Fire ecology of the forest habitat types of eastern Idaho and western Wyoming

102 Pages·1992·8.9 MB·English

by  Bradley, Anne F

Historic, Archive Document
Do assume
not content reflects current
scientific knowledge, policies, or practices.

United States Fire Ecology of the
Department
of Agriculture
Forest Service Types
Forest Habitat
Intermountain
Research Station
Eastern Idaho and
of
General Technical
Report INT-290
Wyoming
September 1992 Western
Anne Bradley
F.
William C. Fischer
Nonan Noste
V.
THE AUTHORS employed in a variety of fire and resource manage-
ment assignments for the Boise National Forest in
ANNE BRADLEY
F. is currently a planning/appeals Idaho.
specialist for the Fisheries and Wildlife staff of the
Forest Service Pacific Southwest Region in San NONAN V. NOSTE (Retired) was a forester, Inter-
Francisco, CA. Her involvement with this report mountain Research Station, Intermountain Fire
occurred while assigned as an ecologist in the Fire Sciences Laboratory, Missoula, MT. During his Forest
Effects: Prescribed Fire and Wildfire research work Service career, Nonan was involved in fire control
unit at the Intermountain Research Station, Intermoun- research in Alaska, silviculture research in Wisconsin,
tain Fire Sciences Laboratory, Missoula, MT. Anne and fire technology and fire effects research in
earned a B.A. degree in biology from Colorado College Missoula. He earned B.S. and M.F. degrees in
and an M.A. degree in botany from the University of forestry at the University of Montana.
Montana. Early work assignments included that of
RESEARCH SUMMARY
a naturalist for the National Park Service and as a
biological technician and later as a botanist for the
This report summarizes available information on fire
Intermountain Station.
as an ecological factor for forest habitat types occur-
WILLIAM C. FISCHER is a research forester and ring in eastern Idaho and western Wyoming. Habitat
team leader for the fire effects work unit at the Inter- types are assigned to Fire Groups based primarily on
mountain Research Station, Intermountain Fire fire's role in forest succession.
Sciences Laboratory, Missoula, MT. He is a graduate For each Fire Group, the authors discuss (1) the
of Paul Smith's College and the University of Michigan relationships of major tree species to fire, (2) forest
(B.S., B.S.F. 1956). Prior to joining the staff at the fuels, (3) the natural role of fire, (4) fire and forest
Intermountain Fire Sciences Laboratory, he was succession, and (5) fire management considerations.
Intermountain Research Station
324 25th Street
Ogden, UT 84401
CONTENTS
Role of Fire 39
Forest Succession 41
Page
Fire Management Considerations 42
Introduction 1 Fire Group Four: Aspen-Dominated
Format
1 Community Types 42
Nomenclature 6 Stable Aspen Community Types 42
Relationships of Major Tree Species to Fire 6 Aspen Community Types Probably
Quaking Aspen (Populus tremuloides) 6
Serai to Conifers 43
Douglas-fir (Pseudotsuga menziesii) 7 Aspen Community Types That Are
Engelmann Spruce (Picea engelmannii) 7
Grazing Disclimaxes 43
Whitebark Pine (Pinus albicaulis) 7
Vegetation 43
Lodgepole Pine (Pinus contorta) 8
Forest Fuels 44
Subalpine Fir {Abies lasiocarpa) 8 Role of Fire 45
Blue Spruce (Picea pungens) 9
Forest Succession 46
Limber Pine (Pinus flexilis) 9 Fire Management Considerations 46
Rocky Mountain Juniper
Fire Group Five: Persistent Lodgepole Pine
(Juniperus scopulorum) 9 Community Types 50
Undergrowth Response to Fire 10 Community Types, Phases 50
Wildlife Response to Fire 10 Vegetation 50
Fire Use Considerations 25 „
Forest Fuels 50
Fuels 25
Role of Fire 53
Predicting Fire Mortality 27
Forest Succession 56
Crown Scorch and Insect Attack 28 Fire Management Considerations 57
Frequency of Burning 29 Fire Group Six: Mid and Lower Elevation
Large Woody Debris 29
Subalpine Forests 59
Heat Effects on Soil 29 Habitat Types, Phases 59
Prescribed Fire Planning 30 Vegetation 60
Fire Group Zero: Miscellaneous
Forest Fuels 60
Special Habitats 30
Role of Fire 63
Scree 30
Forest Succession 63
Forested Rock 30 Fire Management Considerations 67
Wet Meadow 30 Fire Group Seven: Moist or Wet Subalpine Fir
