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2409.17 - SILVICULTURAL PRACTICES HANDBOOK
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CHAPTER 6 - TIMBER STAND IMPROVEMENT
The direction included in this chapter has been developed through the coordinated efforts of
Regions 1, 2, 3, and 4. This coordination was initiated by the leadership of each Region under
the concept of shared services. All four Regions must concur on future changes to the direction.
Users of information in this handbook must be familiar with the parent information in FSM
2476.
6.05 - Definitions. Definitions for silvicultural practices and systems are found in FSM 2470.5 Definitions. The accepted reference list of definitions can be found in Volume 1 of Terminology
of Forest Service, Technology, Practice and Products edited by F.C. Ford-Robertson (Volume 1)
produced by the Society of American Foresters 1971. There is a current effort to define and
update terminology, but to date it has not been finalized. A draft copy of this work is available
from Regional Silviculturists. Terminology and definitions used in this handbook are defined
using the FSM and Volume 1. All practitioners in timber stand improvement should use these
for activities conducted on National Forest System lands.
6.1 - INVENTORY AND PLANS. Timber stand improvement includes any intermediate
treatment, commercial or precommercial, after establishment and before the final harvest to
improve composition, structure, condition, value, and increment of the stand. Timber stand
improvement is an important part of managing timber stands to achieve management goals and
objectives for forest vegetation. Knowledge in the following areas is important to implementing
timber stand improvement activities:
1. Timber stand composition and structure.
2. Ecological and historical character of individual trees and timber stands, including
genetic factors.
3. Methods of treatment and potential results.
4. Existing and potential markets available and economic feasibilities.
5. Possible destructive agents.
6.11 - Timber Stand Improvement Process. Exhibit 01 displays the proper process for
identifying, developing, planning, and accomplishing a timber stand improvement project.
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6.11 - Exhibit 01
Assessment
↓
Range Of Choices
↓
Environmental Analysis
↓
Preferred Alternative
↓
↓
Alternatives Not Economically or
Environmentally Acceptable
Final Silvicultural Prescription
↓
Financing (KV, R&SI, Other)
↓
Contract or Force Account
↓
↓
Contract Preparation
Determine Size of Crew
↓
↓
Advertise Contract
Determine Equip. Needs
↓
↓
Pre-Bid Showing
Job Hazard Analysis
↓
↓
Award Contract
Description of Job
↓
↓
Report Accomplishment
Job Show-Me Trip
↓
↓
Pre-Work Conference
Mark Sample Area
↓
↓
Mark Sample Area
Inspection of Job
↓
↓
Inspection of Work
Final Acceptance
↓
↓
Payment of Contractor
Report Accomplishment
↓
↓
Final Acceptance
Follow-up Slash Treatment
↓
↓
Follow-up Slash Treatment
Reporting and Recording
↓
↓
Reporting and Recording
Monitor Treatments
↓
Monitor Treatments
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6.12 - Silvicultural Examination and Prescription. Basic information about a stand is needed
before a silvicultural prescription can be made (see regional supplement to chapter 8, Users
Guide for the Rocky Mountain Resource System (RMRIS) for Regions 2, 3, and 4; and Timber
Management Control Handbook for Region 1). Use these inventories as an aid in prescribing the
methods, technique, and timing of initial and subsequent treatments to meet Land Management
Plan objectives. The prescription should also describe the consequences of feasible alternatives
including chemical treatments. The requirements of a silvicultural prescription are contained in
regional supplements to chapter 8. Each Forest shall maintain an inventory of areas requiring
timber stand improvement (TSI) activities. All of these stands must have been examined,
analyzed by an interdisciplinary team, and had the collected data processed.
6.14 - Coordination. All timber stand improvement work must conform with the Forest Land
Management Plan. Prior to undertaking any timber stand improvement project, an environmental
analysis and/or assessment must be completed in advance of implementation. These projects are
often included in assessments for timber sales. Herbicide projects may require separate
assessments and plans (FSM 2151 and 2153.2).
The use of herbicides and chemical silvicides for control of undesirable plants requires careful
planning and coordination with states, other federal agencies, and affected permittees. Such
proposals must develop public understanding and, at the same time, ensure that all resources are
appropriately coordinated (FSM 2140.30).
Thinning normally produces heavy fuel loads and must be coordinated with Fire, Aviation, and
Air Management.
Resource coordination through the Forest Service NEPA process well in advance of the project
should prevent conflicts, making the project beneficial to all resources involved. The advanced
coordination must include interdisciplinary input from specialists in various affected resources.
Timber stand improvement projects may be planned on any National Forest System lands where
land management objectives can be achieved through thinning. Stand treatments designed to
improve tree growth for timber production will be supported by traditional appropriated timber
stand improvement funding. Treatments made for accomplishing other resource objectives
where tree production is not a primary goal will be funded by the benefiting resource.
Benefits to other resources, in addition to increased production of usable wood fiber, include:
1. Increased forage/browse production.
2. Enhanced aesthetic values.
3. Increased production of usable water supply.
4. Reduced fire spread potential.
5. Maintenance of healthy ecosystems.
6. Reduced probability of insect outbreaks.
7. Reduction of tree diseases.
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6.15 - Stand Selection Criteria. Selecting a stand for thinning is dependent upon the silvicultural
characteristics and priorities identified in Forest Land Management Plans. Special
recommendations for setting priorities are included in exhibit 01. Consider the following items
in selecting stands:
1. Age. Age refers to both the chronological age and the length of time in a competitive
status. Ideally, stands should be thinned at a young age, with the chronological ages ranging
from 15 to 30 years. The range in age is principally dependent on the species, site capability, and
other factors which contribute to the trees ability to compete for the most limiting environmental
factors. Thinning should generally be delayed until trees are expressing their mature growth and
quality characteristics and are capable of deterring brush and other site competition by adequate
occupancy of the site.
