Vegetation management
Today's
powerpoint file
- Definitions and ideas:
- vegetation
- management
- Under strictly natural conditions, an ecosystem is generally a
self-perpetuating system that does not require management. So, why manage
vegetation?
- Operational definition of vegetation management includes a component
of usefulness to society
- More specifically, we desire unnatural conditions, with respect
to:
- species composition
- accelerated growth rates
- above-natural establishment rates
- above-natural quality of products
- Therefore, we must manage: even the absence of management represents
a management decision
- Today, vegetation managers must manipulate vegetation to create
desired species composition which will meet management objectives, such
as:
- increase recreational opportunities
- improvement of wildlife habitat
- improvement of habitat for livestock
- improve aesthetics
- timber production
- increase water quantity and quality
- conserve biological diversity
- enhance the ability of vegetation to act as a C sink
- others?
- Historically, managers were faced with 1-2 objectives on each site
- Today, managers must attempt to accomodate multiple objectives
- Clearly, vegetation management is considerably more difficult than it
used to be
- In addition, there are many constraints on management:
Ecological: |
- environment
- microenvironment
- existing vegetation
- pests
|
Social: | |
Managerial: |
- technical
- policy
- conflicting objectives
|
- In addition, there is the large-scale sociological constraint
described as 'command and control' by Holling and Meffe. Individually,
managers may be unable to overcome this constraint, but they should
recognize and acknowledge it.
- Meeting objectives within the context of constraints requires an
understanding of veg. dynamics and ecosystem behavior
- Role of vegetation manager: accurately predict the results of
alternative treatments, and develop prescriptions compatible with
physiological, ecological, managerial, and social constraints
- In other words,
- Take inadequate information base (with respect to ecosystem response
to treatment)
- Apply treatments that will meet management objectives (note that these
objectives often conflict with each other)
- At this point, there is a real temptation to give up (this will ensure
that no objectives are met)
- Fortunately, in many cases, management objectives can be met by
manipulating the vegetation
- This course will attempt to provide the framework for evaluating
ecosystem response to various land-management treatments
Group exercise
You are responsible for developing a management plan for the area shown in
the slides.
You should work with the other students in your group to come
up with a specific, operational plan that addresses the objective within
the context of ecosystem structure and several constraints. Your
management plan should be carried through the next 100 years.
Objective: |
Manage the site for high aesthetic
value; this includes creation and maintenance of a stand of aspen
(Populus tremuloides). |
Site: | The forest stand is located on a
northeastern aspect at 2740 m (8990') elevation adjacent to the
Mt. Lemmon highway (near Ski Valley). Soils are deep,
well-drained loams underlain by Catalina gneiss (granite) parent
material. The site is 10 hectares (25 acres) and is a member of
the Abies concolor/sparse habitat type. |
Structure: | Vegetation is characterized as mixed-conifer forest;
dominant overstory species are white fir (Abies concolor),
Douglas-fir (Pseudotsuga menziesii), ponderosa pine (Pinus
ponderosa), and southwestern white pine (P. strobiformis). The
stand is multi-storied and uneven-aged. |
Constraints: |
Budget for this site is $3000 over the
100-year planning horizon (2006 dollars). Recreation is a
dominant activity in this mountain range, particularly on
weekends during the spring, summer, and fall; management
activities should not unduly interfere with recreational
activities. There is no market for conventional forest products
in the area. |
Additional Information (also see assigned readings):
Chapters 6-7 of McPherson, G.R. 1997. Ecology and Management of North
American Savannas. University of Arizona Press, Tucson.
Matter, W.J. and Mannan, R.W. 1989. More on gaining reliable knowledge:
a comment. Journal of Wildlife Management 53:1172-1176.
Peters, R.H. 1991. A Critique for Ecology. Cambridge University Press,
Cambridge, U.K.
Romesburg, H.C. 1981. Wildlife science: gaining reliable knowledge.
Journal of Wildlife Management 45:293-313.
Simberloff, D. 1983. Competition theory, hypothesis-testing, and other
community ecology buzzwords. American Naturalist 122:626-635.
Underwood, A.J. 1995. Ecological research and (and research into)
environmental management. Ecological Applications 5:232-247.