United States 

Department of 

Agriculture 

Forest 

Service 

Northern 

Region 

200 East Broadway 

P.O. Box 7669 

Missoula, MT 59807 

Report 04-16 December 2004

CHANGES IN FIRE-KILLED WESTERN LARCH 

ON THE GLACIER VIEW RANGER DISTRICT (FLATHEAD NATIONAL FOREST), MONTANA 

ESTABLISHMENT AND YEAR ONE REPORT 

Marcus Jackson 

Plant Pathologist 

INTRODUCTION

Important economic, ecological, and fire 

management questions will be answered with a 

better understanding of changes that take place 

in fire-killed western larch. Western larch is 

harvested for lumber, log homes, utility poles, 

and fuelwood (Keegan et al. 1995). Progressive 

changes in wood after trees are killed by fire 

affect the economic value and use of the wood, 

with fuelwood generally being of less value than 

other uses. Wildlife biologists have shown 

interest in learning more about changes in firekilled larch and how these changes relate to 

wildlife use. Fire managers may find this study 

useful in projecting woody fuel loads on burned 

larch sites. 

Research concerning changes in fire-killed 

western larch is limited. Hadfield and 

Magelssen (1996, 1997, 1998, 1999, 2000) 

conducted a 5-year study in eastern 

Washington, annually observing changes in 

trees killed by fires in 1994. They studied seven 

coniferous species and noted that a review of 

the literature prior to initiating their study showed 

no information in wood changes of fire-killed 

western larch. The Hadfield and Magelssen 

study provides information about the causes, 

types, and rates of wood changes following fire. 

They found that “western larch had no tree fall 

because there was almost no decay” during their 

5 year study and “almost no loss of bark after 

five years even though it was loose on many 

trees.” They also noted, “Bark loosening 

[partially due to wood borer feeding and 

woodpecker foraging] appeared to contribute to 

large numbers of cracks which caused the wood 

to become very dry.” This dry wood likely 

decreased the potential for decay, but also 

contributed to cracking that affected almost 80 

percent of the larch wood volume. Western 

larch was rated by Hadfield and Magelssen as 

one of the three species with the greatest snag 

durability of the seven species in their study. 

They concluded that western larch should be 

salvaged quickly for high-value lumber, but 

could still be salvaged for fuelwood after 5 

years. 

The Hadfield and Magelssen study provides 

good, but limited, information about changes of 

fire-killed western larch. The information is 

limited because of the small number of trees 

measured, limited number of large trees, and the 

short duration of the study. They began their 

study with 100 trees spread equally over 4 plots 

(25 trees per plot), with a d.b.h. (diameter at 
2 

breast height) range of 6.8 inches to 33.7 

inches. Due to severe road damage, one plot 

could only be measured for the first 3 years of 

the study. A total of 15 trees were measured in 

that plot. Seventy-four of the 75 trees were 

measured in the other three plots. Although the 

plot measured for only 3 years had an average 

d.b.h. of 15.4 inches, the other three plots had 

an average (per plot) d.b.h. range of only 9.9-

11.2 inches. Since there was almost no decay 

in larch at the end of the Hadfield and 

Magelssen study, a longer study period coupled 

with a greater number of large trees may provide 

more information about changes affecting 

wildlife habitat, fuel loading, and losses in high 

value merchantable volume early in the study 

and losses in fuelwood value in latter parts of 

the study. 

This study will evaluate 320 trees (240 

dissected), look at a large range (8-32 inches 

d.b.h.) of sizes, and evaluate fire-killed trees 

over an extended period of time (10 or more 

years). The data collected from this study in 

northwestern Montana will be compared to the 

data collected by Hadfield and Magelssen in 

eastern Washington to determine if fire-killed 

western larch changed similarly in these 

different geographic locations. 

