamanders are often found under the loose bark of large fallen trees in
spaces excavated by, wood - eating insects. In fact, young clouded
salamanders show a striking affinity for bark (McKenzie and Storm 1970).
It has been found twenty feet up in standing trees (Maser and Trappe, 1984,pg34-par6).
251. The final level of predation within large so called rotten, fallen
Douglas Firs in class III through V is probably that of small mammals, such
as shrews and shrew moles (Maser and Trappe, 1984, pg 35-par2).
252. Shrews are small, with short legs, tiny eyes, and long, pointed
noses. Although they cannot see well, their senses of touch, smell, and hearing
are acute. The common shrew in western Oregon Douglas-fir forests is
the Trowbridge shrew. This small, “nervous” mammal is abundant around fallen
trees, particularly classes III and IV, that are well settled on the forest
floor and have been in place long enough to act as shrew’s grocery.
The Trowbridge shrew has the most catholic diet of western Oregon shrews.
It eats at least 47 types of food, the most important of which are centipedes,
spiders, internal organs of invertebrates (probably mostly beetles), slugs
and snails. In addition, it shows a definite affinity for fallen trees,
as does some of its prey (Maser and Trappe, 1984, pg35-3). The shrew-mole is
ideally equipped to forage in and around fallen trees because its nose is
extremely sensitive to touch, it is much like a blindman’s cane. In
almost constant motion, it quickly identifies any object it contacts.
Further, this mole’s size, adaptions for digging, and Herculean strength
make it an efficient, burrowing predator within and beneath so called rotten
wood (Maser and Trappe, 1984,pg35-par6).
253. Fungi feeders, E.g., California red-backed voles to black tailed
deer, may obtain some of their protein nitrogen from decaying trees by feeding
on fungal fruiting bodies, such as what some call truffles and mushrooms
(Maser and Trappe, 1984, pg 36-par 3).
254. As a fallen tree decomposes, it creates a gradually changing myriad
of internal and external habitats. Plant and animal communities within
a fallen tree are very different from those outside, but both progress through
a series of orderly changes. As a fallen tree decomposes, its internal structure
becomes simpler, whereas the structure of the plant community surrounding
the fallen tree becomes more complex (Maser and Trappe, 1984, pg 36-par7).
255. The manner, which a fallen tree comes to rest on the forest floor greatly,
influences subsequent diversity of both external and internal plant and animal
habitats. The decomposing fallen tree provides a changing spectrum
of habitats over many decades’ even centuries. It provides diversity
within a given successional stage and forms a physical-chemical link through
the many successional stages of a forest (Maser, Tarrant, Trappe and Franklin,
256. A fallen tree interacts with its environment through internal
surface areas. A newly fallen tree is not yet a habitat for plants or most
animals. But once organisms gain entrance to the interior they consume and
break down wood cells and fibers. Larger organisms – mites, collembolans,
spiders, millipedes, centipedes, amphibians, and small mammals must await
the creation of internal spaces before they can enter. The flow of
plant and animal populations, air, water, and essential elements between
a fallen tree and its surroundings increases as decomposition continues (Maser,
Tarrant, Trappe and Franklin, 1988, pg42-par2).
257. A fallen tree oriented along the contour of a slope. The upslope
side is filled with humus and inorganic material that allows invertebrates
and small vertebrates to tunnel alongside. The downslope side provides protective
cover for larger vertebrates. When under a closed canopy, such trees are
also saturated with water and act as a reservoir during the dry part of the
year (Maser, Tarrant, Trappe and Franklin, 1988,pg 45-fig 2.9).
258. Habitat Function. Logs provide essential habitat for a variety
of invertebrates and vertebrates. They are used as sites for lookouts, feeding
and reproduction, protection and cover, sources and storage of food, and
bedding. The high moisture content of logs makes them particularly important
as habitat for amphibians (Franklin, Cromack, Kermit, et al. others,
259. Logs may contribute significantly to reestablishment of animal
populations by providing pathways along which small mammals can venture into
clearcuts and other bare areas. This has relevance to the reestablishment
of tree seedlings on bared areas since survival and growth of new trees depend
on development of appropriate mycorrhizal associations. Surprisingly, fungal
symbionts apparently disappear from cutover areas shortly after their host
trees are removed (Harvey et al. 1978a), and the sites must be reinoculated
with their spores. Many mycosymbionts have underground fruiting bodies and
completely depend on animals for dissemination of spores. Small mammals are
the vectors. They consume the fungus and carry spores to new areas, thereby
inoculating tree seedlings (Maser et al. 1978a, 1978b; Trappe and Maser 1978)
(Franklin, Cromack, Kermit, et al. others, 1981).
