An Uneven-Aged Management Strategy: 

Lessons Learned1 

Mark T. Smith2 and John D. Exline3 

Abstract 

Use of an ecosystem approach at a landscape scale to program and guide 

accomplishments of multi-resource and social objectives has been discussed between 

researchers and natural resource managers for many years. Presently, great interest exists 

in the applicability of uneven-aged management practices for such an approach in 

conifer forests of the Sierra Nevada of California. The Kings River Sustainable Forest 

Ecosystems Project involves an administrative study by the Sierra National Forest and 

the Pacific Southwest Research Station that is providing an opportunity to implement 

and study uneven-aged management over a large landscape. The study was designed in 

part to answer questions about the effects and costs of implementing the group-selection 

form of uneven-aged management. With the implementation of several projects, some of 

these questions are beginning to be answered. We document some of the lessons learned, 

while implementing small group selections and thinning between those groups. 

The Sierra National Forest Land and Resource Management Plan (LRMP) 

(USDA 1991), like most National Forest Plans, was based on three approaches: 

zoning to allocate land among competing resource objectives, primarily evenaged management, and a philosophy that the analysis and management of 

specific local sites would result in healthy ecosystems at a landscape scale. Since 

these plans were developed, some dramatic changes have occurred that 

eventually resulted in the current study (Verner and Smith, this volume). 

Ronald E. Stewart, Regional Forester of the USDA Forest Service’s Pacific 

Southwest Region (Region 5) from 1992 to 1994, addressed a challenge to evenaged management, especially clearcutting, by designating a committee to 

investigate uneven-aged group selection in the context of an ecosystem approach 

that would assure “continuous forest cover” and mimic the effects of small-scale, 

historical fires. In June 1992, Jack Ward Thomas, then Chief of the Forest Service, 

directed all National Forests to begin implementing ecosystem management at 

extensive landscape scales. Finally, in 1993 the LRMPs for all National Forests in 

the Sierra Nevada were amended to respond to new information about California 

spotted owls (Strix occidentalis occidentalis) (Verner and others 1992). Included in 

this direction was a provision for administrative studies designed to evaluate the 

effects of different forest management systems on owl habitat (USDA 1993). 

One response to the direction for administrative studies is the 64,000-acre 

study area for the Kings River Sustainable Forest Ecosystems Project (fig. 1), 

located on the Kings River Ranger District of the Sierra National Forest, in the 

eastern portion of Fresno County, California. Vegetation types within the 

study area can be grouped into five categories: Chaparral, Ponderosa Pine 

(Pinus ponderosa), Mixed Conifer, Red Fir (Abies magnifica), and Jeffrey Pine 

1 An abbreviated version of this 

paper was presented at the 

Symposium on the Kings River 

Sustainable Forest Ecosystems 

Project: Progress and Current 

Status, January 26, 1998, Clovis, 

California. 

2 	Silviculturist, Sierra National Forest, 

USDA Forest Service, 1600 Tollhouse 

Road, Clovis, CA 93611. 

3 	Timber Management Officer, 

Pineridge and Kings River Ranger 

Districts, Sierra National Forest, 

USDA Forest Service, P.O. Box 559, 

Prather, CA 93651. 

USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 19 
Smith, Exline 

Figure 1—The Kings River 

administrative study area in the 

Sierra National Forest in central 

California includes the 64,000-acre 

Big Creek and Dinkey Creek 

watersheds (indicated by shading). 

An Uneven-Aged Management Strategy: Lessons Learned 

�

Sierra National Forest 

Sierra National Forest 

Study Area 

Dinkey Creek Watershed 

Big Creek Watershed 

(Pinus jeffreyi) (USDA 1994). Elevations range from about 2,400 to 8,100 ft. Two 

large-scale projects—the 10S18 Fuels Reduction Project (10S18 FRP) and the 

Indian Rock Upper Tier Project (IROC)—have been implemented within the 

study area and are in different stages of completion. A third project—the Bear 

Meadow Basin Project—is still in the planning stage. The three projects cover 

approximately 8,000 acres of the 64,000-acre study area and fall within the 

Ponderosa Pine and Mixed-Conifer vegetation types. In this paper, we discuss 

lessons learned through the implementing of uneven-aged management in 

these projects. 

