Stand Dynamics and Ecological Constraints on Growth in Young, Naturally Regenerated Hardwood Stands
In the southern U.S., forests are generally managed as even-aged entities, and
commonly regenerated using a clearcut reproduction method. Alternatives to clearcutting,
namely low- and medium-density shelterwood methods, were assessed in North Carolina,
South Carolina and West Virginia. Results suggested that the alternative methods afforded
little to no advantage over traditional clearcut methods.
Weeding, fertilization and thinning treatments were employed post-harvest on rising
1-yr-old Hill Forest and rising 3-yr-old Duke Forest upland Piedmont sites. Stems at both
sites responded to fertilization. Individual stem volumes increased 2 to 3-fold after three
years. Weeding-alone increased growth on the Hill Forest. The response to weeding and
fertilization treatments was usually additive. Thinning-alone had little effect on stem growth.
However, thinning + weeding treatments simulated large increases in stem growth. For
thinned stems, weeding generally had a greater affect on growth than fertilization at both
Stems on the rising 1-yr-old Hill Forest site were tagged (>3000 stems) and
monitored over three years. Stem survival was greatly affected by the weeding and
fertilization treatments. Fertilization reduced survival for most species, especially for the
lower initial height and diameter size classes. Weeding, by contrast, tended to increase
survival in the small initial size classes. The survival data indicated that some of the growth
response associated with fertilization might be due to mortality in the smaller sized stems.
Three-year growth and survival models based on initial stem size were generated for
each species and treatment combination at the Hill Forest site. Comparisons were made
between treatments for each species, and between Liriodendron tulipifera L. and Cornus
florida L., Prunus serotina Ehrh., Pinus spp., Acer rubrum L. and Quercus alba L. for each
treatment. Generally, most species responded favorably to weeding and fertilization
treatments, although these responses were not always statistically significant. However,
individual species differed in respect to their ability to increase growth and survival, although
yellow-poplar ranked among the fastest growing species in every treatment after 3 years.
These last data can be used to develop floristic models to predict species composition for
other upland stands.
Advisor:Douglas J. Frederick; Charles B. Davey; Daniel J. Robison; H. Lee Allen
School:North Carolina State University
School Location:USA - North Carolina
Source Type:Master's Thesis
Date of Publication:04/20/2005