260. Sound CWD provides secure travel corridors for small mammals (Maser
et al. 1979; Maser and Trappe 1984; Carter 1993), and provides subnivean
habitat during winter. The value of this habitat is positively correlated
with piece size (Maser and Trappe 1984; Hayes and Cross 1987; Carter 1993).
Nordyke and Buskirk (1991) found that southern red-backed vole abundance
was positively correlated with the decay stage of logs in the central Rocky
Mountains. Maser and Trappe, (1984) and Rhoades, (1986) reported associations
of small mammals with CWD because of the food source provided by the fungal
fruiting bodies growing in and on the CWD (Voller and Harrison, 1998).
261. Gyug (1993) reported that fur-bearers (martens and weasels) used
clearcuts with logging debris more than those with no CWD; however, the level
of use was much less than that of the adjacent forest (Voller and Harrison,
262. The value of CWD to mustelids (particularly martens, weasels,
and fishers) is well documented (Baker 1992; Corn and Raphael 1992; Lofroth
1993; Buskirk and Powell 1994; Buskirk and Ruggiero 1994; and others) (Voller
and Harrison, 1998).
263. Martens select habitats partly on the basis of thermal microhabitats
(Taylor 1993), such as those provided by CWD (Lofroth 1993; Buskirk and Powell
1994; Buskirk and Ruggiero 1994). Corn and Raphael (1992) reported that martens
selected subnivean access points that had greater volumes of CWD, more layering
of logs, more sound and moderately decayed logs, and fewer highly decayed
logs than random sites (Voller and Harrison, 1998).
264. NOTE page 200 – 201 has charts on animals known now to be associated
with CWD (Voller and Harrison, 1998).
265. Aubry et al. (1988) found that some species of salamander were
most abundant around CWD. Dupuis (1993) concluded that salamander populations
in logged areas were limited by available moist microhabitats, primarily
because of a lack of large logs in intermediate and advanced stages of decay
(Voller and Harrison, 1998).
266. Salamanders use logs as reproduction sites, as foraging sites,
and for cover, and also lay their eggs in them (Table 7.5 pg202) (Samuelsson
et al. 1994) (Voller and Harrison, 1998).
267. Checklist of plants and animals – There are few checklists of
either plants or animals that inhabit fallen Douglas fir in Pacific Northwest.
[Let alone in other areas with other species in the USA – (Termed as profiles
or unique features)]. No checklist of the microorganisms in fallen
trees of western old-growth forest is available [I know of none in the east.];
the subject has hardly been studied. (Higher fungi have been cataloged
for many kinds of so-called rotten wood in Europe.) Lawton listed the
mosses that occur on so called rotten wood or stumps in the Pacific Northwest.
Deyrup (1975, 1976) has done a thorough job with insects and has identified
about 300 species associated with fallen Douglas fir. The only published
checklist for vertebrates that use fallen trees is for northeastern Oregon
(Maser and others 1979 not listed in references here). (Maser
and Trappe, 1984, page 18-par 2)
268. Some of the mycorrhizal fungi that inhibit both mineral soil and
so called rotten wood develop much more strongly in the wood than in the
soil, and some appear to be restricted to so called rotten wood (Maser and
Trappe, 1984 pg 29-par 1). Mycorrhizae increase plant vitality and
therefore such materials that strengthen the latter also increase survival
of a species.
269. Conclusion: What purpose and need is there, that the capacity
and ability, of CWD, to function as habitat, foraging sites, protection,
reproduction sites, moist microhabitats, thermal microhabitats, secure travel
corridors, lookouts, feeding site, sources and storage of food, bedding over
many decades even centuries and a physical-chemical link through the many
successional stages of a forest go unobserved in this “Burn and Clearcut
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