The longer thinning is delayed after competition among trees begins, the greater is the unrealized
usable production. Tree growth begins to be reduced by competition well before the competition
becomes readily apparent. For instance, in Douglas-fir, by the time lower branches start dying,
competition is already quite advanced.
It will be necessary to compare the actual stocking rate to the density necessary to achieve a
commercial size objective. This comparison may be necessary when there is a small number of
trees per acre, but the first commercially marketable product is relatively large in size. For
example; a ponderosa pine stand which is growing on a Douglas-fir/ninebark habitat type has a
stocking rate of 220 3-inch trees per acre. That stocking should result in the production of 9-inch
to 10-inch trees before moisture competition occurs. That stocking rate would result in severe
competition and mortality occurring over a long period of time if markets changed and a 14-inch
to 15-inch diameter tree was necessary for a first marketable product.
If initial stocking two to three years after disturbance is excessive (10-40 thousand trees per acre)
weeding and cleaning may be needed by age 4-5 if high precommercial thinning costs are to be
avoided.
2. Crown Ratio or Crown Percent. The crown area development is often an expression of
the competitive stature of a tree within a stand. Tolerant species are more capable of maintaining
large crowns even in low-light levels if all other factors are not limiting. Intolerant species lose
lower needles more rapidly from competition for light, with all other factors not limiting. Trees,
however, naturally tend to lose crown area with increasing age.
Within each species, there is an inherent capability for production of photosynthetic surface area.
This surface, primarily the needle area in conifers, will remain relatively constant on a site
resulting in diminished overall crown lengths in denser stands. The crown area length in relation
to the total tree height is expressed as a ratio or percent. For example; a tree 50 feet in total height
with a live crown length of 30 feet has 60 percent crown ratio. For the best thinning response,
crown ratios should be greater than 40 percent of the total bole length, preferably greater than 1/2
the length. In some stands with a high density and young age (5-20 years old), thinning when
crown ratios are 25-35 percent may be appropriate.
Tolerance is expressed below for the most common species in the Regions. The most tolerant
species utilize the photosynthates at lower light levels and higher levels of root competition than
more intolerant species. Most species become less tolerant with age.
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Very Tolerant
Tolerant
Intermediate
Intolerant
Very Intolerant
Pacific Yew
Subalpine fir
Western Red
Cedar
Western
Hemlock
Engelmann
spruce
Grand fir
Incense-cedar
Mountain
hemlock
Red fir
White fir
White spruce
Blue spruce
Douglas-fir
Sugar pine
Western white
pine
Apache pine
Chihuahua pine
Jeffery pine
Junipers
Limber pine
Lodgepole pine
Pinyon pine
Ponderosa pine
Southwestern
white pine
Alpine larch
Bristlecone pine
Cottonwoods
Quaking aspen
Subalpine larch
Western larch
Whitebark pine
3. Stand Density. The benefits of thinning increase as initial density or number of stems
per acre increase. Overstocking results in stands either not reaching merchantable sizes or
reaching them very slowly, especially on lower productivity lands (site classes V, VI, and VII)
(Exhibit 01). High productivity lands will nearly always produce merchantable volume without
major reductions in density. First priority for precommercial thinning should be given to young
stands on lower productive sites that are overdense. These stands are those which would seldom
produce merchantable volume without thinning. It is because little value comes from the stands
without thinning that nearly all the volume gain; hence, economic value is attributable to the
precommercial thinning. If stand density is so high that conventional thinning methods are
economically unfeasible consideration should be give to stand replacement. The methods for
stand replacement should consider the use of prescribed fire.
A primary gain from precommercial thinning is a shortening of the time a stand must be carried
before it is commercially thinned. Generally, the longer the time required for trees to reach
commercial size without thinning, the greater the gain from precommercial thinning. This is
accomplished by placing the growth on the trees which will reach commercial size and
eventually producing the final crop trees.
More usable biomass is captured by completing precommercial thinnings on the young, less
dense stands than on the older larger stands. When density is combined with the relative age of
the stand, it becomes readily apparent that older overdense stands create a larger volume of slash
than a younger less dense stand.
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6.15 - Exhibit 01
Stand Selection Criteria
Site Productivity Class Table
Potential Productivity
Cubic Feet/Acre/Year
Site Class
0-19
20-49
50-84
85-119
120-164
165-224
225-500
VII
VI
V
IV
III
II
I
4. Height - Diameter. Both height and diameter provide a relative expression of the
chronological age of a stand. Many species have varying height growth patterns that can be
determined in yield tables, site index, and height growth curves. In many cases, these curves will
allow the prediction of the potential height and diameter within a specific timeframe. Thus, in
young stands, the point of culmination of annual height growth can be determined. Gains from
thinning decline very rapidly after this point of culmination.
Percentage gains in mean annual increment (m.a.i.) of useable volume due to precommercial
thinnings are closely related to site quality. Percentage gains from precommercial thinning,
within limits, increase markedly with decreasing site quality. The resulting absolute gains in
useable mean annual increment also increases with decreasing site quality to site class V.
If precommercial thinning is not done until leave trees are about 30 feet or 20 percent of its
rotation height, the opportunity to make potential gains in growth response may no longer be
possible. Leave trees should also be within plus or minus 25 percent of the average diameter for
all leave trees within that portion of the treated stand. Excessively dominant large diameter of
"wolf-trees" should not be left as part of the leave stand. These trees, excessive dominants,
poorly utilize the site, often having extremely long limbs of large size which occupy two to three
times the crown area of normal dominant or co-dominant trees. Where other resource
consideration dominate the management practices or objectives in a stand, retention of the wolf
trees may be necessary or desirable.
Lodgepole pine stands often require that no thinning be accomplished until they are at least 15
feet in height unless the density is so great that trees begin self prunning. Any other precocious
seed producers should be similarly treated. A re-invasion or release of undergrowth shrubs,
brush, or small trees can also be severe competition, especially when moisture is the most
limiting factor for growth. This is to reduce competition due to re-establishment of seedlings.
