WHITE

PINE

in the American West:

A Vanishing Species—

Can We Save It?

United States

Department

of Agriculture

Forest Service

Rocky Mountain

Research Station

General Technical

Report

RMRS-GTR-35

August 1999
PRODUCED BY :

Leon F. Neuenschwander, University of Idaho, College of Forestry Wildlife and Range Sciences

James W. Byler, USDA Forest Service, Northern Region

Alan E. Harvey, USDA Forest Service, Rocky Mountain Research Station

Geral I. McDonald, USDA Forest Service, Rocky Mountain Research Station

Denise S. Ortiz, University of Idaho, College of Forestry Wildlife and Range Sciences

Harold L. Osborne, University of Idaho, College of Forestry Wildlife and Range Sciences

Gerry C. Snyder, University of Idaho, College of Forestry Wildlife and Range Sciences

Arthur Zack, USDA Forest Service, Panhandle National Forest

Design by Donna S. Anderson, University of Idaho, 1998

CONTENTS

How Did We Get Here? ........................................................................................................... 2

White Pine and Its Environment ............................................................................................. 3

White Pine Country................................................................................................................. 4

Historic Dominance of White Pine.......................................................................................... 5

Cultural and Management History of White Pine Country ........................................................ 5

Riverpigs Got the Logs Out ..................................................................................................... 6

Blister Rust—An Alien Disease Becomes a Mortal Enemy ...................................................... 8

Fire and the Evolution of a Forest ........................................................................................... 9

A Place in the Sun ................................................................................................................ 10

Discovery of Resistance ........................................................................................................ 10

Change is the Name of the Game .......................................................................................... 11

The War on Ribes ................................................................................................................ 12

How Do Bark Beetles Kill Trees? .......................................................................................... 15

The Replacement Forest ....................................................................................................... 16

Native Diseases—Both a Problem and an Asset.................................................................... 17

How We Can Help Recovery ................................................................................................. 18

Photo Credits ....................................................................................................................... 19

References/Suggested Reading ............................................................................................. 20
1

Leon F. Neuenschwander, James W. Byler, Alan E. Harvey, Geral I. McDonald,

Denise S. Ortiz, Harold L. Osborne, Gerry C. Snyder, and Arthur Zack

White Pine in the American West:

A Vanishing Species—

Can We Save It?

orest scientists ask that everyone, from the home gardener to the forest manager, help

revive western white pine by planting it everywhere, even in nonforest environments

such as our neighborhood streets, parks, and backyards. White pine, long ago considered the

“King Pine,” once dominated the moist inland forests of the Northwest, eventually spawning

whole industries and historical movements. Now—since the arrival of Euro-Americans and

the stubborn blister rust disease—this sun-loving giant barely survives on about 5 percent of

its former domain. This is the story of the decline of the magnificent western white pine.

F
2

The distribution of western white pine has dramatically declined. In Idaho, for example, the

historical (circa. 1900) areas covered by western white pine forests (map 1) compare markedly to

those of today (map 2). Each map shows only stands with a composition greater than 15 percent

western white pine with a minimal mapping unit of a square kilometer. (Data from Interior

Columbia River Basin Ecosystem Assessment Project; map produced by Landscape Dynamics Lab,

University of Idaho.)

White Pine in the American West:

A Vanishing Species—Can We Save It?

Western white pine

(Pinus monticola). For

centuries white pine dominated the

moist forest ecosystems of the Inland

Northwest, and for decades Americans depended on these dense white

pine forests. One of the region’s

largest species, white pine produces

some of the world’s most desirable

wood. This species used to define the

economic scene in Northwestern

towns. Then its history began to

parallel the human culture around

it—boom, then bust. As the white

pine population began to wither, it

took a big chunk of history with it.

White pine’s decline put major timber

companies out of business and

spurred important shifts in forest

management ideology. Now the

future of western white pine is

uncertain.

Not much of the former forest

remains. The alliance of blister rust,

beetles, and logging killed over

90 percent of white pines in less

than 70 years. Lone white pines in

forests crowded with smaller shadetolerant species are often the only

symbols left of the mighty woods that

once dominated the Inland Northwest. And the mortality rate for these

remaining trees is high.

How Did We Get Here?

The western white pine forests of

the Pacific Northwest are today

occupied by less stable, diverse,

resilient, and productive species than

they were a century ago. This is

primarily because of an introduced

fungus disease, and recent human

activities—especially white pine

logging and the suppression of

natural fire. Today, most of the

remaining mature white pine consist

of individual, mostly dying trees

scattered across forests they once

dominated. A few of these mature

trees survive, but the majority will

eventually succumb to the rust, bark

Continued on page 4...
3

Western white pine (Pinus monticola)

was once the dominant forest type at elevations

of 3,000 to 6,000 feet in areas receiving more

than 30 inches of precipitation a year. It grows

on the slopes of the Cascade and Sierra Mountains, and the interior section of the Northern

Rocky Mountains. It is most abundant in the

moist forests of northern Idaho, eastern Washington, western Montana, and southern British

Columbia, together known as the Inland Empire or Inland Northwest.

The needles of this bluish-green tree with

a whitish tinge occur in bundles of five, each

2 to 4 inches long. A whitish stem near the

top distinguishes mature trees, with otherwise thin gray furrowed bark broken into

small rectangular blocks curled at the

edges. This distinctive color and bark pattern is not found in any other species associated with white pine (Douglas-fir, grand fir,

western hemlock, and western redcedar).

Young trees have a smooth gray bark or no

bark at all.

The tree is tall, reaching 150 feet or

more—about the height of a 15-story

building—and grows fast at 2 to 4 feet per

year. A 30 year old may be 15 inches in

diameter and 65 feet tall; a 300 year old

might be 60 inches thick and still reaching

for the sky at 200 feet.

The cones are the largest among pines

in the Northern Rocky Mountains. Packed

with seed, mature cones are about 2 inches

wide and a full 13 inches long. After 2 years

of ripening, cones drop seed in the fall,

White Pine and Its Environment

The western white pine is easily identified by

its five needles together in what is called a “bundle.”

The western white pine has one of the largest cones

of the Northwest—up to 11 inches long.

The western white pine prefers growing in open, sunny areas. This former cabin

site at the Deception Creek Experimental Forest is ideal for newly emerging

western white pine.

starting mid-September, to germinate in May

or June the next year. High density, mature

white pine forests produce more than a million seeds per acre.

Often growing alongside seven or more

other tree species, western white pine regenerates well after wildfire, logging, or land

clearing. Fire is so good for the species that

50 years after a fire its forests are dense

again with thousands of trees per acre. Then

the forest thins itself to about a third or half

that number by age 100. Yields for a 100

year old white pine forest have been recorded at over 50,000 board feet (b.f.) per

acre—enough to build five medium-sized

houses. Old groves sometimes exceeded

100,000 b.f. per acre. In the same forests

without white pine, yields often dip to less

than half.

