United States 

Department o 

Agriculture 

Forest 

Service 

Northern

Region 

200 East Broadway 

P.O. Box 7669 

Missoula, MT 59807 

Report 04-4 February 2004

Corps of Discovery Campground Hazard Tree Evaluation 

December 2003

Susan K. Hagle, PhD, Plant Pathologist, 

USDA Forest Service, Northern Region 

Kristina Perry, Recreation Technician, 

USDA Forest Service, Northern Region, Lochsa Ranger District 

Rebecca Wiles, BA, SCEP-Recreation, 

USDA Forest Service, Northern Region, Lochsa Ranger District

SUMMARY had advanced root disease. Cedar decline was 

common with most trees having mild to 

moderate crown symptoms. Monitoring or

removal was recommended for trees according

to the severity of their damage or defect,

likelihood that a damage or defect may lead to

tree failure, and probability that a failed tree or 

part of tree would strike a structure or an

occupied site. 

In December 2003, trees near camping sites,

campground trails and roads and other planned 

developed features of the Corps of Discovery 

Campground (formerly Lolo Cr. Campground) 

were mapped and scored for damage, defect

and hazard. This hazard tree evaluation was 

completed in preparation for renovation and 

expansion of the campground. Twelve planned

camping units, a day-use area, two parking

areas and a trail were examined. Two hundred

fifteen trees were mapped, only one of which

was dead. The forest in and around the

campground was mostly mature western 

redcedar and grand fir. 

Removal was recommended for 32 trees, all 

grand fir. They ranged from less than 8.3 inches 

d.b.h. to 29.3 inches. Most had extensive 

heartrot. Cedar decline was the basis for most of 

the 19 trees recommended for monitoring. 

A yearly walk-through exam is recommended for 

this campground with another full assessment in 

5 years. The maps and database we developed 

Many of the grand fir had signs of advanced 

heartrot caused by Indian paint fungus 

(Echinodontium tinctorium). A few grand firs also 
Cedar decline is a common affliction of mature

cedar in northern Idaho but the causes are 

poorly understood (See appendix A). Rood

decay and extensive lesions extending up from

roots on the lower stem are observed. Several

root pathogens have been isolated from

diseased roots, primarily Armillaria ostoyae, 

Heterobasidion annosum and Phellinus weirii. 

in this assessment should make re-assessment 

of these trees relatively easy. A vegetation 

management plan that emphasizes maintaining 

the cedar component is recommended. Tree 

replacement objectives may be accomplished by 

managing advanced regeneration present on the 

site. 

General condition of trees in the 

campground Decay fungi typically work slowly. Stem decay 

generally starts with infections established in

small shade-killed branches of understroy trees. 

These infections usually require decades to

produce significant columns of decay. Similarly, 

root decay is a gradual process and trees may 

survive decades after infection, especially large 

trees. For further discussion of heartrot and root 

pathogen biology and management, see 

appendix A. 

Corps of Discovery Campground, formerly Lolo

Creek Campground, is located near the junction

of Lolo and El Dorado creeks on the 100 road, 

Lochsa Ranger District, Clearwater National 

Forest. The portion of the campground 

previously developed at Lolo Cr. Campground 

will be expanded to provide additional camping 

sites as well as parking for a walk-in site and 

day-use area on Lolo Cr. This part of the new 

Corps of Discovery Campground is designated

the Lewis Loop. Clark Loop will be developed in 

an area along El Dorado Creek that previously 

was used as an undeveloped group camping 

area. 

Monitoring and removal of trees identified as 

potential hazards will minimize the probability of

a tree failure leading to personal injury or 

property damage in Jerry Johnson Campground. 

To this end we tried to make this initial 

assessment as thorough as possible, providing

a database and maps to expedite future reevaluations of the trees.

Late seral cover types with roughly 40% western

redcedar and 60% grand fir in the overstory 

dominate both portions of the campground.

Grand fir, cedar, and occasional Engelmann 

spruce and Pacific yew make up the understory.

Cedar decline is common and fairly advanced in 

some areas of the campground. Stem decay 

caused mostly by Indian paint fungus 

(Echinodontium tinctorium) is also common

throughout the campground, particularly along 

the trail (see map in figure 1). Conks were the 

primary evidence of this disease observed.