Super dense stands left unthinned will lose their growth (diameter and height) potential to
respond to thinning.
Diameter of material being thinned is a very important consideration in determining the volume
and type of fuel hazard created. Excessive amounts of slash and the relatively short period of
time until the tree reaches commercial size should limit thinning to stands with average stand
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diameter less than 5 inches dbh. The most desirable stands to thin would be those of less than 3
inches in average stand diameter, before thinning.
5. Site Quality. Site quality is the sum of all the environmental factors that determine the
productivity of a forest land area. Indirect methods of measuring these environmental factors are
site index and vegetation classification systems. The most typical vegetation classification
system is the habitat type.
Site index, when properly obtained from dominant trees, is an expression of site productivity
especially the height attainable. Overdense stands, especially intolerant species, will not grow to
their full height. Therefore, the site's true potential would not be indicated.
When overdense stands or young stands exist on the site, the vegetational classification system of
Daubenmire's habitat types will provide a rapid approximation of the site's productive capability.
While the common approach has been to invest production dollars on the highest quality sites,
percentage gains from precommercial thinnings increase markedly with decreasing site quality
through site classes IV and V. This results because the gain in usable mean annual increment
attributable for the thinning increases with decreasing site quality. Poorer quality sites have a
number of limiting silvicultural or environmental factors. When these factors are not affected,
through reductions in densities, the resultant stand cannot produce commercial products except
over long time periods, occasionally not at all. High site quality stands nearly always produce
commercial products, even with high densities.
6. Vigor. This factor is a relative expression normally associated with trees in the main or
dominant story of the stand. Attributes normally used to describe vigor are terminal elongation
and needle color, size, and length. Tree vigor often aids in the evaluation of the leave stands
ability to dominate the site through response to a decrease in any of the limiting factors.
The rate of leader growth or the distance between internodes provides an excellent measure to the
release potential of the site. Elongation of the crown area provides the greatest carbohydrate
production potential for height and diameter growth.
The position of a tree's crown in relation to trees adjacent to it provides the best overall
assessment of a tree's capability to respond to reductions in density. Kraft's even-aged crown
classification system portrays the crown of a tree in relation to the exposure to sunlight and
relative height within the stand. The classifications are:
a. Dominant Trees. Dominant trees are somewhat above the general level of the
canopy and are exposed to full sunlight from above and to a certain extent laterally.
"Wolf Trees" are coarse, heavy-limbed, broad-crowned trees that have usually
developed with a lack of lateral, co-dominant competition. Wolf trees are
undesirable in a stand from a timber management standpoint. These trees may be
desireable for other resource considerations.
b. Co-Dominant-Trees. Co-dominant trees are not as tall as dominants, with crowns
receiving overhead light. They may be confined laterally by dominants and usually
make up the main canopy with the dominants.
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c. Intermediate Trees. Intermediate trees are definitely subordinate in position
receiving direct sunlight only through holes in the canopy. All trees of this class are
subject to strong lateral competition.
d. Suppressed Trees. Suppressed trees are definitely overtopped with no free
overhead light. Commonly weak and slow growing.
e. Dead Trees. Self-explanatory.
Stand leave trees should normally be selected from dominant and co-dominant crown classes
especially in precommercial stand sizes. When necessary, intermediate crown classes may be left
to maintain crown coverage and site occupancy if no others are available or if a specific species
is desired to meet other resource concerns. Suppressed trees will seldom respond to thinning and
should not be selected as leave trees.
Tolerant species (6.15, item 2), when overtopped or overdense, may have thin bark and a well
developed "shade leaf" crown. Sudden exposure of trees in these stands to light through removal
of an overstory and thinning can result in "sunburning" or "sunscald" of the bole and loss of
needles. This normally causes diminished growth and delayed site occupancy or death.
Occasionally, mortality may be high in these stands if other stressful environmental conditions,
such as aspect, coincide with the induced stress of treatment. "Sunburning" is necrosis caused by
excessive heating of the cambial tissue under the thin bark, which often results in flattened sides,
bark sluffing, and poor wood quality.
Grand fir stands more than 30 years of age that have been suppressed and released through
logging should not be thinned until 2 to 5 years after release. This will allow an assessment of
release ability to occur. Grand fir will not respond to thinning when crown ratios are below 40
percent.
7. Stand Damage. This single element often holds the key to the final selection of a stand
for thinning. All potential insect and disease hazards in the stand proposed for thinning must be
evaluated or rated.
Thinning is often an effective method of reducing current losses from insects and disease in
young stands. It is also an effective method of controlling insects in the future. The general
vigor of the stand will be improved by thinning, and the ability to overcome insects, such as the
western and mountain pine beetle, will be increased. Changes of environment within the stand,
especially the increase in temperatures within the stand, appears to be detrimental to a number of
insects.
Thinning under an overstory infected with dwarf mistletoe should not be done. Early removal of
the affected overstory, preferably by commercial sales, will benefit the stand. When thinning in
stands infected with dwarf mistletoe, it will be necessary to preprogram several follow-up
inspections and possibly some additional treatments to deal with latent infections that becomes
visible 3 to 5 years after the initial treatment. Hawksworth's 6-class dwarf mistletoe rating
system (ex. 02) should be used in programming treatments for dwarf mistletoe infected stands.
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6.15 - Exhibit 02
Hawksworth 6-Class Mistletoe Rating System
INSTRUCTIONS
/\
/
STEP 1. Divide live crown into thirds.
/
EXAMPLE
\
\
/ 0 \
_________/_______\__________
STEP 2. Rate each third separately.
/
\
Each third should be given a
/
1 \
rating of 0, 1 or 2 as described
/
\
below.
_ _____/_________\_______
(0) No visible infections.
/
\
(1) Light infection (1/2 or
/
2
\
less of total number of
/
\
branches in the third infected.)
/___________\
(2) Heavy infection (more
| |
than 1/2 of total number
| |
of branches in the third
| |
infected.)
| |
/
\
STEP 3. Finally, add ratings
of thirds to obtain rating
for total tree.
