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Ecology and Management of Pinyon-Juniper
Communities Within the Interior West:
Overview of the "Management Implications
Session" of the Symposium
Mike Pellant
Abstract-Categories of papers in the "Management Implications
Session" were (1) ecological guidelines and thresholds, (2) collaboration, (3) rehabitation after wildfire, (4) weed management, and (5)
miscellaneous management topics. The application of science, experience, and collaboration is a necessity for properly managing these
diverse and ecologically complex ecosystems. Failure to undertake
this task could result in woodland landscapes dominated by weeds
and frequent and intense disturbance events.
A number of interesting and effective management strategies for pinyon pine (Pinus spp.) and/or juniper (Juniperus
spp.) woodlands (hereafter referred to generically as woodlands) were presented in the "Management Implications"
session of this symposium. I have attempted to synthesize
the salient and innovative points from the 14 papers that
were prepared for these proceedings. I also included one
abstract in this synthesis from a symposium presenter who
did not prepare a paper for these proceedings. This synthesis
is a brief summary, and the reader is encouraged to review
the individual papers cited for more detailed information.
Finally, this review is couched by my experiences managing
woodlands for the Bureau of Land Management (BLM) in
southeastern Utah in the late 1970's.
Management of woodlands is affected by a wide variety of
natural and anthropogenic influences. Management decisions must be considered in scientific and political framework to implement management prescriptions effectively
and to obtain a desired outcome. These decisions are based
upon the land manager's experience and available science
related to woodland management. Due to information gaps
on some aspects of the ecology and restoration, woodlands
management has been more of an "art" and less of a "science." These proceedings certainly provide much needed
information (such as science and practical experience) to
improve woodland management.
I have organized the papers in the "Management Implications" section into the following categories to facilitate their
synthesis:
a
1. Ecological Guidelines and Thresholds
In: Monsen, Stephen B.; Stevens, Richard, comps. 1999. Proceedings:
ecology and management of pinyon-juniper communities within the Interior
West; 1997 September 15-18; Provo, UT. Proc. RMRS-P-9. Ogden, UT: U.s.
Department of Agriculture, Forest Service, Rocky Mountain Research
Station.
Mike Pellant is Rangeland Ecologist, Bureau of Land Management, Idaho
State Office, 1387 S. Vinnell Way, Boise, ID 83709.
USDA Forest Service Proceedings RMRS-P-9. 1999
2.
3.
4.
5.
Collaboration
Rehabilitation After Wildfire
Weed Management
Miscellaneous Management Topics
Ecological Guidelines and
Thresholds _ _ _ _ _ _ _ _ __
The five papers in this section provide managers with the
framework to incorporate community ecology and the new
"state and transition models" in developing and implementing management strategies forwoodlands. All authors agree
that woodlands are ecologically complex and vary greatly
both spatially and temporally. Incorporation of science and
research into management decisions is essential if resource
issues and political controversy associated with woodlands
are to be resolved.
Benchmarks or reference areas are one of the cornerstones
to sound management of rangelands and woodlands. Miller
and others described characteristics and val ues ofold growth
juniper and pinyon woodlands. Old growth woodlands are
characterized by pre settlement trees (established prior to
1870), which are typically present in open stands with
understory species. Managers can benefit by recognizing
and maintaining these woodlands given the diversity of
plant and wildlife species that inhabit these areas and the
recreational, cultural, and spiritual opportunities they offer.
The authors recommended conducting inventories to identify and describe old growth woodlands and to closely evaluate fire suppression and prescribe fire policies in these areas.
Eddleman concurred with the previous assertion that a
serious limitation in management of woodlands is the lack of
information from benchmark or reference areas and inadequate research on postsettlement woodlands. He provided
the following guidelines for the "ecological" management of
woodlands:
1. Establish clear management goals and objectives.
2. Identify ecological problems on the area under consideration.
3. Inventory (tree age classes, understory vegetation, and
ecological or functional status).
4. Evaluate landscape conditions around the area under
consideration.
5. Implement management and restoration activities.
I would add a sixth element to this list, "Monitor and adjust
management accordingly." It is also important to obtain and
share information on the success or failure of management
or restoration activities in meeting goals and objectives.