METHODS 

In June 2002, 367 fire-killed western larch trees 

were selected at five sites with varying slope, 

aspect, and habitat types on the Glacier View 

Ranger District (RD) of the Flathead National 

Forest (NF) (Table 1 and Figure 1). Five sites 

were necessary to identify an adequate number 

of trees in each of the four size classes 

described below. The trees were killed by the 

Moose Fire that burned in northwestern 

Montana from mid-August through early October 

of 2001.

Table 1. Site Characteristics.

Site 

No. of 

TreesA

 SlopeB AspectC Habitat TypeD ElevationE

1 105 25% (0-54%) West ABLA/CLUN 3,880 (3760-3920) 

2 28 20% (8-65%) Southwest ABLA/LIBO 3,880 (3840-4080) 

3 65 14% (1-28%) VariableF ABLA/CLUN 3,840 (3840-4080) 

4 89 35% (2-102%) West ABLA/CLUN 3,720 (3640-3800) 

5 80 38% (12-68%) Northeast ABLA/MEFE 4,100 (3920-4280) 

A

 Number of trees tagged at the site. 

B

 Average percent slope across site. Within parentheses is the range of slope at the locations of all trees on 

that site. 

C

 Predominant aspect at the site. 

D

 Predominant habitat type (h.t.) as defined in Pfister et al. (1977). Site 1 has some trees 

 that are in ABLA/XETE h.t., Site 2 has some ABLA/XETE h.t. and PICEA/CLUN h.t., 

 and Site 5 has some in the ABLA/CLUN h.t. 

E

 Elevation in feet at the geographic center of the site. Within parentheses is the range of elevation across 

the site. 

F

 Mostly southwest and northeast. 

Trees were identified, labeled with numbered 

aluminum tags, and marked with a band of 

orange tree paint. Their locations were recorded 

with a gps (global positioning system) unit and 

hand-drawn field maps. Data recorded at 

establishment included: d.b.h., tree height, spur 

loss, woodpecker activity, bark loss and insect 

activity. Crown scorch and basal scorch were 
3 

also estimated, but these data were unreliable 

due to reduced visibility caused by overcast 

weather conditions. Burn severity was generally 

high at the five sites (Figure 2). Four pictures 

were taken from the south side of each tree. 

These pictures are: (1) the crown, looking up 

from the base of the tree, (2) the bole from a 

distance of 6 feet, (3) the top half of the tree, 

and (4) the bottom half of the tree. These 

pictures are repeated immediately before the 

dissection of each tree. 

Of the 367 tagged trees, 1 was eliminated from 

the study after it was identified as a Douglas-fir. 

Thirty-five trees were too close to water to be 

dissected, 20 had major defects such as basal 

scars or broken tops, and 14 showed green 

foliage—albeit very little—2 years after the fire. 

After 240 trees were selected for dissection 

during the first 10 years post-fire, remaining 

trees were categorized into four groups: (1) 57 

useable trees that randomly were not selected 

for dissection, (2) 20 trees with observable 

defects, (3) 35 trees near water, and (4) 14 trees 

that were living 1 year after the fire. These four 

groups account for a total of 126 trees. Some of 

these trees may be used as replacements for 

trees lost to logging, firewood cutting, or other 

causes. Otherwise, some of them may be 

dissected at a later time or monitored 

continuously as longevity snags. Twenty trees 

will be identified in each size class as longevity 

snags to continue monitoring conk development 

and snag longevity. Depending on results of the 

10-year dissections, these trees may be 

removed for measurements (e.g., year 15 or 

year 20) or may be left uncut for continued 

observation. Due to the limited number of trees 

of certain sizes, two trees with observable 

defects, one with a broken top and one with a 

basal scar, were included in the list of trees to 

be dissected. 

Trees were placed into one of four size classes 

(8-11.9 inches d.b.h., 12-15.9 inches d.b.h., 16-

19.9 inches d.b.h., and 20+ inches d.b.h.). Ten 

trees were randomly selected to be cut down in 

each size class during each dissection year. 