Seedlings do not do well in shady moist

forest, hence their need for wildfires that

clear the forest to allow full sunlight on the

young trees. Without openings created by

wildfire, even mature white pine eventually

succumb to insects, fungi, or old age and

are replaced by shade-tolerant species—

grand fir, western hemlock, and western

redcedar. As these competing species grow

and the white pine die, the forest is gradually changed.

Because white pine seedlings tolerate

frost, you often find them in the lower portion

of the subalpine fir zone (Abies lasiocarpus),

and frequently along cold air drainages, river

bottoms, and mountain meadows.
4

This Washington Air National Guard photograph shows the landscape perspective of western

white pine along Idaho Route 6, White Pine Scenic Drive. The year is 1935.

After 60 years, a ride on White Pine Scenic Drive shows that the texture of the once-dominant

white pine forests has changed to that of the smaller, shade-tolerant trees of today.

beetles, or both. The prognosis for

nonresistant younger white pine is

gloomy. The majority of these young

trees will die before they have the

opportunity to reproduce. The

remainder consist of plantations that

came out of a blister rust-resistance

breeding program, and the prognosis

for these blister rust-resistant plantations is hopeful. But a lot more work

is necessary. Without action now, the

reign of this popular United States

native could end forever.

White Pine Country

Let’s look at a brief history of the

king of pines. Early explorers and

settlers described with awe the Rocky

Mountain-Inland Northwest landscape as dominated by a dense green

forest of unusually large trees. Trees

on the best sites were 150 to 200 feet

tall and so dense that little light

penetrated to the forest floor. There

were about a dozen tree species, but

the most prominent was the towering, long-lived western white pine,

one of the largest trees in the woods.

The interior of the Western United

States is generally desert-like or

prairie-like with dry juniper or

ponderosa pine forests. But the

powerful jet stream winds in the

Northwest carry moist marine air

off the Pacific Ocean and over the

Cascade Mountains to create a region

unlike the rest of the Interior United

States. The Northern Rocky Mountains

of the Inland Northwest (northern

Idaho, adjacent parts of western

Montana, northeastern Washington,

and British Columbia) make up the

wettest area in the Interior West. The

ecosystems of this interior wet belt

support the largest, most productive,

and most diverse forests in the

western interior—the home of

“King Pine.”

Western white pine dominated

many ancient moist inland forests

before the 1860’s, comprising 25 to

50 percent of the moist forest area

and 15 to 80 percent of the forest’s

entire composition. Where the

composition was more than 15

percent white pine, foresters considered the forest the western white pine

type because of the economic

importance of the species.

Timber surveys by the University

of Idaho and the USDA Forest

Service in Idaho (Miller and others

1927) indicate that normal timber

yields for a 100 year old white pine

forest could be over 50,000 board feet

(b.f.) per acre. Old groves of white

pine sometimes exceeded 100,000 b.f.

per acre—enough wood to build 10

medium-sized houses. Western white

pine stood with a variety of other

conifers including western larch

(Larix occidentalis), Douglas-fir

(Pseudotsuga menziesii), grand fir

(Abies grandis), western hemlock

(Tsuga heterophylla), and western

redcedar (Thuja plicata). White Pine

occupied a significant portion of the

Inland Northwest and parts of the

Continued from page 2...
5

White pine blister rust needs the Ribes plant to survive. The Civilian Conservation Corps of the

1930’s employed thousands of men to eradicate this troublesome host in the western white pine

forest. The CCC’s methods included hand-pulling, spraying, and using a bulldozer.

Pacific Northwest and California’s

Sierra Nevada Mountains.

Historic Dominance of

White Pine

Why was white pine historically

the dominant tree in moist Northern

Rocky Mountain forests? We know

that white pine does not thrive in a

shady forest. We also know that forest

fires were common and extensive,

often burning more than 10,000 acres

in a single wildfire. High intensity

forest fires tended to revisit a forest

location about once every 200 years.

Some areas burned more often and

some took longer to burn. Western

white pine owes its existence to these

large wildfires of past centuries.

Commonly living from 250 to 400

years or more, white pine was well

adapted to regenerate and dominate

after forest fire. So it is no surprise

that when early settlers gazed across

the landscape, they saw a forest

dominated by white pine, a lush

calico of different forest ages created

by past wildfires.

By the 1930’s things were changing for both the white pines and their

admirers. The same settlers and their

descendants who had delighted in the

white pine dynasty brought with

them the very instruments of its

eventual decline: logging, a foreign

disease, and wildfire suppression to

protect people and property. Currently the regeneration long-lived

pines and larches through natural fire

is also limited. The most recent fire

episode began in 1910 and ended in

1934. Since then, wildfires have been

successfully suppressed with only two

large fires in the Inland Northwest

since that time.

Cultural and Management

History of White Pine

Country

Another major liability for the

trees is their value to humans.

Because of the high economic value

of the species and its performance in

building, staining, and painting, the

demand for white pine logs continues

even today. Starting in 1880, the farreaching western white pine forests

became the principal target for

logging. The Inland Northwest’s first

timber mill was built in 1880, and

the second followed in 1882. Logging

removed massive white pine groves

for more than 100 years. After the

1910 fire episodes and the onset of

logging, the young trees then fell

victim to yet another challenge: white

pine blister rust, an Asian fungus

introduced to western North America

in 1921 by way of Europe.

The white pine species’ ability to

regenerate in diverse environments

and following fire only made it more

susceptible to blister rust when it

arrived. Blister rust has intermediate

hosts—the currant and gooseberry

shrubs (Ribes) that share the forest

floor with white pine and that, like

white pine, also regenerate after fire

and logging. The blister-rust-infected

shrubs in burned areas killed most

western white pine before they could

produce seed.

In the 1930’s, President Roosevelt’s

Civilian Conservation Corps (CCC)

workers marched into Inland Northwest forests with the mission of

finding and killing Ribes shrubs, an

effort that largely failed. In the end,

blister rust eliminated most of the

white pine from logged and burned

areas in the Inland Northwest.

Then from 1929 to the mid1950’s, a lesser assault, this time from

white pine pole blight that killed trees

6 to 10 inches in diameter, further

reducing the population. Pole blight

is a tree disease that attacks pole-sized

pines on drought-prone soils,

reducing their growth and foliage,

and scarring their trunks with lesions.

By the late 1950’s, Inland Northwest National Forests accelerated

timber harvests to meet timber

demand resulting from the postWorld War II housing boom. At the

same time, despite Ribes control

efforts, blister rust mortality accelerated in mature white pine. By the late

1960’s it became obvious that the war

against Ribes was lost. In 1968 the

Forest Service officially abandoned

both its Ribes control efforts and its

antibiotic treatments of white pine.

The 1968 Forest Service policy

Continued on page 10...
6

The glory days of white pine harvest were the days of big timber, big men, and big

money. Towering stands of virgin white pine literally enveloped the Coeur d’Alene,

St. Joe, and Clearwater River valleys and moist slopes of the Inland Northwest before

1900, stands that produced a versatile wood good for match sticks, fruit boxes, door and

window parts, trim and molding, and fine finish lumber.

