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FOREST SERVICE HANDBOOK
DENVER, CO
FSH 2409.26 - SILVICULTURAL PRACTICE HANDBOOK
Region 2 Amendment No. 2409.26-96-10
Effective June 29, 1996
POSTING NOTICE: Amendments are numbered consecutively by Handbook
number and calendar year. Post by document name. Remove entire document and
replace with this amendment. Retain this transmittal as the first page of this
document. The last amendment to this Handbook was Amendment 2409.26-96-9 to
2409.26,10.
Document Name
2409.26,20
Superseded New
(Number of Pages)
--
Digest:
20 - This is a technical amendment to reformat chapter text.
ELIZABETH ESTILL
Regional Forester
11
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FSH 2409.26 - SILVICULTURAL PRACTICE HANDBOOK
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CHAPTER 20 - SPECIES SUMMARIES
20.1 - Introduction. Silvicultural techniques should vary by management
objectives, the environmental setting, and the species being managed. Most cutting
methods and/or other techniques will have some applicability to any given species
at some point in time. Consequently, no unyielding guidelines can be applied
without exception.
Within this broad context, however, methods that have been successfully used
within various cover types, and problems experienced with other methods, can be
discussed. The major regeneration methods and intermediate cutting methods are
discussed for each cover type.
State-of-the-art publications and other references listed in the Appendix shall be
kept on each Ranger District and used to supplement information in this Handbook.
21 - ENGELMANN SPRUCE - SUBALPINE FIR (SAF 206).
21.1 - Even-Age Silvicultural System.
21.11 - Clearcut Method. The resource objectives commonly met at least partially
by means of the clearcutting method includes snow management, water yield
increases, habitat diversity, insect and disease control, forage production, harvest of
very high windthrow risk areas, or to increase the proportion of a seral species such
as aspen.
Clearcutting can be used to meet management objectives in spruce-fir type. If
clearcuts are larger than a few acres in size, prompt regeneration through planting
is necessary if regeneration is to be assured within a reasonable time. Clearcuts on
southwest aspects have proven to be very difficult to regenerate regardless of size or
followup treatments.
Regeneration of clearcuts in spruce has been hampered in the past by lack of site
preparation, delay in planting, refusal to consider seral species such as lodgepole
pine, aspen, or subalpine fir in plainly seral situation, failure to change plans when
clearcuts resulted from blowdown or other unexpected loss of leave trees, or
unnecessary destruction of advance regeneration. None of these situations is
inherent with the method, but lack of regeneration success is more readily apparent
than in other methods.
21.12 - Shelterwood Method. The shelterwood method is most commonly used to
obtain natural regeneration in the type and to remove mature timber without
dramatic short-term changed affecting the visual resource.
A three-step variant of the method has been most successful and is most commonly
used. Situations where two-step or four-step shelterwood methods are desirable
also occur.
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In the three-step shelterwood, the first cut is often termed a preparatory cut and is
a light cut removing 10 to 20 percent of the basal area. In this type, the cut most
often is a test of windfirmness rather than to meet the textbook definition of
developing windfirmness. If significant numbers of leave trees blow down and are
salvaged promptly, the cut may have effect of a seed cut.
The second cut is usually scheduled within 10 to 20 years and removes 30 to 50
percent of the remaining basal area, and is usually termed a seed cut. The best
trees are retained to provide seed and shelter. If considerable advance regeneration
is present, the second cut may function as a removal cut.
The third cut removes all remaining mature trees not reserved for wildlife or other
purposes when the regenerated stand meets minimum stocking standards, normally
within 10 to 20 years following the seed cut. Care to prevent destruction of the
established understory during logging is especially critical for this treatment.
21.13 - Seed Tree Method. Under ordinary circumstances this method is not
suitable for spruce-fir type in Region 2.
21.14 - Commercial Thinning. This method is applicable to the type and is applied
to accessible, immature or poletimber stands. Stocking guides are given in the
Appendix.
Damage to residual trees from logging, windthrow or sunscald are concerns in
application of the method within the spruce-fir type.
21.15 - Sanitation - Salvage. This method is applied to remove dead, dying, insectinfested, or blown-down timber. Under many circumstances it will fill the role of
preparatory cutting, but under others it allows for stand tending until a
regeneration cut can be scheduled.
21.16 - Precommercial Thinning, Weeding, and Release. Precommercial treatments
are applicable to this type but are not needed as often as in types more prone to
overcrowding. If consistent with multiple use objectives, subalpine fir and aspen
are discriminated against to favor the more valuable spruce in thinnings.
