77. What makes a healthy tree or plant? The availability
in the proper proportions of the right "STEW" - Space, Temperature,
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.
78. Forest managers need to know what actually happens in order to
plan harvests that will protect essential element and nutrient cycles and
streams from low pH precipitation (Hornbeck, 1992, page 151).
79. Increasing demands for wood products, especially chips for fuel
and pulp, coupled with new, highly mechanized logging equipment are resulting
in more intensive harvesting of wood out of once fertile forests. When applied
in the form of whole-tree clear- cutting, intensive harvesting is a severe
disruption of forest nutrient cycles and
essential elements. The first 5-10
years after harvest are especially critical in terms of nutrient and essential
element transformations, movement, and loss from the ecosystem. (Hornbeck
et al., 1990, pg 55)
80. In New England, intensive harvesting (wood removal) in the form
of whole-tree clearcutting results in important losses of plant essential
elements such as Ca, K, and N. Shortages of plant-available essential
elements might develop in regenerating stands, particularly in the years
immediately after harvest when leaching losses and plant uptake are high.
Net losses in input-output budgets and preferential uptake by trees for essential
elements such as Ca suggest that there also could be essential element limitations
during future rotations. Until these concerns are researched more carefully,
whole-tree clearcutting should be applied with caution (Hornbeck et al.,
1990, page 63)
81. Research in old-growth Douglas-fir forests, have shown about as
much nitrogen accumulates in decaying, fallen trees as in the forest floor.
Other essential elements, such as calcium and magnesium also accumulate in
decomposing woody substrates. Although here we are concerned with Douglas
fir, neither decaying wood nor research data are unique to forests of the
Pacific Northwest (Maser and Trappe, 1984, pg16-par2).
82. Decomposition of fallen trees releases essential elements for microbial
and plant growth (Maser, Tarrant, Trappe and Franklin, 1988, pg37-par1).
Elements other than nitrogen such as calcium and magnesium,
also accumulate in decomposing woody substrate. (Maser and Trappe, 1984, pg
83. A snag may accumulate moisture – carried essential elements and
have a higher essential element capital when it falls than does a tree with
symplast (Maser and Trappe, 1984, pg 19-par 2).
84. Woody duff, regardless of type or size, takes considerably longer
to decompose than needle and leaf duff. 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).
85. Although nitrogen fixation in wood is modest compared with that
occurring in other substrates in forests, the persistence of decaying wood
allows small increments of nitrogen to accrue over many decades (Maser and
Trappe, 1984, pg 16-par3).
86. Further, decomposing wood undergoes changes in other chemical constituents
and pH as well as physical structure. Very old, decayed wood can even
become somewhat humified and leave long lasting substrate resistant to further
decay (Maser and Trappe, 1984, pg 16-par 4).
87. Decaying trees comprise considerable accumulations of mass, nutrients
and elements in unmanaged, old growth forest. Some of the largest accumulations
occur in the unmanaged forest of the Pacific Northwest. Coarse woody debris
can range from 130 to 276 tons per acre in stands from 100 to more than 1,000
years old. Although here we are concerned with Douglas fir, neither decaying
wood nor research data are unique to forests of the Pacific Northwest.
McFee and Stone ( 1966) Observed that decaying wood persisted for more than
100 years in New York and others pointed out that substantial accumulations
in old-growth forest in Poland. These observations evidence the long-term
continuity of decaying trees as structural components in forest (Maser and
Trappe, 1984, pg 16-par1).
88. Decayed logs on the floor of a once fertile forest are a reservoir
for nutrients as well as essential elements. They also 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,
1991). Note: Trees absorb of essential elements that are water-soluble
and dissolved in water. For the elements to enter the tree, moisture
89. Note: I say “so called” because many trees and animals would
have moisture during dryer times, i.e., if coarse woody debris were in place
and functioning over time as designed (A unique survival feature of a forest).
Thus, with the removal of CWD come several depletions, which include, but
are not limited to, the depletion of water, essential elements and nutrients
for plants and animals above as well as below ground. “The Demons Of
D” at work. So, drought is what we call the trigger puller, not the
primary agent causing lack of water during dryer times.
90. 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 nutrients
and water, provide a source of energy and essential element flow, serve as
seedbeds, and provide habitat for decomposers and heterotrophs (Harmon and
91. An important feature of woody debris is that nutrients are released
at slower rates than from fine duff. This slow release allows nutrients to
be retained within the ecosystem until tree production recovers. Timber harvest
and salvage after disturbance reduces this pool of stable nutrients and essential
elements (Harmon and Hua, 1991).
92. Few studies have examined processes, other than nitrogen fixation,
that are responsible for net changes in nutrient content of coarse woody
debris. It is tempting to assume that the processes are the same as in fine
duff, but recent research being conducted at Andrews indicates some differences.