357
Tausch related the concepts of transitions and thresholds
to the management of woodlands. He defined a threshold as
"a significant change in the species composition or functioning of the community found on a site that usually results
from some level of disturbance." A transition is the process
of crossing a generally irreversible community threshold
that is permanent unless major management actions are
taken or a significant natural disturbance occurs.
It is important for managers to recognize thresholds and
transitions in woodland management. Examples of "crossed"
thresholds included sagebrush steppe vegetation that is
invaded by and eventually dominated by woodland trees or
sites where cheatgrass (Bromus tectorum) invades and dominates woodland sites following wildfires. Managers also
need to be aware of the potential for certain plant associations to decrease and reach "dormant" thresholds. The
threshold may be crossed following a disturbance (such as
cheatgrass existing in the understory of woodlands susceptible to wildfires). There is also a spatial aspect to thresholds
that must be considered in management. A disturbance in a
surrounding area may influence or even "push" a nearby site
over a threshold. For example, erosion and weed invasion
after a woodland wildfire may impact surrounding areas
causing them to become more susceptible to degradation
after future disturbances.
Managers should recognize when a threshold is being
approached for a woodland landscape unit and decide what,
if any, management actions are required to reduce the
probability of the threshold being crossed. The invasion of
sagebrush steppe communities by juniper trees is an example of a plant community transition that will eventually
result in a closed canopy woodland if management actions
(such as prescribed fire) are not applied in a timely manner.
If this threshold is crossed, accelerated erosion may occur,
and the site potential may be changed to a degree that sagebrush steppe vegetation may no longer be adapted to the site.
Restoration activities-including woodland manipulations
(chaining, burning, thinning, and so forth) and seedings
with introduced species-shoul.d also be evaluated for transitions and thresholds. Such manipulations may meet shortterm management objectives such as increased forage for
herbivores, but they may also prove to be ecologically unsound. We need a better understanding of thresholds and
transitions to implement appropriate management for almost all woodlands.
Miller and others described the threshold that is crossed
as shrub steppe vegetation converted to ajuniperwoodland.
Early indicators of such a conversion are the reduction in
leader growth on dominant and understory trees and the loss
ofvigor and mortality of shrubs near large j uni per trees. Once
this threshold is crossed, fire potential is reduced, and loss of
native species and accelerated erosion generally increases.
On low elevation rangelands (below 5,000 ft) exotic annual
grasses, principally cheatgrass, may increase with poor
livestock grazing management in juniper woodlands. It is
essential that managers recognize the resource management implications of crossing this threshold and apply
treatments to check the conversion in a timely manner. All
of these actions must be considered in the context of the
spatial and temporal heterogeneity that exists in woodlands
across the landscape as well as the political, environmental,
and budgetary issues influencing their management.
358
In the final paper in this section, Goodrich and Barber
1999 discuss the return interval for pinyon pine (Pinus
edulis Engelm.) and Utah juniper (Juniperus osteosperma
[Torr.] Little) following several wildfires that occurred about
100 years ago in northeastern Utah. They found a slow
return rate of pinyon pine and Utah juniper for the first 40
to 50 years following the fires with an accelerated return
rate thereafter. An estimated 150 to 200 years would be
required to achieve preburn tree density for the Green River
corridor of Utah. Therefore, a relatively small annual burning program would result in an adequate mix of sera1stages
on the landscape given this long woodland recovery period
after fire.
Collaboration _ _ _ _ _ _ _ __
Management of woodlands is becoming a controversial
and contentious issue. Environmental groups are challenging management actions, especially chaining, on these woodlands. Concerns over the past management practice oflarge
"block" chainings and reseeding introduced grasses has
caused a heightened concern about any management action
that results in a loss of woodlands.
Nelson and others described a collaborative process that
was successfully used to implement chaining and seeding of
pinyon-juniper woodlands in Spanish Fork Canyon, Utah.
Early public participation in the planning process, clear and
simple objectives, good interagency cooperation combined
with nonagency partnerships, and follow-up monitoring all
contributed to the successful chaining and seeding of small
tracts of pinyon-juniper woodlands.