By the early 1900’s, the major Eastern railroads, financed by grants from timberlands

along the route, finally reached the West Coast, in the process touching the lakes and

river margins of the untapped “White Pine King.” Late 1890’s loggers and small-time

lumbermen had eaten away at the margins of these white pine forests for the better part

of a decade. Farther east the Great Lakes lumbermen, encountering the end of white pine

in Minnesota, Wisconsin, and Michigan, were eager to move on. The time was right, the

pine were big and ripe, and railroads provided easy routes to Western, Midwestern, and

Eastern markets. All that was needed was big money to build the mills and the transportation system to “get the logs out.”

One late night in 1899 in a fashionable St. Paul, Minnesota, neighborhood,

Frederick Weyerhauser purchased 900,000 acres of West Coast Pacific Northwest timberlands from Northern Pacific Railroad magnate James J. Hill for $6 per acre. Then,

between 1899 and 1908, Weyerhauser and his Midwestern lumber associates, sometimes known as the “Weyerhauser Syndicate,” put their money into seven Idaho ventures, five of them in the white pine region. The first big blocks were railroad lands,

willingly sold to lumber companies in a race against other lumbermen, sometimes in the

dead of night. The spoils often went to the fastest horse and to timber cruisers and land

agents with somewhat questionable ethics. Nevertheless, a new timber empire was born.

All that remained was to get the logs out, a challenge for the strong, fleet-of-foot “riverpigs.”

The ground they worked was steep, sometimes rocky, and winter stayed on the

mountains for 5 to 6 months. When the warm spring rains came, riverpigs, dancing

from log to log with sharpened, steel-caulked boots, herded, pried, and poled millions

of board feet of logs down flumes, chutes, and racing rivers to log booms waiting on

White pine logs at a railroad siding await transport to an Idaho mill.

Photo courtesy of Potlatch Corporation.

Riverpigs Got the Logs Out

Early white pine loggers called themselves “riverpigs.”

For the perfect dream of a riverpig

Is a river smooth and flat,

Where a log will ride like a ship at tide,

And a man can float his hat.

And they love their work as a sailor his,

And they come back year by year

To answer the call where the big jams haul,

As the spring flats lure the deer.

For it is a work they love and know

That none can do so well

As a riverpig, with his snoose and swig

And a hearty scorn for hell.

Paul Croy, “The Riverpig”

Excerpt from Idaho’s Poetry, A Centennial Anthology, R. E. McFarland, W. Studebaker, eds.

University of Idaho Press, 1988
7

sheltered lakes. Other logs went directly to mill by logging railroad on the hundreds

of miles of rail lines that crisscrossed the forests.

The colorful days of logging were from 1900 to 1925 when men and animals—

first oxen and then horses—literally wrestled logs from steep hillsides, often using

more wood for transporting logs than they got to the mill. They might also build

bridges to reach creek-bottom pines using enough wood to construct a medium-sized

house...or 2,500 to 4,000 rail ties per mile. Massive white pines and other valuable

species such as ponderosa pine, Douglas-fir, larch, and redcedar were cut with twoman crosscut saws, limbed with an ax, and bucked to log lengths. Horse teams pulled

the logs directly to the river bank, to the waiting railroad car, or along greased

wooden log chutes that led to river flumes or to railcars.

In some areas logs were skidded to the mountain stream where a series of splash

dams had been constructed to hold water and logs. Periodically these dams were

flushed down the stream in a savage flood of water and logs, mud, rocks, and fish and

frogs, all headed in the direction of the sawmill. Occasionally a logger or riverpig

would slip and fall into the rush, only to be caught and lost in the flood. The last

Idaho log drive was on the Clearwater River in 1962.

The stream environment suffered greatly from erosion of banks and streambeds as

most of the stream’s vegetation had been removed so logs would not hang up. Men

lived in camps, sometimes far back in the woods. Though the pay was good, the work

was demanding and extremely dangerous. After an extended stay in a logging camp,

hard drinking, hard fighting loggers would typically “blow into town” to be accommodated by brothels and taverns.

With the introduction of crawler dozers and heavy logging trucks in the early

1930’s, the glory days of logging ended, leaving behind hundreds of miles of dry

chutes, water flumes, logging railroads, and their supporting cabins and camps. Also

left behind were a legacy of scoured stream channels, entrenched skid trails, and deforested mountains. Forest historians have gone to great lengths to search the recovering forest to locate and document the old camps, railroads, steam donkeys, and

other remnants of this era of big timber, big men, and big money. Much white pine remained on the upper slopes, far back in the hills, and on the tougher ground, but

modern logging methods and extensive road construction eventually reached those

trees too. Today’s loggers are more likely to live in their camper trailers during the

week and spend the weekend back in the local towns with their children and wives—

or their husbands, as today’s logger workforce has also changed with the times.

Western White Pine was prized for its beautiful and abundant wood. Following a forest fire

in the 1920’s, western white pine loggers salvaged by horse and steam donkey to get the wood

to the mill. (Photo courtesy of Potlatch Corporation.)

In 1890, the forests of the Inland Northwest seemed endless and inexhaustible,

sometimes even a barrier to settlement and development. Then World War II saw an

end to the timber exploitation phase and a recognition that other values such as wildlife, water quality, and scenic attributes of forests were also important. People had

more leisure time and the automobile and interstate highway system allowed easy access to the forest. The multiple use of forests escalated along with an increasing demand for wood and paper products. Tree farming cropped up, and the philosophy

that trees and other resources should be managed for the maximum good ushered in

the practice of reforestation after harvest. “Forestry gardens” created by clearcutting

and then replanting offered an environment friendly to western white pine regeneration, but the king of pines had other survival worries (see Blister Rust and Mountain

Pine Beetle sidebars).

The current view is that forests are places where the human, biological, and physical dimensions of natural resource management are blended together. Sustainable forests involve more than just growing wood and getting the logs out. “Ecosystem management” is the new way of thinking, with the goal of sustaining all the resources in

the forest.
8

Blister Rust—An Alien Disease Becomes a Mortal Enemy

In 1910, a timberland owner in Vancouver, British Columbia, determined that western white pine planting stock could be more cheaply produced in France than on

Vancouver Island. He shipped seed to France and in return received infected seedlings,

which he outplanted. Upon taking root, the seedlings produced spores that then infected the nearby currant and gooseberry shrubs—the perfect alternate host for a disease-causing fungus, and shrubs usually growing in western white pine ecosystems.

From this single location, blister rust spread throughout the white pines of Western

North America, continuing to infect the region until 1943 when it was officially considered a universal epidemic.

Despite the hardy endurance of the tree species that

created 200- to 300-year-old

white pine forests, in blister

rust the great white pine had

met its match. White pine is

fairly tolerant of native root

diseases common among the

young trees of any species, and

the pine was less likely to be

killed by root disease. But blister rust was a fungus and a disease from another ecosystem

in another part of the world.

