Skip to Main Content
A finite mixture of two Weibull distributions for modeling the diameter distributions of rotated-sigmoid, uneven-aged standsAuthor(s): Lianjun Zhang; Jeffrey H. Gove; Chuangmin Liu; William B. Leak
Source: Canadian Journal of Forest Research. 31: 1654-1659.
Publication Series: Scientific Journal (JRNL)
Station: Northern Research Station
PDF: Download Publication (571.54 KB)
DescriptionThe rotated-sigmoid form is a characteristic of old-growth, uneven-aged forest stands caused by past disturbances such as cutting, fire, disease, and insect attacks. The diameter frequency distribution of the rotated-sigmoid form is bimodal with the second rounded peak in the midsized classes, rather than a smooth, steeply descending, monotonic curve. In this study a finite mixture of two Weibull distributions is used to describe the diameter distributions of the rotated-sigmoid, uneven-aged forest stands. Four example stands are selected to demonstrate model fitting and comparison. Compared with a single Weibull or negative exponential function, the finite mixture model is the only one that fits the diameter distributions well and produces root mean square error at least four times smaller than the other two. The results show that the finite mixture distribution is a better alternative method for modeling the diameter distribution of the rotated-sigmoid, uneven-aged forest stands.
- Check the Northern Research Station web site to request a printed copy of this publication.
- Our on-line publications are scanned and captured using Adobe Acrobat.
- During the capture process some typographical errors may occur.
- Please contact Sharon Hobrla, firstname.lastname@example.org if you notice any errors which make this publication unusable.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationZhang, Lianjun; Gove, Jeffrey H.; Liu, Chuangmin; Leak, William B. 2001. A finite mixture of two Weibull distributions for modeling the diameter distributions of rotated-sigmoid, uneven-aged stands. Canadian Journal of Forest Research. 31: 1654-1659.
- Rotated sigmoid structures in managed uneven-aged northern hardwood stands: a look at the Burr Type III distribution
- Modelling diameter distributions of two-cohort forest stands with various proportions of dominant species: a two-component mixture model approach.
- New methods for estimating parameters of weibull functions to characterize future diameter distributions in forest stands
XML: View XML