Dissection years are 1, 2, 3, 5, 7, and 10 years 

after the fire. Prior to felling, the following data 

are collected: branch and bark retention, spur 

loss, presence of new woodpecker activity, 
4 

species of conks and locations on trees, top 

breakage, and natural tree falls. The felled trees 

are sawn into 8-foot lengths up to a 4-inch 

diameter. Diameter to the nearest one-eighth of 

an inch, char, checks, wood borers, wood stain, 

and decay are recorded in the field from 

approximately 2-inch thick cross-sectional disks 

taken at the stump and the top of each log. 

Char, wood stain, and wood decay are 

estimated as a percentage of each cross 

section's surface area. After all measurements 

have been recorded, extent of stain and decay 

are better clarified by dissecting the disks. 

Volume affected is estimated by calculating the 

volume of each log using Smalian's Formula for 

a paraboloid frustum as described by Husch et 

al. (1972) and multiplying the total volume of the 

log by the mean of percent area affected on the 

disk at each end of the log. Given we don't fully 

understand how the various stain and decay 

fungi colonize western larch, this seems to be a 

reasonable method for estimating the volume 

affected by these agents. Number and depth of 

peripheral checks and wood boring insect 

galleries are also measured on one surface of 

each cross section. Insects affecting 

deterioration during year 2 were collected for 

identification during a supplemental study that 

was initiated in April 2003 to trap adult woodboring insects as they emerged. Ten-year 

growth increments are measured beginning from 

the outside and moving inward toward the center 

of the tree on each stump cross section. Tree 

age at time of death is estimated by counting 

annual rings at the stump and a photo is taken 

of the cross sections for future reference. 

In addition to the measurement described 

above, a Forest Service certified scaler 

determines merchantable volume in each log 

using Cubic Scale Rules (USDA-Forest Service 

1991) and Scribner Scale Rules (USDA-Forest 

Service 1985). Data is collected on the agents 

causing defects and the agents are divided into 

two categories (pre-existing and post-fire). “Preexisting” defects were likely present when the 

trees were killed by fire and “post-fire” defects 

were likely initiated after trees were killed. 

Decay and sapwood staining fungi were isolated 

from disks. Decay fungi were isolated on 2 

percent malt agar (20 grams malt extract and 20 
5 

 grams agar in 1 liter of distilled water), while 

stain fungi were isolated on 2 percent malt agar 

with 200 mg of cycloheximide added per liter. 

Decay isolates were sent to the Forest Products 

Laboratory in Madison, Wisconsin for 

identification and stain fungi were sent to the 

University of Montana for identification. 

Year 1 Data Collection 

In October 2002, 10 trees were identified in each 

size class for dissection. Two of the trees (one 

each at Site 3 and Site 4) had a small amount of 

green growth not detected during study 

establishment. Two replacement trees were 

selected and the live trees were left standing. 

Figure 1. Site locations for fire-killed western larch on the Moose Fire.
6 

Figure 2. Fire severity for the five sites on the Moose Fire. 
7 

RESULTS 

One year after the fire, all bark was retained and 

no conks or snag falls were observed. The 

dissection results of this study are reported in 

two parts. “Agents” describes and quantifies the 

agents of change that were observed in the 

trees. Most of the agent data was derived from 

disk observations. Results of disk observations 

are summarized in Table 2. “Defects” describes 

and quantifies the agents, both pre-existing and 

post-fire, that reduced merchantable wood 

volume as determined by the scaler. Data 

generated by the scaler are summarized in 

Table 3. 

Agents 

Char. No char was observed on any disks. 

Checks. Shake was the only type of crack seen. 

No peripheral checks were observed. 

Decay. All observed decay was pre-existing, 

with most of it in the heartwood. Minimal 

sapwood decay was seen in only three trees 

(694, 696, and 784), all of it contiguous with 

white pocket rot of the heartwood. Phellinus 

chrysoloma (Fr.) Donk, a white pocket decay 

fungus, was isolated from white pocket rot in 

one tree. Other decay fungi isolated from 

heartwood included Antrodia serialis (Fr.:Fr.) 

