Combining Silviculture and Landscape

 Architecture to Enhance the Roadside View

Philip M. McDonald R. Burton Litton, Jr.

United States

Department

of Agriculture

Forest Service

Pacific Southwest

Research Station

Research Paper

PSW-RP-235

http://www.psw.fs.fed.us/
Publisher:

Albany, California

Mailing address:

PO Box 245, Berkeley CA

94701-0245

510 559-6300

http://www.psw.fs.fed.us

September 1998

Pacific Southwest Research Station

Forest Service

U.S. Department of Agriculture

Abstract

McDonald, Philip M.; Litton, R. Burton, Jr. 1998. Combining silviculture and landscape

architecture to enhance the roadside view. Res. Paper PSW-RP-235. Albany, CA: Pacific

Southwest Research Station, Forest Service, U.S. Department of Agriculture; 20p.

On a high-quality site in the mixed conifer forest of northern California, understory and

overstory vegetation along a 3-mile paved county road were manipulated to enhance the

view for the traveler. Traditional silvicultural cutting methods and landscape architectural

techniques were blended to give contrast and variability to the vegetation along both sides

of the highway. Understory vegetation (hardwoods, shrubs, forbs, graminoids, ferns,

conifer seedlings); saplings (hardwoods, conifers, shrubs); and trees (California white fir,

sugar pine, coast Douglas-fir, incense-cedar, California black oak, ponderosa pine, and

Pacific dogwood) were sampled before logging, after logging, after brush disposal, and 6

years later in 10 distinct visual segments along the road and in a control (untreated area).

Measurements included density, foliar cover, height, basal area, and basal area growth.

Plant diversity also was quantified. Major findings were that although the hardwoods and

shrubs obscured about 25 percent of the view 6 years after brush disposal, the view is still

vastly improved over what it was before. And with careful logging and other vegetation

management, the roadside stand can yield both pleasing scenery and timber.

Retrieval Terms: landscape management, mixed conifer forest, northern California, plant

community dynamics, stand growth, view enhancement

The Authors

Philip M. McDonald is a research forester, Pacific Southwest Research Station,

Silviculture Laboratory, USDA Forest Service, 2400 Washington Ave., Redding, CA 96001.

R. Burton Litton, Jr., now retired, was a research landscape architect at the Pacific

Southwest Research Station, Berkeley, Calif., and is professor emeritus of landscape

architecture, University of California, Berkeley.
Combining Silviculture and Landscape

 Architecture to Enhance the Roadside View

Philip M. McDonald R. Burton Litton, Jr.

Contents

In Brief . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Location and Study Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Sampling and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Plant Community Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Understory Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Saplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Stand Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Effect of Cutting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Stand Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Discussion and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Pacific Southwest

Research Station

USDA Forest Service

Research Paper

PSW-RP-235

September 1998

USDA Forest Service Res. Paper PSW-RP-235. 1998. 1

Introduction

Millions of people annually travel America’s highways for business andpleasure. Some travelers stare straight ahead engrossed in inner thoughts, but

others look forward to the trip. To them, getting there is half the fun. For many, a

changing sequence of pleasing views makes the difference between an ordinary trip

and a special one. But creating a pleasing view often requires skill and hard work, and

manipulating the trees and understory vegetation can be expensive. To what end?

Does Mother Nature fill new views with vegetation? If so, how long does it

take (fig. 1)? Is the vegetation that comes back the same as that which was

present before?

Pleasing scenery has long been recognized as a major “yield” from forest land.

The National Environmental Policy Act of 1969 and later the Forest and Rangeland

Renewable Resource Planning Act of 1974 and the National Forest Management

Act of 1976 assured productive and esthetically pleasing forests. And ecosystem

management, which is now the operational paradigm for managing forest land,

A

B

Figure l—A typical sprout clump

of shrub tanoak about 20 feet

from the highway (A) after shrub

disposal in August 1979, and (B)

3 years later in September 1982.

The clump is 8 feet in diameter

with stems 5.5 feet tall.
2 USDA Forest Service Res. Paper PSW-RP-235. 1998.

involves a major social (human) component. Amenity and spiritual values are part

of this component. If the scenery along the road is pleasing to the traveler, then

traveling across the landscape also is enjoyable. Not only does enhancement of the

roadside zone fulfil the social component of ecosystem management, it also

addresses two key provisions that are increasingly being recognized as needed.

These are to manage larger areas for longer periods of time. Kimmins (1971)

recognized this in his “roadside ecosystem.” A longer time frame is important,

because it suggests that the high cost of initially creating a scenic roadside

landscape can be amortized over many acres of land for many years.

A major challenge facing landscape architects in the roadside zone, and indeed

in the forest in general, is that society wants pleasing scenery, but does not

recognize that it must be created and maintained—and paid for. Placing a monetary

value on such amenity values as pleasing scenery or spiritual enlightenment is

difficult. Brown (1987) noted that information about monetary value and other

outputs for scenic beauty are not available.

Removing trees and shrubs in a too-dense stand means that more site resources

should be available for those trees that remain. If they grow faster, revenues from

this additional growth can be used to offset the cost of understory manipulation.

Consequently, in this study, a specific goal addressed stand growth: how many

trees of what species and size class remained after logging, and how did they

respond to harvesting and the removal of understory vegetation?

An additional goal was to put the cost/view-enhancement/roadside logging

operation in perspective. Understandably, forest management in the roadside zone

has been nonexistent or “gentle” and often limited to cutting hazardous trees and

thinning some trees around curves for safety. Worse yet, an unmanaged strip next to

the road sometimes is left to hide unsightly human impacts beyond it. Manipulating

vegetation in the roadside zone is easily seen and open to public scrutiny and

criticism. Consequently, the roadside stand on federal land often is viewed by the

timber industry as being “locked up.” Local sawmills cannot count on trees from the

roadside zone. In this paper, we suggest that the roadside zone can be logged and

logged well, with pleasing scenery and wood products being dual yields from the

land. Furthermore, some excess trees have been removed, and the remaining trees

should be more healthy and less susceptible to future damage. And because fuels

and fuel ladders have been reduced, future view-maintenance operations such as

prescribed burning are now feasible. After presenting some ecological, social, and

environmental considerations on highway right-of-ways, Young (1973) asked: “Why

not a [managed] forest 50 feet wide and 150 miles long?”

This paper describes a study that combined traditional silvicultural cutting

methods and landscape architectural techniques to enhance the roadside view

on the Plumas National Forest in northern California.

Location and Study Design

Located on the USDA Forest Service’s Plumas National Forest in northern

California, the county road that runs through the study area is a gateway to rugged

country that offers many wildland recreation opportunities. Our study involved

both sides of 3 miles of road which was paved, two-lane, and curving, with

numerous dips and rises. A prudent driving speed would average about 35 miles

per hour. Potential views ranged from 100 to 500 feet of visual penetration and

encompassed 176 acres. Within this travel influence zone, 10 landscape control

units were located, each identifying a distinct visual reach (fig. 2). They denoted a

range of highway segments of 0.1 to 0.6 mile and units of 5 to 35 acres.