Annosus root disease (Heterobasidion

annosum) was seen in several units of Lewis 

Loop but not recorded in Clark Loop. Fir 

engraver beetles (Scolytus ventralis) and 

annosus root disease (Heterobasidion annosum)

were implicated in the death of one large 

diameter grand fir at the west end of the trail in

Lewis Loop. Fir engraver was also the apparent 

cause of topkill of a large grand fir near unit 3. 

ASSESSMENT METHODS

We assessed the condition of all trees greater 

than 5 inches at breast height that were close

enough to planned developed features of the

campground to cause damage if they failed. The 

height of trees, projected to the ground, 

represented their potential hazard range. 

We concentrated on the trees around future 

developed sites and campground roads. We 

examined all trees within striking distance of the 

proposed trail along Lolo Creek between sites 8 

and 9 but we only mapped the locations of the

few trees tagged for removal. We did not

evaluate trees along the road connecting Lewis 

and Clark Loops of the campground. 

Mapping and scoring trees Tree failure appears to be uncommon in and 

around the campground. Failure and standing

mortality appeared to be restricted to grand fir, 

at least in the past few years. 

Where present, the fire ring was used as the

map center for each site. The West Parking map 

lacked a fire ring or other permanent feature, so 

the trees are mapped with respect to each other 

and a cattle guard that will likely be removed

2 
during construction. The map for the trail 

between units 8 and 9 centered on the existing 

vault toilet. Units 10 through 14 are included on

one map with a large cedar tree (#14) as the plot

center. All trees within target distance of any 

developed feature of the site were mapped and 

scored. Map blanks were used which divided

the site into quadrants beginning with true north

aspect and proceeding clockwise around the fire

ring, or other central map feature. 

Species and diameter at breast height was 

recorded for each tree. They were scored for all 

significant damages and defects observed using

six standard damage categories (appendix B);

decay, wound, canker, lean or sweep, branch or 

forking defects, root damage or disease. For 

each of these categories a severity range of 1-4

was applied, to make a combined code such as 

D3 (decay, severity level 3). 

Where heartwood decay was suspected, trees

were bored to determine the depth of sound 

rind. Trees with sound rind (outer xylem of the 

stem) depth of at least 60% of the radius of the 

stem are considered to be low hazard for failure

due to the heartwood decay. Those with 60% to 

30% sound rind are considered moderate 

hazard, and those with less than 30% have a

relatively high probability of failure. Therefore, 

we used the graph in figure 1 to determine the

severity rating for trees with heartrot. 

oot damage ratings were used to indicate trees 

with root disease symptoms. A rating of R3 

re common

in some sites. Multiple tops were common in 

the 

percent loss of crown: A rating of 1 indicating

than one potential target.

Standard target codes were as follows: 1 =

s

western redcedar is 

much higher than that for grand fir. Cedar trees 

advanced root

disease or heartrot symptoms or signs, 

especially those near or leaning toward

R

indicated trees with significantly deteriorated

crown condition, presumably due to root

disease. R4 indicated trees that were in the final 

stages of dying from root disease. Root damage

ratings of 1 and 2 were used to indicate physical 

damages (wounding and severing). 

Wounds, largely human-caused, we

cedars. Wounds, leans and multiple tops were 

scored according to the table in appendix B. 

Cedar decline severity was based on

10% crown loss, 2 meaning 20% loss, and so 

on. A unique feature of cedar decline is the loss 

of foliage being most severe at the tops of trees,

with spike tops often resulting. 

Determining targets 

Many trees had more

occasional use such as trails or signs with no

vehicle access (this code was not used in this

assessment); 2 = intermittent use such as busy 

trails, the campground road and entry and day 

use areas; 3 = frequent use such as campsites, 

parking areas and permanent structures. Trees 

with more than one target were assigned the

highest code applicable. The exception was in

the case of a lean value of 3 or higher. If the tree

was leaning strongly away from the highest

rated potential target, it was assigned the rating 

of the more likely target.

Action recommendation

Figure 1. Thickness of sound rind based on 30%

and 60% of radius (inside bark).

