Skip to main content

The Declining Even Flow Effect and the Process of National Forest Planning

Buy Article:

$29.50 plus tax (Refund Policy)


Recent literature (McQuillan 1986) has identified what may be a serious flaw in the planning process used by the USDA Forest Service. The problem, which McQuillan called the declining even flow effect (DEFE), can occur during repeated iterations of a planning process in cases where a timber harvest scheduling model whose objective is wealth maximization subject to nondeclining yield constraints is utilized. The DEFE creates a situation in a sequence of plans over time in which the first period harvest level declines below that attained for previous planning iterations. This paper addresses the relationship between the process used by the Forest Service to develop FORPLAN models and the DEFE. An example using Kootenai National Forest planning documents is presented to illustrate the highly constrained nature of Forest Service planning models. The effect of these constraints and other characteristics of FORPLAN models on the DEFE is examined. Two items common to nearly all forest planning models, a land base which is not entirely old-growth and constraints to assure that the 40-ac clearcut limit is not violated, caused a large reduction in the DEFE observed in a FORPLAN version of McQuillan's case study model. However, one characteristic of Forest Service planning models, the use of intermediate harvest options, which plausibly could have reduced the DEFE, did not. The major conclusion of the study is that the regulations, initial conditions, and formulation of the FORPLAN model all tend to reduce the likelihood and magnitude of the DEFE. For. Sci. 36(3):665-679.

Keywords: Timber harvest scheduling; linear programming

Document Type: Journal Article

Affiliations: Branch Chief, Policy Analysis, USDA Forest Service, Washington, DC

Publication date: September 1, 1990

More about this publication?
  • Forest Science is a peer-reviewed journal publishing fundamental and applied research that explores all aspects of natural and social sciences as they apply to the function and management of the forested ecosystems of the world. Topics include silviculture, forest management, biometrics, economics, entomology & pathology, fire & fuels management, forest ecology, genetics & tree improvement, geospatial technologies, harvesting & utilization, landscape ecology, operations research, forest policy, physiology, recreation, social sciences, soils & hydrology, and wildlife management.
    Forest Science is published bimonthly in February, April, June, August, October, and December.

    Also published by SAF:
    Journal of Forestry
    Other SAF Publications
  • Submit a Paper
  • Membership Information
  • Author Guidelines
  • Ingenta Connect is not responsible for the content or availability of external websites

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more