Vegetation management

Today's powerpoint file

Definitions and ideas:


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:

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:

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:

  • environment
  • microenvironment
  • existing vegetation
  • pests
  • legal
  • societal pressure
  • 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,

  1. Take inadequate information base (with respect to ecosystem response to treatment)
  2. 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.