9. Coarse Woody Debris - Other Habitat and Potential Niches
280. The fasted way to destroy an organism is to destroy its niche
– the place where it lives and reproduces (A New Tree Biology Dictionary,
281. Large fallen trees are a finite resource that creates a myriad
of changing habitats through time as they decompose and recycle into the
forest soil and new, living trees benefit. (Maser, Tarrant, Trappe
and Franklin, 1988,pg45-fig216).
282. Often, decay classifications, are based on the external
of a fallen tree and do not adequately convey the internal diversity of niches.
We have found, however, that internal development of niches relates reasonably
well to decay class (Maser and Trappe, 1984 pg 5-par5).
283. We especially need to know more about the fallen tree – soil interface,
probably the single most important habitat and potential niche for the survival
of organisms in drastically altered systems (Maser and Trappe, 1984, pg49-par1).
284. Recent and current research in Old-growth forest are revealing
much about the roles and qualities of fallen trees. Understanding this
information may allow use of fallen trees as sensitive barometers of “habitat
health” of a system (Maser and Trappe, 1984, pg48-par1).
285. 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, 1981).
286. Fallen trees offer multitudes of both external and internal habitats
that change and yet persist through the decades. One needs an understanding
of the synergistic affects of constant small changes within a persistent
large structure to appreciate the dynamics of a fallen tree and its function
in an ecosystem (Maser and Trappe, 1984, pg 17-par 1).
287. 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, pg45-fig2.7).
288. 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 stand successional
history (Maser, Tarrant, Trappe and Franklin, 1988, pg37-par2).
289. During decomposition, logs and other forms of coarse woody debris
(defined as wood pieces more than ten centimeters in diameter and more than
one meter in length) reduce erosion and affect soil development, store essential
elements and water, provide a source of energy and nutrient flow, serve as
seedbeds, and provide habitat for decomposers and heterotrophs (Harmon and
290. During decomposition, logs and other forms of coarse woody debris
(CWD) reduce erosion, affect soil development, store nutrients and water,
are a potentially large source of energy (nutrients) and essential elements,
serve as a seed bed for plants, and form an important habitat for fungi and
arthropods (Kropp, 1982).
291. The flow of plant and animal populations, air, water, and essential
elements between a fallen tree and its surroundings increases as decomposition
continues (Maser and Trappe, 1984, pg 12-par1).
292. 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 and essential elements,
habitat or substrate and nesting (Kruys and Jonsson, 1999).
293. 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).
294. 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).
295. The logs being removed would otherwise serve a key role as erosion
control and animal activity (Page-Dumroese, Harvey, Jurgensen and Graham,
296. 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).
297. 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).
298. Large, fallen trees in various stages of decay contribute much-needed
diversity to terrestrial and aquatic habitats in western forests. When most
biological activity in soil is limited by low moisture availability in summer,
the fallen tree-soil interface offers a relatively cool, moist habitat for
animals and a substrate for microbial and root activity. Intensified utilization
and management can deprive future forests of large, fallen trees. The impact
of this loss on habitat diversity and on long-term forest productivity must
be determined because management need sound information on which to
base resource management decisions (Maser and Trappe, 1984, Abstract-par2).
299. Every living conifer is composed of tissues that perform specific
functions. When a tree dies, the various tissues provide distinguishable
substrates that provide different niches (Maser and Trappe, 1984 pg10-par-3).
300. As fallen trees progress from decay class I to class II, the scavengers
are replaced by competitors with the enzyme systems needed to decompose the
more complex compounds in wood. The fungi involved in this activity are often
mutually antagonistic, so that a given part of the tree may be occupied by
only one fungus that excludes others by physical or chemical means (Maser
and Trappe, 1984, pg 27-par4). (We call this altered area a
301. As the fallen tree progresses through decay Classes II and III
of decomposition, slippage of the bark, and eventually decayed sapwood, removes
a favorable environment and the organisms within it from the top and sides
of the tree; that material, however, does not disappear. Most of it
accumulates loosely alongside the log to provide a new habitat favorable
to many of the same organisms as before, plus larger animals, such as slugs,
snails, salamanders, and small mammals (Maser and Trappe, 1984, pg 29-par
302. It is in the class IV stage that the fallen tree presents the
most diversified habitat and hence supports the greatest array of inhabitants.