21.2 - Uneven-Age Silvicultural System. Many Forest plans prescribe the unevenage silvicultural system for portions of the spruce-fir type.
21.21 - Single Tree Selection Method. The single tree selection method is most often
used to provide vertical diversity within a stand, to remove mature trees without
major disturbance to visual resources, to avoid blowdown, and to naturally
regenerate the type. The method is difficult and costly to properly apply and the
poor results often attributable to the method come form nondescript partial cuts or
high-grading that were labeled selection when described in the Environmental
Assessment and Plan.
To properly prescribe this method the desired diameter distribution or "J" curve
must be given. The shape of this curve is determined by the prescribed distribution
before marking guides can be prepared to remove trees from the appropriate
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diameter classes. Typical "J" curves for various "Q" factors are given in the
Appendix (to be written).
In practice, funding is seldom adequate to get the detailed stand examination and
silvicultural prescription needed. Consequently, marking crews usually get a
residual basal area and some general "cut the big and/or bad tree" admonitions and
the deed is done. The desired regeneration and progress toward the proper
diameter distribution is presumed to result from the harvest. Silviculturists must
strive to improve the application of this method if multiple use objectives are to be
met by it.
21.22 - Group Selection Method. The group selection method is most often
prescribed to meet the objectives described for small clearcuts or to take advantage
of existing group-like distributions in the stand. In Region 2 group cuts shall be 2
acres or less in size. A specified distribution of diameter classes shall be an
objective. If larger group cuts are desired or necessary, or distribution of diameter
classes is not an objective, even-age methods shall be used.
As with the single tree selection method, the stand must be viewed with the desired
distribution of size or age classes and the entries prescribed so that the objectives
for the stand can be met. To do otherwise is to again risk a degraded stand
condition after only a few harvest entries. Entries and groupings must be designed
so that mature groups will be available at each harvest entry and so that
regeneration is attainable on a timely basis. Also, control of the growing stock
levels in the groups not actually clearcut must be considered at each entry if
satisfactory growth of regenerated groups is to be attained. In practice, little more
than cutting of the designated groups is done, and improvement in application of
the method must be a goal of silviculturists if it is to be successful.
21.23 - Release and Weeding. To obtain the diameter distribution needed to sustain
production within uneven-aged stands, treatment of small or noncommercial trees
is needed. The method should be applied following each commercial entry. The
main objective is to be sure desirable trees are available for ingrowth and that
damaged or defective trees do not occupy a substantial proportion of the growing
space. A secondary objective on some habitat types is to slow the rate of progression
toward the more shade-tolerant subalpine fir by releasing spruce seedlings and
saplings.
Failure to fund and apply these treatments as needed can further account for
failure of uneven-age silviculture to meet expectations outlined in Forest Plans or
Environmental Assessments for the spruce-fir cover type.
22 - LODGEPOLE PINE (SAF 218).
22.1 - Even-Age Silvicultural System. The lodgepole pine type in Region 2 is most
easily managed using even-age silvicultural methods.
22.11 - Clearcut Method. The clearcut method is suitable for management of the
type because of silvical characteristics of lodgepole pine and utility of the method in
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controlling dwarf mistletoe in this species. Multiple use objectives for horizontal
diversity, forage production, and timber production are often served by this method.
Regeneration of the clearcuts can be by either natural or artificial means. Both
planting and direct seeding have been successful. Most clearcuts regenerate
naturally if carefully designed and executed. The serotiny of cones in the stand
being cut should be carefully considered in the regeneration and fuel hazard
treatments planned after logging. Conversely, serotiny is a highly heritable trait,
and choice of regeneration method can significantly affect serotiny in the next
generation.
22.12 - Shelterwood Method. The shelterwood method can be used when dwarf
mistletoe infection is at a low level or when the shelterwood method best meets
multiple use objective.
The two-step variant is most useful (seed cut and removal cut) because of the
intolerance of the species and less chance of exposure of seedlings to dwarf mistletoe
from the leave trees. Normally 50 percent or more of the basal area is removed at
the seed cut. The removal cut is normally scheduled within 10 years of the seed cut.
If the species to be regenerated is spruce or subalpine fir, the three-cut shelterwood
may be preferred. Three-cut shelterwood can be used if multiple use objectives are
highly constraining.
If regeneration depends on seed from the leave trees, nonserotinous individuals
should be selected for leave trees. This method will genetically discriminate against
the serontinous trait in lodgepole even if selection of leave trees is random.