Forest managers knew

immediately how serious the situation was for they had witnessed blister rust infection

in the Eastern United States where it had been introduced in 1895 and was well established there by 1910. Both eastern and western white pine, from botanical gardens

stretching across Europe, carried blister rust from its Siberian home to North America.

An obvious option for controlling blister rust was the eradication of currant and

gooseberry shrubs. Such eradication had been relatively successful in the East. So in

1926, forest managers began large-scale eradication via hand-pulling of shrubs in

white pine stands of the West. But by 1968 they realized that the Inland Northwest’s topography, landscape scale, and climate prevented their success with this method, so

they stopped. In the meantime, two other control options emerged: applications of antibiotics to trees, and the development of rust-resistance in trees. Antibiotic treatment

did not meet expectations and was discontinued, but genetic development of resistant trees

showed great promise. It remains the strongest hope for a renewed future for white pine

forests.

The Forest Service in 1950 began the first large-scale breeding of rust-resistant white

pine, starting with only 400 trees that had survived in areas of intense infection. Researchers

selected trees without the characteristic canker sores on their bark from areas throughout

the Inland Northwest that supported thousands of cankers per tree. The probability these

trees were simply accidentally clean was about 1 in 10,000. After a host of genetic tests, scientists found about 100 resistant parent trees that could transmit high levels of resistance to

their offspring. Studies even found about 12 kinds of resistance mechanisms in the seedlings. Since then, a breeding arboretum and seed orchards supply resistant seed for field

testing and production of seed for commercial plantations. Over the last few decades most

trees and seedlings have generally survived under conditions of low to moderate disease

levels. In the most hazardous situations where there are lots of Ribes shrubs in moist environments, resistance may have eroded somewhat. Planting seedlings from the rust resistant

seed orchards continues to look encouraging. The USDA Forest Service and the Inland Empire Tree Improvement Cooperative continues with a breeding program designed to further

improve resistance.

Another possible treatment option being explored is the potential

for saving white pines by pruning off

branches with cankers, a practice

actually begun in the 1930’s and

fairly successful, although labor

intensive.

For now, the best option seems

to be integrated management that

considers all factors affecting a

tree’s potential infection. Using

computer models, managers now

look to (1) match resistance to disease hazard on a site-by-site basis,

(2) remotely track disease development in specific plantations to provide early warning of

high infection years, and (3) predict damage to assess potential for pruning, stocking control, and management of infected host-shrubs.

White pine blister rust begins in the needles and

stems, eventually working its way into the tree

trunk.

Currant shrubs act as an alternate host in carrying

the disease-causing fungus.
9

Fire and the Evolution of a Forest

While powerful forest fires often appear as

disasters to humans, fire has shaped the evolution of plants and forests. Most plant species

have adapted to fire in some way, and some depend upon fire for their reproduction. Some

plants need the heat of a fire to germinate their

seeds. Others need the sunlight in openings

created by fire, or the soil nutrients released by

fire to make their growth successful. White pine

is one of these fire-dependent species. Historically, it has relied upon large openings in the

forest to regenerate, and without these openings, its seedlings cannot thrive in the heavy

shade of the forest. Thus the white pine owes

its dominance to a cycle of wildfire and other

disturbances.

The Northern Rocky Mountains—home of

the white pine—is one of the most lightningprone areas in the Western United States. During the dry summer season when the jet stream

shifts upward to Canada and weak air masses

become thunderstorms, there can be more

than 150 lightning fires per million acres

(Barrows and others 1977). During drought

years, individual lightning fires can scorch tens

of thousands of acres or more. During the extremely dry summer of 1910, some 3.5 million

acres of the Northern Rockies burned in forest

fires.

Fire was common and necessary for western white pine to grow, creating natural

openings in which seedlings thrived. This August 1925 photograph (above) shows

the aftermath of a typical wildfire on the Clearwater National Forest in Idaho.

 Research in the Coeur d’Alene River Basin of northern Idaho documents large forest fires

to as far back as 1542 (Zack and Morgan 1994), and climatic evidence indicates this pattern

is thousands of years old. There was a major forest fire in the 570,000-acre Coeur d’Alene

Basin once every 19 years on average. In individual forests, fire replaced the entire stand

about once every 200 years
10

Past genetic research helped produce seedlings

with a better chance of survival today. These

“disease resistant” seedlings grew from the

seeds of parent trees raised in special orchards

of white pine.

A Place

in the Sun

A big factor in tree survival is tolerance to shade. White pine is a shade-intolerant tree, meaning it cannot grow well

under the shade of other plants. In sunny

openings white pine can establish

quickly, outgrow most other tree species,

and eventually dominate the forest. Add

to that its tallness and abundant wind-carried seed and you have a species well

adapted to regenerate after forest fires.

White pine germinates easily on a burned

surface. Another shade-intolerant species

is Douglas-fir, which also reproduces and

grows in forest openings but does not

grow as fast or tall as white pine, nor is it

as long-lived.

Conversely, grand fir, western hemlock, and western redcedar are shadetolerant species,

meaning they are capable of reproducing

and growing in the

shade of other forest

plants. Because they

require high moisture

and may not grow as

fast or as tall as white

pine in open sunny

areas, they occupy

mostly the understory

position in white pine

forests. Periodic droughts slow their

growth and create stress that increases

their susceptibility to insects and diseases.

discontinued planting of non-blister

rust-resistant white pine, emphasized

regeneration and thinning of species

mixes that did not include white

pine, and focused major commercial

timber harvests on white pine groves

threatened by blister rust. Commercial harvests after 1968 were clearcuts

planted with Douglas-fir. Most of the

remainder were partial harvests that

removed white pine and left other

trees in the forests. Not only were

dead and dying white pine harvested,

but entire populations of white pine

were removed—effectively also

removing any blister rust-resistant

genes that might have remained.

From the late 1960’s through the

mid-1970’s the areas formerly holding

the best mature white pine groves

were being converted to other trees—

predominantly Douglas-fir, grand fir,

and hemlock.

Discovery of Resistance

The fact that some white pines

survived blister rust suggested that

some trees might be genetically

resistant to the rust. In the 1950’s the

search began for blister rust-resistant

parent trees to produce rust-resistant

seedlings. Tests showed that some of

the surviving white pine were indeed

resistant to the rust. These trees

became the foundation for a breeding

program aimed at producing blister

rust-resistant white pine seedlings for

reforestation. Tree genetic research,

and especially tree breeding, takes a

long time. Thirty years after the

genetics effort began several seed

orchards were producing rustresistant seed.

By the early 1980’s significant

amounts of blister rust-resistant white

pine seed became available for

reforestation. White pine reforestation accelerated on Forest Service,

State, and private lands, peaking in

1991.

Typical of forests today, dense stands of trees

allow little light for the western white pine to

grow in. These shady forests favor trees such

as western redcedar, grand fir, and western

hemlock.