Approach 

“The term, selection system, is applied to any silvicultural program aimed at the 

creation or maintenance of uneven-aged stands . . . [and]. . . there is not, in the 

strictest sense of the term, any such thing as an uneven-aged stand. Even when a 

single large tree dies it is replaced, not by one new tree, but by many that 

appear nearly simultaneously. This is true even if the new trees are from 

advanced regeneration. The uneven-aged stand is an artificial entity required 

for the comprehension of what might otherwise be a chaos of little stands” 

(Smith 1962, p. 467). 

One objective of the study is to develop quickly a forest of uneven-aged 

groups so that the effects on wildlife and the risk of large-scale wildfires become 

evident as soon as possible. We therefore decided to use not only the periodic 

creation and reforestation of small groups but also an initial thinning of the 

existing matrix of trees to develop an uneven-aged structure and preferred 

species composition. Our approach for locating reforestation groups and for 

thinning in the matrix led to our first lesson learned: the forest can be transformed 

into one with a substantially uneven-aged group structure in a few decades. 

20 USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 
An Uneven-Aged Management Strategy: Lessons Learned 

Using the J-Curve to Regulate the Stand 

When the objective is to have a balanced or regulated, uneven-aged stand, a 

histogram depicting the diameter distribution of trees in the stand (trees per acre 

vs. diameter class) approximates a smooth, inverse, J-shaped curve (fig. 2) 

(Alexander and Edminster 1978). It has three key parameters: first is slope, which 

results from the diminution quotient (Dq—a value that, when divided into the 

number of trees in one size class, gives the number of trees expected in the next 

smaller size class); second is the largest size a tree is allowed to grow before 

being harvested; and third is the stocking level (basal area of trees per acre), 

represented by the area under the curve. 

The numbers of saplings and poles needed to provide adequate growth into 

the large-tree classes is usually a significant influence on the beginning point of 

the J-curve (number of trees per acre in the smallest diameter class) and its Dq. In 

this study, however, two contradictory objectives influenced the beginning point. 

Silviculturists desired to have sufficient numbers of small trees to assure growth 

into the larger diameter-classes, but fuels specialists wished to minimize the 

contribution of seedlings, saplings, and poles to fuel ladders leading into the 

upper tree canopy. Analysis and discussion lead to the compromise values for 

reforestation groups shown in table 1. 

We did not expect a typical acre to be fully stocked with conifers, estimating 

instead that 80 percent would be occupied by conifers, 10 percent by large oaks, 

and 10 percent by rock patches and other openings. Thus, the stocking of conifers 

Table 1—Compromise numbers of seedlings and poles to be provided for adequate ingrowth into large-tree 

classes, based on competing silvicultural needs and desired fuel ladders 

Smith, Exline 

Figure 2—A typical inverse J-shaped 

curve; closed circles designate a 

moderately dense forest; closed 

squares designate a very dense forest. 

Forest Site Planting Resulting Estimated First-thin Resulting

type quality spacing seedlings percent spacing poles per

per acre mortality acre

Ponderosa 

pine 

Good1 9 x 18 ft 270 20 18 x 18 ft 135 

Mixedconifer Good1 8 x 16 ft 340 20 16 x 16 ft 170 

1 Forest Survey Site Class 3. 

USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 21 
Smith, Exline An Uneven-Aged Management Strategy: Lessons Learned 

in the smaller diameter classes (1 to 16 inches) of the J-curve should be about 110 

trees per acre in ponderosa pine stands and 135 in mixed-conifer stands. 

Different Dq’s for a J-curve comprised of 2-inch diameter classes were tried 

and discarded until we identified the one that satisfied the desired number of 

saplings and poles. For ease of use in the field, equivalent curves were then 

developed by using 4- or 8-inch diameter classes. 