Goodloe described the value of integrated resource management in his paper in the "Restoration" session of this
proceedings. He applied holistic livestock management and
reintroduced fire on his ranch in New Mexico to reverse the
effects of80 years of fire suppression and year-long grazing
responsible for the conversion of productive grassland communities to woodland species. He first thinned the tree
stands and sold the wood as fenceposts, fuel wood, and
Christmas trees. This treatment was followed by prescribed
fire and reseeding with native grasses. Rotation livestock
grazing systems now maintain these restored plant communities, which benefits livestock, wildlife, and recreation
users, and stabilizes watershed values.
Native Americans also value and rely on the products from
woodlands, and Miller reminds us that deeply rooted traditional values are associated with woodlands by various
tribes. His agency (Bureau ofIndian Affairs) is working with
the tribes to manage these woodlands in a sustainable
manner guided by tribal culture and tradition.
Rehabilitation After Wildfire _ __
Two papers addressed rehabilitation efforts by the Bureau of Land Management (BLM) after wildfires in woodlands. Roberts described the financial and ecological impacts on public lands caused by the increasing frequency of
woodland wildfires. In 1996, Utah BLM implemented nearly
$9 million of rehabilitation projects on burned range and
woodlands. Roberts identifies cheatgrass as the primary
cause of the increased fire frequency. He is also concerned
USDA Forest Service Proceedings RMRS-P-9. 1999
about the potential for other even more pervasive noxious
weeds moving into these woodlands after wildfires.
MacDonald described the initial results of rehabilitation
practices applied in 1996 on 102,100 acres of burned woodlands in south-central Utah. Aerial seeding followed by oneway anchor chaining resulted in better seeded species establishment than aerial seeding with no cover. Anchor chaining
to cover seeds was controversial, yet the preliminary study
results clearly demonstrate the value of seed coverage in
ensuring that seeded species are successfully established.
The need for rehabilitation of woodlands will accelerate in
the future given the increase of cheatgrass (and thus wildfires) in the understory or on the periphery of Western
woodlands. Managers must give more consideration to the
concept of thresholds in planning rehabilitation practices,
especially in deciding whether to seed or allow natural
recovery to occur, what seed mix to use (native, introduced,
or a combination), and where seeding is necessary. The
short-term and long-term trajectories of postfire plant communities, including weeds, will be greatly influenced by the
decisions made during the rehabilitation planning process.
Weed Management
The role of cheatgrass and other weeds in the management of pinyon or juniper woodlands is the focus of the
majority of the papers in this section. Two papers dealt with
weed potential problems in planning woodland treatments
and management of weeds before and after seeding. Svejcar
cautions managers against automatically assuming that
just because a weed is present, it will dominate the site if
woodland species are removed. The response of weeds in
woodland conversion projects is site specific and governed by
the pretreatment plant community, susceptibility ofthe site
to weed encroachment, and posttreatment management
actions and climate. Svejcar suggests six steps to consider
when planning any woodland conversion project and calls
for the development of state and transition models to assist
managers in making better decisions.
Goodrich and Rooks evaluated the effectiveness ofa postfire
seeding in reducing dominance of cheatgrass and musk
thistle (Carduus nutans L.). They described the weed infestation that occurred after the 1976 wildfire in a pinyonjuniper woodland in northeastern Utah. Subsequently, a
portion of the 1976 burn area was burned again in 1990 to
reduce cheatgrass and reseeded to introduced grasses to
compete with weeds that dominated the site after the original burn. The nonseeded area had 10 times more musk
thistle plants than did the seeded area 6 years after the
prescribed burn and seed treatment Cheatgrass frequency
and vigor were also reduced in the seeding compared to the
unseeded area.
Goodrich and Rooks also addressed the seeding of natives
versus selected introduced species to exclude weeds in disturbed pinyon-juniper woodlands. They contend that until
availability of native plant materials improves, competitive
introduced species should be planted to prevent establishment and dominance of cheatgrass or other weeds after
woodland treatments. They further caution against requiring only the use of "local natives" on large-scale restoration
projects because costs and availability of seed could be too
restrictive.
USDA Forest Service Proceedings RMRS-P-9. 1999
The potential for weed expansion after disturbance in
many woodlands is high and should be a concern for managers. Early detection, aggressive treatment, and monitoring
are a few of the required steps to minimize this threat to the
integrity of Western woodlands. This task is one of the most
challenging in regards to woodland management and will
increase as disturbances such as wildland fires continue to
increase and weeds adapt and evolve to new environments.
