Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List Pinus albicaulis as Endangered or Threatened With Critical Habitat, 42631-42654 [2011-17943]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 138 (Tuesday, July 19, 2011)]
[Proposed Rules]
[Pages 42631-42654]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-17943]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R6-ES-2010-0047; MO 92210-0-0008]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List Pinus albicaulis as Endangered or Threatened With 
Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list Pinus albicaulis (whitebark 
pine) as threatened or endangered and to designate critical habitat 
under the Endangered Species Act of 1973, as amended (Act). After 
review of all available scientific and commercial information, we find 
that listing P. albicaulis as threatened or endangered is warranted. 
However, currently listing P. albicaulis is precluded by higher 
priority actions to amend the Lists of Endangered and Threatened 
Wildlife and Plants. Upon publication of this 12-month petition 
finding, we will add P. albicaulis to our candidate species list. We 
will develop a proposed rule to list P. albicaulis as our priorities 
and funding will allow. We will make any determination on critical 
habitat during development of the proposed listing rule. In any interim 
period, we will address the status of the candidate taxon through our 
annual Candidate Notice of Review.

DATES: The finding announced in this document was made on July 19, 
2011.

[[Page 42632]]


ADDRESSES: This finding is available on the Internet at https://www.regulations.gov at Docket Number FWS-R6-ES-2010-0047. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, Wyoming Ecological Services Field Office, 
5353 Yellowstone Road, Suite 308A, Cheyenne, WY 82009. Please submit 
any new information, materials, comments, or questions concerning this 
finding to the above address.

FOR FURTHER INFORMATION CONTACT: R. Mark Sattelberg, Field Supervisor, 
Wyoming Ecological Services Field Office (see ADDRESSES); by telephone 
at 307-772-2374; or by facsimile at 307-772-2358. If you use a 
telecommunications device for the deaf (TDD), please call the Federal 
Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(A) of the Act (16 U.S.C. 1531 et seq.) requires 
that, for any petition to revise the Federal Lists of Endangered and 
Threatened Wildlife and Plants that contains substantial scientific or 
commercial information that listing a species may be warranted, we make 
a finding within 12 months of the date of receipt of the petition. In 
this finding, we determine whether the petitioned action is: (a) Not 
warranted, (b) warranted, or (c) warranted, but immediate proposal of a 
regulation implementing the petitioned action is precluded by other 
pending proposals to determine whether species are threatened or 
endangered, and expeditious progress is being made to add or remove 
qualified species from the Federal Lists of Endangered and Threatened 
Wildlife and Plants. Section 4(b)(3)(C) of the Act requires that we 
treat a petition for which the requested action is found to be 
warranted but precluded as though resubmitted on the date of such 
finding, that is, requiring a subsequent finding to be made within 12 
months. We must publish these 12-month findings in the Federal 
Register.

Previous Federal Actions

    On February 5, 1991, the Great Bear Foundation of Missoula, 
Montana, petitioned the Service to list Pinus albicaulis under the Act, 
stating the species was rapidly declining due to impacts from mountain 
pine beetles, white pine blister rust, and fire suppression. After 
reviewing the petition, we found that the petitioner had not presented 
substantial information indicating that listing P. albicaulis may be 
warranted. We published this finding in the Federal Register on January 
27, 1994 (59 FR 3824).
    On December 9, 2008, we received a petition dated December 8, 2008, 
from the Natural Resources Defense Council (NRDC) requesting that we 
list Pinus albicaulis as endangered throughout its range and designate 
critical habitat under the Act. The petition clearly identified itself 
as such and included the requisite identification information for the 
petitioner, as required by 50 CFR 424.14(a). Included in this petition 
was supporting information regarding the species' natural history, 
biology, taxonomy, lifecycle, distribution, and reasons for decline. 
The NRDC reiterated the threats from the 1991 petition, and included 
climate change and successional replacement as additional threats to P. 
albicaulis. In a January 13, 2009, letter to NRDC, we responded that we 
had reviewed the information presented in the petition and determined 
that issuing an emergency regulation temporarily listing the species 
under section 4(b)(7) of the Act was not warranted. We also stated that 
we could not address the petition promptly because of staff and budget 
limitations. We indicated that we would process a 90-day petition 
finding as quickly as possible.
    On December 23, 2009, we received NRDC's December 11, 2009, notice 
of intent to sue over our failure to respond to the petition to list 
Pinus albicaulis and designate critical habitat. We responded in a 
letter dated January 12, 2010, indicating that other preceding listing 
actions had priority, but that we expected to complete the 90-day 
finding during the 2010 Fiscal Year. On February 24, 2010, we received 
a formal complaint from NRDC for our failure to comply with issuing a 
90-day finding on the petition. On May 7, 2010, we responded in writing 
to the formal complaint and provided answers to their claims and 
allegations.
    We completed a 90-day finding on the petition, which was published 
in the Federal Register on July 20, 2010 (75 FR 42033). In that finding 
we determined that the petition presented substantial information such 
that listing Pinus albicaulis may be warranted, and announced that we 
would be conducting a status review of the species. We opened a 60-day 
information collection period to allow all interested parties an 
opportunity to provide information on the status of Pinus albicaulis 
(75 FR 42033), and received 20 letters from the public.
    This 12-month finding is based on our consideration and evaluation 
of the best scientific and commercial information available. We 
reviewed the information provided in NRDC's petition, information 
available in our files, other available published and unpublished 
information, and information received from the public. Additionally, we 
consulted with recognized Federal and non-Federal Pinus albicaulis 
experts, plant pathologists, and plant geneticists. All information 
received has been carefully considered in this finding.
    Funding was made available during the 2010 and 2011 Fiscal Years 
for work on the status review. This notice constitutes our 12-month 
finding on the December 9, 2008, petition to list Pinus albicaulis as 
endangered throughout its range and designate critical habitat under 
the Act.

Species Information

Taxonomy and Life History
    Pinus albicaulis Engelm. (whitebark pine) is a 5-needled conifer 
species placed in the subgenus Strobus, which also includes other 5-
needled white pines. This subgenus is further divided into two sections 
(Strobus and Parrya), and under section Strobus, into two subsections 
(Cembrae and Strobi). The traditional taxonomic classifications placed 
P. albicaulis in the subsection Cembrae with four other Eurasian stone 
pines (Critchfield and Little 1966, p. 5; Lanner 1990, p. 19). However, 
recent phylogenetic studies (Liston et al. 1999, 2007; Syring et al. 
2005, 2007; as cited in Committee on the Status of Endangered Wildlife 
in Canada (COSEWIC) 2010, p. 4) showed no difference in monophyly 
(ancestry) between subsection Cembrae and subsection Strobi and merged 
them to form subsection Strobus. No taxonomic subspecies or varieties 
of P. albicaulis are recognized (COSEWIC 2010, p. 6). Based on this 
taxonomic classification information, we recognize P. albicaulis as a 
valid species and a listable entity.
    Pinus albicaulis is typically 5 to 20 meters (m) (16 to 66 feet 
(ft)) tall with a rounded or irregularly spreading crown shape. On 
higher density conifer sites, P. albicaulis tends to grow as tall, 
single-stemmed trees, whereas on open, more exposed sites, it tends to 
have multiple stems (McCaughey and Tomback 2001, pp. 113-114). Above 
tree line, it grows in a krummholz form (stunted, shrub-like growth) 
(Arno and Hoff 1989, p. 6). This pine species is monoecious, (both male 
pollen and female seed cones are on the same tree). Its characteristic 
dark brown to purple seed cones are 5 to 8 centimeters (cm)

