FOREST PEST CONTROL - Montana Department of Agriculture
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FOREST PEST CONTROL Montana Department of Agriculture
FOREST PEST CONTROL
A Study Manual for Commercial and Governmental Pesticide Applicators
This manual is intended for applicators that apply chemicals (pesticides) to conifer forests, forest nurs-
eries and forest seed producing areas. Forest Pest Control applicators need to demonstrate a practical
knowledge of the types of forests, pests involved, and pest management strategies used in forestry
production. They should also possess practical knowledge of the cyclic occurrence of certain pests and
specific population dynamics as a basis for planning pesticide applications.
A special thank you to Peter Kolb, Montana State University Extension Forestry Specialist; Ken Gibson,
US Forest Service entomologist; Amy Gannon, Montana Department of Natural Resources and Con-
servation; Marcus Jackson, US Forest Service-Northern Region Plant Pathologist; and Janet Kirkland,
Montana Department of Agriculture, for guidance and direction in developing this manual.
Developed by the Montana Department of Agriculture
and the
Montana State University Cooperative Extension Service
Jessica Fultz
IPM Survey Assistant/Insect Diagnostician
Monica Pokorny
Weed Specialist
Reeves Petroff
Montana Pesticide Education Specialist (1999-2005)
Agricultural Sciences Division, Technical Services Bureau, P.O. Box 200201,
Helena, Montana 59620-0201, (406) 444-5400
TABLE OF CONTENTS
CHAPTER: PAGE:
I. INTRODUCTION......................................................................................................................... 1
FORESTS................................................................................................................................... 1
Tree Biology........................................................................................................................ 2
How forests develop......................................................................................................... 3
MONTANA’S FORESTS.......................................................................................................... 3
Pine trees............................................................................................................................. 3
Spruce trees........................................................................................................................ 4
Fir trees............................................................................................................................... 5
Other important trees...................................................................................................... 6
MONTANA’S FOREST INDUSTRY....................................................................................... 6
SILVICULTURE........................................................................................................................ 7
PRACTICE QUESTIONS........................................................................................................ 7
II. MONTANA FOREST PESTS...................................................................................................... 9
INSECTS.................................................................................................................................... 9
Bark beetles........................................................................................................................ 10
Terminal feeders............................................................................................................... 12
Defoliators.......................................................................................................................... 13
Wood borers....................................................................................................................... 14
FUNGAL DISEASES................................................................................................................ 15
Root diseases...................................................................................................................... 15
Foliage diseases................................................................................................................. 17
Canker and stem diseases................................................................................................ 18
VEGETATION........................................................................................................................... 19
Parasitic plants................................................................................................................... 19
Undesirable vegetation.................................................................................................... 20
Weeds.................................................................................................................................. 20
PRACTICE QUESTIONS........................................................................................................ 27
III. FOREST PEST MANAGEMENT............................................................................................... 30
INTEGRATED PEST MANAGEMENT................................................................................ 31
FOREST PEST MANAGEMENT........................................................................................... 36
PRACTICE QUESTIONS........................................................................................................ 38
CHAPTER: PAGE:
IV. PESTICIDES................................................................................................................................... 40
PESTICIDE LABELS................................................................................................................ 40
PESTICIDE SAFETY................................................................................................................. 41
Exposure............................................................................................................................. 42
Toxicity................................................................................................................................ 43
Personal Protective Equipment (PPE)............................................................................ 44
Cleaning PPE...................................................................................................................... 45
Pesticide poisoning........................................................................................................... 45
First aid............................................................................................................................... 46
PESTICIDE FORMULATIONS............................................................................................... 46
Selecting formulations...................................................................................................... 46
Mixing formulations......................................................................................................... 48
Pesticide compatibility...................................................................................................... 48
Water quality and pesticide performance...................................................................... 48
APPLICATION METHODS.................................................................................................... 49
Foliar application............................................................................................................... 50
Basal bark application....................................................................................................... 50
Frill, or hack and squirt application................................................................................ 51
Injection application.......................................................................................................... 51
Cut-stump application...................................................................................................... 51
Soil application.................................................................................................................. 51
Pre-emergent applications............................................................................................... 52
APPLICATION EQUIPMENT................................................................................................ 52
Hydraulic sprayers............................................................................................................ 52
Air sprayers........................................................................................................................ 52
Foggers and aerosol generators....................................................................................... 52
Power dusters..................................................................................................................... 53
Hand-held equipment...................................................................................................... 53
Granular applicators......................................................................................................... 53
Sprayer components......................................................................................................... 54
Cleaning application equipment..................................................................................... 54
CALIBRATION......................................................................................................................... 55
Test strip method............................................................................................................... 55
Nozzel output.................................................................................................................... 56
Adjusting output............................................................................................................... 57
Calculations for mixing.................................................................................................... 57
CHAPTER: PAGE:
PESTICIDE STORAGE & DISPOSAL.................................................................................... 58
Storage................................................................................................................................ 59
Disposal.............................................................................................................................. 59
Pesticide Spills................................................................................................................... 60
PESTICIDE RESISTANCE....................................................................................................... 61
ENVIRONMENTAL HAZARDS............................................................................................ 61
Pesticide movement.......................................................................................................... 62
Pesticide losses in water................................................................................................... 63
Non-target organisms....................................................................................................... 64
Pesticide residues.............................................................................................................. 64
BEST MANAGEMENT PRACTICES.................................................................................... 64
APPLICABLE PESTICIDES.................................................................................................... 65
PRACTICE QUESTIONS........................................................................................................ 66
APPENDIX A: Practice Question Answers...................................................................................... 69
APPENDIX B: Noxious Weed List..................................................................................................... 70
APPENDIX C: References................................................................................................................... 71
APPENDIX D: Drawing & Photo Credits......................................................................................... 72
I. INTRODUCTION
The forestlands of Montana form the headwaters FORESTS
for a number of major river basins. These river
A tree can be defined as a woody plant that is at
systems supply large quantities of high quality
least 20 feet tall at maturity, has a single trunk,
water that nurtures some of the West’s best fisher-
is un-branched for at least several feet above the
ies and is used for irrigation and livestock water,
ground and has a definite crown. Trees are divid-
as well as for domestic, recreational and industrial
ed into two biological categories: softwoods and
purposes. These same lands supply the logs that
hardwoods.