Our approach to determining the largest size a tree would be allowed to 

grow before harvest was driven by a desire to maintain the presence of very large 

trees in the stand. Initially, we estimated the diameter at breast height (dbh) in 

inches, expected in 200 years, based on professional judgment and data from 

yield tables (Dunning and Reineke 1933, Meyers 1938). Subsequent modeling 

with the uneven-aged routine in the Forest Vegetation Simulator (USDA 1996) 

resulted in the following diameters at 200 years of age: 

Good site1 Poor site1 Average site1 

Thin at 50 years, 58 inches 49 inches 54 inches 

then every 20 

No thinning 39 inches 33 inches 36 inches 

1 Forest Survey Site Classes 3, 5, and 4, respectively. 

Substantial public interest in assuring continuous presence of very large 

trees throughout the forest matrix, for wildlife and aesthetic values, led to 

consideration of other approaches. Analysis and discussion resulted in the study 

team’s recommending an approach, initially suggested by the Yosemite Area 

Audubon Chapter, that allows the J-curve to tail off to a point that it represents 

only a few hundredths of a tree per acre. Summing the parts of trees in the largest 

diameter classes (>50 inches) suggests a total of about one such tree per acre. 

Thus, the practical approach to field implementation would be to leave in clumps 

the largest trees (those >50 inches in dbh) with desired characteristics, producing 

an average of about one very large, old tree per acre. 

The stocking level of trees was taken from even-aged yield tables, based on 

the suggestions of Curtis (1978) and Foiles (1978). Commercial thinning schemes 

were developed both for groups of existing trees and for new groups established 

by reforestation by using the Forest Vegetation Simulator and professional 

judgment. Desired basal area per acre was set at 65 percent of full stocking 

(growing space 100 percent occupied) in the applicable yield table, which, 

according to the Simulator, would result in stands returning to 85 percent of full 

stocking in about 20 years (fig. 3). 

Field Techniques 

The average size and arrangement of groups of trees of the same age usually is 

influenced by the structure of the stand needed to provide habitat for particular 

species, the tolerance of the tree species to shade, and the practicality of 

maintaining group size and arrangement through management. The J-curve is 

applicable over a wide range of arrangements and group sizes, from a few acres 

down to openings that mimic the crown width of the largest tree desired. 

Implementing the uneven-aged strategy involved primarily the identification 

and layout of the reforestation groups and marking for thinning in the matrix. 

Because the strategy was new to the sale preparation crew, we thought it would 

be difficult to learn and control work quality if both tasks were attempted at the 

same time. Initially, therefore, the crew located stand boundaries and 

reforestation groups so that it was evident which task was to occur in what areas 

of the stand. Next, the crew marked the thinning, focusing on guidelines for this 

22 USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 
An Uneven-Aged Management Strategy: Lessons Learned Smith, Exline 

Figure 3—Simulation of a mixedconifer forest at about 65 percent of 

full stocking (above) and 85 percent of 

full stocking (below), by the Forest 

Vegetation Simulator (USDA 1996). 

task, without having to dwell on starting and stopping lines or the guidelines for 

establishing reforestation groups. 

Locations of stands were determined by traditional approaches, like 

homogeneity of the vegetation, logging systems, and geography. Determination 

of stand size, however, did not follow the traditional approach. Because the 

intent is to develop an uneven-aged structure, stand by stand, the structure 

should be present at all larger scales, even in larger watersheds. The larger the 

stand, the easier and more efficient it was to implement the approach, resulting 

in stands of 75 to 150 acres. 

Guidelines for locating reforestation groups focused on finding understocked areas within a stand that had resulted from past harvest, small fires, and 

insect-caused mortality. Usually under-stocked areas were evident because the 

majority of the area in most stands was moderately to densely stocked. Once 

identified by the crew walking through the stand, the boundary was located by 

expanding the under-stocked area until edges were located where the stand was 

at least moderately stocked with trees. Five acres is the largest group allowed 

under the guidelines (USDA 1995). The technique resulted in only 2 percent of 

the under-stocked areas expanding to a group larger than 5 acres. 

USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 23 
Smith, Exline An Uneven-Aged Management Strategy: Lessons Learned 

Guidelines for thinning in the matrix focused on a desired basal area per 

acre where most trees to remain in an area were at least 16 inches in dbh, but on 

a spacing scheme where trees were mostly 15 inches in dbh and smaller. The 

split approach stemmed from the stark reality that small trees contribute little to 

stand basal area, so some other approach, like a spacing standard, is essential. 

The dbh split could be anywhere from 10 to 16 inches, depending on existing 

stand structure and the desirability of minimizing the complexity of marking 

guidelines. 