[[Page 42633]]

(2 to 3 inches (in.)) long and grow at the outer ends of upper branches 
(Hosie 1969, p. 42).
    Stone pines (so-called for their stone-like seeds) include five 
species worldwide, and Pinus albicaulis is the only stone pine that 
occurs in North America (McCaughey and Schmidt 2001, p. 30). 
Characteristics of stone pines include five needles per cluster, 
indehiscent seed cones (scales remain essentially closed at maturity) 
that stay on the tree, and wingless seeds that remain fixed to the cone 
and cannot be dislodged by the wind. Because P. albicaulis seeds cannot 
be wind-disseminated, primary seed dispersal occurs almost exclusively 
by Clark's nutcrackers (Nucifraga columbiana) in the avian family 
Corvidae (whose members include ravens, crows, and jays) (Lanner 1996, 
p. 7; Schwandt 2006, p. 2). Consequently, Clark's nutcrackers 
facilitate P. albicaulis regeneration and influence its distribution 
and population structure through their seed caching activities (Tomback 
et al. 1990, p. 118).
    Pinus albicaulis is a hardy conifer that tolerates poor soils, 
steep slopes, and windy exposures and is found at alpine tree line and 
subalpine elevations throughout its range (Tomback et al. 2001, pp. 6, 
27). It grows under a wide range of precipitation amounts, from about 
51 to over 254 cm (20 to 100 in.) per year (Farnes 1990, p. 303). Pinus 
albicaulis may occur as a climax species, early successional species, 
or seral (mid-successional stage) co-dominant associated with other 
tree species. Although it occurs in pure or nearly pure stands at high 
elevations, it typically occurs in stands of mixed species in a variety 
of forest community types.
    Pinus albicaulis is a slow-growing, long-lived tree with a life 
span of up to 500 years and sometimes more than 1,000 years (Arno and 
Hoff 1989, pp. 5-6). It is considered a keystone, or foundation species 
in western North America where it increases biodiversity and 
contributes to critical ecosystem functions (Tomback et al. 2001, pp. 
7-8). As a pioneer or early successional species, it may be the first 
conifer to become established after disturbance, subsequently 
stabilizing soils and regulating runoff (Tomback et al. 2001, pp. 10-
11). At higher elevations, snow drifts around P. albicaulis trees, 
thereby increasing soil moisture, modifying soil temperatures, and 
holding soil moisture later into the season (Farnes 1990, p. 303). 
These higher elevation trees also shade, protect, and slow the 
progression of snowmelt, essentially reducing spring flooding at lower 
elevations. Pinus albicaulis also provides important, highly nutritious 
seeds for a number of birds and mammals (Tomback et al. 2001, pp. 8, 
10).
    Pinus albicaulis trees are capable of producing seed cones at 20-30 
years of age, although large cone crops usually are not produced until 
60-80 years (Krugman and Jenkinson 1974, as cited in McCaughey and 
Tomback 2001, p. 109). Therefore, the generation time of P. albicaulis 
is approximately 60 years (COSEWIC 2010, p. v). Like many other species 
of pines, P. albicaulis exhibits masting, in which populations 
synchronize their seed production and provide varying amounts from year 
to year. During years with high seed production, typically once every 
3-5 years in P. albicaulis (McCaughey and Tomback 2001, p. 110), seed 
consumers are satiated, resulting in excess seeds that escape predation 
(Lorenz et al. 2008, pp. 3-4). Pinus albicaulis seed predators are 
numerous and include more than 20 species of vertebrates including 
Clark's nutcracker (Nucifraga columbiana), pine squirrels (Tamiasciurus 
spp.), grizzly bears (Ursus arctos), black bears (Ursus americanus), 
Steller's Jay (Cyanocitta stelleri), and Pine Grosbeak (Pinicola 
enucleator) (Lorenz et al. 2008, p. 3). Seed predation plays a major 
role in P. albicaulis population dynamics, as seed predators largely 
determine the fate of seeds. However, P. albicaulis has co-evolved with 
seed predators and has several adaptations, like masting, that has 
allowed the species to persist despite heavy seed predation (Lorenz et 
al. 2008, p. 3-4).
    Seeds not retrieved by Clark's nutcrackers or other seed predators 
are subsequently available for germination when conditions are 
favorable (McCaughey and Tomback 2001, p. 111). In years with low seed 
production, most seeds are predated and, therefore, unavailable for 
germination (Lorenz et al. 2008, p. 4). A single nutcracker can cache 
up to an estimated 98,000 P. albicaulis seeds during good seed crop 
years (Hutchins and Lanner 1982, p. 196). They may bury seeds near 
parent trees or travel up to 22 kilometers (km) (14 miles (mi)) away at 
varying elevations. Cache sites have been found to occur on forest 
floors, above treeline, in rocky outcrops, meadow edges, clearcuts, and 
burned areas (Tomback et al. 1990, p. 120). Pinus albicaulis seedlings 
have highly variable survival rates; seedlings originating from 
nutcracker caches ranged from 56 percent survival over the first year 
to 25 percent survival by the fourth year (Tomback 1982, p. 451).
    While Pinus albicaulis is almost exclusively dependent upon Clark's 
nutcracker for seed dispersal, the reverse is not true as Clark's 
nutcracker forage on seeds from numerous species of pine. The frequency 
of nutcracker occurrence and probability of seed dispersal from a P. 
albicaulis forest is strongly associated with the number of available 
cones. A threshold of 1,000 cones per hectare (ha) (2.47 acres (ac)) is 
needed for a high likelihood of seed dispersal by nutcrackers, and this 
level of cone production occurs in forests with a live basal area (the 
volume of wood occurring in a given area) greater than 5 square meters 
(m) per ha (McKinney et al. 2009, p. 603). For an adult Clark's 
nutcracker to survive a subalpine winter (accounting for those seeds 
consumed by rodents and those fed to juvenile nutcrackers), it would 
need to cache seeds from 767 to 2,130 cones (McKinney et al. 2009, p. 
605). Clark's nutcrackers are able to assess cone crops, and if there 
are insufficient seeds to cache, they will emigrate in order to survive 
(McKinney et al. 2009, p. 599).
Distribution
    Pinus albicaulis occurs in scattered areas of the warm and dry 
Great Basin but it typically occurs on cold and windy high-elevation or 
high-latitude sites in western North America. As a result, many stands 
are geographically isolated (Arno and Hoff 1989, p. 1; Keane et al. 
2010, p. 13). Its range extends longitudinally between 107 and 128 
degrees west and latitudinally between 27 and 55 degrees north 
(McCaughey and Schmidt 2001, p. 33). The distribution of P. albicaulis 
includes coastal and Rocky Mountain ranges that are connected by 
scattered populations in northeastern Washington and southeastern 
British Columbia (Arno and Hoff 1990, p. 268; Keane et al. 2010, p. 
13). The coastal distribution of P. albicaulis extends from the Bulkley 
Mountains in British Columbia to the northeastern Olympic Mountains and 
Cascade Range of Washington and Oregon, to the Kern River of the Sierra 
Nevada Range of east-central California (Arno and Hoff 1990, p. 268). 
Isolated stands of P. albicaulis are known from the Blue and Wallowa 
Mountains in northeastern Oregon and the subalpine and montane zones of 
mountains in northeastern California, south-central Oregon, and 
northern Nevada (Arno and Hoff 1990, p. 268; Keane et al. 2010, p. 13). 
The Rocky Mountain distribution of P. albicaulis ranges from northern 
British Columbia and Alberta to Idaho, Montana, Wyoming, and Nevada 
(Arno and Hoff 1990, p. 268; Keane et al. 2010,