This open forest encourages young white

pines to grow (Kaniksu National Forest in

northern Idaho, 1937).

Continued from page 5...

Continued on page 14...
11

Scientists measure forest characteristics in the number of tree species present, their

size, and the relative abundance. Diversity in these characteristics is achieved through

natural changes in a forest, or disturbances. Every ecosystem has these natural disturbances, and the plants and animals evolve to adapt to those disturbances. In fact, the

whole ecosystem incorporates disturbances into the long-term way it functions.

Forest succession—how vegetation changes over time—is the primary way the forest responds to disturbance. For example, following a lethal forest fire the forest is a

skeleton of dead trees called snags. Starting the next spring after the fire, grasses and

small plants may dominate the site for a couple years, then shrubs for a decade or two,

then tree species that need open sunlight, and ultimately (if no new disturbance resets

the successional clock) slower growing tree species that can regenerate in the shade.

This entire process may take hundreds of years.

During the past 70 years, succession in white pine forests has changed. Wildfire

suppression has reduced opportunity for natural regeneration. White pine blister rust

killed many existing tree stands and prevents most naturally regenerating trees from

living to maturity. Although some forms of harvesting provided the opportunity to plant

rust-resistant white pines, much of it selectively removed white pine and other high

value species. The net result is a continuing loss of seral white pine, western larch, and

ponderosa pine—species that once grew to towering size and prominence in our early

history.

The interaction of disturbances and forest succession determine the mix of successional stages present across the landscape. A landscape with some grassy openings,

some shrub fields, some young forest, and some older forest is more diverse than a

landscape with all young or all old forest. More diverse forests also provide habitats for

a wider variety of animals.

Scientists do not know what we lost when the white pine began to die off. A truly

white pine-dominated forest could present us with flora, lichens, and possibly different

wildlife populations than we are used to today.

Change is the Name of the Game

Efficiently growing white pines at Deception

Creek on Idaho’s Panhandle National

Forests, 1929.
12

The War on Ribes

It is a tribute to Northwestern foresters of the turn of the century that they recognized the importance of white pine to the ecosystem and the gargantuan threat of the blister rust. Would those

Victorian-era foresters have guessed we would still be fighting the blister rust today?

Researchers and managers determined that getting rid of Ribes—currant and gooseberry

shrubs—would help prevent the spread of the rust to western white pine. Eradication of alternate

host species, those surrounding plants that first contract a disease and then spread it to the important crops around them, was already being used against the black stem rust that afflicted wheat. In

that case the alternate host was both the cultivated and wild barberry species. To this day, the U.S.

Bureau of Plant Quarantine regulates cultivation of barberry. Against this historical and scientific

background were played out the first efforts to control blister rust infection of western white pine

trees.

Canada’s West Coast at Point Gray first saw the rust in 1910. From there, it radiated east to infect white pines in Washington State’s Puget Sound region and Interior British Columbia by 1922.

The infection reached eastern Washington and then Idaho by 1923. Because host eradication had

worked with pines in the Eastern United States, and scientists were similarly fighting black stem

rust successfully in wheat, the natural choice for curing western white pine of blister rust was

eradication of host shrubs. But the eradication effort in the West would be different, shaped by the

magnitude of the problem and by human events, specifically the Great Depression of the 1930’s.

The Depression released thousands of job-searchers who would become the labor force making

such a huge eradication attempt feasible.

Starting with an annual expenditure of $300,000 in 1932, the western rust control effort grew

to $1.2 million in Public Works Administration (PWA) dollars. In 1934 the eradication effort received an infusion of PWA and Civilian Conservation Corps (CCC) workers. These programs, together with regular appropriations, put 13,000 men to work in the “War Against Ribes.” By 1935

the CCC in the Inland Northwest alone employed 7,000 men. From 1930 to 1946, a work force

averaging 2,500 men annually would dig, bulldoze, and spray Ribes shrubs on over 2.5 million

acres of the 5 million-acre Inland Northwest white pine forest. All told they destroyed 444 million

Ribes plants.

Ribes along streams were treated differently from Ribes elsewhere in the forest. About 5 percent, or 36,000 acres, of these sensitive areas were treated by hand and sown with 1.8 million

pounds of sodium chlorate (50 pounds per acre). Although the effort was labor-intensive, scientists now know that the number of bushes eradicated in those years still left 100 times the density

that would have secured safe conditions for growing susceptible western white pine.

The second half of the eradication story would unfold over the subsequent 20 years, from

1947 to 1968. Some 20,000 man-years of effort (1,000 men per year) removed 70 million plants

from 900,000 acres. By 1949 the eradication program was ready to mount a full-scale stream and

upland assault armed with a new weapon: the plant hormone herbicides 2-4-D and 2-4-5-T .

For the first time a tool was available that would kill all species of Ribes and could be transported by backpack across the forest landscape. From 1949 to 1966 workers sprayed 41,000

acres of stream and forest with 13.3 million gallons of herbicide. This reduced Ribes populations to about seven bushes per acre, 10 times the efficiency of the previous eradication, but

still 10 times away from what it needed to be. In the end, the eradication program had impacted almost half the 2.5 million acres originally targeted.

The Civilian Conservation Corps employed thousands of people in the 1920’s and 1930’s to

pick, pull, spray, dig, and scrape out Ribes shrubs from the western white pine region.

Continues...
13

Why was the war on Ribes so difficult? Understanding the shrub species may provide

an answer. Sometimes the worst adversary is the one whose habits are just like yours.

Like white pine, Ribes shrubs (currant and gooseberry) grow along streams, in moist

open forests, in drier forest woodlands, and on subalpine woodlands. Almost all forest

types that are open and contain deciduous shrubs contain Ribes and the possibility of pinekilling blister rust. The two species most commonly acting as alternate host for the rust (Cronartium ribicola) are Ribes lacustre and Ribes viscosissimum. They are found on

the best growing sites for western white pine. And like the white pine, Ribes shrubs regenerate well after forest fire.

Part of the reason the Ribes survived the CCC’s herbicide attacks during the 1930’s is

that it is well adapted to long intervals between forest fires. Fire kills the trees and provides a chance for Ribes to regenerate from seeds placed by the previous generation...seeds

used to waiting a long time for an opportunity to grow. The mother plants also regenerated after wildfire, a wait of perhaps 300 years.

The small Ribes seeds have a hard seed coat and over time are buried by the litter of

trees and shrubs that make up forest soil-building processes. One plant can produce

many thousands of seeds. Not all seeds survive, but after the next fire or other disturbance such as logging, wind, or ice storm, the seeds germinate and the young plants

quickly grow to sexual maturity within 7 years, producing more seed. Once established,

Ribes grow to about 6 feet high and about the same width. If topped, the shrub sprouts

new, quick-growing shoots from latent buds at the base of the plant. However, the tenacious plant that can live for 50 years or more may not be as fortunate as it appears. The

forest itself also begins to grow after fire or disturbance. As soon as the trees outgrow the

shrubs and produce shade, Ribes parent shrubs die. Mostly they leave only their seed to

wait in the shady forest for the next fire.

