Understory Density Characteristics and LOS in Various Vegetation Biomes
Krause PF, Puffenberger HB, Fatale LA, Champion DC. 2004. Understory Density Characteristics and LOS in Various Vegetation Biomes. National Park Service. US Army Corps of Engineers, Engineer Research and Development Center
A total of 177 forestry transects were performed at eight (8) locations in the contiguous United States, Alaska and the Republic of Panama. Six (6) different vegetation biomes were sampled. The goal of the research was to gather overstory information so that understory plant densities could be estimated. Overstory data included tree height, mean crown diameter, diameter at breast height, tree species and the x,y location of the overstory trees within the transect. This information became the predictor variables. Understory information was individual plant counts. These were recorded in 25-foot contiguous quadrats for later analysis concerning understory variability. The data were entered onto spreadsheets and exploratory data analysis (EDA) was performed. It was discovered that classical statistical approaches (e.g., multiple regression) could not be used to model understory plant densities. Statistically significant regression coefficients (p-values <=0.05) could not be generated. Instead, regression trees (a data mining approach) was utilized. This yielded estimate errors fairly consistent to those obtained by KPGG03 for sites in east-central Virginia. The understory quadrat counts were grouped by location and statistics were generated so that average curves could be replicated for modeling and simulation activities. The relationship between average transect understory density and the maximum and minimum understory quadrat densities is quite good in the majority of cases. The mean crown diameter and diameter at breast height (d.b.h.) relationship is also quite strong.
- Type
- Unpublished Report
- Authors
- Krause, Paul; Puffenberger, Harry; Fatale, Louis; Champion, Danny
- Date of Issue
- 2004-09
- Publisher
- National Park Service
- Units
- GRSM
- Keywords
- Forest Structure, GRSM-00285, Hemlock, red bud, Understory, vegetation biomass, Viburnum, yellow poplar
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Forest/Woodland Communities