Donk, Fomitopsis cajanderi (P. Karst.) Kotlaba & 

Pouzar, and a Stereum sp. Ten percent of the 

trees from 8-11.9 inches and 12-15.9 inches 

d.b.h. size classes had heartwood decay, while 

50 percent of 16-19.9 inches d.b.h. size class 

and 70 percent of >20 inches d.b.h. size class 

had heartwood decay. 

Wood Stain. Small amounts of sapwood stain 

were present across the size range of trees. A 

greater proportion of wood volume of 8-11.9 

inches (2.7 percent) and 12-15.9 inches d.b.h. 

(3.0 percent) size classes were affected by stain 

than trees in the 16-19.9 inches (1.2 percent) 

and >20 inches d.b.h. (0.5 percent) size classes. 

Two isolates of Ophiostoma minus (Hedgcock) 

H. and P. Sydow, one with ostiolar hyphae and 

one without, and an isolate of Ophiostoma huntii

(Robinson-Jeffrey) de Hoog and Scheffer were 

isolated from stained wood near wood borer 

holes (Figure 3). 

Figure 3. Stain associated with 

wood borer holes. 

Wood borers. Disk observations revealed that 

75 percent of the trees were infested with wood 

borers. Cerambycid and Buprestid galleries 

were found in the wood, nearly all of them in the 

sapwood. No Buprestid larvae were found, but 

Cerambycid larvae remained in the wood. Most 

of the holes counted on each disk were believed 

to be caused by Cerambycid feeding. The 

average number of wood borer holes seen per 

disk in each tree varied from 0-5.8, without much 

variation between the size classes except the 

16-19.9 inches d.b.h. size class had about 50 

percent more holes than the others averaging 

1.5 holes per disk. 

New Woodpecker Activity. Approximately 63 

percent of the trees showed some signs of 

woodpecker foraging since the trees were killed. 

Foraging was seen on 50 percent, 90 percent, 

60 percent, and 50 percent of 8-11.9 inches, 12-

15.9 inches, 16-19.9 inches, and greater than 20 

inches d.b.h. size classes, respectively. 

Defects 

The scaler determined that there were 13,220 

board feet or 2,287 ft.3

 in the forty trees 

dissected (Table 3). Most defects appeared to 

be caused by heartwood decay, ring shake, 

massed pitch, and butt swell that were present 

prior to the fire. Pre-existing defects caused 

about 13 percent cubic volume and 17 percent 

board foot volume loss for the combined volume 

of the forty trees. Cubic volume losses from 

these pre-existing defects were 2.5 percent, 3.1 

percent, 6.9 percent, and 20.9 percent of the 
8 

total volume of the 8-11.9 inch, 12-15.9 inch, 16-

19.9 inch, and greater than 20 inch size classes, 

respectively. Board foot losses were 0 percent, 

5.9 percent, 10.4 percent, and 25.3 percent of 

total board feet for the 8-11.9 inch, 12-15.9 inch, 

16-19.9 inch, and greater than 20 inch size 

classes, respectively. Minor losses from wood 

borers were the only post-fire defects observed. 

Borers caused less than 1 percent cubic volume 

loss and about 0.2 percent board foot loss 1 

year after the Moose Fire. Eight trees lost 

merchantable cubic volume to wood borers, with 

the greatest loss being about 26 percent of the 

total volume of one tree. Three trees lost board 

feet volume to wood borers, with the greatest 

loss being 10 percent of the total volume of one 

tree. 
9 

Table 2. Disk Data One Year After the Moose Fire - Summarized by Tree 

Tree 

No. 

