Skip to main content

Density Frontiers for Even-Aged Douglas-fir and Western Hemlock Stands in Coastal British Columbia

Buy Article:

$21.50 plus tax (Refund Policy)

Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) and western hemlock (Tsuga heterophylla [Raf.] Sarg.) are the two most common and commercially important species on the coast of British Columbia, Canada. Our research focused on determining the relationship between maximum density and top height for pure stands of these species. These relationships can be used to provide a constraint on mortality functions in individual-tree growth and yield models for even-aged stands. Our data consist of density and top height from experimental plots established along the coast of British Columbia, Washington, and Oregon. These experiments yielded 2,930 observations from 628 plots. We fit stochastic frontier functions to the density/top height data. Stochastic frontier functions have a stochastic component that allows data points to lie on either side of the frontier. The fitting of the frontier functions using maximum likelihood estimation resulted in maximum density lines as an exponential function of top height for both species. The fitted model is based loosely on the −3/2 power thinning law. Our analysis shows that these relationships hold across sites with differing quality. The maximum density line is greater for western hemlock than for Douglas-fir up to a height of about 35 m, at which point they are almost the same. The higher maximum density of western hemlock is likely related to its greater shade tolerance. We used the growth-and-yield model Table Interpolation Program for Stand Yields (TIPSY) to simulate the growth of high-density stands of Douglas-fir and western hemlock. These simulations gave similar results to our fitted density frontier line.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
No Metrics

Keywords: Douglas-fir; density; mortality; self-thinning; western hemlock

Document Type: Research Article

Publication date: 2007-12-01

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.

    2016 Impact Factor: 1.782 (Rank 17/64 in forestry)

    Average time from submission to first decision: 62.5 days*
    June 1, 2016 to Feb. 28, 2017

    Also published by SAF:
    Journal of Forestry
    Other SAF Publications
  • Submit a Paper
  • Membership Information
  • Author Guidelines
  • Podcasts
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
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