Although the war on Ribes was sound in concept, it needed to reduce a hazard so vast

that success was virtually unattainable. That the forest professionals of the time would

make such a massive attempt is powerful testimony to their understanding of the importance of western white pine to its ecosystem—and to American culture. It is also powerful testimony that society may need to rethink the prevailing attitude that humans can control nature.

Removing Ribes shrubs with bulldozers along riparian and

floodplain areas was a common approach during the

eradication effort. The top photo shows an area before

bulldozing; the bottom photo reveals the aftermath.
14

This western white pine tree trunk is infected

with the white pine blister rust. The tree

produces resin in an effort to defend itself.

Blister rust often kills the tops of

large trees to the point they cannot

defend themselves against other

forces of nature. Once weakened, a

white pine stands vulnerable to

insects and root rotting fungi.

The species’ fate again intertwined

with changes in human activities.

Between the 1970’s and the 1990’s,

Federal policy led to a decline in

support for white pine research and

breeding programs. Meanwhile,

public priorities for National Forests

shifted away from producing commercial wood products and toward

endangered fish and wildlife species,

esthetics, and recreation. Clearcuts

fell into disfavor, harvest levels were

drastically scaled back, and many of

the harvests that did take place were

partial cuts that failed to provide

adequate openings for successful

white pine regeneration. These partial

cuts favor regeneration of shadetolerant grand fir, redcedar, and

hemlock. Regeneration of rustresistant white pine on National

Forest lands had fallen below 1991

levels, and the trend continues

downward. Currently, a lack of

research dollars dedicated to white

pine and, more significantly, the lack

of appropriate habitat, threatens the

survival of white pine.

On Federal lands, harvest rates

that create openings seem headed for

such low levels that it appears

questionable whether significant

white pine restoration can take place.

Without some sort of disturbances

that create openings, forest succession

will lead to the replacement of white

pine by other species.

For economic and policy reasons,

planting of rust-resistant white pine

has also declined significantly on

most State and private lands. On

some of these lands, the desire for

short-term economic returns dictates

short rotation timber harvests.

Economic timber rotations on these

lands have some potential for

producing young white pine plantations but will not create the full range

of successional stages and white pine

forest types that existed historically. Tree inventory data taken

from the Panhandle National

Forests (Idaho) illustrates the

decline of white pine relative

to its companion species.

Continued from page 10...

Continued on page 16...

60

45

30

15

0

1920 1945 1970 1995

Western White Pine

60

45

30

15

0

1920 1945 1970 1995

Douglas-fir

60

45

30

15

0

1920 1945 1970 1995

Grand Fir/Western Hemlock

60

45

30

15

0

1920 1945 1970 1995

Western Larch
15

How Do Bark Beetles Kill Trees?

A tiny black insect with a huge appetite and a big family, the mountain pine beetle is

a major killer of all pine species in its range. Native to the West, it kills trees by massattacking them, feeding on them, girdling them, and introducing fungi into the sapwood.

Beetle populations may increase rapidly to cause tremendous tree mortality over large

areas in just a few years.

Outbreaks of mountain pine beetle were recorded in white pine as early as 1910.

Historically, the beetle killed large, mature, old-growth white pine. Forests sustaining the

most damage contained 40 to 60 percent white pines over 160 years old growing in

dense forests. The beetle also targeted younger trees, but mortality generally occurred

only in trees older than 80 years (Terrell 1962). “The mountain pine beetle caused a

serious loss of timber,” lamented the 1910 report of a beetle epidemic in Idaho white

pine forests at that time. Beetles killed an average of 20,000 mature trees per year on

80,000 acres of north Idaho white pine from 1928 to 1950. From 1934 to 1953, it was

estimated they killed at least half the mature white pine volume on the Clearwater National Forest. Over the past 30 years, the pine beetle has killed an average 500 trees per

acre, many of them the last remnant old-growth trees. Recently, the insect has begun attacking younger trees—60 years old—that are 12 to 14 inches diameter in second

growth stands. Often these stands are also infected with white pine blister rust or root

disease.

The Forest Service attempted to control beetles in white pine starting in 1929 and

continuing until 1951. Bark beetle-infected trees have red tops, so foresters conducted

red top surveys by counting fading trees from a distance (from an observation tower, for

example), then did ground surveys to estimate the number of currently assaulted trees.

Treatments consisted of falling and peeling, falling and burning, or falling and treating

with chemicals.

But the mountain pine beetle isn’t always a bad guy. Like other native pests, the pine

beetle was a major driver of change in the mature white pine forests of the past. Like

fire, the beetle can be a recycling agent, returning nutrients to the soil when it kills

trees. In historic white pine forests, beetle-kill created openings and fuels in the forest,

predisposing it to larger fires that favored white pine regeneration. In today’s fireless,

mixed conifer woods, the loss of white pine allows more shade-tolerant species to dominate, species also less fire-resistant and less disease-resistant. The role of the beetle

combined with blister rust has changed from that of a recycler to an eliminator of

white pine.

From top to bottom:

Bark beetles kill a tree by

tunneling and feeding in

the tissue beneath the

bark; a dying pine’s

needles turn red; the life

history of the mountain

pine beetle starts with the

parent beetle.
16

These young 10-year-old white pines grow at Deception Creek Experimental Forest located near Coeur d’Alene, Idaho. Several other rust-resistant

white pine plantations exist in the area as well.

The Replacement Forest

When it goes, white pine is

replaced by grand fir, western

hemlock, and western redcedar. This

climax forest of shade-tolerant, slowgrowing, and shallow-rooted trees is

not tolerant of insects, root disease,

drought, wind, or fire. This results in

high rates of change, forests in a

constant widespread state of death

and renewal. Such a cycle is normal

for healthy forests, but the western

white pine is not experiencing the

renewal—only death. The tragedy of

blister rust is not so much the demise

of large white pines in existing

forests but the end of the white

pine’s ability to replace itself. As a

result, soils, water quality, wildlife

populations, and aquatic systems

will increasingly feel the loss of the

majestic white pine.

Continued from page 14...
17

Native Diseases—Both a Problem and an Asset

Disease in trees is as dangerous and contagious as it is to humans. A tree “catches”

root rot caused by fungi and then passes it

along to other trees through contact with

their roots. Every root rot has a fungus that

caused it. Common Northwest root rots are

laminated root disease, Armillaria root disease, brown cubical rot, and butt rot. It is

common for more than one species of root

pathogen to occur on one stand or even in a

single tree.

Like children holding hands in a classroom during flu season, the roots of a diseased tree touch the root of a healthy tree,

causing a bridge that allows transmission of

the fungus from one tree to another, under the soil. Pathogens can live several decades in the

roots of even dead trees or stumps, so young trees can be infected when their roots simply touch

those of diseased and dead trees from the previous generation. Death results in a few years in

young trees while older trees may survive several decades after infection.