The treatment in each landscape control unit involved using classical

silvicultural cutting methods to accomplish landscape architecture goals. Each

treatment took advantage of the vegetation that was there and either left it

unaltered or modified it to be unique (fig. 3). Treated vegetation also had to blend
USDA Forest Service Res. Paper PSW-RP-235. 1998. 3

Figure 2—Schematic of

prescriptions and landscape

control areas (numbers 1 to 10)

for improving the view of the

traveler, Plumas National

Forest, California.

Figure 3—The widely spaced

young trees give the traveler not

only a view of the contrasting

older trees, but also the comfort

of forest renewal.

B.D.

M.P.

2

0 0.5 1

miles

Diamond

Spring

1

DDD

3

4

5 D

D

M

M M

6

M

7

B B

BB 8 PP

9

D

10

D D

House

To LaPorte

4900

4800

4700

4800

4700

4600

4500

4600

X4700

4700

4600

4500

4400

4400

N

4400 2

American

L E G E N D

Station point

Side road

Typographic sight barrier

Sight line

Visual lane

"Monarchs"– old singles

"Parkland,"25'-30' spacing, large classes

"Parklang, 25'-30' spacing small classes

Spacing closer that 25'

Young growth

Clumps or groups–may be thinned

"As is" groups or stands

Clearcut or overstory removal

Highway

Species: black oak, dogwood,

maple, ponderosa pine, etc.

View-Enhancement Plan

Landscape Ecology Management Project

Plumas National Forest

La Porte District

California

September 1986
4 USDA Forest Service Res. Paper PSW-RP-235. 1998.

Figure 5—Not only do travelers

see a clean foreground and large

trees, they also get a glimpse of

oncoming traffic in the curve (left

center of the photo).

into adjacent units and fit the character of the highway. Logging and cutting of

understory vegetation were the means for accomplishing the view-enhancement

prescriptions. National Forest foresters and crews were in charge of these

operations. Single-tree selection, group selection, shelterwood, and clearcutting

were employed (U.S. Department of Agriculture 1977). In places, a single large tree

or group of trees was featured; in others, areas were modified to give a parklike

appearance of open-spaced trees (fig. 4) or to form a stand composed of widely

separated groups of trees. In still others, the stand was opened up to provide safety

around curves (fig. 5) or held dense to provide contrast to forthcoming views. In

Figure 4—This parklike stand

features large, tall trees and

suggests a healthy forest.
USDA Forest Service Res. Paper PSW-RP-235. 1998. 5

Figure 6—This large sugar pine

can now be fully seen by cutting

a visual lane from the road to its

base.

many places, visual lanes that extended the view were created (fig. 6). Distinct

assemblages of vegetation that provided contrast and variability also were favored.

Colorful hardwoods, which give accent to spring and contrast and beauty to fall,

were retained alone or with conifers (fig. 7). In one unit, dogwoods in the lower

stratum were featured to provide contrast with overstory conifers.

Typical of timber stands in the mixed conifer forest cover type of the Sierra

Nevada (Tappeiner 1980), overstory species (taxonomy from Little 1979), in

decreasing order of abundance, were California white fir (Abies concolor var.

lowiana) [Gord.] Lemm.), sugar pine (Pinus lambertiana Dougl.), incense-cedar

Figure 7—Heavy cutting in the

foreground has freed the

hardwoods in the background

and provided a pleasing color

contrast, especially in the spring

and fall.
6 USDA Forest Service Res. Paper PSW-RP-235. 1998.

(Libocedrus decurrens Torr.), coast Douglas-fir (Pseudotsuga menziesii [Mirb.]

Franco var. menziesii), California black oak (Quercus kelloggii Newb.), and

ponderosa pine (Pinus ponderosa Dougl. ex Laws. var. ponderosa). Most of these

species and Pacific dogwood (Cornus nuttallii Audubon) also occupy the middle

stand stratum, whereas white fir, incense-cedar, and woody shrubs (taxonomy

from Hickman 1993) such as shrub tanoak (Lithocarpus densiflorus [Hook. & Arn.]

Rehder var. echinoides [R.Br. Campst.] Abrams), golden chinkapin (Castanopsis

chrysophylla [Hook.] Hjelmq. var. minor [Benth.] Munz), California hazel (Corylus

cornuta var. californica [A. DC.] Sharp), and Sierra coffeeberry (Rhamnus rubra E.

Greene), plus numerous herbaceous species, reside in the understory.

Deep soil, plentiful rainfall, and moderate temperatures combined to make

this a high-quality site for growing several species of trees (Biging and Wensel

1984). As observed in road cuts, the soil is at least 5 feet deep, of loam-clayloam

texture, and moderately well drained. Precipitation averages about 80 inches per

year, with more than 100 inches annually being fairly common. The average

annual temperature is about 50oF with the frost-free season averaging 150 days.

The elevation ranges from 4,475 to 4,975 feet.

Because of this favorable environment, the forested stands consist of many

plant species, several size classes, and high densities. The trees and shrubs tend

to grow to the edge of the highway and create a monotonous view (fig. 8) that

lacks contrast and variability—the keys to a pleasing visual experience (Litton

1975, U.S. Department of Agriculture 1995).

Local residents and visiting recreationists had a stake in the study, and

needed to be informed of study goals, the amount of cutting, and the overall look

of the forest after harvesting and slash disposal. Before cutting commenced, the

public was invited to a widely advertised “town meeting” that resulted in

general approval, but one expression for no cutting. Although an on-the-ground

tour of the area with the no-cut people was held, the question of cutting was

never fully resolved. From then on, liaison with the public was generally with

individuals and groups who expressed interest in the area and study. After the

work was completed, comments received by the Forest Service were

Figure 8—This stand, typical of

so many in the forests of

northern California, crowds the

highway and severely limits the

view.
USDA Forest Service Res. Paper PSW-RP-235. 1998.

7

overwhelmingly favorable. National Forest foresters commented on the increased

number of photos of study segments being taken by the public.

Logging of conifer trees larger than 12 inches in breast-height diameter began in

May 1976 and was completed in fall 1977. About 5 million board feet of timber and

160 cords of fuelwood were harvested with a value of about $450,000. The number of

trees (defined as having a diameter of 3.5 inches or larger) in each landscape control

area ranged from 80 to 280 per acre and basal areas from 150 to more than 400 ft

2

 per

acre after logging. Brush disposal, which consisted of cutting and piling smaller trees

and shrubs for eventual burning, was completed in July 1980.

Sampling and Analysis

Vegetation in this study was divided into two major parts: plant community

dynamics (understory and saplings) and stand dynamics (trees).