[[Page 42634]]

p. 13), with extensive stands occurring in the Yellowstone ecosystem 
(McCaughey and Schmidt 2001, p. 33). The Wind River Range in Wyoming is 
the eastern most distribution of the species (Arno and Hoff 1990, p. 
268; McCaughey and Schmidt 2001, p. 33) (Figure 1).
BILLING CODE 4310-58-P 
[GRAPHIC] [TIFF OMITTED] TP19JY11.120

BILLING CODE 4310-58-C
    In general, the upper elevational limits of Pinus albicaulis 
decrease with increasing latitude throughout its range (McCaughey and 
Schmidt 2001, p. 33). The elevational limit of the species ranges from 
approximately 900 m (2,950 ft) at its northern limit in British 
Columbia up to 3,660 m (12,000 ft) in the Sierra Nevada (McCaughey and 
Schmidt 2001, p. 33). Pinus albicaulis is typically found growing at 
alpine timberline or with other high-mountain conifers just below the 
timberline and upper montane zone (Arno and Hoff 1990, p. 270; 
McCaughey and Schmidt 2001, p. 33). In the Rocky Mountains, common 
associated tree species include P. contorta var. latifolia (lodgepole 
pine), Picea engelmannii (Engelmann spruce), Abies lasiocarpa 
(subalpine fir), and Tsuga mertensiana (mountain hemlock). Common 
associated tree species are similar in the Sierra Nevada and Blue and 
Cascade Mountains,

[[Page 42635]]

except lodgepole pine is present as P. contorta var. murrayana (Sierra-
Cascade lodgepole pine) and mountain hemlock is absent from the Blue 
Mountains (Arno and Hoff 1990, p. 270; McCaughey and Schmidt 2001, pp. 
33-34).
    Roughly 44 percent of the species' range occurs in the United 
States, with the remaining 56 percent of its range occurring in British 
Columbia and Alberta, Canada (COSEWIC 2010, p. iv). In Canada, the 
majority of the species' distribution occurs on private lands (Achuff 
2010, pers. comm.). In the United States, approximately 96 percent of 
land where the species occurs is federally owned or managed. The 
majority is located on U.S. Forest Service (USFS) lands (approximately 
81 percent, or 4,698,388 ha (11,609,969 ac)). The bulk of the remaining 
acreage is located on National Park Service (NPS) lands (approximately 
13 percent, or 740,391 ha (1,829,547 ac)). Small amounts of P. 
albicaulis also can be found on Bureau of Land Management lands 
(approximately 2 percent, or 119,598 ha (295,534 ac)). The remaining 4 
percent is under non-Federal ownership.
Trends
    Mortality data collected in multiple studies throughout the range 
of Pinus albicaulis strongly suggests that the species is in range-wide 
decline (Table 1). Although the majority of available data was 
collected in the last several decades, the decline in P. albicaulis 
populations likely began sometime following the 1910 introduction of 
the exotic disease white pine blister rust. Although we do not have a 
study that quantifies the rate of decline across the entire range, we 
conclude that the preponderance of data from the studies listed below 
and elsewhere in this status review provides evidence of a substantial 
and pervasive decline throughout almost the entire range of the 
species.

  Table 1--Summary of Results From Studies Documenting the Decline of Pinus albicaulis in the United States and
                                                     Canada
                                    [Adapted from Keane et al. 2010, p. 127]
----------------------------------------------------------------------------------------------------------------
                                                                         Percent
              Study year                        Geographic area          decline               Source
----------------------------------------------------------------------------------------------------------------
                                                  United States
----------------------------------------------------------------------------------------------------------------
1992..................................  Southern Bitterroot National           14  Arno et al. (1993).
                                         Forest.
1992..................................  Western Montana...............         51  Keane and Arno (1993).
1993..................................  Bob Marshall Wilderness.......         44  Keane et al. (1994).
1995..................................  Eastern Cascades..............          2  Hadfield et al. (1996).
1996..................................  Bitterroot National Forest....         29  Hartwell and Alaback (1997).
1997..................................  Intermountain Region..........          1  Smith and Hoffman (1998,
                                                                                    2000).
2000..................................  Selkirk Mountains.............         34  Kegley et al. (2001).
2001..................................  Umpqua National Forest........         10  Goheen et al. (2002).
2003..................................  Western Cascades, Washington..         41  Shoal and Aubry (2004).
2003..................................  Eastern Cascades..............         16  Shoal and Aubry (2004).
2005..................................  Washington, Oregon............         35  Summary of multiple studies
                                                                                    in Ward et al. (2006).
2007..................................  Oregon, Washington............         21  Shoal (2007).
2008..................................  Mt. Rainier, North Cascades...         31  Rochefort (2008).
2008..................................  Greater Yellowstone...........         70  Bockino (2008).
2008..................................  Glacier National Park.........         60  Smith et al. (2008).
2008..................................  Central Idaho.................         31  Hicke and Logan (2009).
----------------------------------------------------------------------------------------------------------------
                                                     Canada
----------------------------------------------------------------------------------------------------------------
1997..................................  British Columbia..............         21  Campbell (1998); Campbell and
                                                                                    Antos (2003).
2001..................................  British Columbia..............         19  Zeglen (2002, 2007).
2007..................................  Canadian Rocky Mountains......         57  Smith et al. (2008).
----------------------------------------------------------------------------------------------------------------

    In Canada, based on current mortality rates, it is anticipated that 
Pinus albicaulis will decline by 57 percent by 2100 (COSEWIC 2010, p. 
19). The value for this anticipated decline is likely an underestimate, 
as it assumes current mortality rates remain constant into the 
foreseeable future. Past trends have shown that mortality rates have 
been increasing over the last several decades (this is discussed in 
more detail under Factor C, Disease or Predation). The range of 
mortality rates for P. albicaulis in the United States are similar to 
those in Canada, which suggests that the anticipated rates of decline 
will be similar.