A key to developing the uneven-aged structure and species composition by 

thinning in the existing matrix of trees was to look for obvious groups by large 

diameter classes (6 to 10 inches) and then to accentuate them by leaving as many 

trees as possible from the dominant diameter class in making up the desired 

basal area. It is important to focus on the obvious groups but not to spend time 

looking closely at variation in stand structure or debating the extent, boundaries, 

etc. Focusing on the obvious groups worked well. When groups were not 

evident, trees were selected to remain in the stand by thinning through all size 

classes present. The written marking guideline states: 

Working by 10-inch diameter classes, recognize the groups that are 

obviously dominated by trees in a single class, then make up as much of 

the desired basal area per acre as possible from favorable trees belonging 

to the dominant diameter class. When domination by a single class is 

not obvious, make up the desired basal area from favorable trees 

belonging to any class or crown position. 

Other key marking guidelines were: 

1. Disfavor the 1- to 10-inch diameter class. 

2.	 Leave the proportion of oaks specified in the prescription, favoring 

black oak (Quercus kelloggii) over live oak (Q. wislizenii). Of the oaks 

to be removed, cut half and girdle half. Select the half to cut from 

those surrounded by pole-sized and larger ponderosa pine and 

incense-cedar (Calocedrus decurrens). 

3.	 Select leave trees with at least 30 percent live-crown ratio that are 

free of damage and have mistletoe ratings of 1 to 2 or less, whenever 

possible. 

4.	 Favor ponderosa pine over white fir (Abies concolor) and 

incense-cedar. 

Implementation 

One of the administrative study’s tasks is to determine whether a typical Ranger 

District can implement this uneven-aged management strategy with its existing 

work force and typical management procedures. Although the first few projects 

are not yet completed, the answer to this question is becoming apparent. Because 

the major phases of implementation are sale preparation and sale administration, 

we focus on these. Two other areas, sale planning and post-sale treatments 

(reforestation, timber stand improvement, fuels reduction work, etc.) also play 

roles in implementation but are premature to discussion here. The planning 

phase has been documented in the Landscape Analysis Plan (USDA 1995) 

prepared for the study. Because post-sale stand treatments have just begun, we 

cannot evaluate performance in this area. 

Timber sale preparation involves layout (establishing unit/stand boundaries 

on the ground), marking, and cruising (designating the trees to be cut or left and 

measuring the amount of wood that will be removed) in accordance with 

silvicultural prescriptions and other sale planning documents. It also involves 

appraising the timber (what it will cost to harvest the sale, and setting the asking 

24 USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 
An Uneven-Aged Management Strategy: Lessons Learned 

price) and putting together the timber sale contract (legal document under which 

the sale operates), along with a prospectus (document describing the sale) and 

advertisement. Timber sale administration takes over once the sale has been sold 

and awarded. The sale administration team is responsible for seeing that the 

contract is followed and executed by the purchaser and that the Federal 

Government’s interests are protected. 

Lessons Learned From Sale Preparation 

The Need to Test Marking Guidelines 

One of the most important lessons learned was the value of practicing and 

testing the various marking guidelines. Small representative areas of individual 

stands were set aside as practice areas to test the marking guidelines developed 

by the silviculturist and the sale preparation forester. They were tested using key 

members of the marking crew and resource specialists. Results were reviewed on 

the ground by the silviculturist, timber and resource management personnel, 

and interested publics. Through this procedure, adjustments were made to the 

marking guidelines to achieve the desired silvicultural outcomes, while making 

the guidelines as simple as possible for the marking crew to follow. Practice 

made a substantial difference. 

Supervision is Critical for Quality and Work Efficiency 

We learned that the “art” along with the science of applying the silvicultural 

prescriptions under this uneven-aged management strategy is more important 

than is true for more traditional, even-aged prescriptions. To facilitate this, we 

used a coaching technique when marking stands. More experienced sale 

preparation personnel walked behind the crew and served as observers. They 

checked basal area and spacing standards, helped identify existing dominant 

groups of a single size-class, and helped direct the crew in making choices 

between trees when needed. This paid off and allowed the use of large marking 

crews. We were able to split crews into groups of three to five markers with a 

supervisor for each. Careful supervision of the marking helped to identify 

problems quickly and assist crews in looking for dominant groups, which clearly 

improved the marking production and resulted in higher quality work. Crew 

composition and size needed to mark and cruise are important factors to consider. 