In the understory portion of the study, the vegetation, which was defined as

being less than 4.5 feet tall, included shorter conifers, hardwoods, and shrubs;

forbs, graminoids (grasses and sedges), and bracken fern. Saplings were defined

as being more than 4.5 feet tall and less than 3.5 inches in diameter, and included

several species of conifers, hardwoods, and shrubs. Saplings were measured on

0.25-acre plots, randomly located in each unit. Because of vegetational

differences, one large unit was represented by four 0.25-acre plots. Understory

vegetation was measured on five circular milacre subplots randomly located in

each plot. A randomly selected untreated control provided comparison to the

view-enhancement areas. For understory vegetation, density, foliar cover (the

sum of shadows that would be cast by leaves and stems of individual species

expressed as a percentage of the land surface [Daubenmire 1968]), and average

dominant height (average of three tallest stems measured from mean groundline

to bud) were measured. These parameters were recorded for each species and

then combined into vegetation classes such as hardwoods, shrubs, and forbs. For

saplings, density and stem height and diameter were quantified. All plant species

were recorded at the beginning and end of the study and at various other times.

After extensive reconnaissance, we determined that it was the shrubs and

hardwoods that blocked most of the potential view, at least in the critical

foreground. We then calculated the combined shrub and hardwood volume

(foliar cover times height) for each plot and ranked all plots by this measure.

Because other foresters and landscape architects could have differing amounts

of view-blocking plant volume in their areas, we then combined plots into

“high-,” “medium-,” and “low-volume” categories after brush disposal in fall

1980. These designations are referred to in text and tables as “shrub volume”

categories, although hardwoods were included. Based on our calculated values,

high volume ranged from 5,100 to 37,240 ft

3

 per acre, medium from 872 to 3,080

ft

3

 per acre, and low from 0 to 120 ft

3

 per acre. Number of plots by category was

high, 4; medium, 5; and low, 4.

In the stand dynamics portion of the study, all trees larger than 3.5 inches in

diameter were tagged and measured on the same 0.25-acre plots in each

landscape control area where the saplings were located. And as before, an uncut

control provided comparison to the view-enhancement areas.

Because other foresters and land managers could have differing amounts

and kinds of trees in their roadside areas, we combined plots into “high,”

“medium,” and “low” categories on the basis of before-logging basal area. Based

on our calculated values, high basal area ranged from 392 to 460 ft

2

 per acre;

medium from 316 to 380, and low from 279 to 307 ft

2

 per acre. Number of plots by

category was high, 5; medium, 5; and low, 4.
8 USDA Forest Service Res. Paper PSW-RP-235. 1998.

Plant Community Dynamics

Understory Vegetation

Before logging, the understory vegetation consisted of 9 shrubs, 10 forbs, 1 graminoid

(grasses and sedges), bracken fern, 3 hardwoods, and 5 conifers for a total of 29

species. By the end of the study in 1986, the total number of species had increased to

36 plus one species of grass that had been seeded in the skid roads for erosion

control. New species were those that took advantage of the soil bared in logging. No

naturally seeded alien species were detected at any time. Ten species occupied the

control from the beginning to end of the study. All were adapted to an environment

of deep shade and a thick layer of organic matter on the forest floor.

Hardwoods, shrubs, forbs, ferns, and conifers were well represented in all three

shrub-volume categories in the before-logging (1976) plant community (table 1).

Forbs, and specifically western star flower (Trientalis latifolia Hook.), were particularly

abundant. Graminoids were generally absent. After logging (1977), all classes of

vegetation generally increased. Graminoids in the high- and low-shrub-volume

categories increased dramatically from almost none to more than 10,000 plants per

acre. Overall, plant density increased 41 percent after logging.

After brush disposal (1980), most classes of vegetation decreased in density,

particularly in the high- and low-shrub-volume categories (table 2). Shrubs in the

high-shrub-volume category and forbs and graminoids in the medium category,

which gained 63, 38, and 3600 percent, respectively, were notable exceptions.

These increases were large enough to outweigh the decreases, and total plant

density increased 2 percent after brush disposal.

Table 1—Average density of understory vegetation before and after logging, Plumas

National Forest, California, 1976-1977

Shrub Vegetation Before logging After logging

volume class ________________________________ ______________________________

Mean SE Mean SE

----------------------- number/acre ----------------------

Hardwoods 1,386 694 2,650 1,284

Shrubs 4,688 1,518 6,300 2,044

Forbs 25,238 6,761 24,600 3,627

High Graminoids 0 - 10,500 4,113

Ferns 1,150 456 2,050 929

Conifer seedlings 1,362 440 2,500 1,377 _______________ _____________

Total 33,824 48,600

Hardwoods 310 236 440 204

Shrubs 4,960 1,884 7,480 2,473

Forbs 11,580 3,344 17,080 8,102

Medium Graminoids 0 - 40 40

Ferns 3,380 2,444 5,360 3,330

Conifer seedlings 880 508 960 331 _______________ _____________

Total 21,110 31,360

Hardwoods 150 79 760 371

Shrubs 1,520 320 3,120 700

Forbs 11,610 3,913 16,040 5,033

Low Graminoids 10 10 12,000 8,000

Ferns 590 287 2,400 1,911

Conifer seedlings 800 165 920 196 _______________ _____________

Total 14,680 35,240
USDA Forest Service Res. Paper PSW-RP-235. 1998. 9

Six years after brush disposal (1986), the density of almost all classes of

vegetation had increased, in many instances from two to ten times (table 2). Forbs

in the high-shrub-volume category, graminoids in the medium category, and forbs

and bracken fern in the low category increased the most. The largest increases,

which occurred in all three shrub-volume categories, were in conifer seedlings.

They apparently had benefitted from the disturbed ground and increased resources

brought about by logging and brush disposal. The only large decrease was for

graminoids in the low-shrub-volume category. Total plant density increased 44

percent during the 6-year period. Foliar cover, which provides a conservative

estimate of horizontal development, ranged from 0 to 6 percent among vegetation

classes just after brush disposal and from 0 to 17 percent after 6 years (table 3).

These low values reflect the shady environment and understory status of the

vegetation. Mean height of understory vegetation also generally increased after

brush disposal. At the end of the study in 1986, hardwood height ranged from 2.0

to 5.0 feet among shrub-volume categories, shrubs from 0.5 to 1.7 feet, and

graminoids from 0.7 to 3.2 feet tall (table 4). Hardwood and shrub height increased

the most with hardwoods gaining 35, 267, and 233 percent in high-, medium-, and

low-shrub-volume categories, respectively. Shrub height increased 88 percent in

the high-shrub-volume category and 70 percent in the medium category. Decreases

in average height occurred in forbs and conifer seedlings and were attributed to

the lower height of the many new plants noted in table 2.

