| Authors: |
Victor A. Rudis, Ronald E. Thill, James H. Gramann, Joseph Picone, Nirmala Kalidindi, Philip A. Tappe |
| Year: |
1999 |
| Type: |
Scientific Journal |
| Station: |
Southern Research Station |
| Source: |
Forest Ecology and Management. 114: 309-320. |
Abstract
Deciding among cutting practices requires knowledge of forest structure, understory vegetation change, rates of recovery, and resource impacts. The authors used two field devices (a screenometer and a density board) and digital images of 35 mm photographs to compare measures and document the change in understory vegetation structure in forests following reproduction cutting disturbances. The study area, mostly 70-year old second-growth shortleaf pine-oak (Pinus echinata-Qercus spp.) had an average basal area of 26 m2 /ha. Treatments retained 13.8 m2 /ha in pine and three levels of hardwood basal area. The 21 m2 /ha treatment retained 33 percent hardwood basal area in a scattered condition. One 17 m2 /ha treatment retained 20 percent hardwoods in a clustered or grouped pattern, and another treatment retained 20 percent hardwoods scattered throughout. A fourth treatment retained no hardwood basal area. When compared with untreated (control) plots, vegetative screening increased on treated plots relative to untreated plots by degree of initial cutting disturbance. Both the screenometer and the density board readings distinguished between control and treated plots, but significant differences occurred by season, year, and height above ground. Digital information from scanned images yielded promising results by detecting significant differences in the amount of blue color intensity and the proportion of line objects. Color intensities were significantly different by season and year after treatment, that is, lowest in summer and highest in spring, and greater 2 years after treatment rather than 6 years after treatment. Results indicated that detection of disturbed conditions and recovery following disturbance varied with the scale and type of measurement. Each device estimated different structural dimensions. The authors concluded that assessment and modeling of understory structure, change, and recovery depended strongly on the cell size of the device used.
Citation
Rudis, Victor A.; Thill, Ronald E.; Gramann, James H.; Picone, Joseph; Kalidindi, Nirmala ; Tappe, Philip A. 1999. Understory structure by season following uneven-aged reproduction cutting: a comparison of selected measures 2 and 6 years after treatment. Forest Ecology and Management. 114: 309-320.