0

2

4

6

8

10

12

14

16

5 10 15 20 25 30 35 40 45 50

dbh

Rind thickness (inches)

60% 30%

The damage threshold for

can withstand considerably more root decay and 

butt or heartrot that grand fir before physical 

failure or standing mortality occurs. These

differences are reflected in the frequency and

type of action recommendations for cedar and

grand fir. Cedar trees with relatively advanced

decline symptoms were designated for

monitoring rather than removal. 

Several grand fir trees with

3 
developed targets were designated for removal.

Recommendation for removal was usually based 

on the probability of eminent death due to root 

disease or an unreasonably high probability of 

failure due to advanced heartrot or butt rot. A 

combination of moderate root disease and a

lean toward a class 3 target, root disease

combined with moderate heartrot (and a class 3

target) or similar combinations of conditions 

resulted in a recommendation for removal. Trees 

thus identified were tagged with metal numbered 

tags at breast height facing the map reference 

point. Nails used to attach tags were aluminum 

to ensure there would be no risk of saw or

planer damage should the nail fail to be

removed before falling or milling. We also

flagged each tree recommended for removal to 

make them easy to spot. 

Data handling 

Data were recorded on field sheets and entered

Excel sheet for analysis using 

Microsoft Access. Maps were converted from

plan, official

designations had not yet been assigned to the 

We assessed 208 trees in 12 campsites in both 

loops and ewis

wis 

ark

ost

umerous species (table 1), constituting 57% of 

his gave the impression of a cedarominated stand. A few Engelmann spruce and

Data were recorded on field sheets and entered

Excel sheet for analysis using 

Microsoft Access. Maps were converted from

plan, official

designations had not yet been assigned to the 

We assessed 208 trees in 12 campsites in both 

loops and ewis

wis 

ark

ost

umerous species (table 1), constituting 57% of 

his gave the impression of a cedarominated stand. A few Engelmann spruce and

Loo

Loo

Loo

Loo

Loo

Loo

Figure 2. Example of unit maps

stored in Microsoft PowerPoint 

into a Microsoft

hand-drawn maps to slides in a Microsoft

PowerPoint presentation. Hand-drawn maps

were electronically scanned to retain relative 

positions of trees around fire rings and standard

mapping symbols were added as location 

markers for each tree with color-coding for easy 

reading (figure 2). Both the database and maps 

should be easily updated from these products 

for future assessments of Corps of Discovery. If 

kept current, they should provide easy tracking 

of campground trees in the future. 

Although we worked from the blueprints of the

approved campground renovation

hand-drawn maps to slides in a Microsoft

PowerPoint presentation. Hand-drawn maps

were electronically scanned to retain relative 

positions of trees around fire rings and standard

mapping symbols were added as location 

markers for each tree with color-coding for easy 

reading (figure 2). Both the database and maps 

should be easily updated from these products 

for future assessments of Corps of Discovery. If 

kept current, they should provide easy tracking 

of campground trees in the future. 

Although we worked from the blueprints of the

approved campground renovation

p. Units we designated 2 - 9 were in Le

p and Units 10 through 14 were in Cl

p (figure 3). Grand fir was the m

p. Units we designated 2 - 9 were in Le

p and Units 10 through 14 were in Cl

p (figure 3). Grand fir was the m

n

the trees. 

However, western redcedar, which constituted

40% of trees, tended to be much larger than the 

grand fir. T

the trees. 

However, western redcedar, which constituted

40% of trees, tended to be much larger than the 

grand fir. T

d

subalpine fir were present, particularly in Clark 

Loop. 

able 1. Tree condition and average diameter at 

reast he

ssessment

T

b ight by species. (Based on December 2003 

a .)

units. Therefore, we assigned tentative numbers

to planned units 2-14, the east and west-end

parking areas (designated 1 and 21,

respectively) and the stand along the trail

between units 8 and 9 (designated 22). The map 

number can be used to assure a correct match 

between the original unit numbers and numbers

assigned in Access. 

RESULTS OF THE ASSESSMENT

units. Therefore, we assigned tentative numbers

to planned units 2-14, the east and west-end

parking areas (designated 1 and 21,

respectively) and the stand along the trail

between units 8 and 9 (designated 22). The map 

number can be used to assure a correct match 

between the original unit numbers and numbers

assigned in Access. 

RESULTS OF THE ASSESSMENT

Species

Average

Total Dead d.b.h. 