If this third has no visible
infections, its rating is (0)
If this third is lightly
infected, its rating is (1)
If this third is heavily
infected, its rating is (2)
The tree in this example
will receive a rating of
0 + 1 + 2 = 3.
The 6-class mistletoe rating system (Hawksworth 1961).
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The level of infection and site productivity must be considered when prioritizing stands with
dwarf mistletoe infections. Better site indices should be given a higher priority because of
greater potential volume growth. As the mistletoe ratings increase, the priority for thinning
should decrease. Stands with a rating class of 2 or less with infections in the lower crown will
benefit from thinning and may produce acceptable yields.
Rust and gall infected stands can be substantially improved by careful selection of leave trees.
Commonly, some trees within the stand have a genetic resistance to these pathogens. The
apparent rate of resistance and lack of galls should be considered in prioritizing these stands for
treatment.
The species susceptibility to current insect or disease problems should be evaluated. Many
mixed stands contain nonhost species which could be featured in management to help eliminate
or control the pathogen or insect.
The development of infection entry points must be considered when prioritizing stands for
treatment. Commercial thinnings or removal of salvage materials must consider the scarring,
limb breakage, season of the year, and other circumstances creating rust or fungal entry points.
True firs are very suscepible to various rots. Treatment types which increase this susceptibility
must be given a low priority.
Timing of thinning operations is essential in many stands. Insect populations such as ips can
build up rapidly in slash. By creating a "green chain" of slash, this problem may be avoided.
This often means attracting the insects into down materials until winter when freezing and drying
kills the overwintering larval stage. There are situations in Arizona and New Mexico when the
"green chain" is not effective because winters are not severe enough to kill ips broods. In these
situations control is provided by limiting the amount of slash (brood material) in any one
location. Specific insects or disease treatments should be discussed with an entomologist or
pathologist.
8. Management Objectives. The items above are the principal silvicultural considerations
that should be weighed in stand selection for thinning. Silviculture properly applied requires that
the stand capabilities be utilized to meet management objectives. The following objectives
further set priorities on stands selected for thinning and other treatments.
a. Species Composition. The species selected may have considerable influence on
insect and disease susceptibility, potential production, economic demand, and legal
or administrative constraints.
Stands of higher valued species will normally show a greater return for the
investment of thinning funds than low value species (all other considerations being
equal). While current price or demand must have a greater weight than future
price/demand considerations, the future should be weighed when considering relative
priorities between species. Continued increases in demand for fiber in the form of
chips will not only change the type of output from the various stands, but could
change the price/market structure changing demands from species having high
quality sawtimber to a dual production species having moderately good wood
structure and fiber quality. This demand picture must be reviewed with the emphasis
on the local demand or market area.
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Ability to alter output rates and types must be evaluated in relation to the overall
stand management objective. The ability to produce a mixture of species is often
desired to maintain vigor over time and reduce susceptibility to damaging agents.
Biologically, many species may be produced on one habitat type, but a seral species
may be more productive than the climax species. Species composition often needs to
be controlled for management purposes. Caution needs to be exercised, however, in
some species because basic biological reactions tend to exclude certain species
because of competitive interactions.
Diversity of the wildlife species inhabiting a stand is directly affected by its
composition. Wildlife habitat objectives may require a broad array of species to
meet stand management objectives.
b. Plans. Management plans, objectives, and constraints often impose thinning
priorities such as spacing, area of treatment, or timing. These constraints should be
considered when setting priorities for expenditures. The objectives and constraints
will normally be found in the silvicultural prescription for the stand or area.
Management plans also place priorities on areas of treatment to meet planned harvest
objectives. These planned harvest objectives may have included economical
efficiency in their initial determination of need and, as such, may have programed
certain management types to be treated over a specific time period.
Some stands are predesignated for thinning by Forest plans rather than silvical
priorities. They are set aside to meet future timber management output objectives or
other resource objectives. These targeted areas are first priority in a management
schedule.
9. Disturbance Regimes (Fire). In addition to stand level silvicultural characteristics and
identified land management objectives, stand selection criteria should consider concepts of
disturbance ecology from a stand and landscape perspective. Understanding of past, current, and
potential future fire regimes for example, can give us clues to sustainable desired conditions in
terms of composition and structure of stands and landscapes. An understanding of historical fire
regimes can give us a clue to the frequency and instensity of fire, the type of stand and landscape
structures that were developed, and possible wildlife habitat that was maintained over time. This
knowledge can then be used to help define desired stand and landscape conditions to be
developed over time as we prepare site specific silvicultural prescriptions. Understanding how
and where fire regimes influenced past composition and structure should aid in setting priorities
for current TSI treatments.
10. Economics. Similar stands are often in need of thinning. An analysis should be
conducted to rank stands so that the greatest return is realized for each dollar invested. Analysis
of these treatments should be included in Land Management Plans, Environmental
Assessments/Impact Statements, and/or final silvicultural prescriptions. The most current
applicable technique for conducting an economic analysis is to be used.
After analysis is completed, implementors of these stand treatment activities will need to
evaluate and select the most cost efficient means for completing the activities. Consideration
will include: available funding; contract versus force account; administration costs; move in and
out costs; season of work; coordination with resource values and uses; and methods to be used.