sustain the forest products industry, an important
component of Montana’s economy. The terms softwood and hardwood do not refer
Montana’s water quality protection program for to the hardness or density of the wood. Softwoods
forestry involves a combination of regulatory and are not always soft, nor are hardwoods always
non-regulatory approaches. Since the 1970’s, for- hard. For example, mountain-grown Douglas fir
estry Best Management Practices (BMPs) have produces an extremely hard wood although it is
provided guidance for water quality protection classified as “softwood,” and balsawood, so useful
for forestry operations. One forestry BMP is to use in making toy models, is classified a “hardwood”
an integrated approach to pest control, including although it is very soft.
manual, biological, mechanical, preventive and In biological terms, softwoods are called gym-
chemical means. nosperms, which are trees that produce “naked
Commercial and governmental applicators that seeds.” The most important group of softwoods
use or supervise the use of pesticides in forests, are the conifers or cone-bearing trees, which have
forest nurseries, and forest seed producing areas seeds that are usually visible inside opened cones.
are placed under the forest pest control category. All species of pine, spruce, hemlock, fir, cedar,
These applicators have a detailed list of responsi- redwood and larch are softwoods. Nearly all soft-
bilities: wood trees have another common characteristic:
Applicators shall demonstrate practical knowledge
their leaves are actually needles or scales and they
of types of forests, forest nurseries, and seed produc- remain on the tree throughout the winter, which
tion in their state and the pests involved. They shall is why they are also called evergreen trees. Excep-
possess practical knowledge of the cyclic occurrence tions are larch (or tamarack) and cypress whose
of certain pests and specific population dynamics as needles drop in the fall, leaving the tree bare dur-
a basis for programming pesticide applications. A
practical knowledge is required of the relative biotic
ing winter.
agents and their vulnerability to the pesticides to be
Hardwoods are called angiosperms; trees that
applied. The applicator shall demonstrate practical
produce seeds enclosed in a fruit or nut. The hard-
knowledge of control methods and the possibility of
secondary problems such as unintended effects on wood category includes the oaks, ashes, elms,
maples, birches, beeches and cottonwoods. In
wildlife. Proper use of specialized equipment shall be
contrast to softwoods, hardwood trees have broad
demonstrated, especially as it may relate to meteoro-
logical factors and adjacent land use. leaves and nearly all North American hardwoods
Identifying and managing the pests that infest are deciduous, which means they drop their leaves
Montana’s forests, forest nurseries, and seed or- in the fall.
chards can be difficult and time consuming. There Though there are many more hardwood species
are more than 1,300 diseases and insect pests com- than there are softwoods, the softwoods produce a
mon on conifer trees in the northern and central larger share of commercial wood products, partic-
Rocky Mountains. Of these, only about 10 percent ularly those used for structural applications. This
account for most of the reported cases of dam- is evident by the dominant use of a few softwood
age. In addition, there is animal damage, noxious species such as Douglas fir, hemlocks, spruces,
weeds, and abiotic injuries that are often encoun- pines and true firs, all of which play crucial roles
tered. This manual will focus only on the most in home construction.
commonly encountered Montana forest pests.
Introduction - 
sunlight to manufacture food (various sugars) for
Tree Biology
the tree’s use. This process is called photosynthe-
The crown consists of the sis. A by-product of this process is the release of
leaves and branches (Fig. 1-1). oxygen. In fact, without the production of oxygen
The leaves contain cells called by trees and other green plants on our planet, hu-
chloroplasts that have chloro- mans and other animals could not survive. The
phyll, the substance that gives nutrients (sugar solutions) manufactured by the
leaves their green color. In leaves are conducted through the inner bark (phlo-
the presence of sunlight, the em) to branch terminals, roots and the cambium
leaves use the carbon dioxide layer (Fig. 1-1 and 1-2). The cambium is the layer
from the air to produce glu- of reproductive cells found between the inner bark
cose and oxygen. The oxygen and sapwood portions of a tree. This narrow layer
is released to the atmosphere of cells creates new sapwood cells toward the in-
Figure 1-1. and the glucose is stored in the side and new phloem cells toward the outside of
trunk and roots. This process the cambium. This process adds a layer of new
is called photosynthesis. wood in the cambium
The trunk, or main stem, of the tree supports the layer every year, which
crown and contains the vascular tissue that runs is between the old
between the roots and the leaves (Fig. 1-1). This wood and the bark. As
tissue allows the movement of raw materials up to rings are added, the
the leaves and the return of manufactured food to tree trunk and branch-
the woodland root systems for growth and storage. es grow in diameter.
Figure 1-2.
The root system is the most important part of a As a tree gets bigger
tree because the roots absorb nutrients and water, around, phloem cells get older; they are pushed
store food, and support and anchor the tree (Fig. farther away from the cambium (toward the out-
1-1). The majority of the root system is located in side) and gradually die. Their water transporting
the upper 12 to 18 inches of soil because of the function is then taken over by younger phloem
high levels of oxygen that the roots require. cells produced by the cambium. Dead phloem cells
Monoecious plants have male flowers (or sta- become part of the outer protective layer of trees
minate flowers) and female flowers (or pistillate that we call bark. Bark is important in protecting
flowers) on the same plant. Therefore, if favorable the tender cells in and near the cambium. Without
environmental conditions occur the plant will bark, these cells would be under continual attack
bear fruit from some of the female flowers scat- from insects, forest animals, fungi and birds and
tered throughout its growth. Examples include susceptible to physical damage from frost, wind
American Beech and Black Walnut. and fire.