Grand fir 122 1 17.2 

Western redcedar 86 0 25.8 

6 0 17.4 

Subalpine fir 1 0 10.7 

All species 215 1 

Engelmann Spruce

the planned p e planned parking areas of L

4 
Clark Loop

Figure 3 

Corps of Discovery Campground 

Hazard Tree Evaluation 

December 2003 

Lewis Loop 

Unit numbers as assigned to 

unfinished campground for 

the purposes of hazard tree

survey.

5 
Tree damages and defects 

The grand fir were mostly mature and many

have multiple Indian paint fungus conks 

throughout the length of their boles. Of 121 live

grand fir, 23% had decay ratings of 3 or 4,

indicative of 60% or less solid rind (table 2). 

Failure rate for these grand fir is likely to 

increase slowly in the future as the developing 

decay columns weaken the stems. Grand fir 

growing in the understory can be expected to 

also have high rates of stem decay when they 

reach maturity owing to current stand conditions 

which favor E. tinctorium infection and decay 

development. The high level of human-caused 

wounding in some of the sites undoubtedly will 

contribute greatly to increased decay rates.

Cambial wounds are known to increase

frequency and extent of stem decay within a few 

decades of wounding (Aho and Filip 1982). 

Table 2. Moderate to severe damages or defects observed on live trees with target codes 2 or greater. 

(Based on December 2003 assessment.) 

Species Total 

live 

Stem Decay Wounds Double or 

broken tops 

Root 

Disease 

Cedar 

Decline 

Sev 3 Sev 

4 

Sev 

3 

Sev 

4 

Sev 3 Sev 4 Sev 3+ Sev 5+ 

Grand fir 121 21 7 11 1 2 3 6 -- 

Western redcedar 86 9 1 7 0 3 9 11 19 

Engelmann spruce 6 0 0 0 0 0 0 0 -- 

Subalpine fir 1 0 0 0 0 0 0 0 -- 

All species 214 30 8 16 1 5 12 17 19 

Both root disease and associated bark beetles 

are currently minor influences in grand fir here. 

The west parking area, and units 2 and 3 have 

evidence of some annosus root disease

mortality (table 3). The disease is likely to 

continue to spread slowly in both locations and

could appear in others eventually, especially 

with disturbance resulting from campground 

renovation. 

Cedar decline, which appears to be primarily a 

root disease-caused symptom, was common in 

both loops of the campground. The highest

rating assigned for cedar decline in Corps of 

Discovery Campground was 6 or 60% crown 

loss. A total of 19 trees (22% of cedars) had the

relatively high ratings of 5 or 6. The high-rated

cedars were mostly clustered in a few sites in 

both loops. Units 2 through 5 in Lewis loop and 

10, 12 and 13 in Clark Loop had the highest 

frequencies of decline. 

Stand of trees along the trail 

Most of the trees along this trail are mature 

grand fir. Six trees were identified for removal

along the trail between units 8 and 9. Those 

tagged for removal were grand fir with either 

severe stem decay or severe root disease, or

both. Even a primary trail has a target class of

only 2 because there is little likelihood that a

failing tree will cause injury or damage. 

Therefore, we tagged only those trees with the 

most advanced symptoms and did not take time 

to map all trees that could have impacted the

trail. We mapped three areas along the trail to

indicate the need to monitor trees fairly closely 

because stem decay in grand fir is prevalent and 

will probably lead to additional tree failures 

(figure 4). 

6 
Table 3. Severe damage codes assigned to live trees by unit. (Based on December 2003 assessment. 

Recommended Action 

Unit 

Total 

live 

Stem 

Decay Wounds 

Root 

Disease 

Cedar 

Decline Monitor Remove 

Sev 3+ Sev 3+ Sev 3+ Sev 5+ Trees Percent 

East Parking 23 4 7 0 0 0 2 8.7

2 & 3 13 0 0 3 4 4 1 7.7 

4 & 5 23 1 6 6 4 4 2 8.1 

6 3 2 1 1 0 0 0 0

7 17 2 1 2 0 0 4 23.5

8 29 5 6 0 0 1 5 17.2

9 34 6 8 3 1 2 6 17.6

West Parking 15 3 0 2 0 0 3 20.0

Trail -- 6 0 2 -- -- 6 --

10 23 3 2 1 2 2 0 0

11 4 0 0 0 0 0 0 0

12 13 2 2 1 5 5 1 7.7

13 12 4 2 1 3 3 2 16.7

14 4 0 0 0 0 0 0 0

All Units 214 38 35 22 19 21 32 15.0

Figure 4. Map of trail between units 8 and 9. 