22.13 - Seed Tree Method. The seed tree method may have some utility in windsheltered locations and nonserotinous stands. It is not widely applicable in the
lodgepole pine cover type.
22.14 - Commercial Thinning. Thinning strand through sale of posts, poles, rails,
mine props, or small sawlogs is normally desirable treatment in accessible stands of
overstocked lodgepole pine.
22.15 - Precommercial Thinning, Release, Weeding, and Sanitation Cuts. Lodgepole
pine regeneration can come in at very high stocking levels that result in stagnated
stands that will never reach commercial-size trees. Thinning between ages 10 and
20 may be essential if such stands are to provide more than vegetative cover. If
initial stocking levels are less than 2000 trees per acre, thinning should be delayed
until age 30. The thinnings may also include guidance that will modify species
composition or reduce dwarf mistletoe infection levels. Stocking guides are included
in the Appendix.
22.2 - Uneven-Age Silvicultural System. Uneven-aged silvicultural methods have
limited applicability in management of the type. Selection methods can be used to
convert lodgepole to more tolerant species. Unusual or overriding multiple use
constraints may indicate a need for specific silvicultural prescriptions to be
developed for application of uneven-age silviculture in the lodgepole pine cover type.
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23 - PONDEROSA PINE (SAF 237).
23.1 - Even-Age Silvicultural System.
23.11 - Clearcut Method. The clearcut method can be used in ponderosa pine to
favor habitat diversity, water yield increase, or forage production. In many
situations the type occupies dry sites where regeneration is costly and difficult.
Unless indicated by multiple use objectives, clearcutting is not normally the method
of choice for regeneration of ponderosa pine.
23.12 - Shelterwood Method. Shelterwood has proven to be the most successful
regeneration method in ponderosa pine in Region 2. It provides the best chance for
securing natural regeneration but may need supplemental planting and/or site
preparation in difficult circumstances.
A three-step method is often used throughout the Region, but good results can be
expected from two-step shelterwood cuts, especially in the Black Hills.
In the three-step method, the first cut is usually described as a preparatory cut. In
most cases, a silvicultural need for preparatory cutting does not exist and the
distinction between preparatory cutting and seed cutting is blurred. The second cut
is normally the seed cut and reduces the basal area to 40 square feet, more or less.
The best trees are retained to provide seed and shelter. If the preparatory cutting
has initiated regeneration, the second cut serves as a removal cut but also
establishes additional regeneration. The third cut is a removal cut. Logging
damage to the understory is the primary concern in implementing this cut.
23.13 - Seed Tree Method. This method may have limited applicability in Black
Hills ponderosa pine but otherwise is an unreliable method for obtaining
regeneration of the type.
23.14 - Commercial Thinning. Commercial thinning to remove small diameter
sawlogs is commonly practiced to enhance growth of residual trees or to improve
production of understory vegetation. The ponderosa pine is relatively resistant to
logging damage and not subject to rapid decay following basal scarring.
Consequently, successful implementation is readily attained if reasonable care is
taken during the logging. Stocking guides are shown in the Appendix.
23.15 - Precommercial Thinning, Weeding, Release, Sanitation. The need for these
treatments is similar to that for lodgepole pine. In many areas of the Region,
ponderosa pine is not prone to overstocking so the need may not be as pressing in
some areas as others.
23.2 - Uneven-Age Silvicultural System.
23.21 - Single Tree Selection Method. This method is sometimes applied to
ponderosa pine where stands are readily accessible and resource values (including
timber) are high. Purposes and drawbacks are similar to those discussed under
spruce-fir. Succession to white fir or Douglas-fir is a likely outcome on some habitat
types. Dwarf mistletoe, if present, can be expected to intensify. Difficulty in
obtaining regeneration can lead to gradual stand depletion. Appropriate "J" curves
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are shown in the Appendix. If, after one or two entries for this method, the number
of seedlings do not come up to the numbers indicated by the curve prescribed,
serious problems in sustaining production for the stand can be anticipated and
efforts to establish regeneration must be made.
23.22 - Group Selection Method. This method is most often applied where
ponderosa pine stands naturally occur in clumpy or group-like arrangements. Total
reliance on natural regeneration using this method is not possible on substantial
areas of the type in Region 2, and planting may be necessary.
