Modeling Prescribed Fire Effects on Vegetation Dynamics in Mid-Atlantic Oak and Pitch Pine Forests
Open Access
- Author:
- Zhao, Anthony
- Graduate Program:
- Geography
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- September 26, 2019
- Committee Members:
- Alan H Taylor, Thesis Advisor/Co-Advisor
Erica A H Smithwick, Committee Member
Cynthia Ann Brewer, Program Head/Chair - Keywords:
- Prescribed Fire
Oak Forests
Pitch Pine Forests
Mid-Atlantic
Modeling
Forest Management - Abstract:
- Fire is an important natural disturbance that drives ecosystem dynamics and is a valuable tool in forest management. Fire regimes and fire effects vary widely among and within regions. Historical data suggest that fire was an important disturbance agent in mid-Atlantic forests prior to widespread logging and other land use changes in the 18th and 19th centuries. These events were then followed by a period of fire suppression management through the 20th century. Exclusion of fire has altered forest composition, and there is increasing interest in using prescribed fire as a tool to restore fire as an important ecological process in these forests. However, the wide range of human-influenced forest conditions suggests that prescribed fire implementation could lead to a variety of ecological outcomes. This research uses simulation modeling to test the effects of varying forest conditions and fire regimes on potential ecological outcomes of prescribed fire. Field data on structure and composition of fire-dependent forests and the Forest Vegetation Simulator (FVS) are used to simulate forest response to variation in fire regimes, specifically fire frequency and duration of fire application. Modeling results suggest that for management of oaks such as in Pennsylvania, recurrent burning at low to medium frequencies, i.e. with a fire return interval of 10-30 years, applied over the long term would generally be effective towards maintaining or restoring oak and controlling the establishment of mesophytic competitors, as well as maintaining healthy forest structure within oak stands. Appropriate regime treatments, however, depend on present stand conditions. More frequent burning, e.g. at a five-year return interval, may be necessary to successfully promote regeneration and establishment of oak in stands that comprise a large mesophyte component. Relative pine dominance was directly and positively related to the presence and recurrence of fire, and increased both with shorter return intervals and with a longer period of fire application. Conversely, relative dominance of mesophytic hardwood species was directly but negatively related to the presence and recurrence of fire, and decreased with shorter return intervals and with a longer period of fire application. For management of pitch pine such as in the Pine Barrens of New Jersey, results show that recurrent burning maintained abundant pine establishment and was necessary to control hardwood establishment in pine stands. Frequent burning, especially over a longer period, increased relative pitch pine dominance and decreased the prevalence and establishment of hardwoods. A long-term regime of relatively frequent recurrent burning is therefore necessary towards maintaining the health and integrity of the pitch pine communities of the Pine Barrens. By exploring the ecological outcomes of prescribed fire, this research aims to provide tangible guidance for local forest management specialists implementing prescribed fire in oak and pitch pine forests in the mid-Atlantic region. Informed fire management will better promote the current and future health of vegetation communities and dynamics.