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11. Review of the Stand Selection Process. The following is a description of an approach
to developing priorities for thinning using the stand selection criteria developed above. While
the stand selection criteria basically is divided into two segments, not all segments must be
considered in making the stand selection. The priorities are provided as a logic pattern to help
order a complex program of scheduling. The questions that are outlined below, when answered,
should provide a ranking of stands for thinning.
a. Age. Has competition between trees developed? Have the trees in the stand begun
to express growth and quality characteristics (Phenotypic)? Are the trees old or
excessively stagnant?
b. Crown Ratio. Is there sufficient crown present to immediately respond to density
reduction? Must the foliage go through adjustment? Can more crown be added?
c. Density. Can the stand reach commercial size without significantly extending the
time needed to achieve the projected size at the end of a typical rotation? What will
be the volume of fuel created in unutilized wood fiber? Is the stand too dense and of
such poor quality as to not achieve an expression of dominance?
d. Height-Diameter. Is the variation in diameter in the leave trees greater than plus
or minus 25 percent? Has the stand differentiated in height? Are trees past the point
of culmination of mean annual and periodic increment?
e. Site Class. Does the habitat type capability indicate that stagnation is common for
the density present?
f. Vigor. Is the dominance freely expressed with extreme variations present in the
upper 1/3 of the crown in internode elongation? Will the trees continue to grow at a
rate that will capture the site and control competing vegetation?
g. Stand Damage. What insects and diseases are present? What are the future
problems with insects and diseases that could be triggered by treatment of the stand?
h. Species Composition. What species will provide the best future returns? Is there
a need to favor a certain species or species mixes for insect and disease purposes?
i. Plans. Is the area included as a priority treatment within the Forest Land
Management Plan? Is stand density or composition controlled by some other
resource constraint? Must scheduling be delayed or the intensity for treatment
reduced?
j. Disturbance Regimes (Fire). Is the stand composition and structure close to the
historic range given the typical historical fire regime on the site? If not, is this stand
condition likely to lead to a sustainable stand and landscape condition in terms of the
current or projected future fire regime? Is the stand so large as to create problems
with fire, other resources, or future forest mamagement activities?
k. Economics. Which of the selected stands to be treated will provide the best
benefit-cost ratio or has the best present net worth?
This list of questions is incomplete and is only provided to stimulate the analysis procedure used
in stand selection.
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6.16 - Project Development.
1. Area Layout. Area layout consists of four basic steps: (1) check the approved
Environmental Analysis or assessment and silvicultural examination to ascertain the general
boundaries of the area and to ensure specific coordination measures are incorporated into the
project; (2) locate and mark boundaries of the specific units to be thinned; (3) develop a project
map to scale; and (4) determine the acreage of each unit.
The first step is to ensure that the Forest Land Management Plan and the parent or specific
project environmental analysis or assessment are being followed. It is also important to ensure
the area and timing of your project do not conflict with other resource and timber projects.
Boundary layout should begin next. Maps, aerial photos with the boundaries of each prescription
unit to be thinned plainly delineated, and flagging should be taken along and used to layout the
area on ground. If transmission lines, roads, or trails are used as boundaries, make sure that they
are correct on your maps and photos. These features sometimes change between the time the
maps were made or aerial photos were taken. Care should be used in the layout phase to ensure
that units are not too large for the available work forces.
Whenever possible, it is best to use topographical or other easily identifiable landmarks as
boundaries as this will help in determination of unit acreage.
Once layout is finished and checked, boundaries should be marked plainly with paint or signs to
ensure that they are easy to identify during the life of the project.
The next step is to develop a project map. It should contain as a minimum the following:
a. Unit name.
b. Unit boundary.
c. Scale.
d. Delineation of slash treatments by area.
e. Special restrictions.
f. Name of person who made the map.
g. Date the map was made.
2. Area Measurement. Area determination can be done by several methods, all of which
are appropriate for use in certain areas at certain times. Listed below are four methods that can
be used.
a. Traversing. This is a method of determining the acreage of a unit. The most
commonly used pieces of equipment are a compass with a hip chain, steel tape, or
pacing as a distance measuring device. Caution should be used to ensure the
equipment is in good working order and that accurate measurements are taken, or
traversing can be as inaccurate as any other method and much more misleading.
There are several programmable calculator programs available which will determine
the error of closure ratio and acreage of the unit.
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2409.17_6-6.17
b. Dot grid or compensating polar planimeter. These two devices are used to
calculate areas from an accurate map of the unit. This method should be used only
where boundaries are easily located on both aerial photos and maps. The boundaries
of the unit are located on aerial photos and then checked. These boundaries are
transferred from the photos to the map by means of a "sketchmaster" or similar
transposing device. Great care should be used in this step to ensure the recommended
number of points are lined up both on the photo and map. When the map is complete
and checked, a dot-grid or compensating polar planimeter is used to calculate
acreage. At least three accurate measurements should be made and averaged to
determine the final acreage.
Caution should be used when determining acreage using this method. Check to see
that maps and photos are accurate and that the scale of the map is correct. Ensure
that dot-grid overlays are correctly printed and that compensating polar planimeters
are correctly calibrated. It is also very important to use the proper correction factor
to convert to acres, if needed.
c. Global Positioning System. In addition to traditional methods of measuring area
there is new technolgy available such as Global Positioning Systems (GPS).
Assistance for using GPS can normally be found in engineering or lands work groups
on Districts or Forests.
d. Laser Equipment. Lazer equipment available on some units can be used
effectively for measuring area. This is new technology with many applications other
than distance measurement.
6.17 - Treatment Priority. Priority for treatments including species preferences should be
established by Land Management Plans, Environmental Analyses/Assessments, and silvicultural
prescriptions. Specific direction by Region(s), if applicable, are included in exhibits for this
section of the handbook (Region 1 ex. 01).
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2409.17_6-6.17
6.17 - Exhibit 01
FOREST VEGETATION MANAGEMENT
Timber Stand Improvement, NFFV
A Prioritizing Strategy
Draft - December 1997
Introduction:
The National Forest emphasis for stand
improvement activities is described in the 1997
Budget Explanatory Notes for Committee on
Appropriations (USDA Forest Service, 1997a)
and more recently within the 1998 Budget
Explanatory Notes for Committee on
Appropriations (USDA Forest Service, 1997b)
before a subcommittee of the Committee on
Appropriations.
"Stand Improvement treatments are essential to
maintain a healthy, resilient forest ecosystem
for the future. These activities will maintain
sufficient timber productivity to meet projected
future desired conditions for the sustained
management of NFS lands. These activities
promote stand health and resiliency that is
essential in creating and maintaining the proper
species composition, density, and stand
structure needed to meet broader landscape or
ecological management objectives.