Root diseases were actually in part responsible for creating the 200- to 300-year-old white

pine forests so abundant when the first Euro-American settlers arrived. Although some mortality

from root diseases is common among the young trees of any species, western white pine and other

pine species are normally quite tolerant of disease and thus less likely to be killed. Certain pathogens prefer certain tree species, so the range of infection varies according to the forest’s make-up.

In general, Douglas-fir, grand fir, and subalpine fir are most susceptible to the mix of pathogens

common to northern Idaho.

Native to the white pine region, root pathogens served a number of successional and nutrient

recycling functions in historic forests. They weeded susceptible trees from stands in mixed species

forests, thus helping convert mixed stands to white pine and larch a long time ago. When fungus

outbreaks did this, they opened up some of the otherwise closed forests by removing small

patches of trees—white pine prefers forests open to the sunlight. Thus, a common theme in

Northwest forests: when some trees die they make room for others.

With fewer disease-tolerant trees such as white pine and more and more forests made up of

mostly disease-susceptible trees, root diseases cut bigger gashes across larger areas of forest than

is healthy and desirable. Root disease is now less frequently a weeding agent in mixed-conifer forests, but now it removes the entire canopy in some places, causing extensive deforestation. In the

absence of disturbances such as wildfire or appropriate human-managed activities, and without

seed sources for white pine and other seral species, this condition could last indefinitely.

Root rot spreads in the forest through tree-to-tree contact. Outbreaks of this fungus vary from the infestation of a single tree to several acres of

trees.

Root rots attack tree roots, weakening them to the point they eventually fall in wind

storms.
18

The Deception Creek Experimental Forest Station shows the change in western white pine forest

condition over the years. The 1936 photograph (top) shows emerging western white pine in a

former clearing behind the cabin. Sixty years later (bottom photograph), the forest shows dramatic

change. Most of the western white pine trees are dead and have been replaced with grand fir,

western redcedar, and subalpine fir. Notice that in both photos, the center trees are western white

pine. Today they are a remnant, dying as the other western white pine have.

How We Can Help Recovery

The human element began the death cycle for white pine, and human actions

could help save it. The re-establishment of viable populations of white pine in

part depends on the pine’s ability to adapt to current circumstances. It will also

depend on whether naturally occurring and human-created blister rust-resistant

white pine is given a chance to persist over the long term.

Potentially, forests much like those of the past can be re-established. But that

will require changing management practices so they are more in concert with

natural disturbance and succession. It will also mean dealing with the special

problems created by introduction of the rust.

The character of our inland forests has changed, perhaps forever. If western

white pine is to return to us, we must create a long-term strategy for its recovery.

We must:

• Conserve and protect the remaining old groves and determine which trees

are rust-resistant.

• Conserve and maintain genetic diversity by collecting seeds and storing

them for the future.

• Use blister rust-resistant seedlings in reforestation.

• Provide opportunities for natural regeneration to promote gene conservation and natural selection.

• Continue genetic research and tree improvement programs aimed at rustresistance.

• Treat existing young forests to maintain white pine (that is, apply integrated

management).

• Plant white pine in Ribes-free areas.

We must adopt this strategy or our opportunities become greatly reduced. Even

the non-forester can help, the landowner, school, or municipality. Plant white pines

along your streets, or in your yards, parks, conservation reserve areas—anywhere. All

you have to do is plant white pine and you can be part of the salvation of a species.

Let’s restore this important piece of our region’s natural history.

For Information:

• USDA Forest Service, Rocky Mountain Research Station, Idaho

(208) 882-3557

• USDA Forest Service’s State and Private Forestry Program, Idaho

(208) 765-7342

For Seedlings:

• University of Idaho Forest Research Nursery (208) 885-3888

• The Inland Empire Tree Improvement Cooperative, University of Idaho

(208) 885-7016

• Idaho Nurseryman’s Association, 1-800-INAGROW or

PO Box 2065, Idaho Falls, ID 83403
19

Photo Credits

Cover—Matured white pine, Kaniksu National Forest (Priest Lake), Idaho

circa 1920. Courtesy of USDA Forest Service, Rocky Mountain Research Station,

Moscow, Idaho.

Montford Creek Natural Research Area, Panhandle National Forests; Gerry

Snyder, Natural Resources Communication Lab, University of Idaho. 1996.

Back Cover—250-year-old stand of western white pine on the Clearwater National

Forest, circa 1930’s. Courtesy of USDA Forest Service, Rocky Mountain Research

Station, Moscow, Idaho.

Page 2—Western White Pine distribution maps. Data Source: Interior Columbia

Basin Ecosystem Assessment Project, USDA Forest Service, Pacific Northwest

Research Station, and USDI Bureau of Land Management, OR, WA, ID and MT

State Offices.

Page 3—White pine needles - Gerry Snyder, Natural Resources Communication

Lab, University of Idaho. 1996.

White Pine cone - Gerry Snyder, Natural Resources Communication Lab, University of Idaho. 1996.

White pine and Ray Boyd - Gerry Snyder, Natural Resources Communication

Lab, University of Idaho. 1996.

Page 4—Looking up Mannering Creek, circa 1935. Photo: Washington Air

National Guard. Courtesy of University of Idaho Special Collections Library.

(#95-49:WG45:4; Camp #39).

(1996 photo) - Gerry Snyder, Natural Resources Communication Lab,

University of Idaho. 1996.

Page 5—CCC worker eradicating Ribes courtesy of USDA Forest Service, Rocky

Mountain Research Station, Moscow, Idaho.

Page 6—Old logging photo - courtesy of Potlatch Corporation.

Page 7—Horse logging photo - courtesy of Potlatch Corporation.

Page 8—Blister Rust on seedling - photo courtesy of USDA Forest Service, Rocky

Mountain Research Station, Moscow, Idaho.

Ribes leaf - photo courtesy of USDA Forest Service, Rocky Mountain Research

Station, Moscow, Idaho.

Page 9—Burned forest above Martin Creek, Clearwater National Forest, 1925.

Fire photo - courtesy of Jim Byler, USDA Forest Service, Panhandle National

Forest, Idaho, USDA Forest Service, Rocky Mountain Research Station, Moscow,

Idaho.

Page 10—Top photo: dense forest - Gerry Snyder, Natural Resources Communication Lab, University of Idaho. 1996.

Bottom photo: open forest - Gerry Snyder, Natural Resources Communication

Lab, University of Idaho. 1996.

Blister rust-resistant seedlings at University of Idaho Forest Research Nursery -

Gerry Snyder, Natural Resources Communication Lab, University of Idaho. 1996.

Page 11—1929 photo of white pines at Deception Creek, Panhandle National Forests (Idaho).

Page 12—CCC worker eradicating Ribes - photo courtesy of USDA Forest Service,

Rocky Mountain Research Station, Moscow, Idaho.