Miscellaneous Management
Topics ____________
Three presentations provided valuable information on the
management of woodlands but did not logically fit into the
previous organization or new categories. Rasmussen and
others proposed the use of a helitorch to burn pinyon or
juniper that has encroached in riparian areas. They speculate that if the treatment were done in the spring, and if the
trees were individually ignited, then successful, albeit expensive, control could be obtained. Given the high resource
values associated with riparian areas, further research or
tests on this technique are warranted.
Stevens and others examined the effects of livestock
grazing on dryland alfalfa planted in several woodland
conversion projects near Ephraim, UT. Annual grazing after
May 15 resulted in little alfalfa regrowth or seed production.
Loss of alfalfa in the stand eventually occurred, reducing the
diversity and forage value of the seedings. This study demonstrates the importance of considering short-term and
long-term effects of livestock and wildlife grazing in the
management of multispecies see dings after woodland conversion projects.
Eager described increasing mortality of pinyon pine
throughout western Colorado and proposed some management actions to reduce these losses. Insect infestations and
fungal root disease are the primary cause of the increased
pinyon pine mortality. Human activity, primarily road,
fence, and home construction, can cause tree damage by
allowing the entry of insects or disease. Managers can
minimize these outbreaks by scheduling disturbance treatments in cool weather and by promptly removing damaged
trees or stumps from work areas.
Summary
These "Management Implications" papers all contribute
to a better understanding of opportuni ties and constraints in
managing Western woodlands. Managers should become
more knowledgeable of the concepts of thresholds and the
ecological implications of management actions they initiate
or even the management actions that they don't take. Prescribed fire, chaining, and thinning are just a few of the
woodland conversion tools that could be used to meet specific
land use or management objectives. However, these treatments in conjunction with climate, livestock management,
or weed invasion may "push" treatment areas across thresholds that mayor may not be compatible with long-term
management objectives (fig. 1).
Management in woodlands, especially controversial treatments such as chaining or seeding with nonnative plants,
must be done collaboratively to minimize conflict and to
359
Figure 1-Utah juniper is invading a historical sagebrush steppe plant community that is now
dominated by cheatgrass. A recent wildfire has burned into the area invaded by the juniper.
Other noxious weeds are in the vicinity and have the potential to invade this disturbed site.
What are the management implications and options in this situation?
ensure that decisions are made by stakeholders and not by
our judicial system. Native Americans have many utilitarian and spiritual ties to woodlands that also need to be
considered in any management strategy.
Wildfires have increased gr~atly in frequency and extent
in certain areas dominated by woodlands in recent years.
Rehabilitation after woodland fires is often necessary to
prevent accelerated erosion and entry of invasive plants.
Where seeding is required, every effort should be made to
cover the seed mechanically to enhance the successful establishment of all seeded species. Rehabilitation planning should
include an analysis of the potential thresholds that may be
crossed given the practices proposed. Postfire livestock grazing, seeding with aggressive nonnative grasses, and not
controlling noxious weeds all have the potential individually
or in combination after fire to direct succession across a
threshold to a new, undesirable stable state.
Perhaps the greatest threat to Western woodlands is the
spread of weeds both invasive weeds (such as cheatgrass)
and noxious weeds. Woodland treatment plans must include
an evaluation of weed invasion potential in the posttreat-
360
ment environment but not to the point where unfounded fear
of a potential weed invasion precludes any manipulation or
change in the management of woodlands. Where weeds are
a threat after woodland disturbance, seeding competitive
introduced grasses could reduce the threat. However, a
better long-term goal is to increase the supply and availability of native plant materials that can both compete with
weeds and provide the diversity and function of the historical woodland communities.
Implications of our actions, or lack of action, in managing
woodlands may affect the Western landscape far into the
future. The application of science, experience, and collaboration is a necessity for properly managing these diverse and
ecologically complex ecosystems. Applied research, monitoring of management actions, and the sharing oflocal knowledge, information, and successes, as well as failures, are all
critical for improving the understanding and proper management of Western woodlands. Ifwe fail in this undertaking, woodland landscapes dominated by weeds and frequent
and intense disturbance events may become an unwanted
reality.
USDA Forest Service Proceedings RMRS-P-9. 1999