These
activities are designed to be consistent with
environmental, social, and economic benefits
and costs."
(USDA Forest Service, 1997b).
Program objectives are best summarized in the
Accomplishment
and
Results
Measures
Information
for
Forestland
Vegetation
Management, (USDA Forest Service, 1994),
"To annually reforest areas and conduct timber
stand improvement activities to meet forests
plan objective and ecosystem management
needs..... Reforestation and stand improvement
treatments are essential to maintain a healthy,
resilient forest ecosystem for the future."
Further
"Timber stand improvement treatments will
promote stand health and resiliency that is
essential in creating and maintaining the proper
species composition, density, and stand
structure needed to meet broader landscape or
ecological management objectives." The
management production process, (USDA Forest
Service, 1994), states that "both program and
project level investments are need to maintain a
flow of timber and other resources consistent
with forest plans. Timber harvest, reforestation
and timber stand improvement projects are used
to help sustain diverse and healthy ecosystem
from which these resources are obtained. "
"The timber stand improvement (TSI) objective
is to improve forest health, vigor and maintain
rapid growth. This is essential toward stated
management objectives at the stand, landscape,
and ecosystem levels. " (USDA Forest Service,
1997b).
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2409.17_6-6.17
6.17 - Exhibit 01--Continued
Timber Stand Improvement Activities listed
within the Timber Stand Management Record
System;
1.
Release treatments to provide for
the removal of competing
vegetation to insure high levels of
growth and vigor. TSMRS codes
4511, 4512.
2.
Precommercial thinning
treatment provide the opportunity
to regulate stand density, control
stand density, reduce standing
fuels, control species composition,
and alter stand structure to better
meet resource management
objectives. TSMRS codes 4521,
4522
3.
Fuel ladder reduction and
controlling understory
vegetation to control, deaden or
reduce the growth of understory
vegetation and TSMRS codes
4541, 4542.
4.
Pruning for improvement of
future product quality by
producing more clear sound wood
or reduce disease intensity.
TSMRS code 4530.
5.
Fertilization treatment provide
and means of maintaining or
improving soil productivity. Note:
Fertilization is currently not
planned in the Northern Region.
Treatment methods in the Northern Region
normally involve hand tools, mechanical
equipment, and/ or prescribed fire. These stand
improvement activities are important for
restoring or maintaining forest health and
sustainable levels of timber production.
As
new stands of trees are regenerated, most will
need to be released from competing vegetation,
and/or thinned to maintain healthy, vigorous
stands.
The majority of our treatments are directed to
lands within the identified timber suitable land
base per the Forest Plan. However, the recent
emphasis for ecosystem management and
reducing the risk of stand replacement fire on
traditionally low intensity high frequency fire
regimes has focused a need for stand
improvement treatments on unsuitable timber
lands as well.
Prioritizing Stand Treatments
Page 2
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6.17 - Exhibit 01—Continued
Purpose:
The purpose of this document is to share
prioritizing schemes for use in scheduling
and
allocating
funding
for
stand
improvement activities. This prioritization
may be useful to assess the target and budget
distribution of scarce NFFV, stand
improvement funds. Specific stand priority
is established at the Ranger District and/or
Forest level from Regional and National
strategic priorities and direction.
Discussion:
Stand improvement has a long history of
timber benefits through controlling species
composition, stand density and increasing
growth and vigor. With the new direction
for implementing ecosystem management
and concern for accumulating live fuels as it
relates to wildfire management, stand
improvement has a renewed emphasis.
Stand improvement activities can be a
significant tool for influencing stand
composition, structure and ecosystem
processes.
This is especially true for
species such as ponderosa pine and western
larch.
Without periodic disturbance to
reduce stocking, many of these stands will
develop into very dense spindly stands and
do a poor job of emulating natural or desired
conditions of stand development.
A system of ranking stands for stand
improvement treatment is not intended to
replace the requirement for silvicultural
diagnosis and detailed prescriptions.
Realistically, no scheme can quantify the
variables prominent at the Ranger District
for all of the potential areas for stand
improvement.
The method here is an
average of the considerations many program
managers find useful in the process of
ranking stands for funding.
Key considerations for ranking stand
improvement treatment areas include the
following. These are not an inclusive list
that might be considered and they are not
listed to imply a priority.
access
density
economics
growth & vigor
management/ resource objectives
productivity potential class
resilience to fire
resilience to insects & pathogens
species composition
stand differentiation
stand/ tree phenotype
stand and ecosystem health
wildlife habitat requirements
These considerations can be key in
determining the better areas in which to
make investments in stand improvement
resources. As National Forest priorities
change, some of the consideration may take
on a new level of emphasis.
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2409.17_6-6.17
6.17 - Exhibit 01--Continued
Consideration
Description
Access
Access or access timing can be significant in terms of costs or logistics for
treatments. Reflected most commonly in unit cost.
A measure of the stems per acre. This may be compared to what is desired at
the stand or landscape level.
Return on investments will remain a high criteria for prioritizing. Benefit/
cost ratios and unit costs are important measures.
Maintaining or enhancing growth and vigor is an overall objective of thinning.
This may be the top consideration for applying a stand improvement activity.
All treatments on the national forests shall be designed and implemented to
achieve land management objectives. Ecosystem management, and forest
health have focused on the broader ecological and social objectives as
articulated within the 1997 and 1998 Budget Explanatory Notes for
Committee on Appropriations (USDA FS 1997a, 1997b).
The amount of response trees achieve to treatment is directly related to site
quality. A measure of comparison of site productivity is currently cubic feet
per acre at culmination of mean annual increment. Also consider the potential
for stagnation which may be common on lower potential productivity sites.
Certain tree species have greater resistance to insects and pathogens. Stocking
control can feature these species. In other instances, where only susceptible
species exist treatments can provide for greater resilience to insects. The
relationship of Douglas-fir and spruce budworm is an example.