Summary of Information Pertaining to the Five Factors

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
(50 CFR part 424) set forth procedures for adding species to the 
Federal Lists of Endangered and Threatened Wildlife and Plants. Under 
section 4(a)(1) of the Act, a species may be determined to be 
endangered or threatened based on any of the following five factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    In making this finding, information pertaining to Pinus albicaulis 
in relation to the five factors provided in section 4(a)(1) of the Act 
is discussed below.
    In considering what factors might constitute threats to a species, 
we must look beyond the exposure of the species to a particular factor 
to evaluate whether the species may respond to that factor in a way 
that causes actual impacts to the species. If there is exposure to a 
factor and the species responds negatively, the factor may be a threat, 
and, during the status review, we attempt to determine how significant 
a

[[Page 42636]]

threat it is. The threat is significant if it drives, or contributes 
to, the risk of extinction of the species such that the species 
warrants listing as endangered or threatened as those terms are defined 
in the Act. However, the identification of factors that could impact a 
species negatively may not be sufficient to compel a finding that the 
species warrants listing. The information must include evidence 
sufficient to suggest that these factors are operative threats that act 
on the species to the point that the species may meet the definition of 
endangered or threatened under the Act.

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of Its Habitat or Range

Fire and Fire Suppression
    Fire is one of the most important landscape-level disturbance 
processes within high-elevation Pinus albicaulis forests (Agee 1993, p. 
259; Morgan and Murray 2001, p. 238; Spurr and Barnes 1980, p. 422), 
and has been important to perpetuating early seral (successional stage) 
P. albicaulis communities (Arno 2001, p. 82; Shoal et al. 2008, p. 20). 
Without regular disturbance, primarily from fire, these forest 
communities follow successional pathways that eventually lead to 
dominance by shade-tolerant conifers such as Abies lasiocarpa, Picea 
engelmannii, and Tsuga mertensiana, to the exclusion of P. albicaulis 
(Keane and Parsons 2010, p. 57). When fire is present on the landscape, 
P. albicaulis has an advantage over its competitors for several reasons 
(Keane and Parsons 2010, p. 57). The Clark's nutcracker serves as the 
main dispersal agent for P. albicaulis by caching seeds in disturbed 
sites, such as burns. Fire creates sites that are suitable for this 
seed caching behavior and that most importantly contain optimal growing 
conditions for P. albicaulis (Tomback et al. 2001, p. 13). In addition, 
Clark's nutcrackers can disperse seeds farther than the wind-dispersed 
seeds of other conifers, thereby facilitating P. albicaulis succession 
in burned sites over a broad geographic area (McCaughey et al. 1985, 
Tomback et al. 1990, 1993 in Keane and Parsons 2010, p. 58). 
Additionally, P. albicaulis has thicker bark, a thinner crown, and a 
deeper root system, which allow it to withstand low-intensity fires 
better than many of its competitors (Arno and Hoff 1990 in Keane and 
Parsons 2010, p. 58). Historically, fire has been an important factor 
in maintaining healthy stands of P. albicaulis on the landscape.
    Fires in the high-elevation ecosystem of Pinus albicaulis can be of 
low intensity, high intensity, or mixed intensity. These varying 
intensity levels result in very different impacts to P. albicaulis 
communities. Low-intensity, surface-level ground fires occur frequently 
under low-fuel conditions. These fires remove small-diameter, thin-
barked seedlings and allow large, mature trees to thrive (Arno 2001, p. 
82). Low-intensity fires also reduce fuel loads and competition from 
fire-susceptible conifers, shrubs, and grasses, thereby opening up 
spaces necessary for the shade-intolerant P. albicaulis to regenerate 
and thus maintain prominence in seral communities (Arno 1986 in Keane 
et al. 1994, p. 215). High-intensity fires occur where high fuel loads, 
ladder fuels (vegetation below the crown level of forest trees, which 
allows fire to move from the forest floor to tree crowns), and other 
compounding conditions result in increased flammability (Agee 1993, p. 
258). High-intensity fires, often referred to as stand replacement 
fires, or crown fires (Agee 1993, p. 16), produce intensive heat, 
resulting in the removal of all or most of the vegetation from the 
ground. High-intensity fires begin the process of vegetative succession 
by opening seed beds that become available for the establishment and 
development of shade-intolerant species like P. albicaulis. High-
intensity fires are generally less frequent because it takes longer 
time intervals to build the large fuel accumulations necessary to 
promote these types of fires (Agee 1993, p. 258). Mixed-intensity fires 
are most common and result in a mosaic of dead trees, live trees, and 
open sites for regeneration (Arno 1980, p. 460; Keane 2001a, p. 17). In 
general, historical fire return intervals in P. albicaulis communities 
have been estimated at between 50 and 300 years (Arno 1980, p. 461).
    Beginning in the 1930s, a policy of fire suppression was 
effectively implemented by the USFS (Arno 1980, p. 460; USFS 2000, p. 
1). During the 1970s, in recognition of the importance of wildfire to 
maintenance of healthy forests, the USFS began a policy shift away from 
total fire suppression (Cohen 2008, p. 21; USFS 2000, p. 1). However, 
despite this shift, fire suppression is still carried out, most 
frequently in areas where a threat to human health and safety are 
anticipated, and we expect this trend of fire suppression to continue 
into the future (Arno 1980, p. 460; Cohen 2008, p. 21; Keane 2011a, 
pers. comm.).
    Fire suppression has had unintended negative impacts on Pinus 
albicaulis populations (Keane 2001a, entire), due to this shift from a 
natural fire regime to a managed fire regime. Stands once dominated by 
P. albicaulis have undergone succession to more shade-tolerant conifers 
(Arno et al. 1993 in Keane et al. 1994, p. 225; Flanagan et al. 1998, 
p. 307). Once shade-tolerant conifer species become firmly established, 
the habitat is effectively lost to P. albicaulis until a disturbance 
like fire once again opens the area for P. albicaulis regeneration. 
Determining the total amount of P. albicaulis habitat lost to 
succession rangewide is difficult, as there is seldom a historic 
baseline for comparison, and the degree of succession is very specific 
to local conditions (Keane 2011a, pers. comm.). Shade-tolerant conifer 
species grow more densely than shade-intolerant conifer species like P. 
albicaulis (Minore 1979, p. 3). Denser stands eliminate the open sites 
that are often used by Clark's nutcracker for seed caching and which 
are also the sites required to facilitate the regeneration of the 
shade-intolerant P. albicaulis. Additionally, the growth of more 
homogeneously structured stands with continuous crowns and increased 
surface fuels has resulted in fires that are larger and more intense 
(Keane 2001b, p. 175).
    Pinus albicaulis cannot withstand high-intensity fires; during such 
fires, all age and size classes can be killed. However, newly burned 
areas provide a seedbed for P. albicaulis, and if stands of unburned 
cone-producing P. albicaulis are nearby (i.e., within the range of 
Clark's nutcracker caching behavior), Clark's nutcrackers will cache 
those seeds on the burned site, and regeneration is very likely. 
However, the introduction of the disease white pine blister rust and 
the current epidemic of the predatory mountain pine beetle 
(Dendroctonus ponderosae) have reduced or effectively eliminated P. 
albicaulis seed sources on a landscape scale (see Factor C, Disease or 
Predation). Although there is variation in the degree to which specific 
stands have been impacted, over the range of P. albicaulis the 
widespread incidence of poor stand health from disease and predation, 
coupled with changes in fire regimes, means that regeneration of P. 
albicaulis following fire is unlikely in many cases (Tomback et al. 
2008, p. 20).
Fire and Fire Suppression and the Interaction of Other Factors
    Environmental changes resulting from climate change are expected to 
exacerbate the already observed negative effects of fire suppression 
(i.e., forest succession, increased fire intensity) (see the Climate 
Change section below). These environmental

