The role of fire in determining the structure and composition of many forested ecosystems is well documented (e.g. North American boreal forests; piñon-juniper woodlands of the western US). Fire is also believed to be important in temperate forests of eastern North America, but the processes acting here are less clear, particularly in xerophytic forests dominated by yellow pine (Pinus, subgenus Diploxylon Koehne) and oak (Quercus L.). In this study, I use dendroecological techniques to investigate fire history and vegetation dynamics of mixed pine-oak forests in the central Appalachian Mountains of Virginia. The study addresses three objectives: (1) develop a lengthy fire chronology to document fire history beginning in the late presettlement era and extending throughout the period of European settlement, industrialization and modern fire exclusion; (2) explore fire-climate relationships; and (3) investigate vegetation dynamics in relation to fire occurrence. The study was conducted on three study sites within the George Washington National Forest. I used fire-scarred cross-sections from yellow pine trees to document fire history. Fire-climate relationships were investigated for each study site individually and all sites combined using superposed epoch analysis (SEA). Fire-history information was coupled with dendroecological data on age structure to explore stand development in relation to fire occurrence. Results of fire history analysis reveal a long history of frequent fire with little temporal variation despite changes in land use history. Mean fire intervals (MFI) ranged from 3.7–17.4 years. The most important change in the fire regime was the initiation of fire suppression in the early twentieth century. Results of SEA show that periodic droughts may be important drivers of fire activity. Drought the year of fire was important at two of the three study sites and when all sites were combined. Results of age structure indicate that vegetation development was clearly influenced by fire. Frequent burning maintained populations of yellow pine throughout the period of study until fire suppression allowed fire-sensitive hardwood trees and shrubs to establish. It is clear from this study that continued fire suppression will likely result in fire-tolerant pines and oaks being replaced by more mesophytic trees and shrubs.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2011-05-9176 |
| Date | 2011 May 1900 |
| Creators | Aldrich, Serena Rose |
| Contributors | Lafon, Charles W. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | thesis, text |
| Format | application/pdf |
Page generated in 0.002 seconds