Resilience to fire relates to the land management objectives and the desire to
prevent stand replacement fire in commonly non-replacing fire regimes, but
possibly within replacing fire regimes as well such as within urban interface
areas.
Generally shade intolerant species are featured in the treatments due to the
adverse impacts of shade and competition on these species. Also consider the
species role in ecosystem function and management goals.
Stand differentiation relates to crown ratio, vigor and inter-tree competition as
clarified by O'Hara (1993) and Oliver (1990). It is a measure of how well
featured trees will compete and express themselves with good vigor, less
suscessibility to insects, disease and environmental conditions and provide
options for future sustainability and management.
Tree height, size and crown characteristics are examples that fit into this
category.
Many health conditions relate to species composition and density, such as
spruce budworm and root disease susceptibility. This in turn leads to
increasing risk of higher intensity fire.
Wildlife habitat needs can be very broad. Examples includes openness
providing for forage on winter range for big game, creating larger diameter
trees of specific species or altering tree species composition or density for
prey species habitat or improving access to special features such as wallows.
Density
Economics
Growth & Vigor
Management and
Resource
Objectives
Productivity
Potential
Resilience to
Insects &
Pathogens
Resilience to fire
Species
Composition
Stand
Differentiation
Stand/ tree
Phenotype
Stand and
Ecosystem Health
Wildlife Habitat
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6.17 - Exhibit 01--Continued
Prioritizing schemes:
Two prioritizing schemes for stand improvement activities are summarized in the appendix A &
B. The Lolo(et al) NF method in appendix A, and the Kootenai NF method in appendix B. The
Lolo (et al) NF method is patterned after the Kootenai method, expanding it with considerations
for economics and ecosystem health. The categories, ecosystem management, growth and yield
and economics are currently separate prioritization schemes.
The Lolo Forest National Forest Plan (1986) specifies that stands will undergo stocking level
control when;
1. Necessary to meet resource management goals, such as wildlife and visual;
2. Necessary to obtain future stand yields......an economic evaluation will be used to
determine the highest priority stands for treatment;
3. Necessary to protect stands from fire, insects, or disease;
REFERENCES
O'Hara, Kevin L. & Oliver, Chadwick Dearing. 1993. Decision Key for Prioritizing Precommercial Thinning Treatments on the Cle Elum and Naches Districts of the Wenatchee
National Forest. From personal correspondance of Kevin O'Hara, School of Forestry,
University of Montana, Missoula, MT 59812. 27 pages.
Oliver, Chadwick D. & Larson, Bruce C. 1990. Forest Stand Dynamics. McGraw, Hill Inc.
467 pages.
USDA Forest Service 1986. Lolo National Forest Plan. Lolo National Forest, Fort Missoula.
USDA Forest Service 1994. Accomplishment & Results Measures Information. 11/18/94,
Washington Office, pages 40-43.
USDA, Forest Service, 1996. Kootenai National Forest TSI Project (Stand) Ranking System.
Forest Silviculturist 2470 memo dated April 14, 1988, updated in 1996.
USDA Forest Service 1997a. 1997 Budget Explanatory Notes for Committee on
Appropriations. Washington Office publication.
USDA Forest Service 1997b. 1998 Budget Explanatory Notes for Committee on
Appropriations. In Hearings before a subcommittee of the Committee on Appropriations,
US House of Representatives, One Hundred Fifth Congress, First Session. Part 3, pages
99-103
Prioritizing Stand Treatments Page 5
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2409.17_6-6.17
6.17 Exhibit - 01--Continued
Appendix A.
Lolo (et al) National Forest
Stand Improvement Ranking System
Three ranking categories allow one to visualize ranking within the each category without the
masking effects of combining the categories. This is useful in assessing different management
objectives and conditions as priorities change.
ECONOMICS
Benefit/ Cost
Unit Cost 1/
ECOSYSTEM
Featured Species
Resilience to Fire
Resilience to Insects &
Pathogens
Stand & Forest Health
Management Objectives
Wildlife Habitat Needs
GROWTH/YIELD
Featured Species
Productivity Class
Tree/ Stand Phenotype
Density in Trees/ Acre
Management Objectives
Stand Differentiation
1/ Currently used by the Northern Region along with historical need to distribute TSI targets and
funds. Unit cost is also a nationally driven issue.
Units will rank each stand or area using the appropriate activity to assign numerical values to
each of these considerations. Mathematical accumulations will then be displayed by category on
a stand/area ranking summary table. Ranger Districts must display unit costs and project size
bounds in the summary of prioritized stands/areas when submitting them for budget and target
allocation. Use of the linked spreadsheets is encouraged for efficency.
FUEL LADDERS
Resilience to Fire
Stand replacement potential within a non-replacement
fire regime and thinning/ understory vegetation
removal/ pruning can mitigate?
Yes
........within a stand replacement fire regime and
thinning/ understory vegetation removal/ pruning can
mitigate?
Yes
No
* If No, then drop stand from consideration.
Featured Species *
WL, PP, WBP
DF
Other
Points
10
5
*
Points
5
3
0
Management Area *
Points
-15
MINMA,NFNIL,RANGE,RDLES,SKI,
WATER,WLDNS
Other Mgmt Areas or
2
Wildland/Urban Interface
3
* TSMRS code
Total Points
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6.17 - Exhibit 01--Continued
PRECOMMERCIAL THINNING
ECOSYSTEM HEALTH CONSIDERATIONS
Preferred Species
WL, PP, WP, WBP
LP
DF
Others
Points
10
5
1
0
Resilience to Fire
Stand replacement potential in a
non-replacement fire regime that
thinning can mitigate?
Yes
No
Points
5
0
Resilience to Insects & Pathogens
Thinning retains species
composition with resistance to
target pests?
Yes
No
Points
Stand/ Ecosystem Health
Is thinning necessary to achieve
desired stand conditions for the
Vegetation Response Unit?