Areas designated for monitoring and location 

of trees recommended for removal.

RECOMMENDED ACTIONS

Only grand fir was recommended for removal. There 

were 32 trees tagged for removal and two others that 

we recommended be monitored in addition to trees 

in the shaded areas in figure 4 along the trail. 

Overall, we recommended removal at this time for 

23% of the 122 grand fir we evaluated—15% of the 

trees evaluated (table 4). Most of the recommended

removals were in units 7-9, the west parking area

and along the trail (table 3). In other units, no trees, 

or only one or two were tagged for removal. 

7 
Table 6. Number of recommended removals by diameter class. 

(Based on December 2003 assessment.) 

Diameter classes (inches at breast height) 

Species 8-11.9 12-15.9 

16-

19.9 20-23.9 24-27.9 >28 

Max 

d.b.h. Total 

Grand fir 4 5 11 7 3 2 29.3 32 

Trees recommended for removal ranged from

8.3 inches to 29.3 inches d.b.h. Table 6

provides a breakdown of recommended

removals by species and diameter classes. Of

the 32 trees recommended to remove, 72% are 

at least 16 inches d.b.h. and all are grand fir. 

Most target codes assigned were in the highest 

class, 3 (table 4). These were primarily the 

campsites themselves, including tent pads, 

tables, fire rings, and parking areas for the units.

Of 215 trees evaluated, 90% were considered to 

have class 3 targets and as a result, 81% of

recommended removals are in class 3 target

locations. 

Table 4. Recommended actions by target code. 

(Based on December 2003 assessment.) 

We noted a need to monitor 19 of the 86 (22%) 

of western redcedar trees because they have 

fairly advanced symptoms of cedar decline with

50 to 60 percent loss of crown (table 5). It is as 

yet unclear how often such decline leads to

failure or death of afflicted trees, and how long 

that end may be in coming. 

We do know that root infections lead to 

enlarging basal lesions and columns of butt 

heartwood decay. While both conditions weaken 

trees structurally, little resulting failure has been 

indicated to date. Studies underway on the

Clearwater National Forest may provide

answers to some of these questions in the near 

future. In the meantime, the trees should be

monitored and their decline ratings updated as 

necessary. 

Table 6. Cedar recommended for monitoring by 

diameter class and reason for recommendation.

(Based on December 2003 assessment.)

Recommended Action 

Target 

Code 

Total 

trees Monitor Remove 

1 1 0 0

2 21 3 6

3 193 18 26

All 215 21 32

Diameter classes 

 (inches at breast height) 

Reason

14-

19.9 

20-

29.9 

30-

39.9 

40

+ Total 

 Decline ( 5+) 2 5 2 9 

Decline (5+) 

and decay 

1 3 1 5

Decline (5+) 

and wounds 

1 1 1 3

Decline (5+) 

and leaning 

1 1

Decline (5+), 

decay, and 

leaning

1 1

All causes 2 9 6 1 19

8 
MANAGEMENT RECOMMENDATIONS

Removal of highest hazard trees before 

campground is occupied 

These trees were mostly grand fir that, if they

failed, would have tent or parking sites, tables,

or fire pits as likely targets. They are trees that

lean, show root heaving, or have heaviest

crowns in the direction of one of these targets. 

Such trees have higher risk of causing property 

damage or injury in the case of failure. All trees 

have some risk of failure and trees with root

disease are at an increased risk because of

decay of structural roots. It is common practice 

in campground maintenance to remove trees

with indicators of hazard (such as root disease 

or stem decay) with priority given to trees with

human-inhabited targets. 

Additional mortality should be anticipated as the

disease continues to progress in remaining 

grand fir. Thinning will not improve the condition

of grand fir trees and few are likely to survive 

more than one or two more decades. Annual 

evaluation of the site and removal of dead or

dying trees is likely to be required. Revegetation 

with species resistant to S-type annosus and 

Armillaria root diseases will be necessary to reestablish tree cover and restore aesthetic 

qualities of the site. 