More people were needed to mark and cruise for these uneven-aged prescriptions 

than would be typical for even-aged prescriptions. A crew-to-supervisor ratio of 

about 1 to 4 was ideal. 

Traverse Regeneration Groups Using a Global Positioning System 

Whether to traverse the regeneration groups within the stands was debated 

due to costs and time constraints. Given the relative ease and low costs of doing 

traverses with a global positioning system (GPS) device, however, we opted to 

do so. Consequently, we were able to keep better track of our regeneration acres 

and accurately map the locations of these groups for our records. Already this 

has proven to be worthwhile in following up with post-sale treatment work 

within these groups. 

Plan Marking Strategies 

We compared marking strategies, either marking “cut” trees (painting a 

narrow ring around trees to be cut) or “leave” trees (painting trees that are to 

remain after the sale). Aho (1983) recommended marking leave trees when 

dealing with fir, based on comparisons of the two marking methods from the 

standpoint of residual stand damage. We found, however, that additional factors 

needed consideration (table 2). 

Stands need to be examined carefully before determining whether to mark 

them as a leave-tree unit or as a cut-tree unit. Also, applying both systems in 

different units may be advantageous, although mixing strategies requires 

Smith, Exline 

USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 25 
Smith, Exline An Uneven-Aged Management Strategy: Lessons Learned 

vigilance by the sale administrator and the logger to avoid confusion about the 

marks. We found that cut-tree designation had a higher cost, but this may be 

offset by higher cruise costs for leave-tree marking. Smaller acreages definitely 

favor cut-tree marking. Dense stands of small trees favor a leave-tree mark. A 

cut-tree designation with a 3P cruise (probability proportional to prediction, a 

modification of variable probability sampling in which the chances of a tree’s 

being selected to measure in the sample varies directly with the size of the tree) 

offers the best way to control the coefficient of variation (CV) of the cruise, if 

meeting sampling error standards is a problem. 

Table 2—A comparison of the relative advantages and disadvantages of “cut-tree” vs. “leave-tree” marking for 

thinnings 

Cut-tree marking Leave-tree marking 

Need clearly designated boundaries.

If the number of cut trees/acre is less than

about 1.5 times the number of leave

trees/acre, cut-tree marking is more

efficient and economical.

Because every tree must be marked,

apply a tree-based cruise such as the 3P

method.1 Using a 3P cruise can minimize

the coeffficient of variation (CV) of the

cruise and result in efficient measurement

costs.

For small acreages, cut-tree marking is

more and economical.

Does not require the unit to be traversed.

Need only one preparation entry into the

unit.

Little risk of not meeting the sampling

statistics for the cruise if insurance trees

are measured (3P).

Skips in mark simply leave more trees in

the unit.

Need clearly designated boundaries.

If few leave trees/acre to mark, leave-tree

marking is efficient. Leave-tree marking

tends to be slightly slower.

Leave-tree marking favors an area-based

cruise for measuring the harvest trees. It

does not require that all cut trees be

visited.

Area-based (plot) cruise methods

generally have high coefficients of

variation (>70 pct) and require many

plots. The number of plots is a function of

the CV, not acres. Need to have a large

acreage to avoid overlapping plots.

Requires the unit to be traversed.

Need three preparation entries (mark,

cruise, traverse).

More plots needed if cruise misses the

sampling error percentages allowed.

Skips in mark may understock the stand

from prescribed levels.

1 The 3P (probability proportional to prediction) method is a sampling method in which the chance of a tree’s selection in the sample varies directly with the relative size (volume) of the tree being

measured. 

26 USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 
An Uneven-Aged Management Strategy: Lessons Learned 

Lessons Learned from Sale Administration 

Mark Sale Boundaries Unambiguously 

Administration of the timber sales affirmed principles that we already knew. 