Points
Yes
No
5
0
5
0
Resource NeedsÄ
Wildlife Biologist deems stand
requires thinning for
Threatened/Endangered Species
habitat or site factor?
Yes
Other resource importance?
Visual, Access, etc. Yes
No
Points
Crop Tree Crown Ratio
<20%
20-70%
>70%
Points
2
10
0
5
4
0
Management Area *
Points
5
SPREC, TM+
3
BGAMW, CAMPG, ELKSU,
MINMA, OLDGR, RIPRN, RNA,
Others
0
Total Points
GROWTH & YIELD CONSIDERATIONS
Preferred Species Differentiation
Preferred species able to
differentiate without thinning?
Yes
No
Crop Tree Crown Ratio
<30%
30-70%
>70%
Points
1
10
Points
2
10
0
Crop Tree Species (major species* )
WL,PP, WP,
LP
DF, C, GF, et al
Points
10
5
1
Crop Tree Age (year of Origin * ) Points
0-8
0
9-30
5
31-50
3
>51
0
Crop Tree Height (average in feet *) Points
<5
0
6-10
1
11-35
4
>36
2
Management Area *
SPREC, TM+
BGAMW, CAMPG,
ELKSU, MINMA, OLDGR,
RIPRN, RNA,
Others
Points
5
3
0
Productivity (CMAI * )
Points
> 85
4
50-84
3
20-49
2
< 20
0
* TSMRS code
Total Points
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6.17 - Exhibit 01--Continued
ECONOMIC
CONSIDERATIONS
Benefit/ Cost Ratio
Points
or Least Cost
Use Fred Stewart's
analysis available mid
January.
>1.0
10
<1.0
2
Unit Cost *
Use absolute value
* TSMRS code
Total Points
Project size may be an important consideration. Projects limited to a specfic acre size should be
specified so that allocation can be efficiently made. Additionally, stand treatments should
consider intermediate entries of other product removals to achieve thinning results. An example
would be using post and pole removals within lodgepole pine dominated stands that would be
accessible to prospective and traditional markets.
Fuel Ladders
Stand No. Rank
or Area
Pts
Acres
Unit
Cost
Prioritizing Stand Treatments Page 8
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6.17 - Exhibit 01--Continued
STAND SUMMARY TABLE
or use linked spreadsheets
Activity
Ecosystem Management
Growth & Yield
Economics
Stand No Rank
Unit Stand No Rank
Unit Stand No. Rank
Unit
or Area Pts Acres Cost or Area Pts Acres Cost or Area Pts Acres Cost
UNIT SUMMARY TABLE
DISTRICT
Ladder
Acres
Unit Cost
$/ acres
Program
Size
Range
Acres
Thinning Unit Cost
Acres
$/ acres
1
2
3
4
5
6
Prioritizing Stand Treatments Page 9
Program
Size
Range
Acres
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6.17 - Exhibit 01--Continued
APPENDIX B.
KOOTENAI NATIONAL FOREST
TSI RANKING SYSTEM
United States
Departmetn f
Agriculture
Kootenai NF
File Code: 2470
Route To:
506 US Highway 2
West
Libby, MT 59923
Date: April 14, 1988
Subject: KNF TSI Project (Stand) Ranking System
To: District Silviculturists and Others
The following system is to be used to compare (prioritize) stands scheduled for Precommercial
thinning (PCT) projects across the forest in relation to each other (Kootenai National Forest,
1996). Districts may find the above useful in developing (balancing, etc.) their programs. The
intent of this ranking is to provide a means of selecting which projects to fund when limited
dollars are available.
This comparison (ranking) will be made after the stand silvicultural prescription (Rx) has been
completed to the diagnosis phase and a PCT is indicated. Actually filling out the ranking will
only be required when projected budgets indicate a lack of funds to complete all the PCT projects
for a given year. Direction provided in the task forces memo on what is required in the Rx
considers information needed to develop the ranking.
The final ranking is the result of totaling the individual category points. The higher the points,
the higher the probability that the project will be selected. A rating of zero for any one item will
generally be sufficient to eliminate a stand from treatment at the time of analysis.
This ranking system method is not intended to supplant the Rx but to provide a treatment
prioritizing. As with any system we will find stands that rate low, but need treatment now. We
will deal with this situation with the district silviculturist making a site specific presentation on
why this stand (or type of condition) should be of higher priority than other stands.
As this is a new development I see us refining the process as we utilize same.
Al Corda
Forest Silviculturist
Prioritizing Stand Treatments Page 10
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6.17 - Exhibit 01--Continued
APPENDIX B. Continued
KOOTENAI NATIONAL FOREST
TSI RANKING SYSTEM
PRECOMMERCIAL THINNING PROJECT RATING GUIDE
STAND ID:
DATE:
Productivity (CMAI)
MCI (>85)
MCII (<84)
LP (>85)
LP (<84)
Crop Tree Species (major)
Intolerant
Tolerant
LP
Points
4
2
3
2
Points
5
1
3
Crop Tree Age (years)
0-8
9-30
31-50
>51
Points
0
3
2
0
Crop Tree Crown Ratio
<30%
30-50%
>51%
Points
0
1
2
Stocking (TPA)
<500
501-1000
1001-3000
3001-5000
>5001
Points
0
1
2
3
5
Crop Tree Height (feet)
<5
6-10
11-35
>36
AccessÄ
Roaded (to stand)
<1/2 Mile Walk
1/2-1 Mile Walk
>1 Mile Walk
Points
3
2
1
0
Management Area
15
17
16
12
11
14
Others (*)
Points
6
5
5
5
3
3
0
* Stands in nonsuitable MA's that are
diagnosed for PCT are generally financed
with funds other than timber monies, thus
targets are agreed to by the benefiting
function (wildlife, recreation, etc.) and not
part of this process.
TOTAL STAND RATING
Points
0
1
4
1
Prioritizing Stand Treatments Page 11