The height values in table 4 do not fully show the effect of the vegetation

on the view. Each vegetation class is an average, and the hardwoods and

shrubs, as examples, include both tall and short species. It is not the species of

Table 2—Average density of understory vegetation after brush disposal and 6 years

later, Plumas National Forest, California, 1980 and 1986

Shrub Vegetation After brush disposal After 6 years

volume class _____________________________________ ___________________________

Mean SE Mean SE category

----------------------- number/acre ----------------------

Hardwoods 1,850 479 2,550 472

Shrubs 10,300 6,773 9,400 5,679

Forbs 23,450 8,779 55,950 22,288

High Graminoids 7,550 4,761 8,050 5,024

Ferns 1,850 532 2,100 881

Conifer seedlings 1,550 690 8,350 2,274 _______________ ________________

Total 46,550 86,400

Hardwoods 760 621 1,160 717

Shrubs 5,213 2,331 6,080 2,170

Forbs 23,560 11,398 33,160 13,119

Medium Graminoids 1,480 995 3,041 2,150

Ferns 3,440 3,095 4,200 2,631

Conifer seedlings 920 377 3,480 1,253 _______________ ________________

Total 35,373 51,121

Hardwoods 160 75 120 49

Shrubs 1,240 325 1,640 382

Forbs 11,800 6,859 21,000 10,500

Low Graminoids 4,400 4,400 1,400 1,205

Ferns 1,080 981 2,480 2,480

Conifer seedlings 320 185 4,240 1,963 _______________ ________________

Total 19,000 30,880
10 USDA Forest Service Res. Paper PSW-RP-235. 1998.

Table 3—Average foliar cover of understory vegetation after brush disposal and 6 years

later, Plumas National Forest, California, 1980 and 1986

Shrub Vegetation After brush disposal After 6 years

volume class _____________________________________ ___________________________

Mean SE Mean SE category

----------------------------- pct ----------------------------

Hardwoods 6 3 17 5

Shrubs 3 2 7 3

Forbs 1 <1 4 2

High Graminoids 1 <1 2 1

Ferns <1 <1 1 <1

Conifer seedlings <1 <1 1 1 ___________ __________

Total 12 32

Hardwoods <1 <1 7 3

Shrubs 3 1 9 3

Forbs 2 1 4 2

Medium Graminoids <1 <1 <1 <1

Ferns 1 1 3 2

Conifer seedlings <1 <1 1 1

___________ __________

Total 8 25

Hardwoods 0 - 0 -

Shrubs <1 <1 1 <1

Forbs 1 1 4 3

Low Graminoids 1 1 <1 <1

Ferns <1 <1 2 2

Conifer seedlings 0 - 0 - ___________ __________

Total 3 8

Table 4—Average height of understory vegetation after brush disposal and 6 years later,

Plumas National Forest, California, 1980 and 1986

Shrub Vegetation After brush disposal After 6 years

volume class _____________________________________ ___________________________

Mean SE Mean SE category

------------------------------ft -----------------------------

Hardwoods 3.7 1.2 5.0 1.5

Shrubs 0.8 0.2 1.5 0.4

Forbs 0.3 0.1 0.3 0.1

High Graminoids 1.6 0.5 2.0 0.6

Ferns 0.7 0.1 1.0 0.1

Conifer seedlings 0.9 0.4 0.7 0.5

Hardwoods 0.9 0.2 3.3 2.3

Shrubs 1.0 0.2 1.7 0.2

Forbs 0.3 <0.1 0.4 0.1

Medium Graminoids 1.5 1.2 3.2 0.2

Ferns 0.9 0.1 1.1 0.2

Conifer seedlings 1.1 0.4 0.7 0.2

Hardwoods 0.6 0.1 2.0 1.1

Shrubs 0.5 0.1 0.5 0.2

Forbs 0.6 0.2 0.3 0.1

Low Graminoids 0.4 0.4 0.7 0.1

Ferns 0.3 0.1 0.9 0.9

Conifer seedlings 0.3 0.1 0.3 <0.1
USDA Forest Service Res. Paper PSW-RP-235. 1998. 11

average height that travelers see as they speed by, but the tallest species. For

the three shrub-volume categories, the range in height (feet) for tallest

hardwoods and shrubs was:

Shrub-volume category Hardwoods Shrubs

High 5.2 - 11.0 2.7 - 4.7

Medium 1.7 - 7.0 2.0 - 4.4

Low 1.6 - 3.9 0.7 - 2.2

After the vegetation in all the shrub-volume categories was totalled and

averaged, it provided a contrast to the uncut control. In general, all classes of

vegetation were well represented in the view-enhancement plots, but less so in

the control (table 5). The control was characterized by large numbers of shrubs

and forbs, plus a few ferns and conifer seedlings. Altogether, there were 53,973

plants per acre in the view-enhancement plots and 77,800 plants per acre in the

control. Much of the density was by the ubiquitous western star flower. Foliar

cover followed a similar trend in both treated plots and control. In the treated

plots, almost all vegetation classes supported some cover; in the control only

shrubs and forbs provided cover. Average height of vegetation in treated plots

and control showed no specific trend: ferns and conifer seedlings were taller in

treated plots; shrubs and forbs were taller in the control. The tallest shrubs in the

control averaged 3.3 feet.

Table 5—Density, foliar cover, and height of understory vegetation 6 years after brush disposal for

treated plots and control, Plumas National Forest, California, 1986

Variable Vegetation class Treated Control Treated Control

plots plots

---------- Means --------- ----- Standard errors ----

Density ----------------------------------- number/acre --------------------------------

Hardwoods 1,186 0 379 -

Shrubs 5,443 16,000 1,847 1,000

Forbs 35,329 60,200 8,883 5,271

Graminoids 3,886 0 1,703 -

Ferns 2,986 1,400 1,246 120

Conifer seedlings 5,143 200 1,123 0 _____________ ____________

Total 53,973 77,800

Foliar ---------------------------------------- pct --------------------------------------

cover

Hardwoods 8 0 3 -

Shrubs 6 28 2 3

Forbs 4 9 1 1

Graminoids <1 0 <1 -

Ferns 2 0 1 -

Conifer seedlings <1 0 <1 - _____________ ____________

Total 21 37

Height ----------------------------------------- ft ---------------------------------------

Hardwoods 3.6 0 0.9 -

Shrubs 1.3 2.5 0.1 0.6

Forbs 0.4 0.5 <0.1 <0.1

Graminoids 1.8 0 0.4 -

Ferns 1.0 0.7 0.1 <0.1

Conifer seedlings 0.6 0.1 0.2 <0.1
12 USDA Forest Service Res. Paper PSW-RP-235. 1998.

Saplings

Most saplings in this study were characterized as being shade tolerant, small,

and extremely slow growing. The conifers tended to have sparse, flat sprays of

needles; the hardwoods, dense masses of leaves. The conifers tended to be

scattered; the hardwoods and shrubs, more clumpy. Where scattered, the

saplings posed no immediate threat to the view, but where clumpy they limited

the view for the highway passers-by.

After logging, conifer, hardwood, and shrub saplings in the high-shrubvolume category decreased from 123 to 109 per acre; in the medium category

decreased from 170 to 129 per acre; and in the low category increased from 35 to

52 per acre. Six years after brush disposal, the conifers showed only minor

changes among shrub-volume categories (table 6). But the hardwoods exploded.

In the high-shrub-volume category, hardwoods increased from 30 to 661 per acre

and, in the medium category, from 9 to 259 per acre. Change in the low-shrubvolume category was minor. Overall, the conifer, hardwood, and shrub saplings

increased 10-fold between 1980 and 1986 in the high-shrub-volume category and

5-fold in the medium category.