Dioecious plants have male flowers (or staminate The woody portion of a tree is called xylem and
flowers) on one plant, and female flowers (or pis- it includes both the sapwood and heartwood.
tillate flowers) on another plant. Therefore, if pol- Heartwood is the darker-colored (caused by tan-
lination and favorable environmental conditions nins) inner part of a trunk. This portion of a tree
occur, a pollinating male plant bears no fruits or is composed of dead cells, which contribute to the
seeds, whereas a female plant may have fruits. Ex- overall strength of the tree trunk. In many ways
amples include Green Ash and Osage Orange. An heartwood is similar to sapwood, but they differ
advantage of dioecious trees is that seedless males in their chemical and physical properties.
can be selected and propagated. Unlike animals, trees have no way to get rid of by-
Water and nutrients are absorbed by roots and products produced by the chemical changes that
transported from the soil up to the leaves through take place in their living tissues. Some of these
hollow cells found in the sapwood. Leaves absorb by-products could be harmful to the tree, so a tree
carbon dioxide from the air, which they combine moves these substances toward its heartwood cen-
with water through the use of chlorophyll and ter. Therefore, heartwood is basically just sapwood
Introduction - 
in which waste substances have accumulated. This 1. Douglas fir - Pseudotsuga menziesii
leads to two major differences in the properties of 2. Lodgepole pine - Pinus contorta
heartwood and sapwood. Because of the presence 3. Ponderosa pine - Pinus ponderosa
of by-products and other substances, heartwood, 4. Western white pine - Pinus monticola
usually has: 1) Greater resistance to insect attack 5. Grand fir - Abies grandis
and decay by fungi, and 2) Reduced permeability, 6. Subalpine fir - Abies lasiocarpa
which can affect timber treatment because the nat- 7. White spruce - Picea glauca
ural cellular channels of heartwood can become 8. Engelmann spruce - Picea engelmannii
clogged with extractive deposits. 9. Western hemlock - Tsuga heterophylla
10. Western red cedar - Thuja plicata
How Forests Develop
11. Western larch (Tamarack) - Larix occidentalis
Vegetation follows established patterns of re-
Forests on the east side of the Continental Divide
growth and change after disturbances by farming,
are dominated by ponderosa pine and Douglas fir
timber harvesting or fire. This process of patterned
and are associated with the many isolated moun-
regrowth and change is called plant succession.
tain ranges like the Snowies, Belt, and Bears Paw
The rate of succession and the species present at
mountains.
various stages depend on the type and degrees
of disturbance, the environment of the particular West of the Continental Divide, in western Mon-
sites and the species available to occupy the site. tana, many more species are present including
Even in the absence of human activity, forest eco- western larch, lodgepole pine, western white pine,
systems are dynamic and change in response to grand fir, subalpine fir, Engelmann spruce, western
variations in climate and to disturbances from hemlock and western red cedar. This abundance
natural sources. For example, when a fire caused of species is mostly due to Pacific weather systems
by a lightning strike occurs, the ecosystem goes that are intercepted by high mountains that in turn
through a sequence of changes. There is a quick deliver enough moisture for tree growth.
flourishing of “pioneer species.” These species Generally, forests across Montana can be separat-
are usually quick-growing grasses and broad- ed into four basic forest species zones:
leaved plants, often including weeds, followed by • Douglas fir (32 percent of forestlands)
a steady advance of slower-growing shrubs and • Lodgepole pine (21 percent of forestlands)
bushes, and trees. This process begins quickly but • Spruce and fir (15 percent of forestlands)
it can take decades or even hundreds of years for a • Ponderosa pine (12 percent of forestlands)
forest ecosystem to move from its early “pioneer”
These zones are created by differences in temper-
stage to its “climax” stage. The different species
ature, moisture, elevation, and soil. Tree species
of a stage in forest growth depend on the envi-
are adapted to specific conditions, although some
ronmental characteristics of the site in which the
tree species have a greater ability to adapt to vary-
disturbance has occurred. For example, average
ing conditions and disturbances.
moisture and temperature, soil types, elevation,
slope, aspect and latitude as well as the seed bank Pine Trees
available all play a role in what species will begin Pine trees (Pinaceae: Pinus) have uncovered seeds
to grow after a disturbance. borne in pairs on the bracts of (female) cones (as
do other genera of the Pinace-
MONTANA’S FORESTS ae family) and needles ar-
Of Montana’s total land area (93 million acres), 17 ranged in bundles of 2 to 5 and
coniferous tree species cover about 22.5 million with a permanent or decidu-
acres. Of these 17 species, there are 11 conifer spe- ous sheath at their bases (fas-
cies of commercial value: cicles) (Fig. 1-3). Pines usually
are among the first trees to es-
tablish after fire or other dis-
turbance and often occur in Figure 1-3.
pure even-age stands.
Introduction - 
Lodgepole pine (Pinus contorta) (Fig. 1-4) com- a long, deep root system that enables it to access
monly grow in dense even-aged deep water and keep the tree from blowing over.
stands across Douglas fir, grand fir Ponderosa pine bark is black on young trees then
and subalpine fir sites where crown yellow-brown, with large scaly plates on mature
fires have occurred. With special heat trees (Fig. 1-7).
resistant cones, these trees need se- Ponderosa pine is generally found at lower eleva-
vere disturbances to re-generate. tions and dry southern slopes across the forest.
This species is considered short-lived Needles of the ponderosa
(150 years), as it is often killed by pine are five to ten inches
bark beetles once it reaches an age long, in fascicles of 2 or 3.
close to 100 years. At this age these Cones are four to six inches
trees can reach 70 to 110 feet tall and long, conical or egg shaped,
one to two feet in diameter. The small with outward pointed
brown woody cones of lodgepole Figure 1-8. prickles (Fig 1-8).
pine are egg-shaped and 1 to 2 inches
.