It pays to put effort, time, and money into sale preparation because it reduces 

headaches encountered during sale administration. One of the few sale problems 

we encountered during preparation for the 10S18 FRP contract involved 

boundary designations. As pointed out by Fiske and others (1993), marking of 

boundary trees is important to prevent theft and to maintain accountability with 

group-selection harvesting. Although these were not issues in our case, the fact 

that we marked boundaries of units (stands) and regeneration groups (group 

selection) with paint of the same color caused some confusion for the logger and 

the sale administrator, especially when regeneration groups were located near a 

unit boundary. This could have resulted in theft and accountability problems, 

except that we mapped each unit and regeneration group with GPS, providing a 

good map for each unit and an accurate location of each regeneration group. The 

sale was sold as a “scaled” sale (trees measured and paid for after they were cut 

into logs and hauled to a designated scaling location) rather than as a “tree 

measurement” sale (trees measured prior to sale and paid for before cutting). 

Each method has pluses and minuses, of course, but our experience with groupselection harvesting indicated that a scaled sale presents fewer problems when 

administering the contract and less temptation to cut undesignated trees. 

A Need for Flexibility 

Flexibility was found to be a key ingredient for accomplishing the work on 

the ground. Given the mix of timber sizes (dbh ranging from about 10 inches to 

over 70 inches), species, and topography (slopes to 75 percent), we tended to be 

more open to suggestions from the timber sale contractor about the types of logskidding and processing equipment and methods that he wanted to use. So far, 

these have included conventional tractor skidding and hand falling, mechanical 

harvesters, in-woods processors, delimbers and processors at the landings (slopes 

<35 percent), helicopter yarding (slopes >60 percent), and skyline yarding (slopes 

40-60 percent). Only by using this mix of different technologies and methods 

were we able to get some of the results that we desired at an economical price. 

Some significant lessons were learned from working with mechanical 

harvesters. They have better control on directing and placing cut trees and are 

able to process small timber faster and more efficiently than conventional falling 

methods on slopes <35 percent. On the other hand, we experienced a slightly 

greater chance of cutting undesignated trees because of the “dog hair” thickets of 

pine and incense-cedar within stands. Also, we found that chances of damage to 

designated leave trees increased with the simultaneous operation of more than 

one piece of machinery in the woods. Most tractor-based units on these sales 

required at least two entries, one with mechanical equipment (such as a feller 

buncher) and another with conventional falling (chainsaws) and skidding, due to 

the various sizes of the trees to be removed. 

More Inspection Time Required Than With Even-aged Harvests 

We found that the logger covered more land at a time than during traditional 

timber sales because of the low volumes per acre. As predicted by Fiske and 

others (1993) this required more time walking more ground than on other 

timber sales, so timely inspections could be made and problems identified 

early. Also, it paid off to have our sale preparation personnel and other 

resource specialists spend some time with the sale administrator during 

harvesting activities. Experiencing first hand what works and what does not 

with the various types of equipment often leads to significant improvements 

in the marking, layout practices, and resource protection measures. Good 

communication is a key with everyone involved in the sale, including the 

contractor, resource specialists, and researchers. 

Smith, Exline 

USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 27 
Smith, Exline 

Figure 4—Costs in dollars per 

1,000 board feet (MBF) for sale 

preparation and administration: 

10S18 Fuels Reduction and Indian 

Rock Upper Tier projects are 

applying uneven-aged management 

strategies; “other” includes evenaged, sanitation, and typical 

thinning sales. 

An Uneven-Aged Management Strategy: Lessons Learned 

Involve Sale Administrators Upfront 

The key lesson learned is that sale administration personnel need to be 

involved in the planning and preparation phases of the project. They are 

responsible for carrying out the intended actions of the project, so the more they 

know about the project the better. Sale administrators can also provide valuable 

input into the design of the project, including legal aspects of a timber sale 

contract and the practical aspects, such as logging capabilities, practicality of 

certain practices, and various ways to accomplish a desired condition. 

Costs 

A major and continuing question for the study involves the cost of timber sales 

when implementing uneven-aged management. The cost includes creating small 

group selections and thinning between the groups to accentuate the existing 

uneven-aged structure of the overall stand. Sale preparation costs that are being 

tracked include salaries, vehicle costs, paint, and miscellaneous supplies needed 

(flagging, signs, etc.). Sale administration costs include administration and 

clerical salaries, vehicle costs, and miscellaneous supplies needed. 