Stand Dynamics

Effect of Cutting

Communication between the Plumas National Forest sale administrator, logger,

and researcher was critical to accomplishing view-enhancement and research

goals. In this study, meetings, phone calls, and on-the-ground communication

resulted in “one of the best logging jobs ever seen,” according to National Forest

timber sale administrators. Several special view-enhancement provisions that

hid skid roads and minimized skinned-up trees were carried out successfully.

Plainly, the logger wanted this area to look good and to be proud of the outcome.

Before logging, the forest stand was composed mostly of California white fir

and incense-cedar, with sugar pine a distant third (table 7). After logging and brush

disposal, only minor changes occurred in the composition of the stand. Sugar pine

and white fir each increased 3 percent, and incense-cedar decreased 7 percent.

When portrayed by diameter classes, the stand typically was made up of many

small trees and a decreasing number of progressively larger trees (table 8). Cutting

was heaviest in the smallest classes and lightest in the largest classes. When

density was averaged over all before-logging basal-area categories, trees in the 3.5-

Table 6—Mean density (standard error) of conifer, hardwood, and shrub saplings after brush disposal and 6

years later, by shrub volume category and control, Plumas National Forest, California, 1980 and 1986

Shrub volume Conifers Hardwoods Shrubs Total

category _______________ ____________ _____________ ______________

1980 1986 1980 1986 1980 1986 1980 1986

-------------------------------------------------- number/acre ---------------------------------------------------

High 45 55 30 661 0 39 75 755

(27) (35) (19) (87) - (14) (28) (121)

Medium 50 58 9 259 5 3 64 320

(36) (43) (6) (95) (5) (2) (42) (252)

Low 27 24 0 12 0 0 27 36

(23) (18) - (12) - - (23) (18)

Control 184 168 0 0 24 32 208 200
USDA Forest Service Res. Paper PSW-RP-235. 1998. 13

to 12-inch diameter class lost 13 percent of their number, and those in the 12.1- to

20-inch class lost 1 percent. Conversely, trees in the 20- to 40-inch diameter range

gained 13 percent, and those above 40 inches in diameter gained 1 percent.

Basal areas showed generally similar trends. Before logging, white fir, with

more than 226 ft2

 per acre, had more than twice as much basal area as any other

species (table 9). Sugar pine and incense-cedar ranked second and third with

almost 82 ft2 and more than 78 ft2 per acre, respectively. After logging and brush

disposal, white fir continued to dominate in this respect. When averaged over all

before-logging basal-area categories, the species that gained the most basal area

per acre was sugar pine (5 percent), and the species that lost the most was

incense-cedar (4 percent). White fir also lost 1 percent of its basal area because of

cutting. When arrayed by diameter classes, more than 50 percent of the basal

area in the stand was in the 20- to 40-inch class (table 10). This was true before

logging and continued after brush disposal, at least in the high and low beforelogging basal-area categories. Overall, basal area per acre decreased 11 percent

in the two smallest diameter classes and increased an equal amount in the two

largest classes. The largest increase was in the 20- to 40-inch class.

Table 8—Average number of trees by diameter class before logging (BL), after logging

(AL), and after brush disposal (ABD) for high, medium, and low before-logging basalarea categories, Plumas National Forest, California, 1976-1980

Diameter class High Medium Low _________________________________ ________________________________ ________________________________

BL AL ABD BL AL ABD BL AL ABD

inches ----------------------------------- number/acre -------------------------------------

3.5-12 120 87 30 152 117 65 141 96 57

12.1-20 59 28 26 56 33 27 55 22 24

20.1-40 63 54 57 38 27 26 33 23 24

40+ 4 43 6 4 4 222

Total 246 173 116 252 181 122 231 143 107

Table 7—Average tree density by species and before-logging basal-area category (high, medium, low)

before logging (BL), after logging (AL), and after brush disposal (ABD), Plumas National Forest,

California, 1976-1980

Species High Medium Low ___________________________________ _________________________________ __________________________________

BL AL ABD BL AL ABD BL AL ABD

------------------------------------------ number/acre ------------------------------------------

Douglas-fir 15 13 10 4 4 3 2 1 1

Ponderosa pine 1 0 0 7 6 4 2 32

Sugar pine 20 14 13 30 24 18 18 15 15

White fir 118 87 72 167 119 84 163 92 65

Incense-cedar 76 48 20 39 23 10 36 24 16

California black oak 3 1 1 4 4 3 10 8 8

Pacific dogwood 13 10 0 1 1 0 0 0 0

_______ _____ _______ _______ _______ ________ ________ ________ _______

Total 246 173 116 252 181 122 231 143 107
14 USDA Forest Service Res. Paper PSW-RP-235. 1998.

Table 9—Average tree basal area (standard error) by species before logging (BL), after logging (AL), and after brush disposal (ABD) for high,

medium, and low before-logging basal-area categories. Plumas National Forest, California, 1976-1980

Species High Medium Low ___________________________________________________ ___________________________________________________ __________________________________________________

BL AL ABD BL AL ABD BL AL ABD

----------------------------------------------------------------- ft2/acre ----------------------------------------------------------------------

Douglas-fir 27.02 19.95 20.93 17.61 18.10 19.53 4.78 0.92 1.04

(2.83) (3.20) (3.30) (.14) (.18) .(0) .(0) .(0) .(0)

Ponderosa pine 1.74 0.00 0.00 20.41 7.42 7.36 11.39 11.68 11.82

.(0) .(0) .(0) (.56) (.63) (.58) (5.37) (5.50) (5.38)

Sugar pine 81.88 68.82 73.61 115.28 103.80 95.89 74.10 65.70 70.38

(4.48) (4.30) (3.87) (12.19) (12.76) (12.40) (5.88) (5.83) (6.20)

White fir 226.35 191.82 190.75 166.22 105.70 103.36 165.27 98.81 102.34

(8.37) (6.71) (7.08) (6.95) (6.18) (6.48) (7.11) (5.78) (6.32)

Incense-cedar 78.37 40.08 36.01 17.39 9.41 5.92 19.20 7.89 6.73

(4.00) (3.04) (3.36) (1.13) (.82) (.78) (1.45) (1.03) (1.01)

California black oak 2.56 1.93 2.52 1.67 1.39 1.18 9.81 7.80 8.26

(.07) .(0) .(0) (.17) (.17) (.20) (.78) (.65) (.63)

Pacific dogwood 1.81 1.33 0.00 0.06 0.08 0.00 0.00 0.00 0.00

(.19) (.17) .(0) .(0) .(0) .(0) .(0) .(0) .(0) _____________ ____________ ____________ ____________ _____________ _____________ ______________ _____________ ___________

Total 419.73 323.93 323.82 338.64 245.90 233.24 284.55 192.80 200.57

Table 10—Average tree basal area (standard error) by diameter class before logging (BL), after logging (AL), and after brush disposal (ABD) for

high, medium, and low before-logging basal-area categories, Plumas National Forest, California, 1976-1980

Diameter class High Medium Low ______________________________________________________ ___________________________________________________ ________________________________________________________