Figure 1-4. long. They also have tiny, sharp prick- Western white pine (Pinus monticola) (Fig 1-9) is
les (Fig. 1-5). In some areas, lodgepole cones are an important timber tree because
sealed by a resin and need heat to it has soft, light weight, non-resin-
open (serotinous). Fires provide ous, straight-grained wood and
the heat to open the cones and free rapidly grows to a large size. It is
millions of lodgepole seeds. Most particularly valuable for sash,
pure stands are therefore estab- frames, doors, interior paneling,
lished on burned areas. Lodgepole building construction, match
pine needles grow one to three wood and toothpicks. Western
inches long and in groups of two white pine requires fire or timber
needle-like bundles. Lodgepole Figure 1-5. harvesting to become established
bark is thin, gray-brown and flaky on older trees. as this removes competing coni-
The bark is very thin, rarely exceeding ½ inch, re- fers. This tree species is intermedi-
ducing the tree’s resistance to fire. ate in fire resistance compared to
other conifers because of its thin
Ponderosa pine (Pinus ponderosa) (Fig. 1-6) is a Figure 1-9. bark and moderately flammable
hard pine with varied grain foliage. As a result of
coarseness that inhabits the warm- fire protection and the
est and driest of forest zones. The lack of major fires, plus
heat tolerance and taproot of pon- blister rust infection,
derosa pine allows it to grow the proportion of west-
where few other native tree spe- ern white pine regener-
cies can. This also allows it to col- ation has decreased. Figure 1-10.
onize severely burned areas on The needles are flexible bluish green, 2 to 4 inches
wetter sites. Soil disturbances long and in clusters of five. The cones are typi-
timed with a good cone crop re- cally found at the tops of the trees. They are 5 to
sult in prolific seedling produc- 10 inches long and green before opening. They are
tion. It has a light brown with thin scales (Fig. 1-10).
large crown,
straight trunk Spruce Trees
Figure 1-6. and can live as In general, spruce
long as 300 years. At 150 years trees (Pinaceae: Pi-
of age it can reach 120 to 180 cea) are rugged ev-
feet tall with trunk diameter of ergreens that can
2 ½ to 4 feet. This tree also has Figure 1-7. withstand extreme
winter cold. Engel- Figure 1-11.
Introduction - mann spruce (Picea engelmannii) and to a lesser de- Fir Trees
gree, white spruce (Picea glauca) are commonly Firs (Pinaceae: Abies) are tall evergreen conifers
found in Montana forests. Spruce trees have stiff, that have a pyramid-shape and are characterized
prickly, four-sided needles that are evenly ar- by short, flat, stemless, flexible needles that grow
ranged around the entire twigs on the sides and
in a “bottle brush” appearance sometimes tops of
(Fig. 1-11). Needles are attached twigs but rarely on
directly to the stem and grow the bottom (Fig. 1-
from woody peg-like bases 16). Firs can be dif-
called sterigmata (Fig. 1-12). Figure 1-12. ferentiated from
White spruce (Picea glauca) (Fig. 1-13) primarily Douglas fir and
grows in northern Montana along spruce trees by their
rivers. It extends northward into upright cylindrical Figure 1-16.
Canada, where it generally replaces cones that shed their
Engelmann spruce north of Alberta. scales rather than dropping off the tree as a whole
Where their ranges overlap, these cone. It should also be noted that the Douglas fir,
two species often hybridize. The Pseudotsuga menziesii, is not a true fir. Many of the
cones of Engelmann spruce (Picea true firs are also incorrectly called balsam. The
engelmannii) true balsam fir (Abies balsamea) is found east of the
are larger Rocky Mountains.
than white In Montana, there are two species of fir trees that
spruce (Picea are of economic importance: the grand fir (Abies
Figure 1-13.
glauca). Also, grandis) and the subalpine fir (Abies lasiocarpa).
the cone scales of Engel-
Grand fir (Abies grandis) (Fig. 1-17) is a large tree
mann spruce are ragged or
reaching 120 feet in height and 3 feet in
notched, while those of
diameter. It typically grows in western
white spruce are smooth Figure 1-14.
Montana at lower elevations (up to
and rounded like a thumb-
4000 feet).
nail (Fig. 1-14).
The needles are ½ to 2 inches long
Engelmann spruce (Picea engelmannii) (Fig. 1-15) with single notched ends and extend
is native to higher elevations of straight from opposite sides of the
the Cascades and Rocky Moun- stem. They have a green surface and
tains, including the mountains of a silvery white bottom. Grand firs are
western and central Montana and economically important as lumber,
is found in most cool air drainages plywood, pulp for paper, framing,
and at higher altitudes. Needles
Figure 1-17. sheathing, other structural uses and
point towards the branch tip, mak- for Christmas tree markets.
ing the branches softer to the
touch. The needles have a distinc- Subalpine fir (Abies lasiocarpa) (Fig. 1-18) is com-
tive, rank odor when crushed. mon at cold, high elevation moun-
The wood is lightweight, straight tain forests in Montana and can reach
grained, soft, stiff, and can be a height of 80 feet with a 2 foot diam-
Figure 1-15. readily air-dried. It is used for eter. The needles are ½ to 1½ inches
home construction lumber and for long and extend in a spiral from the
prefabricated wood products. Engelmann spruce stem. The wood is used as lumber
has a life span of 350 years and can be 8 to 150 feet for home construction, prefabricated
tall at 200 years of age. Trunk diameter can reach 1 wood products and has excellent
½ to 2 ½ feet in diameter. pulping properties.
Figure 1-18.
Introduction - Other Important Trees Western larch (Larix occidentalis) (Fig. 1-22) is a
Douglas fir (Pseudotsuga menziesii) (Fig. 1-19), also deciduous conifer that can reach a
known as red fir, is a valuable tree height of 200 feet. It occurs in north-
used for Christmas trees, lumber and west Montana in open, sunny stands.
plywood. The wood is strong and Needles are 1-1½ inches long, triangu-
dense and is good for structural sup- lar in shape, and soft. Cones can reach
port, beams, trusses, docks, bridges 1½ inches in length with a purple/red/
and railroad ties. This species can brown coloring. The wood is used for
grow on hot and dry sites as the shade construction, railroad ties, pilings, mine
tolerant replacement species, or on timbers, interior and exterior finishing
cool, wet sites as the pioneer species. and pulp. It is also one of the most im-
It is the most versatile and common portant fuel woods. Western larch is a
tree in Montana. It is moderately highly valuable timber species.
adapted to survive the effects of fire Figure 1-22.