D.B.H.A 

(inches) 

AgeB 

(Years) SiteC

Deepest 

BorersD 

(mm) 

No. of 

Borer 

HolesE

StainF

(ft.3) 

SW 

DecayG 

(ft.3) 

Deepest

CheckH 

(mm) 

No. of 

ChecksI

HW 

DecayJ 

(ft.3) 

529 8.2 60 1 0 0 0 0 0 0 7.9 

502 8.6 78 1 0 0 1.2 0 0 0 0 

609 8.8 90 1 0 0 3.5 0 0 0 0 

503 9.7 87 1 16 0.1 0 0 0 0 0 

501 9.9 84 1 *K 0.1 2.8 0 0 0 0 

606 10.2 94 1 40 2.4 6.1 0 0 0 0 

527 10.5 70 1 30 1.1 2.5 0 0 0 0 

637 10.8 90 1 30 1.4 4.8 0 0 0 0 

603 11.2 84 1 * 1.9 2.5 0 0 0 0 

555 11.9 87 1 31 1.4 3.8 0 0 0 0 

MDCL 10.0 84.7 - 29.4 0.8 2.7 0 0 0 0.8 

607 12.1 86 1 36 5.8 10.3 0 0 0 0 

631 12.5 80 1 29 0.8 4.6 0 0 0 0 

914 12.9 80 5 0 0 0.3 0 0 0 0 

559 13.4 93 1 42 0.9 0.8 0 0 0 0 

739 13.8 185 4 25 0.3 0 0 0 0 0.8 

601 14.6 92 1 * 1.4 13.1 0 0 0 0 

735 14.9 293 4 21 0.2 0 0 0 0 0 

688 15.3 80 3 10 0.1 0.3 0 0 0 0 

747 15.4 196 4 24 0.1 0.1 0 0 0 0 

744 15.9 188 4 0 0 0 0 0 0 0 

MDC 14.1 100.6 - 26.7 1.0 3.0 0 0 0 0.1 

938 16.1 140 5 85 0.4 1.7 0 0 0 0.4 

741 16.5 216 4 32 0.3 0.1 0 0 0 0 

533 17.2 90 1 45 3.6 0.9 0 0 0 0 

504 17.4 99 1 78 5.5 5.1 0 0 0 0 

944 17.8 185 5 38 0.9 0.7 0 0 0 0.9 

592 18.2 210 3 34 1.5 1.2 0 0 0 1.7 

758 18.6 185 4 0 0 0 0 0 0 0 

681 19.1 190 3 31 0.8 0.3 0 0 0 0.5 

644 19.5 283 2 26 2.1 1.7 0 0 0 0.2 

757 19.9 202 4 19 0.3 0.2 0 0 0 0 

MDC 18.0 110.7 - 43.1 1.5 1.2 0 0 0 0.4 

667 20.9 208 3 20 0.2 0.2 0 0 0 3.1 

696 21.2 220 3 39 1.8 3.0 0.2 0 0 4.6 

770 22.2 155 4 0 0 0 0 0 0 <0.1 

563 23.2 180 2 26 2.1 0.3 0 0 0 0 

694 24.1 190 3 0 0 0.2 3.0 0 0 24.0 

778 25.1 190 4 0 0 0 0 0 0 0 

697 26.2 213 3 18 0.4 0.1 0 0 0 <0.1 

695 27.2 207 3 38 1.2 0.1 0 0 0 <0.1 

643 28.3 226 2 39 3.5 0.7 0 0 0 0 

784 30.2 226 4 0 0 0 2.7 0 0 17.2 

MDC 24.9 123.4 - 30 0.9 0.5 0.7 0 0 4.9 
10 

A

Diameter at breast height. Measured at 4.5 feet above ground level. 

B

Age - Estimated by counting the annual rings at the stump. 

C

 Tree location (see Figure 1). 

D

Distance of wood borer hole that was furthest from the edge of the wood on any disk from the tree. 

E

Average number of wood borer holes per disk. 

F

Estimated cubic volume percent affected by sapwood stain. Estimated by calculating the volume of each log using 

Smalian's Formula for a paraboloid frustum and multiplying the total volume of the log by the mean of the percent 

area affected by sapwood stain on the disk at each end of the log. The total stain volume in the tree is then divided 

by the total tree volume. 

