Skip to Main Content
Origin of sigmoid diameter distributionsAuthor(s): William B. Leak
Source: Res. Pap. NE-718. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northeastern Research Station. 10 p.
Publication Series: Research Paper (RP)
Station: Northeastern Research Station
View PDF (567.82 KB)
DescriptionDiameter distributions--numbers of trees over diameter at breast height (d.b.h.)--were simulated over 20-years using six diameter-growth schedules, six mortality trends, and three initial conditions. The purpose was to determine factors responsible for the short-term development of the arithmetic rotated sigmoid form of diameter distribution characterized by a plateau, near plateau, or bump in the mid-diameter d.b.h. classes. A distinct rotated sigmoid developed when the diameter-growth schedule dropped precipitously in the mid-diameter classes; this might reflect a decadent overstory and thrifty understory. When the initial diameter distribution was distinctly sigmoid, diameter-growth schedules characterized by slow growth in the small-diameter classes tended to maintain sigmoid characteristics. A parabolic growth trend with or without parabolic mortality, also produced moderate rotated sigmoid characteristics. Under most other growth or mortality schedules, the 20-year diameter distribution was J shaped. The results reinforce the concept that diameter distributions tend to maintain or return to the J shape particularly with respect to New England northern hardwoods.
- 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.
CitationLeak, William B. 2002. Origin of sigmoid diameter distributions. Res. Pap. NE-718. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northeastern Research Station. 10 p.
Keywordsdiameter at breast height (d.b.h.), sigmoid, diameter distribution, northern hardwoods
- Long-term structural change in uneven-aged northern hardwoods
- A finite mixture of two Weibull distributions for modeling the diameter distributions of rotated-sigmoid, uneven-aged stands
- Rotated sigmoid structures in managed uneven-aged northern hardwood stands: a look at the Burr Type III distribution
XML: View XML