5. Coarse woody debris - Plant Bio-Diversity / Threatened and Endangered
142. Much is repeated from (#4. Coarse Woody Debris – Reduction
of Browsing of Sensitive Plants).
143. What makes a healthy tree or plant? The availability in the proper
proportions of the right "STEW" - Space, Temperature, Elements and Water.
And the energy of the sun will be used optimally making a tree into the most
efficient system on earth. Everything is recycled.
144. 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).
145. With respect to fallen trees. Furrows in the bark on the upper
side fill with leaf duff and provide sites for several years for seeds to
germinate. Where the bark is intact, seedlings generally die during
summer drought. If a seedlings roots find a crack or hole in the bark
and grow into the decomposed layer between bark and wood, however, it may
find enough moisture to survive the summer (Maser and Trappe, 1984 pg 25-par
146. Besides nitrogen, other essential elements such as Calcium, Magnesium,
Potassium, and 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).
147. We know some, at least, plants are likely, obligate CWD
user such as Red Hackberry (Vaccinium parvifolium) (Voller and Harrison,
148. 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).
149. Decomposition of fallen trees releases essential elements for
microbial and plant growth (Maser, Tarrant, Trappe and Franklin, 1988, pg37-par1).
150. Woody duff, regardless of type or size, takes considerably longer
to decompose than needle and leaf duff do. Needles, leaves, and small
twigs decompose faster than larger woody material and essential elements
are thereby recycled faster in the forest floor. 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).
151. 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).
152. ...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 calls removal (killing) - “reforestation”).
153. 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).
154. 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,
155. During decomposition, logs and other forms of coarse woody debris
(CWD) reduce erosion, affect soil development, store essential elements,
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).
156. The flow of plant and animal populations, air, water, and essential
elements between a fallen tree and its surroundings increases (Maser and Trappe, 1984, pg 12-par1).
157. 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 essential element in ecosystems
(Kruys and Jonsson, 1999). 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,
158. 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).
159. Plant-nutrient –essential element. The succession of plants
on fallen trees is mediated by changes in essential element availability
and physical properties over time. Three broad phases can be defined:
initial, optimal, final. Early invaders prepare the tree for later colonization
by altering its physical and chemical properties during the initial phase.
The altered tree provides the best substrate for a wide array of organisms
during the optimal phase. Ultimately, the depletion of essential elements
and physical deterioration of the wood during the optimal phase diminish
its value for many organisms, so fewer species inhabit the final phase (Maser
and Trappe, 1984, pg 25-par 5).
160. 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).
161. 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).
162. 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).
163. Fallen trees interact with essential element cycling processes
in a forest through such mechanisms as duff fall (freshly fallen or
slightly decomposed plant material from the canopy), throughfall (rain
or dew that picks up elements as it falls through the canopy), nitrogen fixation,
and essential element uptake by plants associated with the fallen trees (Maser
and Trappe, 1984, pg19-par2).
164. 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).
165. 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 tree 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).
166. 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).
167. The forest's character changes with succession. Net primary productivity
is greater in young forests than in old ones. Old forests conserve essential
elements, whereas very young forests are susceptible to erosion and essential
element loss. Forests of the Coast Range interior valleys produce less wood
than do those on more moist sites nearer the ocean. And internally, the old
managed forest is more diverse than many young and mid-age forests. Old forests
have deeper, multi layered canopies, larger accumulations, of coarse woody
debris (any symplastless standing or fallen tree stem at least 4 inches in
diameter at breast height (d.b.h.) on snags and at the large end on fallen
trees), and more specialized plants and animals than so called young forests
have (Maser, Tarrant, Trappe and Franklin, 1988, pg5-par3).
168. 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).
169. 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,
170. Logs also serve as sites for reproduction of tree species, especially
western hemlock. This is clearly an important function in natural stands
since these seedlings and saplings supply replacements as openings appear
in the overstory canopy. In one old growth stand at mid-elevation in the
Cascade Range, over 64 percent of the western hemlock and 4 percent of the
Pacific silver fir reproduction was rooted in so called rotten wood.
The phenomenon of nurse logs is widespread in the forest types of the Pacific
North- west. Minore (1972) found that seedlings of both Sitka spruce and
western hemlock was more numerous and taller on so called rotten logs than
on the adjacent forest floor at Cascade Head Experimental Forest (Franklin,
Cromack, Kermit, et al. others, 1981).
171. Coarse woody debris, functions as seed beds or nurse logs for
some trees species and many species of bryophytes, fungi, and lichens, and
some flowering plants (Table 7.6) (Samuelsson et al. 1994; D.F. Fraser, pers.
comm., 1995; E.C. Lea, pers. comm., 1995) (Voller and Harrison, 1998).
172, In the Crowsnest Forest, 40-70% of natural seedlings were rooted
in decayed wood in old growth and 24% were rooted in decayed wood in cutblocks
(S. Berch, pers. comm., 1995). CWD may be important to the establishment
of vascular plants around wet sites such as ponds and bogs (Voller and Harrison,
1998) (Voller and Harrison, 1998).
173. NOTE: Page 203 has a list of some vascular plants closely associated
with CWD in BC (Voller and Harrison, 1998).
174. We know other species are either associated with CWD or perhaps
with the fungi that use CWD as their parasitic intermediate, such as the
gnome plant (Hypopitis congestum), candystick (Allotropa virgata), and other
ericaceous species. Ryan and Fraser (1993) reported that cryptogam species
richness in coastal Douglas-fir forests was strongly influenced by available
substrate. In forested sites, the presence and rock substrates resulted
in substantial increases in species richness. The review of Samuelsson et
al. (1994) states that distinct Succession of bryophyte and lichen communities
occurs as trees die, fall, and decay. In B.C., known decomposer macrofungi
that are dependent on CWD include 162 species of bracket or shelf fungi/
conks, 364 species of other macrofungi, and some commercially harvested mushrooms,
such as oyster mushrooms (S. Berch, pers. comm., 1995). These communities
play roles in the germination and growth of other epiphytic and quasi-epiphytic
communities. Climatic factors influence epiphytic communities, with lichens
dominating drier ecosystems and bryophytes replacing them as conditions become
wetter. The longevity of individual pieces is critical to the persistence
of many species with poor dispersal abilities. Dispersal in many species
is from one log to the next, so logs close to each other are required. Samuelsson
et al. (1994) note that large logs play a more important role than small
logs in the ecology of bryophytes and lichens. Large logs last longer, have
greater surface area, and have higher, steeper sides that prevent ground-dwelling
species from invading. They may also be important in providing a relatively
duff-free substrate for the establishment of some species of cryptogams (D.F.
Fraser, pers. comm., 1995) (Voller and Harrison, 1998).
175. Plant species diversity on river bars is related to the area,
sediment, and woody debris of river bars (Malanson and Butler 1990) (Voller
and Harrison, 1998).
176. In class IV element content of the fallen tree at this stage may
exceed the original content because minerals have been added by duff fall
from the canopy and by throughfall of rain, have been brought in by animals
or have been translocated from underlying soil by fungi or roots. Nitrogen
may be added by similar means and by biological fixation. These circumstances
provide an excellent rooting medium for plants. A great variety of
fungi, both decomposers and symbionts, thrive in the complex of niches within
the fallen tree (Maser and Trappe, 1984 pg 26-par 5, pg 27-par 1).
177. 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)
178. Conclusion: What purpose and need is there,
that the capacity and ability, of CWD, to enhance the health of threatened
and endangered species go unobserved in this “Burn and Clearcut Project”.
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