GEstimated cubic volume percent affected by sapwood decay. Estimated by calculating the volume of each log 

using Smalian's Formula for a paraboloid frustum and multiplying the total volume of the log by the mean of the 

percent area affected by sapwood decay on the disk at each end of the log. The total sapwood decay volume in 

the tree is then divided by the total tree volume. 

H

Depth of the deepest check found on all disks from tree. 

I

Ratio of peripheral checks to total number of disks on that tree. 

J

Estimated cubic volume percent affected by heartwood decay. Estimated by calculating the volume of each log 

using Smalian's Formula for a paraboloid frustum and multiplying the total volume of the log by the mean of the 

percent area affected by heartwood decay on the disk at each end of the log. The total heartwood decay volume in 

the tree is then divided by the total tree volume. 

K

Data not taken. 

L

MDC - Mean for the diameter class. This is the mean for the 10 values in the diameter class, except wood borer 

depth means include only trees where wood borers were found. 
11 

Table 3. Scaled Log Data One Year After the Moose Fire - Summarized by Tree 

 Scribner Rule (Board Feet) Cubic Rule (Cubic Feet) 

Tree 

No. 

D.B.H.A 

(inches) AgeB

Preexisting 

DefectC

Post-Fire

DefectD

Total 

Scaler 

DefectE

Gross

Scaler

Vol. F

Preexisting 

DefectG

Post-Fire

DefectH

Total 

Scaler 

DefectI

Gross

Scaler

Vol.J

529 8.2 60 0 0 0 50 2.1 0 2.1 11.7 

502 8.6 78 0 0 0 40 0 0 0 10.6 

609 8.8 90 0 0 0 50 0.3 0.5 0.8 12.8 

503 9.7 87 0 0 0 40 0.4 0 0.4 12.6 

501 9.9 84 0 0 0 60 0 0 0 17.0 

606 10.2 94 0 0 0 60 0 1.6 1.6 16.8 

527 10.5 70 0 0 0 60 0 0 0 16.0 

637 10.8 90 0 0 0 60 1.3 0 1.3 19.2 

603 11.2 84 0 0 0 90 0 0 0 21.2 

555 11.9 87 0 0 0 110 0 0 0 23.9 

MDCK 10.0 84.7 0 0 0 62 0.4 0.2 0.6 16.2 

607 12.1 86 10 10 20 100 1.2 5.8 7 22.0 

631 12.5 80 20 0 20 130 1.6 0 1.6 28.0 

914 12.9 80 0 0 0 140 0 0 0 26.8 

559 13.4 93 20 0 20 110 0.5 0.3 0.8 24.7 

739 13.8 185 30 0 30 210 7.2 0 7.2 41.2 

601 14.6 92 0 0 0 210 0 0 0 40.5 

735 14.9 293 0 0 0 240 0 0 0 45.3 

688 15.3 80 0 0 0 220 0 0 0 40.6 

747 15.4 196 20 0 20 240 0.4 0 0.4 45.3 

744 15.9 188 10 0 10 270 0.6 0 0.6 51.5 

MDC 14.1 100.6 11 1 12 187 1.2 0.6 1.8 36.6 

938 16.1 140 0 0 0 290 1.1 0 1.1 50.7 

741 16.5 216 20 0 20 330 1.8 0 1.8 58.9 

533 17.2 90 0 0 0 260 0 2.8 2.8 49.1 

504 17.4 99 40 10 50 240 3.0 3.0 6 44.3 

944 17.8 185 20 0 20 370 1.6 0 1.6 62.8 

592 18.2 210 20 0 20 360 3.4 0 3.4 61.6 

758 18.6 185 50 0 50 510 4 0 4 85.6 

681 19.1 190 60 10 70 380 9.9 2 11.9 66.0 

644 19.5 283 40 0 40 290 3.4 0 3.4 52.9 

757 19.9 202 120 0 120 520 14.2 0 14.2 85.9 

MDC 18.0 110.7 37 2 39 355 4.2 0.8 5.0 61.8 

667 20.9 208 100 0 100 440 13.8 0 13.8 73.1 

696 21.2 220 170 0 170 530 17.1 0 17.1 86.9 

770 22.2 155 90 0 90 530 14.2 0 14.2 86.7 

563 23.2 180 140 0 140 400 16.5 0 16.5 87.8 