and coexists with ponderosa pine on
Figure 1-19. dry sites, and with larch, grand fir, Western redcedar (Thuja plicata) (Fig. 1-23) is not a
and lodgepole pine on cooler and wetter sites. It true cedar but is a member of the cy-
has the tendency to regenerate in dense thickets press family. It is a large tree that can
under mature ponderosa pines or on cooler north grow to 150 feet and 6 feet in diameter.
and east slopes, which creates a high wildfire haz- These trees prefer moist sites at low el-
ard. Douglas fir needles are ¾ to 1¼ inch long and evations in northwest Montana.
flat, slightly grooved with a The wood is commercially important
sharp tip relative to true firs. because it is resistant to decay. There-
Cones are cylindrical and two- fore it is used for the construction of
to-three inches long with 3- 3-pointed exposed building material such as
pointed bracts protruding from bracts shingles, shakes, and exterior siding.
the scales (Fig. 1-20). The bark is Western redcedar wood is also used
gray-brown, corky looking, and Figure 1-23. for utility poles, fence posts, light con-
deeply furrowed in mature trees. struction and pulp.
Inside furrows often rust, turn-
ing red in color. Douglas fir trees MONTANA’S FOREST INDUSTRY
can have a life span of 300 years Figure 1-20. There are 22.4 million acres of timberland in Mon-
and reach heights of 110 to 170 feet tall and three tana. Nearly 3.4 million acres of forestlands are
to four feet in diameter. permanently reserved as either wilderness areas
or National Parks. Eleven million acres of the re-
Western hemlock (Tsuga heterophylla) (Fig. 1-21) is
maining forestland is administered by the USDA
a large tree that can reach a height of
Forest Service, with 5.2 million acres of this public
175 feet. It is found in the low-to-mid
estate designated by current forest plans as suit-
elevation toe-slope seepages, moist
able for timber production.
benches, and wet bottoms adjacent to
streams of northwestern Montana. Private forestlands occupy some 6 million acres,
These trees dominate where soils are with 1.6 million owned and managed by timber
deep, moist, and nutrient poor. companies. Montana’s timber industry turns trees,
Needles can be ¼-¾ inch long with a renewable resource, into a wide variety of prod-
rounded ends and a grooved center. ucts, including lumber, plywood, particle board,
Cones hang down, are a light brown cardboard boxes, posts and rails, log homes, and
and reach a length of one inch. wood pellets.
Wood from this tree is used for roof The rest of the Montana’s forestlands are comprised
decking, molding, general construc- of State, Bureau of Land Management (BLM), Trib-
Figure 1-21. tion, plywood and newsprint. al, County and other land ownerships.
Introduction - In Montana, the wood products industry contrib- 1) Planting and establishing trees after harvest
utes about $970 million, or 6 percent of the states that are resistant to pests and pathogens that
total economy (Montana Wood Products Associa- were in the area pre-harvest. Site preparation for
tion). specific tree species is necessary.
Quick & Easy ID 2) Managing established forests which may re-
quire thinning to reduce competition for light,
Needle Cone Bark water, and nutrients minimizing the stress expe-
Douglas fir flat, grooved 2-3 in, three- grooved
rienced by the new forest crop. Slash, windfall
pointed bracts and dead trees need to be removed at the ap-
beyond scales propriate seasonal time to decrease pest source
Lodgepole pine bundles of 2 0.75-3 in, spined
scales
orange/
brown/gray
populations.
flaky 3) Harvest of tree crop at the appropriate
Ponderosa pine bundles of
2-3
3-6 in, spined
scales, rounded
brown/or-
ange/yellow
seasonal time.
base plated 4) Salvage and storage at the appropriate
Western white bundles of 5 5-10 in, thin gray, thin, seasonal time.
pine scales smooth
Grand fir single, 2-4 in, scales fall gray/red/
notched end to the ground brown. thin,
resin blisters
PRACTICE QUESTIONS
Subalpine fir single 2-4 in, scales fall gray/red, thin,
to the ground resin blisters
White spruce single, sharp 1-2.5 in, smooth brown/silvery, 1. Closely spaced annual rings indicate_________
rigid tips scales thin
_______ trees.
A. fast growing
Engelmann single, 1.5-2.5 in, thin gray/red/
spruce sharp-point- soft scales purple/brown,
ed tips thin, scaly B. slow growing
Western hemlock single, flat, 0.75-1.5 in brown, broad C. very tall
D. very short
rounded flat ridges,
end, grooved thick
Western redcedar scale-like 0.5 in, 8-10 gray/red/
spined scales brown, thin, 2. The dead, central wood in the trunk and larger
fibrous
branches, usually darker and harder than the sap-
Western larch bundle 14- 1-1.5 in, thin red/brown,
30, triangular scales scaly, thick wood is____________.
A. stomatawood
SILVICULTURE B. timberwood
C. heartwood
Silvics is a specialized branch of forest ecology that D. bractwood
deals with the biological characteristics of indi-
vidual trees and their communities. For example, 3. What type of tree typically colonizes after a dis-
tree growth, reproduction, and biotic (interactions turbance?
with other organisms) and abiotic (environmen- A. Larch
tal interactions) influences are studied as well as B. Spruce
the influence the tree communities have on the C. Pine
environment they grow in. Overall, this informa- D. Fir
tion is then utilized to successfully reproduce and
grow forest crops. Silviculture methods attempt 4. What type of tree has sterigmata?
to control the establishment, composition, charac- A. Larch
ter, and growth of tree stands in order to manage B. Spruce
forests for economic and ecological purposes. This C. Pine
knowledge is required for not only maximized D. Fir
long-term economic return but also the mainte-
nance of important ecological forest functions. Im-
portant areas of silviculture are:
Introduction - 5. An example of a deciduous conifer is the_____. 12. What part of a tree has greater resistance to in-
A. Larch sect and fungi attack as well as reduced perme-
B. Spruce ability?
C. Pine A. stomatawood
D. Fir B. timberwood
C. heartwood
6. The younger, living outer layer of wood in the D. bractwood
trunk and branches, softer and lighter in color
than heartwood is__________.
A. sapwood
B. timberwood
C. heartwood
D. bractwood
7. Waste products of cell processes found in vacu-
oles and cell walls, giving brown colors is______.