Mountain Grassland 30 and Engelmann Spruce Habitat Types 67
Deciduous Riparian Communities 31 Habitat Types, Phases 67
Fire Group One: Limber Pine Habitat Types 31 Vegetation 68
Habitat Types, Phases 31 Forest Fuels 68
Vegetation 31 Role of Fire 68
Forest Fuels 31 Forest Succession 68
Role of Fire 32 Fire Management Considerations .....70
Forest Succession 33 Fire Group Eight: Cold, Upper Subalpine and
Fire Management Considerations 34 Timberline Habitat Types 70
Fire Group Two: Habitat Types Supporting Habitat Types, Phases 70
Cool, Dry Douglas-fir Forests 34 Vegetation 70
Habitat Types, Phases 34
Forest Fuels 71
Vegetation 34
Role of Fire 72
Forest Fuels 35
Forest Succession 73
Role of Fire 35 Fire Management Considerations 74
Forest Succession 36
References 74
Fire Management Considerations 37 Appendix A: Eastern Idaho-Western Wyoming
Fire Group Three: Moist Douglas-fir Forest Habitat Types and Phases and
Habitat Types 38 Assigned ADP Codes 86
Habitat Types, Phases 38 Appendix B: Scientific and Common Names
Vegetation 38
of Plants Appearing in Text 90
Forest Fuels 38

—
Fire Ecology of the Forest
Habitat Types of Eastern Idaho
and Western Wyoming
Anne F. Bradley
William C. Fischer
Nonan V. Noste
INTRODUCTION
guide. The individual land manager must evaluate
conditions on a site-by-site basis to determine the
This report summarizes the available fire ecology most likely results offire.
and management information relating to the forest
habitat types ofeastern Idaho and western Wyoming,
Format
west ofthe crest ofthe Wind River Mountains. Fire
ecology offorest habitat types in the Bridger-Teton, This report is patterned after "Fire Ecology of
Caribou, and Targhee National Forests are described, Montana Forest Habitat Types East ofthe Conti-
with the exception ofthe western portion ofthe nental Divide" (Fischer and Clayton 1983). The ma-
Targhee's Dubois District. The fire ecology ofcen- jor topics presented in this report are organized into
tral Idaho forests including the western Targhee sections, described below.
National Forest is described in Crane and Fischer
Relationship ofMajor Tree Species to Fire
(1986). The information in the present publication
This section discusses each principal tree species
also applies to the forested portions ofYellowstone
and Grand Teton National Parks. The primary pur- with regard to its resistance or susceptibility to fire
pose ofthis report is to promote the understanding and its role as a successional component offorest
communities. Particular attention is given to spe-
offire's role in forest ecosystems, particularly its
role in forest succession. Several companion docu- cial adaptations to fire, such as corky bark, seroti-
ments may be ofinterest to managers in western nous cones, or seeds that require mineral soil for
germination.
Wyoming and southeastern Idaho. The fire ecology
—
ofWyoming forests from the crest ofthe Wind River Undergrowth Response to Fire This section
Range eastward are described in Crane and others summarizes the effect offire on the response ofim-
(in preparation). Utah forest and woodland fire portant grass, forb, and shrub species associated
ecology is discussed in Bradley and others (1992). with the major conifer species. Particular attention
The fire ecology ofeastern Montana forests to the is given to fire-adaptive traits or survival strategies
north is described by Fischer and Clayton (1983). that determine whether fire generally increases or
Habitat types and community types described by decreases species cover in the immediate postfire
Steele and others (1983) and Mueggler (1988) are period.
assigned to eight "Fire Groups" based on the re- Wildlife Response to Fire—This section briefly
sponse ofdominant tree species to fire, potential fre- summarizes the general effects offire on common
quency offire, and similarity in postfire succession. mammals, reptiles, amphibians, and birds occurring
The successional path taken by any given forest in western Wyoming or southeastern Idaho. Fire re-
site following fire depends on many variables. The
sponse ofwildlife is largely inferred from expected
preburn vegetation, size and severity ofthe fire, to-
changes in habitat as a result offire.