We assumed at the start that implementing uneven-aged prescriptions would 

entail a higher cost than even-aged prescriptions. Sale preparation costs were 

higher for uneven-aged prescriptions, using 1996 as the base year and a 4 percent 

discount rate for cost calculations (fig. 4): 10S18 FRP at $9.33 per thousand board 

feet; IROC at $11.25; and other (average for even-aged, sanitation, and typical 

thinning sales) at $8.09. Although the costs were higher, the difference was not as 

high as many of us expected. Factors such as the complexity associated with 

these sales, the lower timber volumes harvested per acre, and the amount of 

ground that needed to be covered all tended to inflate costs. We expect costs to 

decrease, however, as our experience with these sales increases. 

Estimates of the sale administration costs were $5.83 per thousand board feet 

for the 10S18 FRP, $6.49 per thousand for IROC, and $5.55 per thousand for the 

other sales types (fig. 4). These estimates are preliminary, with the exception of 

the “other” costs shown, because the 10S18 FRP and IROC sales are still being 

harvested. Sale administration costs may increase for these two sales because of 

the complexity of the ground yet to be harvested and the fact that helicopter and 

skyline yarding remain to be used. Based on past experience with these 

harvesting systems, we expect sale administration costs to increase. 

28 USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 
An Uneven-Aged Management Strategy: Lessons Learned 

Administration costs have typically ranged from $5.30 per thousand board feet 

for an easy tractor-yarding operation up to $10.00 per thousand for helicopter 

yarding operations, where steep terrain makes all tasks more time-consuming. 

The two sales sold to date have been cost-effective. Both had at least two 

prospective bidders and both sold for more than their appraised rate. Generally 

speaking, we have received few complaints by purchasers on the way these sales 

were packaged. Continued attention to sale economics, along with resource 

objectives, needs to be emphasized for all projects if one expects them to be 

successful. 

Summary and Recommendations 

The willingness to try new ideas, a major principle behind adaptive management, 

is probably the most important factor in our success with these projects. This 

principle is sometimes hard to accommodate, especially in a bureaucratic setting. 

Support from management and being open minded are effective in bringing 

about a willingness to try new ideas. It is important to be willing to listen and to 

discuss ideas from a wide variety of sources, including the public, academic 

community, and management, then to build on the ideas that work and learn 

from the ones that fail. 

The more complicated and varied the expected outcomes or desires, the 

harder it will be to implement the project, especially through a timber sale in 

which market forces typically play a critical role. Other avenues to accomplish 

multiple resource objectives, such as those described by Ringgold (1998) in his 

paper on stewardship contracting, need to be considered and tried. Economic 

viability is a key to successful implementation of any package involving the 

market for services or commodites. 

What have we learned so far, and what still needs to be explored? 

Preliminary results from the 10S18 Fuels Reduction Project have shown that we 

can successfully implement the desired silvicultural prescriptions. On the units 

logged with a tractor, the desired basal areas per acre have been attained, and 

canopy covers meet the minimum of 40 percent for spotted owl foraging habitat. 

Vertical structure within the groups became less diverse, however, tending to 

become single storied with little to no understory, especially after post-sale 

treatments. Thinning of the forest matrix between regeneration groups 

accentuated their existing group structure, as planned, so stands are 

conspicuously more patchy and uneven-aged than before thinning. What effect, 

if any, the stands with little or no understory, but more diversity in horizontal 

structure, will have on spotted owls and other wildlife species remains to be 

determined. 

Although it cost more to implement uneven-aged prescriptions than is typical 

for even-aged prescriptions, the difference was less than expected. Spreadsheets 

developed for the costs of sale preparation and administration need to be 

expanded to capture time spent in the office and to more accurately track 

overhead costs. Time and funding permitted, production time and cost studies 

would add much to our assessments of costs from an operations standpoint. 

The project has given us the opportunity to test implementation of an unevenaged management strategy at a landscape scale. Although the study is still in an 

early stage, we are already gaining important insights. For example, we now 

know that a typical Ranger District probably can implement the uneven-aged 

management strategy across a large landscape, and at costs comparable to 

traditional even-aged management. 

Smith, Exline 

USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002. 29 
Smith, Exline An Uneven-Aged Management Strategy: Lessons Learned 

Acknowledgments 

For their dedication and commitment, we are indebted to employees of the Sierra 

National Forest, especially those on the Kings River Ranger District, and to 

employees of the Pacific Southwest Research Station, who have participated in 

this project. Without their help, this study would be impossible. We also thank 

Phyllis Banaducci, John Fiske, and Douglas D. Piirto for their constructive 

reviews of an early draft of this paper. 