A. carotenoids
B. tannins
C. chlorophyll
D. xylem
8. Green pigment in chloroplast necessary for
photosynthesis is_________.
A. carotenoids
B. chlorophyll
C. anthocyanin
D. tannins
9. ___________ is the water-conducting tissue that
transports water upward in a tree.
A. xylem
B. phloem
C. outer bark
D. cambium
10. Roots do not perform the function of___ .
A. support
B. manufacturing plant food
C. absorbing moisture
D. absorbing plant nutrients
11. What is the study of tree biology and commu-
nity ecology?
A. forestry
B. dendrology
C. ecology
D. silvics
Introduction - II. MONTANA FOREST PESTS
Pests can be defined as any organism that causes includes all animals with segmented legs, segment-
economic or aesthetic damage to humans or their ed bodies and exoskeletons (spiders, ticks, mites,
property. Examples include exotic weeds that dis- centipedes, millipedes, shrimps, lobsters, and
place native vegetation, deer mice (Peromyscus many other organisms). Insects can be differenti-
maniculatus) that carry the deadly hantavirus, and ated from the majority of other arthropods by the
gypsy moths (Lymantria dispar) that defoliate oaks following distinctive traits (Fig. 2-1):
(Quercus spp.). Pests can be classified as key pests, (1) a body
occasional pests or secondary pests (Table 2-1). divided into
Table 2-1. three parts:
Key Pests Occasional Pests Secondary Pests head, thorax
Cause major damage Become intolerable Occur as a result of and abdo-
on a regular basis. on an irregular basis. actions taken to con- men, (2)
three pairs
Example: Often as a result of trol a key pest.
An 80 percent infes- changes in climate, Example: Figure 2-1.
tation of leafy Spurge environment, or hu- Cheatgrass establish- of legs, (3)
usually one pair of antennae and a pair of com-
can reduce livestock man activity. ment in areas that
carrying capacity by Example: have been sprayed for
100 percent. Dry conditions can spotted knapweed. pound eyes (a few exceptions to these characteris-
Grasshoppers con- cause seed bugs to Ticks and fleas plague tics are found), (4) usually two pairs of wings, al-
move from rangeland
sume up 25 percent
of the available forage to areas of higher
people after their
natural hosts have
though insects such as lice, fleas and ants do not
in the western United moisture like lawns, been eliminated. have wings and flies have one pair of wings.
States annually. flower beds, swim-
ming pools and Less than one percent of the estimated one mil-
lion insect species on the earth are pests. An even
houses.
Forests have a varied occurrence of pest species. smaller percentage are considered forest pests. Yet,
At times the damage caused by these pests may insect pests of conifer trees are capable of limiting
have reached levels that require no action because timber production, creating tree and fire hazards,
costs of treating are greater than the profit gained. reducing visual quality, affecting wildlife use, and
However, if a pest is detected and accurately iden- degrading watershed properties.
tified steps preventing an increase in population Of the 31 insect orders, 3 contain most of the forest
and the ensuing damage can be taken. insect pest found in Montana: Coleoptera (beetles,
weevils), Hymenoptera (sawflies, wasps, bees),
INSECTS and Lepidoptera (moths, butterflies). These insects
All living organisms are grouped or classified by are organized into their respective orders given
common characteristics. The major groups are specific morphological characteristics (Table 2-2).
called kingdoms. Each kingdom is then further Table 2-2.
divided into increasingly smaller groups based
on similarities. The different levels of groups are Order Coleoptera
named by the convention of taxonomists (sci- Elytra
Adult beetles have one pair
of hardened outer wings
entists who study classifications). The standard Hind wing (elytra) that act as a pro-
groups in a typical complete classification of spe- tective cover for the sec-
ond pair of membranous
cies are (the example is for mountain pine beetle wings. Adults have one
Dendroctonus ponderosae): pair of antennae, a pair
of compound eyes, and
KINGDOM (Animalia) chewing mouthparts.
PHYLUM (Arthropoda)
CLASS (Insecta)
ORDER (Coleoptera) Thoracic legs The larvae (grubs) have
FAMILY (Scolytidae) three pairs of thoracic
legs and a well developed
GENUS (Dendroctonus)
head capsule with chewing
SPECIES (ponderosae) mouthparts.
Head capsule
Insects belong to the phylum Arthropoda which
Pests - Order Lepidoptera April and July can be used to determine the inten-
Adult moths and butter- sity of infestation later in the season.
flies usually have two pairs Insecticides can be used for direct control of bee-
of large wings covered with
scales. Adults have one tles. Unfortunately, control requires the combined
pair of antennae, a pair of efforts of all landowners within the designated
compound eyes, and si-
phoning mouthparts. management area and, therefore, broadcast appli-
cations. Pesticide control of bark beetle control is
only valuable in the spring when adult beetles are
The larvae (caterpillars)
have three pairs of thoracic
flying. Once the adult beetles, eggs, or larvae are
legs, three to six pairs of in the bark, pesticides are ineffective. Treatments
prolegs with crochets, and
chewing mouthparts
are only effective before adults lay eggs. Infested
trees cannot be saved with in-
secticide treatments and sanita-
Order Hymenoptera
tion harvesting should be prac-
Adult sawflies and bees
have two pairs of mem- ticed. To limit beetle population
branous wings. Adults the infested tree should be re-
have one pair of anten-
nae, a pair of compound moved. Then the tree’s bark
eyes, and chewing/lapping should be burned, the tree
mouthparts.
should be limbed and exposed
to the sun, submerged in water,
The larvae may or may or sprayed with insecticide.
not have thoracic legs and Chemical attractants (moun-
chewing mouthparts. Saw-
fly larvae have at least four tain pine beetle: exo-brevicomin
pairs of prolegs without trans-Verbenol Myrcene; Doug-
crochets. The larvae of
bees and wasps usually las fir beetle: Frotalin MCOL
are more grub-like without or Seudenol Ethanol) can be Figure 2-2.
prolegs.
used as tree baits to stimulate attacks in selected
Bark Beetles (Scolytidae) stands and influence landscape pattern of mortal-
ity. They can also be used in conjuction with fun-
Management of bark beetle populations is depen-
nel traps (Fig. 2-2) to monitor beetle populations.
dent on preventive measures and the maintenance
Anti-attractants can also be used (mountain pine
of healthy trees. General silvicultural practices that
beetle: Verbenon; Douglas fir beetle: methylcyclo-
improve tree vigor limit the susceptibility of a tree
hexenone or MCH).
to bark beetle infestation. Infestations have been
Several predators and parasites feed on bark bee-
found to be linked to windthrow, snow breakage,
tle adults and larvae. Natural enemies of moun-
spring/early summer drought, logging, fires, road
tain pine beetle, Douglas fir beetle, western pine
and housing development and other human activ-
beetle and the fir engraver are predaceous beetles
ities. Slash from these activities act as reservoirs of
such as the checkered clerid (Enoclerus lecontei and
beetle population growth and should be removed.