The decayed heartwood (of heartwood forming trees) is relatively stable,
so plants that become established on it have time to grow substantial root
systems (Maser and Trappe, 1984, pg 17-par 3).
303. 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).
304. External succession is related to the changes that take place
in the plant community surrounding a fallen tree. A fallen tree is a connector
between the successional stages of a community; it provides continuity
of habitat from the previous forest through subsequent successional stages.
A large fallen trees therefore provides a physical link – an essential element
savings account – through time and across successional stages. Because
of its persistence, a fallen tree provides a long- term, stable structure
on which some animal (both invertebrate and vertebrate) populations appear
to depend on for survival (Maser and Trappe, 1984, pg 38-par 1).
305. Machine entry on an area, which contains trees, reduces diversity
because heavy equipment fragments and scatters class IV and V so called rotten
wood. (Sorry to mention equipment) Habitat diversity declines to a
fraction of what had been available, probably fewer kinds of organisms can
thrive. Further, because woody substrates serve as long-term soil organic
material and essential element reservoirs, increasingly intensive timber
management, coupled with shorter rotations, could significantly alter the
role of decaying wood in the essential element cycling processes (Maser and
Trappe, 1984, pg 48-par 1).
306. 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, 42-par2).
307. Habitats, both external and internal, are influenced by tree size.
An uninterrupted supply of new, immature wood in young forests decomposes
and recycles essential elements and energy rapidly. Habitats provided by
the death of the symplast of young trees are short-lived and rapidly changing.
(E.g., specifically speaking, heartwood-forming trees lack chemical alterations
required for production on heartwood). In contrast, the less frequent,
more irregular mortality of the symplast of large trees in old forests is
analogous to slow-release fertilization. The lasting quality of large fallen
trees creates stable habitats in which large woody debris accumulates. Scattered
accumulations of large woody debris are associated with openings in the forest
canopy. Large fallen trees in such an area often contact each other physically,
creating external habitats of intense biological activity (Maser, Tarrant,
Trappe and Franklin, 1988, pg44-par2).
308. Decaying, fallen trees contribute to long-term accumulation of
soil organic matter, partly because the carbon constituents of well-decayed
wood are 80-90 percent residual lignin and humus. Decaying wood in the soil
and establishment of conifer seedlings and mycorrhizal fungi on dry sites
are positively correlated. Fallen trees also create and maintain diversity
in forest communities. Soil properties of pits and mounds differ from those
of surrounding soil; such chemical and topographic diversity in turn affects
forest regeneration processes. All this, especially large fallen trees
that reside on the forest floor for long periods, adds to spatial, chemical,
and biotic diversity of forest soils, and to the processes that maintain
long-term forest productivity (Maser, Tarrant, Trappe and Franklin, 1988,
309. 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).
310. So called rotten wood is also critical as substrate for ectomycorrhizal
formation. In one forest which contained coniferous trees, over 95 percent
of all active mycorrhizae were in organic matter of which 21 percent were
in decayed wood. In another study in the northern Rocky Mountains,
decayed wood in soil was important. In moist, mesic, and arid habitat
types (Harvey et al. 1979); it was the most frequent substrate for active
ectomycorrhizae on the dry site, probably because of high moisture levels
in the wood. Mycorrhizal fungi can colonize logs, presumably using them as
sources of water, essential elements and nutrients. (Franklin, Cromack,
Kermit, et al. others, 1981).
311. Coarse woody debris plays numerous key roles in providing habitat
for organisms in ecosystems (Voller and Harrison, 1998).
312. 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).
313. 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, 1988, pg41-par4).
314. 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 such as hickory –
(Termed as profiles or unique features of trees)]. 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
315. Conclusion: Logging does not increase habitat. System health
and habitat interconnect. What purpose and need is there, that the
capacity and ability, of CWD, to function as habitat, go unobserved, in the
“Burn and Clearcut Project”?
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