pography, climate and soil, and chance all contribute —
to the process. Thus, a single habitat type may be a Fire Use Considerations This section summa-
member ofmore than one Fire Group. The groups rizes cautions that apply to the use offire for re-
defined in this report are offered only as a general source management purposes. Emphasis is on
1
effective use offire, site protection, minimizing dam- Wyoming" (Steele and others 1983) and "Aspen
age to residual stand, and wildlife habitat protection. Community Types ofthe Intermountain Region"
Fire Groups and Their Relationship to Cover (Mueggler 1988). The coniferous forest habitat
Types—The Fire Groups are defined with reference types assigned to eastern Idaho and western
Wyoming Fire Groups are listed in appendix A
to "Forest Habitat Types ofEastern Idaho-Western
and summarized in table 1.
—
Table 1 Summary of eastern Idaho and western Wyoming habitat type Fire Groups (see appendix A for formal listing of
habitat types)
Habitat type Habitat type Habitat type
FIRE GROUP ZERO POTR/SYOR/THFE ABLA/PERA
Misc. special habitats POTR/SYOR/TALL FORB ABLA/PHMA
POTR/TALL FORB ABLA/SPBE
FIRE GROUP ONE POTR/THFE ABLA/SYAL
PIFLVCELE POTR/WYAM ABLA/THOC
PIFL/FEID-FEID POTR-ABLA/AMAL ABLAA/AGL-PAMY
PIFUHEKI POTR-ABLA/PERA ABLAA/AGL-VASC
PIFLVJUCO POTR-ABLA/SHCA ABLAA/AGL-VAGL
POTR-ABLA/TALL FORB ABLA/VASC-CARU
FIRE GROUP TWO POTR-ABLA/SYOR ABLAA/ASC-VASC
PSME/ARCO-ASMI POTR-ABLA/SYOR/THFE ABLA/XETE-VAGL
PSME/ARCO-ARCO POTR-PICO/CAGE ABLA/XETE-VASC
PSME/BERE-SYOR POTR-PICO/SYOR PIEN/ARCO
PSME/CELE POTR-PSME/AMAL PIEN/HYRE
PSME/FEID-FEID POTR-PSME/CARU PIEN/JUCO
PSME/JUCO POTR-PSME/SYOR
PSME/SYOR FIRE GROUP SEVEN
FIRE GROUP FIVE ABLA/ACRU
FIRE GROUP THREE PICO/ARCO ABLA/CACA-LEGL
PSME/ACGL-PAMY PICO/CAGE ABLA/CACA-VACA
PSME/BERE-CAGE PICO/CARO ABLA/CACA-CACA
PSME/BERE-JUCO PICO/CARU ABLA/MEFE-MEFE
PSME/BERE-BERE PICO/JUCO ABLA/STAM-STAM
PSME/CARU-PAMY PICO/LIBO PIEN/CALE
PSME/CARU-CARU PICO/SHCA PIEN/CADI
PSME/OSCH PICO/SPBE PIEN/EQAR
PSME/PHMA-PAMY PICOA/AGL PIEN/GATR
PSME/PHMA-PSME PICO/VASC PIEN/LIBO
PSME/PHMO PIEN/PHMA
PSME/SPBE-CARU FIRE GROUP SIX
PSME/SPBE-SPBE ABLA/ACGL-PAMY FIRE GROUP EIGHT
PSME/SYAL-SYAL ABLA/ARCO-ASMI ABLA/LUHI-VASC
PSMEA/AGL-VAGL ABLA/ARCO-PIEN ABLA/RIMO-PIAL
ABLA/ARCO-SHCA ABLA/RIMO-RIMO
FIRE GROUP FOUR ABLA/ARCO-ARCO ABLAA/ASC-PIAL
POTR/AMAL-SYOR/CARU ABLA/ARLA PIEN/RIMO
POTR/AMAL-SYOR/TALL FORB ABLA/BERE-CAGE PIENA/ASC
POTR/AMAL/TALL FORB ABLA/BERE-BERE PIAL/CAGE
POTR/AMAL/THFE ABLA/CAGE-CAGE PIAL/CARO-PICO
POTR/ARTR ABLA/CARO PIALVCARO-CARO
POTR/ASMI ABLA/CARU-PAMY PIAUFEID
POTR/BRCA ABLA/CARU-CARU PIAL/JUCO-SHCA
POTR/CARO ABLA/JUCO PIAUJUCO-JUCO
POTR/EQAR ABLA/LIBO-VASC PIALA/ASC
POTR/POPR ABLA/LIBO-LIBO
POTR/SHCA ABLA/OSCH-PAMY
POTR/SYOR/CARU ABLA/OSCH-OSCH
2
Habitat types are designated in the standard for- flux affects the ability ofshrubs to resprout or seeds
mat of"series/type-phase," in which "series" desig- dormant in soil to become active. Ryan and Noste
nates the potential climax dominant tree, "type" (1985) have summarized easily observed soil and
designates a definitive undergrowth species, and fuel charcteristics that can be used to classify fire
"phase" provides a further subdivision where needed. severity in timber, shrub, or grass fuels (table 2).