Page 13—Before bulldozer - photo courtesy of USDA Forest Service, Rocky Mountain Research Station, Moscow, Idaho.

After bulldozer - photo courtesy of USDA Forest Service, Rocky Mountain

Research Station, Moscow, Idaho.

Page 14—Infected white pine trunk - Gerry Snyder, Natural Resources Communication Lab, University of Idaho. 1996.

Blister rust-weakened white pine forest at Deception Creek, Panhandle National

Forests (Idaho) - Gerry Snyder, Natural Resources Communication Lab, University of Idaho. 1996.

Tree inventory data from Panhandle National Forests (Idaho) - Chart prepared

by Gerry Snyder, Natural Resources Communication Lab, University of Idaho.

1996.

Page 15—Mountain pine beetle galleries - photo courtesy of USDA Forest Service,

Panhandle National Forests, Idaho.

Dying tree - courtesy of USDA Forest Service, Northern Region.

Bark beetle life cycle chart - courtesy of USDA Forest Service, Rocky Mountain

Research Station, Moscow, Idaho.

Page 17—(root diagram)- original artwork, Susan Hagle, 1988, USDA Forest Service,

Panhandle National Forests, Idaho. Digitally enhanced by Gerry Snyder, Natural

Resources Communication Lab, University of Idaho. 1996.

(root wad)- Roots of tree affected by root rot. Courtesy of Dr. Art Partridge,

College of Forestry, Wildlife and Range Sciences, University of Idaho. 1996.

Page 18—1936 - former Northern Rocky Mountain Experimental Station, Deception

Creek, Panhandle National Forests. Sept. 1996. Gerry Snyder, Natural Resources

Communication Lab, University of Idaho.

1996 - Northern Rocky Mountain Experimental Station, Deception Creek,

Panhandle National Forests. Oct. 1936. Courtesy of USDA Forest Service, Rocky

Mountain Research Station, Moscow, Idaho.
20

References/Suggested Reading

Barrows, J.S., D.V. Sandberg, and J.D. Hart. 1977. Lightning fires in Northern Rocky Mountain Forests. Unpublished report. USDA Forest Service,

Intermountain Fire Sciences Laboratory, Missoula, MT. 192 p.

Baumgartner, D.M., J.E. Lotan, and J.R. Tonn. 1994. Interior cedar-hemlock-white pine forests: ecology and management. March 2-4, 1993, Spokane, WA. Symposium Proceedings, Washington State University, Cooperative Extension, Pullman, WA.

Bingham, R.T. 1983. Blister rust resistant western white pine for the Inland

Empire: the story of the first 25 years of the research and development

program. Gen. Tech. Rep. INT-146, USDA Forest Service, Intermountain

Research Station, Ogden, UT.

Bingham, R.T., A.E. Squillace, and J.W. Duffield. 1953 Breeding blister-rust

resistant western white pine. Journal of Forestry. 51:163-168.

Evenden, J.C., W.D. Bedard, and G.R. Struble. 1943. The mountain pine

beetle, an important enemy of western pines. Circular 664, USDA, Forest

Service, Washington, D.C.

Farbo, T. 1996. White pine, wobblies and wannigans, A history of Potlatch

logging camps, north central Idaho 1903-1986. Steeley Print and Binding,

Lewiston, ID. 356 pp.

Hagle, S.K., G.I. McDonald, and E.A. Norby. 1989. White pine blister rust

in northern Idaho and western Montana: alternatives for integrated management. Gen. Tech. Rep. INT-261, USDA Forest Service, Intermountain

Research Station, Ogden, UT.

Haig, I.T., K.P. Davis, and R.H. Weidman. 1941. Natural regeneration in the

western white pine type. Tech. Bull. 767, USDA, Washington, D.C.

Hubert, E.E. 1950. Rootrots of the western white pine type. Northwest Science. 24:5-17.

Leaphart, C.D., and A.R. Stage. 1971. Climate: A factor in the origin of the

pole blight disease of Pinus monticola Dougl. Ecology. 52:229-239.

McDonald, G.I., and R.J. Hoff. 1991. History and accomplishments of

white pine blister rust research in the USDA Forest Service. INF Rep.,

NOR-X-317, Proceedings IUFRO Rusts of Pine Working Party Conference,

Sept. 18-22, Banff, Alberta, Forestry Canada, Northwest Region, Northern

Forestry Centre.

Milke, J.L. 1943. White pine blister rust in western North America. Bulletin No. 52, Yale University School of Forestry, New Haven, CT.

Miller, F.G., R.N. Cunningham, S.V. Fullaway, Jr., C.N. Whitney, and C.B.

Morse. 1927. The Idaho forest and timber handbook. School of Forestry,

University of Idaho, Moscow, ID. 155 p.

Peterson, K.C. 1987. Company town, Potlatch, Idaho and the Potlatch Lumber Company. Washington State University Press, Pullman, WA. 284 pp.

Shiplett, B., and L.F. Neuenschwander. 1993. Fire ecology in the cedarhemlock zone of north Idaho. In: Interior Cedar-Hemlock White Pine Forests : Ecology and Management, Proceedings. Washington State University Cooperative Extension System, Pullman, WA. pp. 41-51.

Strong, C.C. and C.S. Webb. 1970. White pine: king of many waters.

Mountain Press Publishing Company, Missoula, MT. 212 pp.

Terrell, T.T. 1962. Mountain pine beetle infestation, Clearwater National

Forest, 1961. Unpublished survey and control Report. USDA Forest Service, Region 1. 6 p.

Zack, A.C., and P. Morgan. 1994. Fire history on the Idaho Panhandle National Forests. Review draft, March 22, 1994. Coeur d’Alene, ID: USDA Forest Service, Idaho Panhandle National Forests. 44 p.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and

activities on the basis of race, color, national origin, gender, religion, age, disability, political

beliefs, sexual orientation, and marital or familial status. (Not all prohibited bases apply to all

programs.) Persons with disabilities who require alternative means for communication of program

information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at

202-720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-

W, Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-9410 or call

202-720-5964 (voice or TDD). USDA is an equal opportunity provider and employer.

D E F I N I T I O N S U S E D I N T H I S P U B L I C A T I O N

Seral, Climax: Forest succession refers to the stages of development in

forest communities. The early stage is called the pioneer. The last (mature) stage is called the climax, hence a “climax forest.” The phases

between pioneer and climax are called the seral stages.

Efficient/Thrifty growing white pine: Refers to the ability of white pine

to utilize available resources (water, nutrients, and light) effectively,

especially in the early stages of forest development. This ability tends to

produce excellent growth, stability, and longevity of forests where white

pine is a significant component.

Canopy: Foliar cover in a forest, may consist of one or several layers, any

of which may be dense or sparse.

Overstory: Uppermost canopy layer, may be one or several lower layers

(understories). Thus, can be multistoried or multilayered. Also referred to

as “laddered” or “ladder fuels” when referring to multiple layers as fuel for

forest fires.