[[Page 42637]]

changes are predicted to increase the number, intensity, and extent of 
wildfires (Aubry et al. 2008, p. 6; Keane 2001b, p. 175). Already, 
large increases in wildfire have been documented and are particularly 
pronounced in Northern Rockies forests, which account for 60 percent of 
documented increases in large fires (Westerling et al. 2006, p. 941, 
943). Some of the increase has been independent of past management 
activities and, thus, appears to be a direct result of warming trends 
in the last several decades (Westerling et al. 2006, p. 943).
    Fire suppression is also expected to negatively interact with white 
pine blister rust and mountain pine beetle predation. As forests become 
more dense, individual Pinus albicaulis are more vulnerable to white 
pine blister rust and infestation by mountain pine beetle (see Factor 
C, Disease and Predation). As mortality from white pine blister rust 
and mountain pine beetle increase, forest succession to more dense 
stands of shade-tolerant conifers is accelerated (Keane 2011a, pers. 
comm.).
Summary of Impacts of Fire and Fire Suppression
    Fire suppression results in conditions that favor the dominance of 
shade-tolerant species such as Abies lasiocarpa, Picea engelmannii, and 
Tsuga mertensiana, which form dense stands that eventually exclude 
Pinus albicaulis (Agee 1993, p. 252; Arno 2001, p. 83). We assume that 
fire suppression efforts that create these impacts will continue to 
occur into the future. Where P. albicaulis persists, dense forest 
structure crowds and stresses individual trees, making them more 
susceptible to white pine blister rust, infestation by mountain pine 
beetle, and mortality. Succession to more shade-tolerant species also 
results in less P. albicaulis regeneration because P. albicaulis is 
shade-intolerant, and seeds will not survive if cached in heavily 
shaded forest stands. The interaction between fire suppression and 
environmental effects from climate change exacerbates the impacts to P. 
albicaulis, and in the future will be particularly devastating to P. 
albicaulis populations as P. albicaulis seed sources are expected to 
become increasingly limited by continued impacts from white pine 
blister rust and mountain pine beetle.
    The balance of a natural fire regime with related vegetative 
successive processes has been disrupted across the Pinus albicaulis 
ecosystem. As a result, Pinus albicaulis has lost its competitive 
advantage and trends indicate its presence has been reduced on the 
landscape. Because there is seldom a historic baseline for comparison 
and the degree of succession is very locally specific, we are not able 
to quantify what portion of the species decline can be attributed to 
fire management and changes in fire regimes. However, we consider the 
current fire regime and fire management practices to be threats that 
limit the abundance of the species and weaken P. albicaulis 
communities, such that other factors create additional negative impacts 
to the species.
    The effects of changing fire regimes and fire suppression on Pinus 
albicaulis, combined with the interaction of white pine blister rust 
and mountain pine beetles, have created more homogenous forest stands 
with reduced numbers of P. albicaulis compared to historic subalpine 
landscapes. These effects are becoming more pronounced with climate 
change (Morgan and Murray 2001, p. 300), creating a trajectory toward 
forest stands without P. albicaulis. The species appears likely to be 
in danger of extinction, or likely to become so within the foreseeable 
future, because of habitat losses due to changes to the fire regime, 
particularly when viewed in combination with climate change, disease, 
and predation.
Climate Change
    The Intergovernmental Panel on Climate Change (IPCC) was 
established in 1988 by the World Meteorological Organization and the 
United Nations Environment Program in response to growing concerns 
about climate change and, in particular, the effects of global warming. 
Although the extent of warming likely to occur is not known with 
certainty at this time, the IPCC has concluded that warming of the 
climate is unequivocal, and that continued greenhouse gas emissions at 
or above current rates will cause further warming (IPCC 2007, p. 30). 
Climate change scenarios estimate that the mean air temperature could 
increase by over 3 [deg]C (5.4 [deg]F) by 2100 (IPCC 2007, p. 46). The 
IPCC also projects that there will very likely be regional increases in 
the frequency of hot extremes, heat waves, and heavy precipitation 
(IPCC 2007, p. 46), as well as increases in atmospheric carbon dioxide 
(IPCC 2007, p. 36).
    We recognize that there are scientific differences of opinion on 
many aspects of climate change, including the role of natural 
variability in climate. In our analysis, we rely primarily on synthesis 
documents (e.g., IPCC 2007; Global Climate Change Impacts in the United 
States 2009) that present the consensus view of a very large number of 
experts on climate change from around the world. We have found that 
these synthesis reports, as well as the scientific papers used in those 
reports or resulting from those reports, represent the best available 
scientific information we can use to inform our decision and have 
relied upon them and provided citations within our analysis.
    Direct habitat loss from climate change is anticipated to occur 
with current habitats becoming unsuitable for P. albicaulis as 
temperatures increase and soil moisture availability decreases (Hamman 
and Wang 2006, p. 2783; Schrag et al. 2007, p. 8; Aitken et al. 2008, 
p. 103). Habitat loss is expected because (1) temperatures become so 
warm that they exceed the thermal tolerance of P. albicaulis and the 
species is unable to survive or (2) warmer temperatures favor other 
species of conifer that currently cannot compete with P. albicaulis in 
cold high-elevation habitats. Pinus albicaulis is widely distributed 
and thus likely has a wide range of tolerance to varying temperatures 
(Keane 2011c, pers.comm.). Therefore, increasing competition from other 
species that can not normally persist in current P. albicaulis habitats 
is possibly the more probable climate-driven mechanism for habitat 
loss.
    Given the anticipated loss of suitable habitat, P. albicaulis 
persistence will likely be dependent on the species' ability to either 
migrate to new suitable habitats, or adapt to changing conditions 
(Aitken et al. 2008, p. 95). Historical (paleoecological) evidence 
indicates that plant species have generally responded to past climate 
change through migration, and that adaptation to changing climate 
conditions is less likely to occur (Bradshaw and McNeilly 1991, p. 12; 
Huntley 1991, p. 19). Adaptation to a change in habitat conditions as a 
result of a changing climate is even more unlikely for P. albicaulis, 
given its very long generation time of approximately 60 years (Bradshaw 
and McNeilly 1991, p. 10). The rate of latitudinal plant migration 
during past warming and cooling events is estimated to have been on the 
order of 100 m (328 ft) per year (Aitken et al. 2008, p. 96). Given the 
current and anticipated rates of global climate change, migration rates 
will potentially need to be substantially higher than those measured in 
historic pollen records to sustain the species over time. A migration 
rate of at least a magnitude higher (1,000 m (3,280 ft)) per year is 
estimated to be necessary in order for tree species to be capable of 
tracking suitable habitats under projected warming trends (Malcolm et