For example, during the early stages of log decomposition, fungal sporocarps
transfer essential elements to the forest floor. Thus, in fine duff, fungi
immobilize nitrogen, but in coarse woody debris they actively transfer it
to the soil. Another important consideration in understanding nutrient release
from coarse woody debris is that tree boles are composed of several distinct
substrates. While wood may be slowly releasing nutrients, other parts such
as the inner bark (phloem) decompose and release nutrients at rates similar
to those of leaf duff. Hence an overall pattern of release from symplastless
trees may be a rapid loss of 10-20% of the nutrients followed by an extended
slower release of nutrients. Finally, the role of fragmentation in transferring
nutrients to fine duff in the later stages of woody debris decomposition
is not revealed by patterns of net accumulation. The omission of transfers
via fragmentation from previous calculations suggests (Harmon and Hua, 1991).
(NOTE: it may be specifically unclear whether the paper is referring
to essential elements or a true nutrient. Both exist, and are
essential for system health.)
93. 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. Despite growing recognition that symplastless trees play major
roles in ecosystem function, many aspects of the specific processes involved
are poorly understood. Consider, for example, the importance in forest
essential element cycles. Aside from nitrogen fixation, few studies have
directly examined the processes responsible for the net changes in essential
element content of decaying wood. The actual proportion of tree nutrition
that is derived from CWD is not known (Kropp, 1982).
94. Symplastless trees are structural components of great importance
for forest dynamics and forest biodiversity. The decomposition of trees
provides an important link in cycling on 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).
95. Soil, nutrients and essential elements deposited along the up slope
side of fallen trees reduce loss of nutrients 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).
96. 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).
97. Duff fall and throughfall are major pathways for the flow of essential
elements and energy within forests, they contribute essential elements,
nutrients and water to so-called rotten wood. The larger a fallen tree, the
more duff it accumulates on its surface and the more essential element -
rich moisture it intercepts from the canopy. The moisture gathers essential
elements as it passes through the accumulated duff and soaks into the fallen
tree (Maser and Trappe, 1984, pg 19-par 2).
98. CWD, and the associated epiphytic bryophytes act as both essential
element and moisture buffers for the ecosystems (FEMAT, 1993). This buffering
allows the slow release of water and essential elements to surrounding plants.
In mature and old growth coastal forests, a large proportion of western hemlock
and Sitka spruce seedlings germinate and grow on CWD substrates (Harmon and
Franklin 1989; G. Davis, pers. comm., 1994).
99. The main chemical differences among substrates are: (1) nitrogen
content; (2) mineral or ash content-phosphorus. Potassium, calcium, magnesium;
(3) the carbon matrix-cellulose, lignin, pentosans and (4) the content of
other organic compounds-waxes, pigments, carbohydrates, fats,
resins, phenolic compounds (Maser and Trappe, 1984 pg11-par2).
100. Plant - essential elements. 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).
101. 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).
102. In addition, coarse woody debris has the potential to store a
large amount of carbon in the ecosystem. The role of coarse woody debris
in storing carbon is often overlooked, with only living plants or soil carbon
being considered. Relatively little is known about the formation and rate
of decay of coarse woody debris or the factors controlling these processes,
despite the relevance of this information to the global carbon cycle (Harmon
and Hua, 1991).
103. 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,pg27-par4). (We call this altered area a
104. The decomposing wood of a fallen tree serves as a savings account
of essential elements and organic material in the forest soil (Maser and
Trappe, 1984, pg 16-par2).
105. 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).
106. Ground contact by fallen trees creates opportunities for various
interactions with the biotic components of soil and duff. Fungi, for instance,
translocate essential elements within the soil- system, as both decomposers
and root symbionts. Fungi also immobilize translocated essential elements
and thereby enrich the decomposing wood substrates they inhabit. In addition,
the colonization of decomposing fallen trees by nitrogen-fixing bacteria
permits additional nitrogen accretion within the decaying wood (Maser and
Trappe, 1984, pg 19-par 3).
107. Western hemlocks colonize so-called rotten wood over many decades
to insure long-term interactions by root zone processes. Decaying wood thus
serves as a savings account of soil organic materials and essential elements
in forest (Maser and Trappe, 1984, pg19-par4).
108. Internal succession is also influenced by temperature, moisture,
and stage of decay. A class I fallen tree, for example, has many readily
available essential elements that support opportunistic colonizers. As decay
proceeds its moisture holding capacity increase but essential elements become
less available because either they have been used or the remain locked in
the more decay resistant compounds of the wood. Ultimately, the rapidly
growing opportunists are succeeded by organisms with more sophisticated enzyme
systems, and decay continues (Maser and Trappe, 1984, pg37-par2).
109. 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).
110. Machine entry on an area, which contains trees, reduces diversity
because heavy equipment fragments and scatters class IV and V so called rotten
wood. 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).
111. Humus formation is important in regulating the incorporation of
nitrogen into humic materials. Because of its high cation exchange
capacity and slow decomposition, so called rotten wood can retain available
mineral nitrogen from throughfall and decomposition as well as organic nitrogen
compounds mineralized within the wood chemical matrix. Roots and mycorrhizae
of plant species that colonize decaying wood use its available nitrogen (Maser,
Tarrant, Trappe and Franklin, 1988, pg40-par2).