Forest cover types have been described for For the purpose ofthis report three levels offire
Yellowstone National Park (U.S. Department ofthe severity are defined: low severity or cool fire, moder-
Interior 1991). Unlike habitat types, cover types are ate fire, and high severity or severe fire. A low se-
not based on potential vegetation, but on the vegeta- verity or cool fire is one that has minimal impact on
tive cover presently observed on a site. As a result, the site. It burns in surface fuels consuming only
cover types that designate serai vegetative stages the litter, herbaceous fuels, and foliage and small
may be in more than one fire group. For example, twigs on woody undergrowth. Very little heat trav-
Yellowstone cover type 40 designates "... recently els downward through the duff. A moderatefire
disturbed wet areas or high-elevation cirques where burns in surface fuels also but may involve a tree
reproduction is clearly dominated by Englemann understory as well. It consumes litter, upper duff,
spruce and subalpine fir." Stands in this cover type understory plants, and foliage on understory trees.
may fall in Fire Groups Seven or Eight, which in- Individual and groups ofoverstory trees may torch
A
clude subalpine habitat types found in very moist or out iffuel ladders exist. severe fire is one that
timberline sites, respectively. Managers should use burns through the overstory and consumes large
care when relating the cover type system to the Fire woody surface fuels, removes the entire dufflayer,
Group system described in this document. Lodge- or both, over much ofthe area. Heat from the fire
pole pine cover types (30-34) correlate well with Fire impacts the upper soil layer and often consumes
Group Five: Persistent Lodgepole Pine. The avail- the incorporated soil organic matter.
able fuel information for the cover types has been —
Forest Succession For each Fire Group, succes-
incorporated in the description ofGroup Five.
sional pathway flow charts represent a synthesis of
—
Vegetation Following the list ofhabitat types both knowledge and speculation about the effects
that comprise each Fire Group, we describe the offire at several points in the life history ofa stand.
characteristic overstory and undergrowth vegetation They illustrate the many possible influences fires of
for that Group. Climax and serai tree species are varying severities have on stands ofdiffering ages,
identified. densities, and species composition. The flow charts
— follow the method suggested by Kessell and Fischer
Forest Fuels The fuels likely to occur in each
(1981).
Fire Group are characterized in this section. Where
How trees respond to fire often depends on their
data are available, representative downed and dead
woody fuel loadings are reported. To date, the most size. Tree size classes used in our flow charts ar—e
(Society ofAmerican Foresters 1958): Saplings
complete data in the region are from Montana.
2 to 4 inches in diameter at breast height (d.b.h.);
Summaries from Montana fuel studies are provided — —
as examples when local data have not been pub- smallpoles 4 to 8 inches, d.b.h; largepoles 8 to
12 inches, d.b.h.
lished. Live and standing dead fuels are discussed
The tree species names are symbolized in order to
where they contribute significantly to fire hazard, and
simplify the diagrams and flow charts. The symbols
typical fire behavior in the Fire Group is described.
are defined as follows:
—
Role ofFire Information on the important trees
Abies lasiocarpa, subalpine fir (ABLA)
and forest fuel characteristics is integrated with the
Juniperus scopulorum, Rocky Mountainjuniper
results offire history studies to describe the histori-
(JUSC)
cal (presettlement period, generally prior to 1900)
Picea engelmannii, Engelmann spruce (PIEN)
role offire in shaping the vegetative composition of
Piceapungens, blue spruce (PIPU)
a particular Fire Group.