[[Page 42638]]

al. 2002, entire). Latitudinal migration rates on this scale may 
significantly exceed the migration abilities of many plant species, 
including P. albicaulis (Malcolm et al. 2002, p. 844-845; McKenney et 
al. 2007, p. 941).
    Pinus albicaulis may have an advantage in its ability to migrate 
given that its seeds are dispersed by Clark's nutcracker. As mentioned 
above, Clark's nutcrackers can disperse seeds farther than the wind-
dispersed seeds of other conifers (McCaughey et al. 1985, Tomback et 
al. 1990, 1993 in Keane and Parsons 2010, p. 58). However, migration of 
P. albicaulis to the north may be impeded by the disease white pine 
blister rust, which is currently present at the northern range limits 
of P. albicaulis (Smith et al. 2008, Figure 1, p. 984; Resler and 
Tomback 2008, p. 165).
    Pinus albicaulis already is typically the first species to 
establish on cold, exposed high-elevation sites, thus the species could 
potentially migrate higher in elevation to more suitable habitats. 
Shifts in the optimum elevation for many high-elevation plant species 
have already been documented under current warming trends (Lenoir et 
al. 2008, p. 1770). However, elevational migration as a refuge from 
temperature increase has limits, because eventually, suitable habitat 
may not be present even on mountaintops due to continuing temperature 
increases.
    Climate change is expected to significantly decrease the 
probability of rangewide persistence of Pinus albicaulis. Projections 
from an empirically based bioclimatic model for P. albicaulis showed a 
rangewide distribution decline of 70 percent and an average elevation 
loss of 333 m (1,093 ft) for the decade beginning in 2030 (Warwell et 
al. 2007, p. 2). At the end of the century, less than 3 percent of 
currently suitable habitat is expected to remain (Warwell et al. 2007, 
p. 2). Similarly, climate envelope modeling on P. albicaulis 
distribution in British Columbia estimated a potential decrease of 70 
percent of currently suitable habitat by the year 2055 (Hamman and Wang 
2006, p. 2783). The area occupied by P. albicaulis in the Greater 
Yellowstone Ecosystem also is predicted to be significantly reduced 
with increasing temperature under various climate change scenarios 
(Schrag et al. 2007, p. 6). Pinus albicaulis is predicted to be nearly 
extirpated under a scenario of warming only and warming with a 
concomitant increase in precipitation (Schrag et al. 2007, p. 7).
    The above studies all suggest that the area currently occupied by 
P. albicaulis will be severely reduced in the foreseeable future. We 
recognize, however, that there are many limitations to such modeling 
techniques, specifically for P. albicaulis. For example, climate 
envelope models use current environmental conditions in the 
distribution of the species' range to determine whether similar 
environmental conditions will be available in the future given 
predicted climate change. Pinus albicaulis, however, is a very long-
lived species, and current environmental conditions may not closely 
resemble environmental conditions present when the trees currently on 
the landscape were established (Keane 2001c, pers. comm.). 
Additionally, these models also describe current environmental 
variables in averages taken over large areas. Pinus albicaulis may 
experience very different environmental conditions even over a small 
range as individuals can be separated by thousands of meters (Keane 
2011c, pers. comm.).
Climate Change and the Interaction of Other Factors
    In addition to direct habitat loss, Pinus albicaulis is expected to 
experience decrease in population size from synergistic interactions 
between habitat changes as a result of climate change and other threat 
factors including altered fire regimes, disease, and predation. Pinus 
albicaulis has evolved with fire, and under many conditions, fire is 
beneficial to the species (see Fire and Fire Suppression above). 
However, environmental changes resulting from climate change are 
expected to alter fire regimes resulting in increased fire intervals, 
increased fire severity, and habitat loss (Westerling et al. 2006, p. 
943).
    Pinus albicaulis also evolved with the predatory native mountain 
pine beetle (Dendroctonus ponderosae). However, the life cycle of the 
mountain pine beetle is temperature dependent, and warming trends have 
resulted in unprecedented mountain pine beetle epidemics throughout the 
range of P. albicaulis (the interaction of mountain pine beetle and P. 
albicaulis is discussed further below under Factor C, Predation) (Logan 
et al. 2003, p. 130; Logan et al. 2010, p. 896). At epidemic levels, 
mountain pine beetle outbreaks become stand-replacing events killing 80 
to 95 percent of suitable host trees, and in many parts of the P. 
albicaulis range, those levels of mortality have already been reached 
(Gibson et al. 2008, p. 10). Even populations of P. albicaulis once 
considered mostly immune to mountain pine beetle epidemics are now 
being severely impacted; mountain pine beetles have now moved into 
areas previously climatically inhospitable for epidemic-level mountain 
pine beetle population growth (Carroll et al. 2003 in Gibson et al. 
2008, p. 4; Raffa et al. 2008, p. 503; Logan et al. 2010, p. 895). 
Given ongoing and predicted environmental changes resulting from global 
climate change, we expect the expansion of habitat favorable to 
mountain pine beetle (and mountain pine epidemics) to continue into the 
foreseeable future.
Summary of Impacts of Climate Change
    Given projected increases in temperature, a significant loss of the 
cool high-elevation habitats of Pinus albicaulis is expected. Rapid 
warming is likely to outpace the ability of P. albicaulis to migrate to 
suitable habitats. Additionally, adaptation to warming conditions for 
this long-lived species seems unlikely. Synergistic interactions 
between environmental changes resulting from climate change, wildfire, 
disease, and mountain pine beetle also are negatively impacting P. 
albicaulis rangewide. In particular, mountain pine beetle epidemics 
brought about by increasing temperatures are currently having 
significant negative impacts on P. albicaulis rangewide. The species 
appears likely to be in danger of extinction, or likely to become so 
within the foreseeable future, because of environmental changes 
resulting from climate change that are exacerbating other threats, 
particularly when viewed in combination with fire suppression, disease, 
and predation, that appear to be beyond the natural adaptive 
capabilities and tolerances of P. albicaulis.