BL AL ABD BL AL ABD BL AL ABD

inches ----------------------------------------------------------------------- ft2/acre -------------------------------------------------------------------------------

3.5-12 36.29 24.35 10.69 41.80 33.35 23.05 41.32 29.52 22.81

(2.02) (1.70) (1.08) (2.02) (1.73) (1.47) (2.47) (2.06) (1.83)

12.1-20 80.05 35.97 33.38 74.13 44.63 38.67 70.80 27.97 30.70

(2.71) (1.86) (1.59) (2.65) (1.87) (1.68) (2.64) (1.89) (2.00)

20.1-40 259.65 226.71 247.47 142.27 107.94 109.45 152.04 114.79 125.26

(8.75) (8.44) (9.03) (8.23) (8.64) (8.42) (9.99) (9.44) (9.91)

40+ 43.74 36.90 32.28 80.44 59.98 62.07 20.39 20.52 21.80

(5.13) (2.34) (1.46) (11.04) (11.00) (11.03) (1.61) (1.47) (1.80)

____________ ___________ _____________ _______________ ___________ ____________ ______________ ___________ _____________

Total 419.73 323.93 323.82 338.64 245.90 233.24 284.55 192.80 200.57
USDA Forest Service Res. Paper PSW-RP-235. 1998. 15

Stand Growth

Basal-area growth for the 1980-1986 period tended to be highest where the

largest number of bigger trees was present. Thus white fir and sugar pine

contributed most to stand growth in the 20- to 40-inch diameter class (table 11).

When totalled for all species and diameter classes, and presented as a percent of

the after-brush-disposal totals in tables 3 and 4, basal-area growth per acre for

each before-logging basal-area category was:

Category Total after-brush- Six-year basal- Increase

disposal basal area area growth

------------------------ ft2/acre ----------------------- pct

High 323.82 21.63 7

Medium 233.24 21.21 9

Low 200.57 19.22 10

Comparable 6-year basal-area growth in the control was 4 percent.

Consequently, view-enhancement cutting did improve overall stand growth

slightly, but not consistently for all species in all age classes. A given species would

grow better in treated plots versus the control in one diameter class and not as well

in the next (table 12). White fir is an example. Its growth averaged 0.16 ft2 per tree in

the 12.1- to 20.0-inch diameter class in treated plots and 0.65 ft2 per acre in the

control. In the 20.1- to 40-inch class, trees in the view-enhancement plots averaged

0.31 ft2 per acre and those in the control averaged 0.25 ft2 per acre.

Table 11—Six-year basal area growth by species and diameter class for high, medium, and low before-logging basal-area categories, Plumas

National Forest, California, 1980-1986

Species Before logging Basal area growth when breast-height

basal-area diameter class (inches) was:

catagory

3.5–12 12.1–20 20.1–40 40+ __________________________ __________________________ __________________________ _______________________

M1 SE M SE M SE M SE

------------------------------------------------------------------------- ft2/acre ---------------------------------------------------------------------

High 0.16 0.06 0.42 0.33 3.21 0.74 0.00 0.00

Douglas-fir Medium 0.07 0.00 0.29 0.00 0.00 0.00 0.55 0.00

Low 0.00 0.00 0.24 0.00 0.00 0.00 0.00 0.00

High 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Ponderosa pine Medium 0.00 0.00 0.24 0.13 0.65 0.06 0.00 0.00

Low 0.00 0.00 0.00 0.00 0.24 0.00 0.30 0.00

High 0.00 0.00 0.00 0.00 4.75 0.60 0.11 0.00

Sugar pine Medium 0.10 0.03 0.65 0.08 4.85 0.56 2.01 0.55

Low 0.06 0.03 0.74 0.01 3.93 0.38 1.54 0.41

High 0.52 0.08 1.50 0.43 7.47 0.77 0.71 0.33

White fir Medium 1.98 0.27 3.91 0.43 5.23 0.67 0.00 0.00

Low 2.25 0.29 4.12 0.48 4.15 0.38 0.00 0.00

High 0.16 0.10 1.29 0.30 1.33 0.22 0.00 0.00

Incense-cedar Medium 0.19 0.06 0.42 0.07 0.00 0.00 0.00 0.00

Low 0.76 0.22 0.41 0.18 0.00 0.00 0.00 0.00

High 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

California Medium 0.07 0.01 0.00 0.00 0.00 0.00 0.00 0.00

black oak Low 0.23 0.10 0.25 0.11 0.00 0.00 0.00 0.00

1

M and SE are mean and standard error, respectively.
16 USDA Forest Service Res. Paper PSW-RP-235. 1998.

Ingrowth of trees to the 3.5- to 12-inch diameter class and tree mortality were

negligible and virtually in balance during the study. Ingrowth to study plots

from 1980 through 1986 totalled 13 trees; 9 white firs and 4 incense-cedars.

Ingrowth occurred in only 4 of the 14 plots. One white fir became ingrowth in the

control. Mortality during the study amounted to 14 trees in 7 plots with almost

80 percent being white fir. Diameters ranged from 4 to 32 inches. Because

suppression was the main cause of death, most trees grew very little before they

died. Two California black oaks died in the control, also from suppression.

Discussion and Conclusions

Enhancing the view by manipulating roadside vegetation is nothing new, but

doing it with a team made up of a research silviculturist, research landscape

architect, and National Forest foresters and crews is. Several other aspects of this

study also were unique. Denoting the actual cost of creating the view (McDonald

and Litton 1987) seldom is done. And even more seldomly are species diversity

and density quantified, let alone evaluated for growth and development after

several years. The time that vegetative regrowth closes the view is mentioned as

being important (Noyes 1969), but details are scant. Rare also are studies that

document the effect of roadside cutting in terms of longer-term (6-year) tree and

stand growth, ingrowth of new trees, and mortality of the old.

In this 1976-1986 study, we began by removing some of the dense vegetation

along the highway. We did this by heavy cutting in places, light cutting in certain

areas, and no cutting in specific locales. We removed many merchantable trees in

a typical timber sale, and we removed many smaller trees and cut shrubs in a

not-so-typical brush disposal operation that was intensive in places. It also was

expensive, costing $462 per acre or $27,126 per mile for the 3 miles of highway in

the study (McDonald and Litton 1987).

In terms of plant diversity, the view-enhancement cutting had no major

effect. The number of natural plant species increased slightly, and no alien

species became established.