Monitoring of all trees 

A walk-through exam including reassessment of 

trees previously noted as needing monitoring

should be done each year. A thorough 

assessment should occur about every 5 years,

at which time the database and maps should be

updated. Conditions are not expected to change

rapidly in this campground although we can 

anticipate some amount of mortality, particularly 

grand fir, following disturbances related to 

campground renovation. 

A vegetation management plan 

A comprehensive vegetation management plan

should be developed for this campground.

Cedar and Engelmann spruce regeneration

should be favored over grand fir to eventually 

minimize the impact of heartrot-caused Indian

paint fungus. Root disease is present, and may 

expand in response to hazard tree removal and

tree removals necessitated by campground

renovation. Douglas-fir, grand fir and subalpine

fir are highly susceptible (particularly Douglasfir) and should be minimized in target vegetation.

Western redcedar, western white pine and

western larch are resistant (though not immune) 

to most root pathogens and are likely suitable

species for this site. Native hardwood trees and 

shrubs are immune to annosus root disease. 

As the mature cedar component continues to

decline, provisions should be made for their

replacement. This process is expected to be 

very slow but with as little as we know about the

syndrome, it will bear watching. At our current

stage of knowledge, we still recommend cedar 

as a highly desirable campground tree, in part 

because of its ability to withstand abuse. 

Cedar can be expected to reproduce naturally 

as well as grand fir and Engelmann spruce. 

White pine and, perhaps western larch are also

good choices for regeneration, but would

undoubtedly require planting and tending. 

Hardwoods such as mountain maple and 

serviceberry are immune to common root

diseases of conifers. 

SELECTED REFERENCES

Hazard tree evaluation and management 

Johnson, D. W. 1981. Tree hazards: recognition

and reduction in recreation sites. Forest Pest

Management, State and Private Forestry,

Rocky Mountain Region, USDA Forest

Service, Technical Report R2-1. 17 p. 

Mills, L. J., K. Russell. 1980. Detection and

Correction of hazard trees in Washington’s 

recreation areas. A how-to guide for 

recreation site managers. Department of

Natural Resources, State of Washington,

DNR Report No. 42. 35 p. 

Robbins, R. 1986. How to Recognize and 

reduce tree hazards in recreation sites.

Northeastern Area. USDA Forest Service, 

Report NA-FR-31. 28 p. 

Wallis, G. W., D. J. Morrison, D. W. Ross. 1980. 

Tree Hazards in Recreation Sites in British 

Columbia. Management Guidelines. British

Columbia Ministry of Lands, Parks and

9 
Housing, Canadian Forestry Service, Joint 

report No. 13. 52 p. 

Annosus Root disease identification, biology

and management: 

Hagle, S. K., K. E. Gibson, S. Tunnock. 2003. 

Root Disease. Pp. 72-81. In: Field guide to 

diseases and insect pests of northern and 

central Rocky Mountain conifers. Northern 

and Intermountain Regions, USDA Forest 

Service. Publication Number R1-03-08. 197 

p. 

Worrall, J. J., J. R. Parmeter, Jr., F. W. Cobb, Jr. 

1983. Host specialization of Heterobasidion

annosum. Phytopathology. 73: 304-307. 

USDA Forest Service. 1998 (Update). Annosus

Root Disease. In: Insect and Disease

Management Handbook, Forest Health 

Protection, State and Private Forestry,

Northern Region, USDA Forest Service. 8 p. 

Heartrot biology and management: 

Aho, P., J. Hadfield. 1975. How to estimate

defect in grand fir in the blue mountains of

Oregon and Washington.USDA Forest

Service, Pacific Northwest Forest and Range 

Experiment Station. Pamphlet. 8 p. 

Etheridge, D. E., H. M. Craig. 1976. Factors

influencing infection and initiation of decay 

by the Indian paint fungus (Echinodontium 

tinctorium) in western hemlock. Can. J. For.

Res. 6: 299-318. 

Cedar decline and cedar root disease 

Koenigs, J. W. 1969. Root rot and chlorosis of 

released and thinned western redcedar. 

