Pinus Pungens The Tablemountain Pine PDF Download

Table Mountain pine is an Appalachian endemic that occurs in a patchy distribution from Georgia to Pennsylvania and is prolific at sites with a history of fire disturbance. The purpose of this dissertation was to reconstruct the fire regimes of Table Mountain pine stands in the Jefferson National Forest, Virginia. Sections from firescarred Table Mountain pines were collected at four sites to analyze fire history, while increment cores and stand composition information were collected from macroplots within each fire history site to investigate the possible influence of fires that were more ecologically severe. Results show that fire was frequent before the fire suppression era, with a Weibull median fire return interval between 2-3 years. The majority of fires occurred during the dormant season and beginning of the early growing season. Two of the four sites had a more even distribution of fire seasons, and these sites also had significant Table Mountain pine regeneration. Cohorts of tree establishment were visible in the fire charts of three of these sites, indicating fires that were likely moderate in severity. The canopy at three of the four sites is currently dominated by Table Mountain pine, but the understory at all sites has large numbers of fire-intolerant hardwoods and shrubs. These Table Mountain pine stands will likely succeed to xeric oak and fire-intolerant hardwoods, such as red maple and black gum, in the future. Fire statistics indicate that all four sites currently exist outside their range of historical variation in fire occurrence. Table Mountain pine was found to be sensitive to climate (monthly precipitation and temperature, PDSI and PHDI, North Atlantic sea surface temperatures, and NAO). Climate analyses revealed that Table Mountain pine growth is reduced when the previous year's September is drier than normal, the current year's February is wetter than average, and the winter is colder than average. Results of these climate analyses illustrate a regional climate signal in Table Mountain pine stands. The best overall relationship between Table Mountain pine growth and climate was captured using the Palmer Drought Severity Index, which was used to reconstruct climate at the four sites for superposed epoch analysis (SEA). The SEA found no indication that antecedent weather patterns in previous years pre-condition these stands for fire occurrence. Rather, the SEA showed that fire is significantly associated with drought during the year of fire.