23.23 - Release and Weeding. This precommercial treatment generally will be
needed to regulate the diameter distribution and to control species composition of
the submerchantable stand components. Damaged or diseased trees should also be
removed. Internal defect caused by scarring of stems during logging is not as
serious as in the spruce-fir type, consequently trees skinned up during the logging
can be retained if needed to meet the desired stocking.
24 - ASPEN (SAF 217).
24.1 - Even-Age Silvicultural System. In Region 2 the even-age silvicultural system
shall be used to manage aspen under all but the most unusual circumstances.
24.11 - Clearcut Method. Clearcutting is used almost exclusively to regenerate
aspen. Prompt regeneration from sprouts is readily attainable if mature trees are
harvested during the dormant season or late in the growing season. Most often, all
trees are cut, regardless of size. In some instances retention of dead or cull trees is
desirable for wildlife habitat or to help reduce snow damage to sprouts and
seedlings.
Aspen sprouts are desirable forage for big fame and livestock, and if animal
population levels are high they will completely eliminate the aspen after only a few
grazing seasons. Protection from grazing or browsing may be required, at least
until sprouts grow to a height above the reach of animals. Sites thus converted to
grass and forb communities are essentially permanent conversions, and techniques
to return such sites to tree cover have not been developed or implemented on a wide
scale in Region 2.
24.12 - Shelterwood Method. Shelterwood cutting is seldom necessary but may be
desirable in certain situations. Aspen sprouts and seedlings are sensitive to late
springs frosts and in frost-prone sites may benefit from shelter of the mature tree
until sapling or small pole sizes are reached. Some risk of favoring shade-tolerant
conifers will result from use of this method.
Presence of larger trees or dead stems may lessen damage to sprouts form snow
bending.
24.13 - Seed Tree. Not normally useful in aspen management.
24.14 - Commercial Thinning. Aspen is easily damaged by logging and the practice
tends to cause damage that more than offsets possible gains.
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24.15 - Precommercial Thinning. Aspen is reasonably good at self thinning.
Precommercial thinning in aspen is not authorized in Region 2.
24.16 - Weeding and Release. If retention of aspen cover on a site is necessary,
felling of spruce, subalpine fir, or other conifers may be needed to retard plant
succession.
25 - DOUGLAS-FIR - WHITE FIR (SAF 210).
25.1 - Even-Age Silvicultural System.
25.11 - Clearcut Method. Clearcuts may be used to meet objectives for habitat
diversity, forage production or water yield. This method can be prescribed to favor
establishment of seral stands of ponderosa pine. Unless very carefully designed and
in a favorable site, natural regeneration may not occur. Planting and site
preparation normally will be needed.
25.12 - Shelterwood Method. This is commonly used in Region 2 and is generally
successful. Both white fir and Douglas-fir are favored by the method as is limber
pine on some habitat types. Ponderosa pine, a valuable seral species, is
discriminated against.
The three-step variant is often used, but a two-step shelterwood should be equally
successful. Susceptibility to windthrow is not as severe as in lodgepole pine or
Engelmann spruce. Seed cuts with ponderosa pine providing a significant
proportion of the leave trees should be prescribed if this species is to be
perpetuated. Twenty to forty-five mature trees per acre are usually retained at the
seed cut.
25.13 - Seed Tree. The seed tree method has not been used extensively for this type
in Region 2. On most habitat types that support the type, drought or periodicity of
cone crops lessens the reliability of this method for obtaining regeneration.
25.14 - Commercial Thinning. The practice is appropriate in this type. White fir is
easily damaged by logging and is subject to rapid decay following basal scarring.
Douglas-fir and ponderosa pine are relatively resistant to logging damage and are
good choices for final crop trees. Stocking guides are given in the Appendix.
25.15 - Precommercial Thinning, Weeding, and Release. These treatments are
appropriate as needed. Stocking guides are given in the Appendix.
25.2 - Uneven-Age Silvicultural Systems. The uneven-age methods will tend to
favor white fir or limber pine over the less tolerant ponderosa pine or white fir. See
ponderosa pine for discussion of the cutting methods.
26 - LIMBER PINE (SAF 219), WHITEBARK PINE (SAF 208), BRISTLECONE
PINE (SAF 209), PINYON-JUNIPER (SASF 239), AND ROCKY MOUNTAIN
JUNIPER (SAF 220).
26.1 - Even-Age Silvicultural System.
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26.11 - Clearcut Method. Methodology for artificial reforestation with these species
has not been worked out in Region 2. Reliance on natural regeneration is thus
necessitated. As a consequence, clearcutting is not recommended as a method for
regeneration of these types unless local experience shows a reasonable expectation
of natural regeneration within 5 years.