694 24.1 190 290 0 290 560 42.3 0 42.3 91.1 

778 25.1 190 50 0 50 800 4.8 0 4.8 125.3

697 26.2 213 130 0 130 740 18.9 0 18.9 117.5

695 27.2 207 20 0 20 900 0.6 0 0.6 138.6

643 28.3 226 170 0 170 920 22.3 1 23.3 140.2

784 30.2 226 660 0 660 1360 87.8 0 87.8 194.4

MDC 24.9 123.4 182 0 182 718 23.8 0.1 23.9 114.2

Total - - 2300 30 2330 13220 296.3 17 313.3 2287.1
12 

A

Diameter at breast height. Measured at 4.5 feet above ground level. 

B

Age - Estimated by observing the annual rings at the stump. 

C

Number of board feet deducted from tree volume due to pre-existing defects such as crook, heart shake, 

heartwood decay, etc. 

D

Number of board feet deducted from tree volume due to wood borer galleries. 

E

Total number of board feet deducted from tree volume due to both pre-existing and post-fire defects. 

F

Total number of board feet in the tree at time of dissection. 

GCubic volume deducted from tree due to pre-existing defects such as crook, heart shake, heartwood decay, etc. 

H

Cubic volume deducted from tree due to wood borer galleries. 

I

Cubic volume deducted from tree due to both pre-existing and post-fire defects. 

J

Total cubic volume in tree at time of dissection. 

K

MDC - Mean for the diameter class.
13

DISCUSSION 

Agents of change. There are many 

similarities and a striking difference in the 

changes of fire-killed western larch 

reported in eastern Washington (Hadfield 

and Magelssen 1996) as compared to 

this report on the Moose Fire. Hadfield 

and Magelson found wood stain in 95 

percent of the western larch they 

observed in eastern Washington 1 year 

post-fire. Also, a high number of trees, 

78 percent, were found here to contain 

stain 1 year after the Moose Fire. Ten 

percent of Washington larch contained 

sapwood decay 1 year after the fire and 

none of the larch they sampled 2 years 

post-fire contained sapwood decay. The 

only decay found in sapwood after the 

first year of this study appeared to be an 

extension of pre-existing heart rot into 

sapwood. All of their larch were infested 

with wood borers 1 year post-fire and this 

study found 75 percent infested based 

on disk observations. The greatest 

difference between the eastern 

Washington study and the Moose Fire 

results thus far concern peripheral 

checks. Hadfield and Magelssen 

reported cracks in 65 percent of their 

trees 1 year post-fire while this study 

reports no peripheral checks after 1 year. 

Hadfield (2004) noted that they found no 

cracks 1 year post-fire in ABLA habitat 

series plot, but most trees at the 3 PSME 

habitat series plots were cracked 1 year 

after the fire. The difference in 

peripheral checking may be due—at 

least in part—to greater moisture on 

ABLA habitat series on Montana sites 

and the one eastern Washington site as 

compared to drier PSME habitat series 

reported at the other three eastern 

Washington sites. 

