Date of Award

2004

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Forest Resources

Advisor

Robert S. Seymour

Second Committee Member

Robert G. Wagner

Third Committee Member

Jeremy S. Wilson

Abstract

Relationships between leaf area index (LAI) and relative density (RD) were examined in even-aged stands of Abies balsunzen (L.) Mill. and Piceu rubens Sarg. Twelve sites distributed across the Acadian forest in Maine were used to test conformance to three hypothesized models of LA1 over RD: A) constantly increasing LA1 over increasing RD, B) constant LA1 with increasing RD, or C) decreasing LA1 with increasing RD. Multivariate ordination suggested young, precommercially thinned (PCT), high-siteindex (SI) A. balsamea stands should be analyzed separate from older, unspaced (NOPCT), lower-site P. rubens stands. All-sided A. balsamea LAIs ranged from 6.2 - 14.8 over RDs of 0.23 - 0.60, P. rubens LAIs ranged from 7.5 - 14.9 over RDs of 0.5 1 - 0.76. Data for both species suggested an increase in LA1 with increasing RD. At a given RD, LA1 was strongly and positively correlated with SI. Lack of data across a complete range of RDs for both stand types limited testing of any hypothesized relationship between LA1 and RD; however, when LAIs were adjusted to a common SI, conformance to trend A was evident. Volume increment (VINC) and growth efficiency (GE) were also studied for A. b~~lsnn?aenad P. rubens in the CTRN sites. Dominant and codominant trees were used to test for differences in GE by site quality. Young A. balsamea trees (n = 205) were precommercially thinned (PCT) 15 - 20 years ago while the older P. rubens trees (n = 173) were not. A model incorporating individual tree all-sided leaf area (ALA) and site index (SI) best predicted VINC. A monotonic decreasing pattern of GE over ALA was found for both species; GEs were higher overall for P, rubens. GE was used with previously reported LAIs from the same sites to calculate mean annual increments, periodic annual increments (PAI), and stand-level GE. These metrics showed all sites in this study have yet to achieve culmination of mean annual increment. Stand-level GEs were similar for both species, although P. rzrbens occurred on lower-quality sites. P. rubens were more productive when viewed in terms of PA1 per unit of SI.

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