Enoclerus sphegus), trogossitid beetles (especially
Trees that are mature or over mature, and are in
Temnochila chlorodia), a predaceous dolichopodid
dense stands are more likely to be infested. Dense
fly (Medetera aldrichii) and parasitic wasps. Some
stands will also increase the likelihood of infesta-
nematodes (internal parasitic worms) limit or pre-
tion of younger, smaller diameter trees. Stands
vent egg production within females whereas other
with high incidence of root disease also have a
nematodes feed on beetle eggs. Woodpeckers, nut
greater chance of infestation. Thinning and patch
hatches, and a few other bird species are common
cutting of stands into an age and size class mosaic,
predators. Aggregations of bark beetles attract
and selective harvesting of risky trees (in riparian
natural enemy populations and may eventually
area, along roads or edges) are valuable preven-
limit the infestation.
tion tools. Predicting outbreaks is another impor-
tant preventive tool. Precipitation levels between The bark beetles are the most economically
injurious insects to Montana forests. Notable pest
Pests - 10species are mountain pine beetles (Dendroctonus Fir engravers (Scolytus ventralis) attack young and
ponderosae), Douglas fir beetles (Dendroctonus pseu- mature true fir stands such as Abies concolor, Abies
dotsuga), Western balsam bark beetles (Dryocoetes grandis and Abies magnifica but occasionally attack
confusus), fir engravers (Scolytus ventralis), spruce Pseudotsuga, Tsuga and Picea. It typically breeds
beetles (Dendroctonus rufipennis), pine engravers in slash and windthrown trees but outbreaks on
(Ips pini), and Western pine beetles (Dendroctonus living trees can occur
brevicomis). due to drought, dis-
ease and defoliation.
The mountain pine beetle (Dendroctonus pondero-
The egg galleries
sae) is stout, black, and
formed by the adults
cylindrical (4-7½ milli-
are scored trans-
meters (mm) long)
versely across the
with the head visible
grain of the wood
when viewed from
from each side of the Figure 2-6.
above (Fig. 2-3). The
entrance (Fig. 2-6).
antennae are elbowed
Figure 2-3.
with a flattened club. It Western balsam bark beetle (Dryocoetes confusus)
is considered one of the most destructive forest adults (about 4 mm in length) at-
pests attacking mature lodgepole forests. In 2005, tack subalpine fir, but other occa-
820,400 acres of Montana forests were infested. sional hosts are Abies species, En-
Adult beetles tunnel under bark to construct egg gelmann spruce and lodgepole
galleries (less than or equal to 90 centimeters (cm) pine (Fig. 2-7). Blue-stain fungus
long) in the cambium parallel to the grain of the can be introduced during feeding.
wood. The adult beetle may also introduce blue- Females have a dense patch of yel-
staining fungi into the sapwood, decreasing the low hair on the head while males
translocating abilities of the tree. Larvae feed on Figure 2-7. have lit-
the wood, creating galleries at right angles to the tle hair. The adults lightly
initial gallery. The tree can be girdled when larval score the wood, creating
density is high. Indications of galleries that radiate from
infestation: pitch tubes (Fig. 2- the central entrance (nup-
4), red foliage, and circular tial chamber) (Fig. 2-8). Figure 2-8.
emergence holes without frass
(waste material produced by Pine engravers (Ips pini) (Fig. 2-9) are frequent
feeding insects). It takes one pests of ponderosa
year for the beetle to complete
Figure 2-4. pine and at times are
its life cycle. important pests of
lodgepole pines. Typi-
The Douglas fir beetle (Dendroctonus pseudotsuga) is cally only trees that are
very similar to the mountain pine beetle in size and stressed by wind, fire,
shape. It attacks Douglas fir and western larch, and drought will be
preferring slash, windfall and diseased trees, but Figure 2-9. attacked. In outbreak
will attack living trees if populations reach epi- years young trees may be killed and mature trees
demic levels. The adult constructs galleries less may be top damaged by
than 50 cm, with an average of 25 cm (Fig. 2-5). the beetle infestation.
Indications of infestation: fresh frass found in bark The adults are yellow to
crevices, red foliage, and entrance holes with bor- brown (3-7 mm long)
ing dust visible on bark. Pitch tubes will not be with a concavity at the
present. It takes approximately one year for this rear of the elytra which
beetle to complete its life cycle. is marginated on each
side with 4 tooth-like Figure 2-10
spines. The third spine
Pests - 11is more prominent in males than in females. Gal- Terminal Feeders (Curculionidae)
leries radiate from the entrance (nuptial chamber) Terminal weevil management like bark beetle
forming a Y- or H-pattern aligned with the grain management requires preventive measures and
of the wood (Fig. 2-10). The boring dust and frass the maintenance of healthy trees. Several manage-
is pushed to the outside of the entrance during ment strategies are useful in controlling terminal
construction of the gallery. weevil damage: 1) Plant pure stands at high den-
Spruce beetle (Dendroctonus rufipennis) adults (Fig. 2- sities (2½ meter (m) spacing or less). Dense grow-
11) are light brown to red- ing conditions do not prevent weevil infestation
dish-brown (4-7 mm in but increase upward growth benefiting the gener-
length). They can be distin- al form of the tree. Spacing (pre-commercial thin-
guished from the mountain ning) and brush control should be delayed until
pine beetles by the sclero- the stand reaches 25 years of age or 5 m in height.