Loss in merchantable volume. Preexisting defects, such as heartwood 

decay, increased with increasing size 

classes. This may be associated with 

greater average ages seen with 

increasing size classes. Trees that have 

been on the landscape for longer periods 

of time are perhaps more likely to 

experience broken tops or other injuries 

that could provide entries for decaycausing fungi. Western larch forests are 

generally considered more susceptible to 

heartwood decay as they become 

overmature (Carlson, et al. 1995). Wood 

borers—the only post-fire agent that 

produced defect—caused minimal losses 

in merchantable volume 1 year after the 

Moose Fire. The scaler measured less 

wood borer-caused defect in the >20 

inches d.b.h. size class, but this may be 

a product of small sample size. Although 

stain was observed, it does not reduce 

merchantable volume and therefore is 

not considered a volume defect 

(Danielson 2002). 

Wildlife. Fire-killed larch provides 

important foraging and cavity nesting 

sites for various forms of wildlife. About 

63 percent of the fire-killed larch showed 

signs of woodpecker foraging for insects 

1 year after the fire. Since woodpecker 

foraging was observed on 4 of the 10 

trees that didn't show wood borer activity 

in the disks, disk observations may have 

underestimated wood borers. As may be 

expected, the two size classes with the 

greatest average number of wood borer 

holes, 12-15.9 inches d.b.h. and 16-19.9 

inches d.b.h., also had more woodpecker 

foraging than the smallest and largest 

size classes. About 13 percent of 

dissected trees contained substantial 

columns of pre-existing decay, perhaps 

future cavity-nesting sites. 

REFERENCES CITED 

Carlson, C. E., Byler, J. W., Dewey, J. E. 

1995. Western Larch: Pest-tolerant 

conifer of the northern Rocky 

Mountains. In Ecology and 

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Danielson, R. L. 2002. Personal 

communication. 

Hadfield, J. S. 2004. Personal 

communication. 
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Hadfield, J. S., Magelssen, R. M. 1996. 

Wood Changes in fire-killed Eastern 

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progress report. USDA-Forest 

Service, Wenatchee National Forest, 

Wenatchee, WA. 25p. 

Hadfield, J. S., Magelssen, R. M. 1997. 

Wood Changes in fire-killed Eastern 

Washington tree species--Year two 

progress report. USDA-Forest 

Service, Wenatchee National Forest, 

Wenatchee, WA. 34p. 

Hadfield, J. S., Magelssen, R. M. 1998. 

Wood Changes in fire-killed Eastern 

Washington tree species--Year three 

progress report. USDA-Forest 

Service, Wenatchee National Forest, 

Wenatchee, WA. 37p. 

Hadfield, J. S., Magelssen, R. M. 1999. 

Wood Changes in fire-killed Eastern 

Washington tree species--Year four 

progress report. USDA-Forest 

Service, Wenatchee National Forest, 

Wenatchee, WA. 35p. 

Hadfield, J. S., Magelssen, R. M. 2000. 

Wood Changes in fire-killed Eastern 

Washington tree species--Year five 

progress report. USDA-Forest 

Service, Wenatchee National Forest, 

Wenatchee, WA. 34p. 

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1972. Forest Mensuration. 2nd Ed. 

The Ronald Press Company. 

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D. P. 1995. Use and value of western 

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ACKNOWLEDGEMENTS 

My thanks to Heidi Trechsel, Silviculturist 

on the Hungry Horse and Glacier View 

Ranger Districts, for helping identify field 

sites and providing a great deal of local 

support. 

I also thank Jessie Micales, of the Forest 

Products Laboratory in Madison, WI for 

identifying the decay fungi, and Diana 

Six, Associate Professor of Integrated 

Forest Entomology/Pathology at the 

University of Montana, for identifying the 

stain fungi mentioned in this report. 

Thanks also go to Skip Danielson, of the 

Clearwater National Forest, for scaling 

the logs and Larry Stipe, of the Forest 

Health Protection field office in Missoula, 

for preparing the maps and providing 

other GIS/GPS support. Reviews and 

constructive comments provided by 

Gregg DeNitto, of the Forest Health 

Protection field office in Missoula, Skip 

Danielson, and Jim Hadfield, of the 

Forest Health Protection-Wenatchee 

Service Center, are greatly appreciated.