Summary of Factor A

    We analyzed the effects of fire and fire suppression and climate 
change as related to the present or threatened destruction, 
modification, or curtailment of the habitat or range of Pinus 
albicaulis. As identified in our analysis above, fire historically 
played an integral role in maintaining healthy stands of P. albicaulis 
on the landscape. As a result of past and present fire suppression, 
forest stands where P. albicaulis were once prominent have become dense 
stands of shade-tolerant conifers. This change in forest composition 
and structure combined with the exacerbating environmental effects 
resulting from climate change, has resulted in an increase in the 
severity, intensity, and frequency of wildfires. We expect that 
changing fire regimes and fire suppression efforts that create these 
impacts will continue to affect the species into the foreseeable 
future. Pinus albicaulis can regenerate, even following stand-replacing 
burns, if

[[Page 42639]]

a seed source is available. However, widespread predation and disease 
currently impacting P. albicaulis are limiting available seed sources, 
reducing the probability of regeneration following increasing wildfire 
episodes, and increasing the rate of forest succession.
    The pace of predicted effect of climate change will outpace many 
plant species' ability to respond to the concomitant habitat changes. 
Pinus albicaulis is potentially particularly vulnerable to warming 
temperatures because it is adapted to cool, high-elevation habitats. 
Therefore, current and anticipated warming is expected to make its 
current habitat unsuitable for P. albicaulis. The rate of migration 
needed to respond to predicted environmental effects of climate change 
will be significant (Malcolm et al. 2002, p. 844-845; McKenney et al. 
2007, p. 941). Whether P. albicaulis is capable of migrating at a pace 
sufficient to move to areas that may be more favorable to survival 
under future habitat conditions is not known. Moreover, the degree to 
which Clark's nutcracker could facilitate this migration is also not 
known. In addition, the presence of significant white pine blister rust 
infection in the northern range of P. albicaulis could serve as a 
barrier to effective northward migration. P. albicaulis survives at 
high altitudes already, so there is little remaining habitat for the 
species to migrate to higher elevations in response to warmer 
temperatures. Adaptation in response to a rapidly warming climate also 
is unlikely as P. albicaulis is a long-lived species. Climate models 
suggest that climate change is expected to act directly to 
significantly decrease the probability of rangewide persistence in P. 
albicaulis within the next 100 years. This time interval is less than 
two generations for this long-lived species. In addition, projected 
environmental changes resulting from climate change are a significant 
threat to P. albicaulis, because the impacts of these environmental 
effects interact with other stressors such as mountain pine beetle 
epidemics and wildfire, resulting in habitat loss and population 
decline.
    On the basis of a review of the best scientific and commercial 
information available concerning present threats to Pinus albicaulis 
habitat, their synergistic effects, and their likely continuation in 
the future, we conclude that the present or threatened destruction, 
modification, or curtailment of its habitat or range is a threat to P. 
albicaulis.

Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

Commercial Harvest
    Pinus albicaulis is not targeted for commercial timber production 
in any part of its range (Arno and Hoff 1989, p. 5; COSEWIC 2010, p. 
12; Keane et al. 2010, p. 30). At lower elevations where P. albicaulis 
occurs with species of commercial interest, some incidental harvest of 
P. albicaulis does take place. The average yearly estimated harvest of 
P. albicaulis in the United States is less than 405 ha (1,000 ac) 
(Losensky 1990 in Keane et al. 2010, p. 30). We have no information to 
indicate that harvest is a significant threat to the species or is 
contributing to the rangewide decline, or decline in any portion of the 
range of P. albicaulis.
Recreational Use
    Pinus albicaulis stands are subject to a variety of nonconsumptive 
recreational activities including hiking and camping. These activities 
have the potential to cause negative impacts in localized areas through 
degradation of habitat in areas experiencing overuse. However, we have 
no information to indicate that recreational use is a threat to P. 
albicaulis.
Scientific and Educational Use
    Pinus albicaulis is the subject of many scientific research 
studies. Currently, there is significant interest in collecting seed 
cones from individuals identified as being resistant to white pine 
blister rust. Given the relatively low number of seeds being collected, 
it is highly unlikely that seed removal is contributing to P. 
albicaulis declines. We have no information to indicate that P. 
albicaulis is being used consumptively for educational purposes. 
Therefore, the best available scientific information does not indicate 
that scientific and educational uses are a significant threat to P. 
albicaulis.

Summary of Factor B

    We conclude that the best scientific and commercial information 
available indicates that overutilization for commercial, recreational, 
scientific, or educational purposes is not a threat to Pinus 
albicaulis.

Factor C. Disease or Predation

Disease
White Pine Blister Rust
    White pine blister rust is a disease of 5-needled pines caused by a 
nonnative fungus, Cronartium ribicola (Geils et al. 2010, p. 153). It 
was introduced into western North America in 1910 near Vancouver, 
British Columbia (McDonald and Hoff 2001, p. 198). White pine blister 
rust initially spread rapidly through maritime and montane 
environments, which have environmental conditions more conducive to 
spread of infection, but over several decades, it spread through 
continental and alpine environments throughout western North America 
(Geils et al. 2010, p. 163). White pine blister rust's rate and 
intensity of spread is influenced by microclimate and other factors 
(described below). Therefore, the incidence of white pine blister rust 
at stand, landscape, and regional scales varies due to time since 
introduction and environmental suitability for its development. It 
continues to spread into areas originally considered less suitable for 
persistence, and it has become a serious threat, causing severe 
population losses to several species of western pines, including Pinus 
albicaulis, P. monticola (western white pine), and P. lambertiana 
Dougl. (sugar pine) (Schwandt et al. 2010, pp. 226-230). Its current 
known geographic distribution in western North America includes all 
U.S. States (except Utah, as well as the Great Basin Desert) and 
British Columbia and Alberta, Canada (Tomback and Achuff 2010, pp. 187, 
206).
    The white pine blister rust fungus has a complex life cycle: It 
does not spread directly from one tree to another, but alternates 
between living primary hosts (i.e., 5-needle pines) and alternate 
hosts. Alternate hosts in western North America are typically woody 
shrubs in the genus Ribes (gooseberries and currants) but also may 
include herbaceous species of the genus Pedicularis (lousewort) and the 
genus Castilleja (paintbrush) (McDonald and Hoff 2001, p. 193; McDonald 
et al. 2006, p. 73). Ribes is widespread in North America and, while 
most species are susceptible to white pine blister rust infection, they 
vary in their susceptibility and capability to support innoculum 
(spores) that are infective to white pines, depending on factors such 
as habitat, topographic location, timing, and environment (Zambino 
2010, pp. 265-268). A wide-scale Federal program to eradicate Ribes 
from the landscape was conducted from the 1920s to the 1960s. However, 
due to the abundance of Ribes shrubs, longevity of Ribes seed in the 
soil, and other factors, white pine blister rust continued to spread, 
and pathologists realized that eradication was ineffective in 
controlling white pine blister rust. White pine blister rust is now 
pervasive in high-altitude 5-