Table 12—Average 6-year basal-area growth (standard error) by species and diameter class for view-enhancement plots and control,

Plumas National Forest, California, 1980-1986

Species Basal area growth when breast-height

diameter class (inches) was:

3.5–12 12.1–20 20.1–40 40+ ______________________________ ____________________________ ________________________________ ____________________________

Cut Control Cut Control Cut Control Cut Control

-------------------------------------------------------------- ft2/tree ----------------------------------------------------------------

Douglas-fir 0.05 0.06 0.27 0.09 0.62 0.00 0.50 0.00

(0.02) (0.04) (0.08) (0.00) (0.18) (0.00) (0.00) (0.00)

Ponderosa pine 0.00 0.00 0.15 0.00 0.34 0.00 0.00 0.00

(0.00) (0.00) (0.04) (0.00) (0.03) (0.00) (0.00) (0.00)

Sugar pine 0.29 0.00 0.20 0.00 0.45 0.28 0.39 0.68

(0.06) (0.00) (0.03) (0.00) (0.06) (0.03) (0.12) (0.14)

White fir 0.45 0.02 0.16 0.65 0.31 0.25 0.32 0.56

(0.01) (0.00) (0.02) (0.03) (0.04) (0.07) (0.11) (0.00)

Incense-cedar 0.05 0.00 0.12 0.07 0.31 0.30 0.00 0.00

(0.02) (0.00) (0.04) (0.00) (0.12) (0.13) (0.00) (0.00)

California black oak 0.60 0.01 0.05 0.00 0.00 0.00 0.00 0.00

(0.02) (0.00) (0.02) (0.00) (0.00) (0.00) (0.00) (0.00)
USDA Forest Service Res. Paper PSW-RP-235. 1998. 17

In the understory, where initial shrub and hardwood volumes had been

high, the density of shrubs and hardwoods returned to their previously high

levels (fig. 9). Not only was density high, but so was height growth. In the high

shrub volume category the density of the understory vegetation was more than

86,000 understory plants and 755 saplings per acre. The tallest hardwoods ranged

from 5 to 11 feet, and the tallest shrubs from 2.7 to 4.7 feet. In these areas, the

view has closed. Where initially medium amounts of vegetation had been present

after shrub disposal, a medium amount of vegetation returned. Here the density

of the understory vegetation was more than 51,000 plants per acre, with the

tallest hardwoods ranging from 1.7 to 7 feet and the tallest shrubs from 2 to more

than 4 feet. In these areas, the view has closed in places. In still other places, it

may close later, and in still others it will probably not close at all. Even in those

areas that had a low amount of initial shrub volume, the plant community

doubled in density, and height increased, but not to the point that it affected the

view. The shrub component was not a factor in these areas either.

In the overstory, almost 53 percent of the trees and 27 percent of tree basal

area were removed in logging and brush disposal. In spite of this reduction, no

species gained or lost more than 7 percent of stand density or more than 5

percent of total stand basal area. Concomitantly, no diameter class gained or lost

more than 13 percent of trees or 11 percent of basal area. Overall, white fir and

sugar pine were the most abundant species when the study began, and they were

the most abundant after it ended. The 20- to 40-inch diameter class had the most

basal area when the study began and also when it ended. Net changes were a

slight increase in sugar pine density and basal area at the expense of incensecedar, and a slight gain in these values in the 20- to 40-inch diameter class at the

expense of the 3.5- to 20-inch class. Six-year basal-area growth of residual trees

ranged from 7 to 10 percent for the high, medium, and low before-logging basalarea categories and 4 percent in the control.

Plenty of trees of all species and age classes remain in the roadside stand (fig. 10).

At the end of the study about 115 trees per acre, which supported an average

basal area of 253 ft2

 per acre, were present. And at least for the study period,

ingrowth was in balance with mortality. Species composition was similar to that

before logging, and tree growth did not differ between view-enhancement plots

and control. The traveler probably knew that some vegetation had been

manipulated, but the overall stand was the same after cutting as it was before.

The Forest Service’s landscape management objective of “partial retention”

(retaining the major impression of the original landscape) was achieved.

A B

Figure 9—(A) After brush

disposal in 1980, this high-shrubvolume area resembled a

parklike stand. (B) After two

growing seasons, sprouting

shrubs and hardwoods were

rapidly covering the ground.
18 USDA Forest Service Res. Paper PSW-RP-235. 1998.

The primary goal in this view-enhancement study was to break up the dense

stand along the highway through which the traveler had to pass. This meant

manipulating the vegetation in a special way to bring contrast and variation to

the view of the traveler. We did this by creating pleasing “features” at specific

locations along the way, and also by blending the features and other prescriptions

together so that the unity of the entire view was maintained. The manipulation of

vegetation was a success if the traveler enjoyed one small view or felt good after

driving through the entire study area. Consequently, the fact that the vegetation

grew back in certain areas and obscured about 25 percent of the view that had

been laboriously and expensively created does not mean that the entire view was

ruined in 6 years. In some instances a feature view has been lost and in other

instances a longer view is not as wide or as sharp. But, many pleasing features

are present, and the overall contrast and variability of the view remain.

Roadside cutting complements ecosystem management both in an obvious

manner and perhaps in a manner not given much thought. Ecosystem management

obviously concerns humans, and enhancing visual resources through forest

management allows the forest to both be functional and fulfill a basic human need.

A fundamental precept of ecosystem management is sustainability—continuance

for posterity of the plants and animals that belong in a specific area or habitat.

Sustainability of the view is a corollary to ecosystem management that has merit.

The traveler who enjoys a pleasing view perceives a healthy forest and one that

will be present (sustained) for future generations.

Figure 10—Even with heavy

cutting in places, many trees

remain in the roadside zone.
USDA Forest Service Res. Paper PSW-RP-235. 1998. 19

On the plus side of the balance sheet in this study, some timber was harvested

from the roadside zone, and income was received from it. Stand growth increased

slightly, and future mortality probably will be less, at least in the near term. Most

important, the overall view has been enhanced, even though part of it was

obscured in a few years. And because the heavy cutting of trees and shrubs has

reduced the amount of fuels and fuel ladders along the highway, the rate of

spread of wildfire has been reduced. Crews now have more time to extinguish a

flare-up that starts in the fire-prone roadside zone (Wilson 1979).

On the minus side of the balance sheet was the high initial cost. Although

daunting, some mitigating factors need to be considered. First of all, the current

emphasis on ecosystem management creates the long timeframe needed to

amortize vegetation manipulation costs. And because additional silvicultural

manipulations will need to be applied to maintain the view, they too can be

amortized over time. These manipulations should be less expensive and involve

only “touch-up” operations such as thinning, application of herbicides to dense

resprouting shrubs, and broadcast burning. Broadcast burning is now feasible,

whereas before, the dense fuels and fuel ladders made it too risky.

Is the improved scenery worth the cost? Because the view cannot be improved

until trees are removed, the question really becomes “Are harvested trees and an

improved view worth the cost?” We believe that the combined yield of timber

(fig. 11) and improved recreational experience shift the balance—the pluses

outweigh the minuses. The roadside zone need not be off limits to such

management activity as a careful timber harvest. Magill (1992) presented an

interesting suggestion regarding managed landscapes and view acceptance. His

extensive survey noted that most respondents were urbanites that are “immersed

in some kind of management every day.” Thus they likely “would accept

management and perceive it favorably.” Why not a managed forest 50 feet wide

and 150 miles long?

Figure 11—With careful

management, the roadside zone

can yield both pleasing scenery

and wood products.
20 USDA Forest Service Res. Paper PSW-RP-235. 1998.