112. The long-term input by nitrogen fixation in decaying fallen trees
and by canopy inhabiting lichens maintains a positive balance of nitrogen
in the ecosystem (Maser, Tarrant, Trappe and Franklin, 1988, pg40-par5).
113. Decaying wood has long-term potential for contributing nitrogen
for tree growth as residual lignin and humus are decomposed (Maser, Tarrant,
Trappe and Franklin, 1988, pg41-par1).
114. With respect to tree maturity, habitats, both external and internal,
are influenced by tree size – maturity ( Internal Regulating System). 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, species of young trees, which produce protection
wood such as heartwood, would have not formed 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).
115. 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,
116. Mycorrhizal fungi can colonize logs presumably using them as sources
of water and essential elements. (Franklin, Cromack, Kermit,
et al. others, 1981).
117. Coarse woody debris is a significant factor in essential element
cycling processes (Harmon et al. 1986; Caza 1993). Although the relative
concentration of essential elements in wood and bark is low, much of the
essential elements capital and carbon are stored here because of the large
biomass involved (Harmon et al. 1986; Caza 1993) (Voller and Harrison, 1998).
118. Symplastless wood facilitates a slow release of essential elements,
ameliorates leaching, and provides a growing substrate for bryophytes. These
buffer water and essential element release from duff and aboveground processes,
especially processes such as nitrogen fixation in aboveground plants such
as hepatics (Harmon et al. 1986; FEMAT 1993; Samuelsson et al. 1994) (Voller
and Harrison, 1998).
119. Free-living bacteria in woody residues and soil wood fix 30-60%
of the nitrogen in the forest soil. In addition, 20% of soil nitrogen is
stored in these components (Harvey et al. 1987). Harmon et al. (1986) reported
that CWD accounted for as much as 45% of aboveground stores of organic matter.
Symplastless wood in terrestrial ecosystems is a primary location for fungal
colonization and often acts as refugia for mycorrhizal fungi during ecosystem
disturbance (Triska and Cromack 1979; Harmon et al. 1986; Caza 1993) (Voller
and Harrison, 1998).
120. Colonization of symplastless wood by fungi and microbes may be
one of the most important stages in essential element cycling (Caza 1993);
however, these processes are still relatively poorly understood. Soil wood
contains a disproportionate amount of the coniferous non-woody roots or ectomycorrhizae
in forests (Harvey et al. 1987). As one of the dominant sources of organic
matter, symplastless wood is an important determinant in soil formation and
composition (Caza 1993) (Voller and Harrison, 1998)
121. Symplastless wood provides physical structure to the ecosystem
and fills such roles as sediment storage (Wilford 1984), protecting the forest
floor from mineral soil erosion and mechanical disturbance during harvesting
activities. It ameliorates the affects of cold air drainage on plants, helps
stabilize slopes, and minimizes soil erosion (Maser et al. 1988). Symplastless
wood provides elevated germination platforms with reduced duff fall accumulation
and relatively consistent moisture regimes (Harmon et al. 1986; Maser et
al. 1988; Caza 1993; D.F. Fraser, pers. comm., 1995). In stream ecosystems
it protects stream banks from erosion and maintains channel stability (Triska
and Cromack 1979; Sedell et al. 1988). Features that influence the ability
to fulfill these functions include size (length and diameter), whether roots
are still attached, orientation, degree of burial, and proportion of the
piece that remains submerged (Sedell et al. 1988) (Voller and Harrison,
122. The substrate of poorest quality is the decay-resisting outer
bark, which is low in moisture, carbohydrates, cellulose, and carbon to nitrogen
(C:N) ratio but high in lignin, taxifolin, total extractives, and density.
(Maser and Trappe, 1984 pg 1-par4 ).
123. 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).
124. Conclusion: What purpose and need is there, that the capacity
and ability, of CWD, to function as a nutrient and essential element storehouse,
go unobserved in this “Burn and Clearcut Project”? Technical reports
clearly point out that the long-term continuity of decaying trees, are structural
components of forests. CWD are reservoirs for nutrients as well as
essential elements for long periods of time. CWD provides a source
of energy and essential element flow. Timber harvest and salvage after
disturbances reduces pool of stable nutrients and essential elements. Symplastless
trees are structural components of great importance for forest dynamics and
forest biodiversity. Many species of plants, fungi and animals are
dependent on symplastless trees for nutrients, essential elements, habitat
or substrate and nesting. The benefits and their persistence, in the cycling
of essential elements and providing nutrients is a function which contributes
to system health and a obligatory function to operate at a high quality state,
i.e., operating about the means in which is was designed. Therefore
the removal of such materials that would provide a physical link – an essential
element savings account – through time and across successional stages is
not indicative or technically published to be, a treatment, which would protect
or increase forest health. In all honestly, it will reduce protection
thus forest health as well.
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