References 

Aho, Paul E; Fiddler, Gary; Srago, Mike. 1983. Logging damage in thinned, young growth true fir 

stands in California and recommendations for prevention. Res. Paper PNW-304. Portland, OR: 

Pacific Northwest Forest and Range Experiment Station, Forest Service, U.S. Department of 

Agriculture; 8 p. 

Alexander, Robert R.; Edminster, Carleton B. 1978. Regulation and control under uneven-aged 

management. In: Proceedings of uneven-aged silviculture and management in the United States. 

Washington, D.C.: Timber Management Research, Forest Service, U.S. Department of 

Agriculture; 217-230. 

Curtis, Robert O. 1978. Growth and yield of uneven-aged stands. In: Proceedings of uneven-aged 

silviculture and management in the United States. Washington, D.C.: Timber Management 

Research, Forest Service, U.S. Department of Agriculture; 186-201. 

Dunning, Duncan; Reineke, L. H. 1933. Preliminary yield tables for second-growth stands in the 

California pine region. Tech. Bull. No. 354. Washington, D.C.: U.S. Department of Agriculture; 

24 p. 

Fiske, John N.; Husari, Susan J.; Ratcliff, Tom; Rogers, Robert R.; Smith, Mark T. 1993. Effects of a 

group selection strategy for the Sierra Nevada mixed conifer: report of a Regional ad hoc team. 

San Francisco, CA: Pacific Southwest Region, Forest Service, U.S. Department of Agriculture; 78 

p. [Unpublished internal report.] 

Foiles, Marvin W. 1978. Stand structure. In: Proceedings of uneven-aged silviculture and 

management in the United States. Washington, D.C.: Timber Management Research, Forest 

Service, U.S. Department of Agriculture; 176-185. 

Hallin, William E. 1959. The application of unit area control in the management of ponderosaJeffrey pine at Blacks Mountain Experimental Forest. Technical Bulletin No. 1191, Berkeley, 

CA: Forest Service, U.S. Department of Agriculture; 96 p. 

Helm, John A., ed. 1998. The dictionary of forestry. Bethesda, MD: The Society of American 

Foresters; 210 p. 

Meyers, Walter H. 1938. Yield of even-aged stands of ponderosa pine. Tech. Bull. No. 630. 

Washington, D.C.: U.S. Department of Agriculture; 59 p. 

Ringgold, Paul C. 1998. Land stewardship contracting in the national forest: a community guide to 

existing authorities. Washington, D.C.: Pinchot Institute for Conservation; 182 p. 

Smith, David M. 1962. The practice of silviculture. New York, NY: John Wiley and Sons, Inc.; 578 p. 

USDA [U.S. Department of Agriculture]. 1991. Forest land and resource management plan. Clovis, 

CA: Sierra National Forest; 281 p. 

USDA [U.S. Department of Agriculture]. 1993. California spotted owl: Sierran Province interim 

guidelines Environmental Assessment. San Francisco, CA: Pacific Southwest Region, Forest 

Service, U.S. Department of Agriculture; 309 p. 

USDA [U.S. Department of Agriculture]. 1994. Forest inventory and analysis user’s guide. San 

Francisco, CA: Pacific Southwest Region, Forest Service, U.S. Department of Agriculture; 1200 p. 

USDA [U.S. Department of Agriculture]. 1995. Landscape analysis plan, Kings River administrative 

study. Prather, CA: Kings River Ranger District, Sierra National Forest, U.S. Department of 

Agriculture; 117 p. 

USDA [U.S. Department of Agriculture]. 1996. Forest vegetation simulator. San Francisco, CA: 

Pacific Southwest Region, Forest Service, U.S. Department of Agriculture; electronic version 

only. 

Verner, Jared; McKelvey, Kevin, S.; Noon, Barry R.; Gutiérrez, R.J.; Gould, Gordon I., Jr.; Beck, 

Thomas W. 1992. The California spotted owl: a technical assessment of its current status. Gen. 

Tech. Rep. PSW-GTR-133. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. 

Department of Agriculture; 285 p. 

30 USDA Forest Service Gen. Tech. Rep. PSW-GTR-183. 2002.