Journal of Forestry, 67 (3) 312-315. 

Weir, James R. 1920. A guide to silvicultural 

practice. Forest Service, District One,

Protection, Forest Pathology. 60 p. 

APPENDIX A 

Annosus root disease biology and 

management 

There are two types of Heterobasidion annosum

in Idaho that are distinguished on the basis of

host range. The P-type, which causes its 

greatest damage in ponderosa pine, appears to

be far less common in Idaho than the S-type. Stype, named for it’s significance as a pathogen 

of spruce species in Europe, is a very common

and damaging pathogen of Douglas-fir, grand fir 

and subalpine fir in Idaho. Western redcedar is 

also a common host to H. annosum, though it 

seems to survive infections for many decades.

Although we have not determined whether 

western redcedar is host to P-type or S-type, it is

most likely to be S-type based the presence of 

root disease in Douglas-fir and grand fir growing

in association with infected cedar. Pines,

western larch and hardwoods are resistant to Stype H. annosum. 

The disease, as the name implies, mostly 

involves the roots. The fungus attacks the root

cambium, girdling and killing roots. Once dead, 

H. annosum decays roots. The disease spreads 

throughout root systems and the fungus moves 

from tree to tree through root contacts and for

short distances through soil or duff. In general,

the disease kills Douglas-fir more rapidly than

grand or subalpine firs. Thus, by the time grand 

or subalpine firs are visibly declining, the 

Douglas-fir component of stands has already 

been killed. Once established on a site the

fungus is essentially a permanent feature. They 

are long-lived organisms that can take 

advantage of the presence of hosts from one 

generation of trees to the next. They survive 

forest fires by slowly decaying root systems well 

below ground. 

Stump surface infection can be an important

means of spread of P-type annosum so 

management recommendations often include

treatment of stump surfaces to prevent spread of 

the disease. S-type annosum does not provide 

10 
this opportunity. High rates of root infection exist

in most Douglas-fir and grand fir stands that

render stump infection inconsequential. Partial 

harvest, leaving Douglas-fir, grand fir or

subalpine fir is discouraged because high rates 

of mortality of leave trees generally result. 

Mortality rates between 3% and 7% per year are 

common if apparently healthy Douglas-fir and 

true firs are left after harvest. (Rates are higher if

symptomatic trees are left.) 

Stem decay biology and management 

Indian paint fungus, Echinodontium tinctorium

and the white pocket rot, Phellinus pini, are 

thought to have similar biology. Infections are 

initially established in shade-killed branches. 

The fungus produces a “quiescent” infection in 

which it fails to progress much beyond the

original point of establishment for some years.

As the tree grows, the dead, infected branch

stub is incorporated in the heartwood. Once

surrounded by the no longer living, thereby no

longer resistant, heartwood, the fungus begins

to grow. It lives entirely by decaying dead 

heartwood, never invading live sapwood. 

Decay caused by E. tinctorium can be especially 

extensive. A single young E. tinctorium conk 

may indicate a decay column extending 8 feet

above and 8 feet below the conk. Larger, older 

conks may indicate 20 feet below and 21 feet

above the conk. Two or more conks, widely 

separated on the stem, probably indicate that

virtually the full length of the stem has a central 

column of decay. The longer the column is, the

greater the width of the decay column. Phellinus 

pini decay is generally considered more limited

in extent, extending about 3 feet in either 

direction from a conk. However, there are often 

many conks scattered throughout the length of 

the stem. 

Wounds that kill a patch of cambium are known

to greatly accelerate the extent and perhaps the

rate of decay caused by Indian paint fungus. It is 

thought the dead tissue, which essentially 

becomes a part of the heartwood by virtue of

being dead, increases aeration of the heartwood

and improves growing conditions for the fungus. 

Whatever the cause, wounds are a highly 

significant factor in predicting decay volumes in

grand fir. Infected overstory grand fir with

stagnated understory grand fir provides the ideal 

situation for development of Indian paint fungus

infection. 

Cedar decline 

Cedar decline appears to be a widespread 

phenomenon in northern Idaho and parts of 

western Montana. The progress of the decline 

and eventual outcome is unknown. It appears 

that spike tops are commonly formed and that 

trees may live for many decades in advanced 

stages of decline. The cause or causes are also

largely unknown. 