Pinus albicaulis, whitebark pine (PIAL)
Fire severity is a qualitative measure used to de-
Pinus contorta, lodgepole pine (PICO)
scribe the biological impacts offire. It reflects the
Pinus flexilis, limber pine (PIFL)
mortality offlora and fauna and the loss oforganic
Populus tremuloides, quaking aspen (POTR)
material. Both upward and downward heat flux af-
Pseudotsuga menziesii, Douglas-fir (PSME)
fect mortality. Upward heat flux is usually ex- —
pressed by terms like fireline intensity and flame Fire Management Considerations This sec-
length. It is largely responsible for aboveground tion discusses how the preceding information for each
plant mortality. Downward heat flux is related to Fire Group can be used to develop fire management
fuel consumption and exposure ofmineral soil plans that support land and resource management
(Brown and DeByle 1989). The downward heat objectives. Suggestions given are offered as an aid
3
—
Table 2 Visual character of ground char from observation of depth of burn1 (Ryan and Noste 1985)
Ground
char Site
class Timber/slash Shrubfields Grasslands
Unburned The fire did not burn on the See timber/slash See timber/slash
forest floor.
Some damage may occur to
vegetation due to radiated
or convected heat from
adjacent areas.
Ten to 20 percent of the
area within slash burns is
commonly unburned.2
Percentage of unburned area varies
widely within burns in natural fuels.
Light Leaf litter is charred or Leaf litter is charred or Litter is charred orconsumed,
ground consumed. consumed, and some leaf but some plant parts are still
char structure is still discernible. discernible.
Upper duff may be charred,
but the duff layer is not The surface is predomin- Charring may extend slightly
altered over the entire depth. antly black, although some into the soil surface, but
gray ash may be present the mineral soil is not
The surface generally appears immediately after the fire. otherwise altered.
black immediately after the fire.
Gray ash soon becomes Some plant parts may still be
Woody debris is partially burned. inconspicuous. standing.
Some small twigs and much of the Charring may extend slightly Bases of plants are not
branch wood remain. into soil surface where leaf deeply burned and are still
litter is sparse, but the mineral recognizable.
Logs are scorched or blackened soil is not otherwise altered.
but not charred. Surface is predominantly
Some leaves and small twigs black immediately afterthe
Crumbled, rotten wood is remain on the plants. Burns burn, but this soon becomes
scorched to partially burned. are irregular and spotty. inconspicuous.
Light ground char commonly makes Less than 60 percent of the Burns may be spotty to
up 0-100 percent of burned areas brush canopy is commonly uniform, depending on the
with natural fuels and 45-75 consumed. continuity of the grass.
percent of slash areas.
Moderate Litter is consumed.3 Surface leaf litter is Litter is consumed, and the
ground consumed. surface is covered with gray
char Duff is deeply charred or con- or white ash immediately
sumed but the underlying mineral Some charred litter may afterthe burn.
soil is not visibly altered. remain but is sparse.
Ash soon disappears, leaving
Light-colored ash prevails Charring extends up to bare mineral soil.
immediately after the fire. 0.5 inch into mineral soil
but does not otherwise Charring extends slightly
Woody debris is largely consumed. alter the mineral soil. into mineral soil, but the
plant parts are no longer
Some branch wood is present, but Gray orwhite ash is con- discernible, no plant parts
no foliage or twigs remain. spicuous immediately after standing, and the bases of
the burn, but this quickly plants are burned to ground
Logs are deeply charred. disappears. level.
Moderate ground char commonly Some charred stems remain Plant bases are obscured in
occurs on 0-100 percent of on the plants, and these the ash immediately after
natural burned areas and 10-75 are generally greater than burning.
percent on slash burns. 0.25-0.50 inch in diameter.
(con.)
4