[[Page 42640]]

needled pines within most of the western United States (McDonald and 
Hoff 2001, p. 201).
    White pine blister rust progresses through five spore stages to 
complete each generation: Two spore stages occur on white pine (Pinus 
spp.), and three stages occur on an alternate host. The five fungal 
spore stages require specific temperature and moisture conditions for 
production, germination, and dissemination. The spreading of spores 
depends on the distribution of hosts, the microclimate, and the 
different genotypes of white pine blister rust and hosts (McDonald and 
Hoff 2001, pp. 193, 202). Local meteorological conditions also may be 
important factors in infection success, infection periodicity, and 
disease intensity (Jacobi et al. 2010, p. 41).
    On white pines, spores enter through openings in the needle 
surface, or stomates, and move into the twigs, branches, and tree 
trunk, causing swelling and cankers to form. White pine blister rust 
attacks seedlings and mature trees, initially damaging upper canopy and 
cone-bearing branches and restricting nutrient flows; it eventually 
girdles branches and trunks, leading to the death of branches or the 
entire tree (Tomback et al. 2001, p. 15, McDonald and Hoff 2001, p. 
195). White pine blister rust can kill small trees within 3 years, and 
even one canker can be lethal. While some infected mature trees can 
continue to live for decades, their cone-bearing branches typically 
die, thereby eliminating the seed source required for reproduction 
(Geils et al. 2010, p. 156). In addition, the inner sapwood moisture 
decreases, making trees prone to desiccation and secondary attacks by 
insects (Six and Adams 2007, p. 351). Death to upper branches results 
in lower or no cone production and a reduced likelihood that seed will 
be dispersed by Clark's nutcrackers (McKinney and Tomback 2007, p. 
1049). Similar to a total loss of cone production, even when cone 
production is low there could be a loss of regeneration for two 
reasons: (1) Clark's nutcrackers abandon sites with low seed 
production; and (2) the proportion of seeds taken by predators becomes 
so high that no seeds remain for regeneration (COSEWIC 2010, p. 25).
    Each year that an infected tree lives, the white pine blister rust 
infecting it continues to produce spores, thereby perpetuating and 
intensifying the disease. A wave, or massive spreading, of new blister 
rust infections into new areas or intensification from a cumulative 
buildup in already-infected stands occurs where Ribes shrubs are 
abundant and when summer weather is favorable to spore production and 
dispersal. Spores can be produced on pines for many years, and 
appropriate conditions need to occur only occasionally for white pine 
blister rust to spread and intensify (Zambino 2010, p. 265). The 
frequency of wave years depends on various factors, including 
elevation, geographical region, topography, wind patterns, temperature, 
and genetic variation in the rust (Kendall and Keane 2001, pp. 222-
223).
    Because its abundance is influenced by weather and host 
populations, white pine blister rust also is affected by climate 
change. If conditions become moister, white pine blister rust will 
likely increase; conversely, where conditions become both warmer and 
drier, it may decrease. Because infection is usually through stomates, 
whatever affects the stomates affects infection rates (Kliejunas et al. 
2009, pp. 19-20). Stomates close in drought conditions and open more 
readily in moist conditions.
    In general, weather conditions favorable to the intensification of 
white pine blister rust occur more often in climates with coastal 
influences than in dry continental climates (Kendall and Keane 2001, p. 
223). Due to current climate conditions in western North America, white 
pine blister rust now infects Pinus albicaulis populations throughout 
all of its range except for the interior Great Basin (Nevada and 
adjacent areas) (Tomback and Achuff 2010, Figure 1a, p. 187). However, 
the small uninfected area in the Great Basin accounts for only 0.4 
percent of P. albicaulis distribution in the United States. The 
incidence of white pine blister rust is highest in the Rocky Mountains 
of northwestern Montana and northern Idaho, the Olympic and western 
Cascade Ranges of the United States, the southern Canadian Rocky 
Mountains, and British Columbia's Coastal Mountains (Schwandt et al. 
2010, p. 228; Tomback et al. 2001, p. 15).
White Pine Blister Rust Infection Rates
    Researchers have used various sampling methods to assess the 
effects of white pine blister rust on Pinus albicaulis and the amounts 
of infection present; therefore, exact comparisons between studies are 
not possible. While white pine blister rust occurs throughout almost 
all of P. albicaulis' range, not all trees are infected and infection 
rates vary widely. Furthermore, it can be difficult to detect white 
pine blister rust, especially if cankers occur on gnarled canopy 
branches where infections may remain undetected (Rochefort 2008, p. 
294). However, despite slight differences in sampling methods general 
trends can be identified from the published literature (Schwandt et al. 
2010, p. 228). Trends strongly indicate that white pine blister rust 
infections have increased in intensity over time and are now prevalent 
even in trees living in cold, dry areas originally considered less 
susceptible (Tomback and Resler 2007, p. 399), such as the Greater 
Yellowstone Ecosystem (Table 2).

 Table 2--Percentage of Live Trees With Blister Rust Infection on Plots/
                      Transects From Recent Surveys
               [Adapted from Schwandt 2006, Table 1, p. 5]
------------------------------------------------------------------------
  Geographic region--number of reports       Range of
               [reference]                infection  (%)     Mean  (%)
------------------------------------------------------------------------
British Columbia (rangewide) [Campbell             0-100            50.0
 and Antos 2000]........................
British Columbia (rangewide) [Zeglen             11-52.5            38.0
 2002]..................................
Northern Rocky Mountains (United States            0-100            43.6
 and Canada) [Smith et al. 2006]........
Selkirk Mountains, northern Idaho--5               57-81            70.0
 stands [Kegley et al. 2004]............
Colville National Forest, northeast                23-44            41.4
 Washington--2 reports [Ward et al.
 2006]..................................
Greater Yellowstone Ecosystem [2005]....           0-100            25.0
Intermountain West (Idaho, Nevada,                 0-100            35.0
 Wyoming, California) [Smith and Hoffman
 2000]..................................
Blue Mountains, northeast Oregon [Ward             0-100            64.0
 et al. 2006]...........................
Coast Range, Olympic Mountains,                     4-49            19.0
 Washington--2 reports [Ward et al.
 2006)..................................
Western Cascades, Washington and Oregon--          0-100            32.3
 6 reports (Ward et al. 2006]...........
Eastern Cascades, Washington and Oregon--           0-90            32.3
 13 reports [Ward et al. 2006]..........
Coastal Mountains, southwest Oregon                0-100            52.0
 [Goheen et al. 2002]...................

[[Page 42641]]

 
California, Statewide [Maloney and                  0-71            11.7
 Dunlap 2006]...........................
------------------------------------------------------------------------

    While numerous studies have reported the incidence of white pine 
blister rust on Pinus albicaulis and subsequent mortality, few have 
reported on rates of change. The Greater Yellowstone Whitebark Pine 
Monitoring Working Group's monitoring results from resurveys conducted 
in 2008-2009 indicated an average of 32.4 percent of live trees had 
blister rust, a 12.4 percent increase from their overall 2007 baseline 
estimate of 20 percent (Greater Yellowstone Whitebark Pine Monitoring 
Working Group 2010, p. 67).
    Additional information on trends has been reported for Canada. In 
the Canadian Rockies, stands surveyed in 2003 and 2004 had an overall 
infection level of 42 percent and 18 percent mortality. These were 
remeasured in 2009 and found to have increased to 52 percent infection 
and 28 percent mortality (Smith et al. 2010, p. 67). Infection and 
mortality from white pine blister rust were present in all stands, with 
the highest levels occurring in the southern portions of the study 
area. The high mortality and infection levels, high crown kill, and 
reduced regeneration potential in the southern portion of their study 
area suggests that long-term persistence of P. albicaulis is unlikely 
(Smith et al. 2008, p. 982).
    Pinus albicaulis infected with white pine blister rust has 
increased in all regions of the Canadian Rockies, where it ranged from 
7 to 70 percent in 2003-2004 to 13 to 83 percent in 2009. Further, 
based on current mortality rates, the estimated P. albicaulis 
populat