Figure 1. Cedar decline 

crowns are thin at top; 

spike tops are common.

Efforts are underway to map the extent and

relative severity of and to determine the cause 

or causes of the decline 

Severe root decay and girdling of root crowns 

has been found in association with advanced 

crown symptoms of decline. Girdling rates of

70% to 80% are common in living cedars. Two

common root pathogens, Armillaria (probably 

ostoyae), and Heterobasidion annosum were

consistently isolated pathogens in some

locations. Phellinus weirii was the nearly 

exclusive pathogen isolated from a relatively 

undisturbed site with advanced decline

symptoms. 

Tree age, disturbance by tree cutting or burning,

site factors such as soil type, and weather 

influences such as drought are all considered

suspected factors in driving the cedar decline 

syndrome 

11 
APPENDIX B 

INSTRUCTIONS: Find the description of defect that most closely describes an observed situation and 

enter the severity code on the evaluation form. If three or more defects of the same severity are 

recorded for a single tree (e.g., 3D, 3W, 3L), the overall severity rating for the tree may be increased 

by one level (column A on the evaluation form). Your situation may not be described or exactly fit a 

description; the descriptions are simply provided to assist you in assigning an appropriate severity 

level for each defect. Dead trees are automatically assigned a severity of 4.

SEV. 

CODE 

DECAY OR CAVITY: trees where significant decay is suspected should be increment bored to 

determine sound wood remaining (Rind) and excluding bark; severity may be influenced by tree 

i 1D Staining, including wet wood, or incipient decay, but no advanced decay or fruiting bodies, no

cavities. 

2D Advanced decay or cavities observed; sound wood (rind) >60% of radius; may have unusual pitch 

or watery slime seeping from cracks or openings. 

3D Advanced decay or cavities observed; sound wood (rind) 60-30% of radius (excluding bark); 

fruiting bodies may be present. 

4D Advanced decay or cavities observed; sound wood (rind) < 30% of radius; numerous conks or 

fruiting bodies or other defects. 

STEM DAMAGE AND WOUNDS: Lightning, frost cracks, mechanical, animal, human

1W Cracks or wounds of any size but well-calloused or superficial, no decay

2W Minor structural damage involving <10% of circumference; small cracks, fire scars. 

3W Some structural damage and associated decay; 10-50% circumference; large fire scars; severe 

cracks extending through stem. 

4W Multiple cracks or wounds causing severe structural damage and associated decay in > 50% of 

circumference; or movement detected in major crack.

CANKERS: Blister rust, gall rust, dwarf mistletoe, etc.

1C < 10% of bole girdled; burls of any size

2C 10-30% of bole girdled 

3C 30-75% of bole girdled 

4C >75% of bole girdled or associated with other defects.

LEAN/SWEEP: growth at the very top of the tree may indicate how long a tree has been leaning.

1L Natural long-term lean <10%, fully compensated by growth (top of tree is vertical for many years).

2L Natural long-term lean 10-15 degrees, fully compensated by growth (top of tree is vertical for many

3L Lean 15-20 degrees or some indication of root movement (soil mounding, etc.), or associated with 

4L Lean >20 degrees with evidence of failure (e.g., obvious recent soil movement, root wrenching); 

associated with decay or cracks. 

BRANCHES, FORKS, WITCHES BROOMS AND TOPS

1B Small dead or hanging branches or dead top <”; small witches brooms. 

2B Large brooms, dead or hanging branches or dead top 3-5”; unbalanced canopy due to poor 

pruning or multiple tops; codominant stems with no included bark. 

3B Dead or broken branches or dead top 6-9”; large codominant stems with included bark (weak

4B Dead or broken branches or dead top >9”.

ROOT DAMAGE, ROOT DISEASE

1R Minor exposed roots, not sprung, no decay

2R Exposed roots with minor damage or decay on small roots (<3”); no evidence of root disease.

3R Substantial damage to roots >3” but <50% or root system affected; root disease suspected (slow 

growth, or other symptoms) but not obvious or confirmed. 

4R Exposed, decayed roots or substantial damage to roots >3” on >50% of root system; obvious root 

disease symptoms or signs (e.g., thinning, fading crown, stress cone crop, basal resinosus). 

12