26.12 - Shelterwood Method. The limited experience in Region 2 indicates that the
shelterwood with either the two-cut or three-cut variation offers the best prospect
for successfully regenerating these types., Refer to the discussion under spruce-fir.
26.13 - Seed Tree Method. Not recommended for these types.
26.14 - Commercial Thinning. See discussion for lodgepole pine. Accessibility and
product markets will determine feasibility for these types.
26.15 - Precommercial Thinning, Weeding, and Release. These treatments are not a
general practice, but if needed, recommendations for lodgepole pine should be
followed.
26.2 - Uneven-Age Silvicultural System. The prospect for successfully
implementing the more complex uneven-age regeneration methods in these types is
poor. Low product values, typically difficult to access, and low volumes all but
preclude uneven-age systems under normal circumstances. Use of uneven-age
regeneration methods may be warranted in specific situations where values are
high enough.
27 - WHITE SPRUCE (SAF 201), BLUE SPRUCE (SAF 216).
27.1 - Even-age Silvicultural System.
27.11 - Clearcut Method. The clearcut method has utility to increase habitat
diversity and water yields or to establish stands of seral species such as aspen or
ponderosa pine. It is not especially desirable for establishing natural regeneration
of either blue spruce or white spruce but can be successful on favorable sites.
27.12 - Shelterwood Method. Refer to discussion of shelterwood for spruce-fir. The
method can be expected to produce satisfactory regeneration of the types under
most circumstances.
27.13 - Commercial Thinning. Refer to guidelines for spruce-fir.
27.14 - Precommercial Thinning, Release, and Weeding. Refer to guidelines for
spruce-fir.
27.2 - Uneven-Age Silvicultural System. This system has applicability to these
types where accessibility is good and product values are high enough to permit its
use.
27.21 - Single Tree Selection. This method is often used. Roadsides, riparian areas,
and recreation sites often support these types, and retention of visual quality is
most easily obtained with this method. Refer to guidelines for spruce-fir.
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27.22 - Group Selection. Circumstances that would favor use of this method seldom
occur in these types.
27.23 - Release and Weeding. Refer to discussion of spruce-fir.
28 - BUR OAK (SAF 236), AND GAMBEL OAK.
28.1 - Even-Age Silvicultural System.
28.11 - Clearcut Method. These species reproduce almost entirely by sprouting
(coppice) in Region 2. Clearcutting rapidly and reliably regenerates these types. If
stands have trees of sufficient size, fuelwood demand will usually provide the means
to accomplish the treatment. The method is most useful to improve forage or
browse production.
28.12 - Shelterwood Method. This method may be prescribed to produce even-aged
stands while reducing visual impacts. Seed and shelter for the regenerating stands
is not usually a consideration.
28.13 - Seed Tree Method. Seed trees may provide wildlife habitat but usually have
no bearing on the regeneration process which occurs by sprouting.
28.14 - Commercial Thinning and Precommercial Thinning. Not generally useful in
these types.
28.15 - Release and Weeding. May be used to encourage oak by felling or conifers or
other tree species.
28.2 - Uneven-Age Silvicultural System. Either regeneration method under this
system may have applicability. Maintaining stands with larger diameter trees for
wildlife purposes is usually an objective for these methods. Economic incentive for
tree removal is concentrated entirely around the largest trees, so treatments are
difficult to implement. Investment in release and weeding treatments will be
needed to favor development of larger trees.
29 - COTTONWOOD WILLOW (SAF 235).
29.1 - Even-Age Silvicultural System. this riparian type is comprised of intolerant
seral species that can be expected to do well in even aged stand conditions.
29.11 - Clearcut Method. This method could be expected to successfully reproduce
the type. The riparian situation seldom permits a significant area of clearcutting,
however. Once the cut is made, protection of seedlings and sprouts from grazing is
essential if livestock are present.
29.12 - Shelterwood Method. If this method is used, a two-step variant would be
most successful for securing regeneration of the light-demanding cottonwood and
willow.
29.13 - Seed Tree Method. Not generally applicable to this type.
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29.14 - Commercial Thinning, Precommercial Thinning, Weeding and Release. Not
generally applicable to this type.
29.2 - Uneven-Age Silvicultural System. Group selection would be the preferred
uneven-age regeneration method if uneven-aged strands are necessary. Control of
livestock is needed to prevent excessive grazing of seedlings and sprouts that occur
in the openings. Release and weeding would not usually be needed in this type.