References

Biging, Greg S.; Wensel, Lee C. 1984. Site index equations for young-growth mixed conifers of

northern California. Res. Note 8. Berkeley, CA: Department of Forestry and Resource

Management, University of California; 13 p.

Brown, Thomas C. 1987. Production and cost of scenic beauty: examples for a ponderosa pine

forest. Forest Science 33(2): 394-410.

Daubenmire, R.F. 1968. Plant communities: a textbook on plant synecology. New York: Harper

and Row; 300 p.

Hickman, James C., ed. 1993. The Jepson manual, higher plants of California. Berkeley: University

of California Press; 1,400 p.

Kimmins, J.P. 1971. The ecology of roads. Vancouver, B.C. Paper presented at the VIII Canadian

roadside development conference, June 1971; 10 p.

Little, Elbert L., Jr. 1979. Checklist of United States trees (native and naturalized). Agric. Handb.

541. Washington, DC: Forest Service, U.S. Department of Agriculture; 375 p.

Litton, R. Burton, Jr. 1975. Esthetic resources of the lodgepole pine forest. In: Proceedings of a

symposium on management of lodgepole pine ecosystems; 1973 October 9-11; Pullman, WA:

285-296.

Magill, Arthur W. 1992. Managed and natural landscapes: what do people like? Res. Paper PSWRP-213. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of

Agriculture; 28 p.

McDonald, Philip M.; Litton, R. Burton, Jr. 1987. Enhancing the roadside view-initial costs. Journal

of Forestry 85(11): 19-23.

Noyes, John H. 1969. Woodlands, highways, and people. Public. 33, Cooperative Extension Service.

Amherst: University of Massachusetts; 21 p.

Tappeiner, John C., II. 1980. Sierra Nevada mixed conifer. In: Eyre, F.H., ed. Forest cover types of

the United States and Canada. Bethesda, MD: Society of American Foresters; 118-119.

U.S. Department of Agriculture. 1977. Timber. In: National Forest landscape management. vol. 2,

ch. 5 (timber). Agric. Handb. 559. Washington, DC: Forest Service, U.S. Department of

Agriculture; 223 p.

U.S. Department of Agriculture. 1995. Landscape aesthetics: a handbook for scenery management.

Agric. Handb. 701. Washington, DC: Forest Service, U.S. Department of Agriculture; various

pagination.

Wilson, Carl C. 1979. Roadsides—corridors with high fire hazard and risk. Journal of Forestry

77(9):576-577, 580.

Young, Harold E. 1973. Management of forest stands on highway right-of-ways. Research in the

Life Sciences 20(12): 1-9.
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PSW-RP-235

Research PaperResearch StationPacific SouthwestForest Serviceof AgricultureDepartmentUnited States

 Architecture to Enhance the Roadside ViewCombining Silviculture and Landscape

In Brief

McDonald, Philip M.; Litton, R. Burton, Jr. 1998. Combining silviculture and landscape

architecture to enhance the roadside view. Res. Paper PSW-RP-235. Albany, CA: Pacific

Southwest Research Station, Forest Service, U.S. Department of Agriculture; 22 p.

Retrieval Terms: landscape management, mixed conifer forest, northern California,

plant community dynamics, stand growth, view enhancement

All too often, the forest roadside zone is a hands-off zone for timber harvest.

Activities there are easily seen and subject to the traveler’s scrutiny and

positive or negative response. But this zone contains trees that are a valuable

commodity, and scenery that is a valuable amenity. The two need not conflict.

The zone also contains numerous shrubs and small trees that grow to the edge of

the highway and limit the variability and contrast needed for a pleasing visual

experience. In addition, the dense stand is a fire waiting to happen in the sense of

being a large amount of fuel near a source of ignition (a burning cigarette from a

passing motorist) with a fuel ladder straight to the top of tree crowns. And if the

highway twists and turns, dense stands of trees impede visibility of oncoming

traffic. Plainly, the typical forested roadside stand in northern and central

California could use some forest management. But how to extract trees, remove

view-blocking shrubs and smaller trees, provide pleasing scenery, and not lose

the inherent character of the forest landscape? A critical question involves cost.

Society has stated many times that it wants an enhanced esthetic quality to the

forest (and roadside zone), but the question of how to cover the cost of making it

attractive and maintaining that attractiveness is seldom addressed.

We quantified the initial cost in a previous paper (McDonald and Litton

1987). Enhancing the view and initiating forest management in the roadside zone

with very careful logging and shrub removal techniques cost $81,379. When

allocated to the 176 acres in the travel influence zone, the cost was $462 per acre

or $27,126 per mile for work on both sides of the 3-mile roadway in the study.

About 5 million board feet of timber and 160 cords of fuelwood were harvested

with a value of about $450,000.

Research questions also abounded. How much of what species of vegetation

came back after cutting? Was the species makeup the same? What happened to

the remaining trees: did they die, did they grow? Answering these and other

questions was the purpose of this study.

We began with a team made up of a research silviculturist, a research landscape

architect, and National Forest foresters and crews. We also solicited input from the

public before the study began. And we talked to the logger about the potential to

unlock the roadside zone for timber yield. We got “one of the best logging jobs ever

seen” according to several knowledgeable timber sale specialists.

We also gained some knowledge about plant community and stand

dynamics. In terms of plant diversity, the harvesting and shrub removal

operations had no major effect. Total number of plant species increased slightly,

and no alien species were found. In the understory, the density and foliar cover

of hardwoods, shrubs, forbs, graminoids, ferns, and conifer seedlings more than

doubled between the before-logging and 6-years-after-brush-disposal plant

communities. Density in the highest shrub-volume category after 6 years was

86,400 plants per acre; in the medium category, 51,121 per acre; and in the low

category, 30,880 plants per acre. A major contributor to density was a ubiquitous

forb. Corresponding heights of view-blocking hardwoods ranged from 3.9 to 11

feet. By the end of the study, we judged that about 25 percent of the view that we

created had been compromised by vegetative regrowth.

USDA Forest Service Res. Paper PSW-RP-235. 1998. iii
In the overstory, many trees remained in the roadside zone—115 per acre;

and much basal area also was present—253 square feet per acre. Almost 53

percent of the trees and 27 percent of tree basal area were removed in logging

and brush disposal. In spite of this reduction, no species gained or lost more than

7 percent of stand density or more than 5 percent of total stand basal area. And

no diameter class gained or lost more than 13 percent of trees or 11 percent of

basal area. Ingrowth of new trees greater than 3.5 inches in diameter at breast

height was in balance with mortality. Six-year basal-area growth of residual trees

ranged from 7 to 10 percent for the high, medium, and low before-logging basalarea categories and 4 percent in the control (untreated area).

Overall, the removal of merchantable trees and unmerchantable trees and

shrubs was best characterized as “gentle.” The traveler could tell that some

vegetation had been removed, but the overall impression of the landscape was

retained. Most important, the view was much improved over that before logging

and brush disposal in spite of vegetative regrowth in places. And the forest

roadside zone yielded some timber and became less prone to wildfire.

iv USDA Forest Service Res. Paper PSW-RP-235. 1998.