tized plate on the dorsal side 2) Plant host tree species in a mixture with suitable
Figure 2-11. of each of the last two ab- non-host species. 3) Plant host trees resistant to
dominal segments. Engelmann, white and Sitka terminal feeders in a mixture with susceptible host
spruce are attacked as well as other Picea species. trees. 4) Clip infested leaders before emergence of
The spruce beetle will usually breed in slash and the adult. Leave one dominant lateral to maintain
windthrown trees. Following blow down events proper terminal shoot growth. Repeat the proce-
and successive warm summers stands of mature, dure for three consecutive years. Clipped leaders
living spruce will be attacked. should be disposed of by burning as adult weevils
The adult will construct an can still emerge. 5) Applications of appropriate
egg gallery about 24 cm in insecticides according to label directions (such as
length (Fig. 2-12). Indications insect growth regulators in late April). However,
of infestation include: the pesticide application over large areas is not cost
presence of loose frass in bark effective and can be detrimental to other insects.
crevices and red foliage. Pitch Birds, other insects, and mammals are predators
tubes will not be present. It of terminal feeding insects. However, natural en-
takes approximately two emies do not significantly control damage.
years for the beetle to com- Important terminal feeders in Montana forests are
Figure 2-12.
plete its life cycle. the white pine weevil (Pissodes strobi) and lodge-
pole pine terminal weevil (Pissodes terminalis).
Western pine beetle (Dendroctonus brevicomis)
(Fig. 2-13) is similar to the
White pine weevils (Pissodes strobi) are reddish
mountain pine beetle but
brown with patches of lighter
attacks ponderosa pine and
brown or grey scales (Fig. 2-
is somewhat smaller (3-5
15). They are about 4-5 mm in
mm in length). It is a minor
length and have long, slender
pest but the susceptibility
snouts and clubbed antennae.
of ponderosa is increasing
Figure 2-15. Major hosts are Colorado blue,
Figure 2-13. with the continually dry
white, and
conditions of Montana.
Engelmann spruce, and Eastern
Egg galleries are ran-
white pine. In early spring,
dom, branched across
adults chew into the bark of a
the grain (Fig. 2-14).
year-old leader and lay eggs.
Indications of infesta-
The larvae (grubs) have a
tion: inconspicuous
smooth-surface, are curved and
pitch tubes and red
legless, and are yellowish white
boring dust. Figure 2-14.
with light brown heads. They
feed gregariously beneath the Figure 2-16.
Pests - 12bark working down into the phloem. Indications population. Usually populations are then self-
of infestation: wilting and deformed/bushy/ regulated by diminishing food supplies, leading
forked leaders (Fig. 2-16). Damage from attack to starvation.
may result in the loss of 3 or 4 years of height Lepidopteran defoliating pest species in Montana
growth, forking and heavy branching. are the Western spruce budworm (Choristoneura
Lodgepole terminal weevil (Pissodes terminalis) (Fig. occidentalis), the Douglas fir tussock moth (Orgyia
2-17) is similar to the pseudotsugata), the Western false hemlock looper
white pine weevil. The (Nepytia freemani) and the larch casebearer (Co-
principal host is lodge- leophora laricella) The most important defoliating
pole pine. Adults lay hymenopteran pest is the pine sawfly (Neodiprion
eggs in the current nanulus contortae).
leader growth. Indi- The Western spruce budworm (Tortricidae: Cho-
vidual larvae mine ristoneura occidentalis) (Fig. 2-18)
Figure 2-17.
into the phloem-cam- is one of the most destruc-
bial region towards the expanding bud then pu- tive forest defoliators in
pate in the pith. Indications of infestation: death of Montana, defoliating a total
the current year’s leader, forking and heavy of 454,176 acres in Montana
branching. Trees most susceptible to initial attack during 2005 and 187,000
are those in poorly drained sites, edge trees, natu- Figure 2-18. acres in 2004. The larvae at-
rally regenerated stands, following fire, and those tack Douglas fir, true firs and
that have been spaced to low densities at an early occasionally western larch and Picea species.
age. Lodgepole terminal weevil management Adults have mottled orange and brown wings
may increase the chances of Western gall rust folded flat over their body. The larvae are initially
and comandra blister rust damage. light green with brownish heads and become
Defoliators brownish with ivory-colored spots as they grow.
Larvae mine into the needles
Defoliating insect management requires effective
and later enter the swelling
monitoring and evaluation of pest populations in
buds. Indications of infesta-
order to maximize suppression of those pests and
tion: malformation, webbed
prevent large outbreaks. Defoliation can easily be
branch tips, foliage discolor-
detected from the air or ground during outbreak
ation, and foliage shedding
years but early detection is possible by annual
(Fig. 2-19). It takes approxi-
monitoring of adult males using sex pheromone
mately one year for the moth
sticky traps. Larvae can be monitored by sam-
to complete its life cycle. Trees
pling foliage in the lower crown of host trees. In-
will recover if defoliation does
creases in population density can then be detected
not exceed two continuous Figure 2-19.
and populations can be suppressed. When out-
years.
breaks are large, chemical control may be required,
although it is usually not practical due to the ex- Douglas fir tussock moth (Lymantriidae: Orgyia
pense and environmental impact. If pesticides are pseudotsugata) adult males have
chosen they should be used on young larvae soon brown forewings, grey hind
after emergence. wings, and feathery antennae.
Many species of parasitic wasps, insect preda- Females are wingless and have
tors, birds, and small rodents feed on defoliating thread-like antennae (Fig. 2-
insects. These natural enemies, as well as disease 20). Larvae (2 - 2.6 cm long)
and poor weather conditions, can keep popula- are colorful with black hairs
tions low. However, when climate and forest Figure 2-20. projecting from the front and
stand conditions are favorable, outbreaks can oc- back and tussocks of hair on
cur and natural enemies have little effect on the the first and fourth abdominal segments
(Fig. 2-21). Indications of infestation: brown and
Pests - 13You can also read
