Dendroecology

Fire history in western Patagonia from paired tree-ring fire-scar and charcoal records

by Andrés Holz

Wildfire activity in rainforests in western Patagonia linked to the Southern Annular Mode

by Andrés Holz

Pilgerodendron uviferum: the southernmost tree-ring fire recorder species

by Andrés Holz

Three centuries of fire in montane pine‐oak stands on a temperate forest landscape

by Serena Aldrich

Boudary-line growth patterns to determine disturbance history of remnant longleaf pine in mixed forests of southeastern Virginia

by Arvind Bhuta

Co-authored with Lisa M. Kennedy (2nd author), Carolyn A. Copenheaver (3rd author), Philip M. Sheridan (4th author), James B. Campbell (5th author)

Removal of canopy dominant trees in temperate closed-canopy forests due to natural or anthropogenic disturbance may... more Removal of canopy dominant trees in temperate closed-canopy forests due to natural or anthropogenic disturbance may allow for the release of co-dominant and sub-canopy trees into the canopy. Historical growth releases of these trees can be reconstructed from the analysis of their annual rings and compared with historical disturbance events to better understand forest dynamics. We applied boundary-line growth patterns, a method for the reconstruction of historical release from disturbance, to annual-ring series of co-dominant longleaf pine in two closed-canopy successional forest sites (Everwoods and Seacock Swamp) the Mid-Atlantic Coastal Plain of southeastern Virginia. The somewhat degraded stands were co-dominated by mixed hardwoods and loblolly pine (Pinus taeda L.) after a long fire-free history. Our study documented recruitment patterns through age-class distribution and reconstructed disturbance events (growth releases) using a modified version of the boundary-line growth method. Ages for all cored individuals at Everwoods (n = 37) ranged from 32–184 years (x = 53 years), and at Seacock Swamp (n = 32), from 56–175 years (x = 94 years). Longleaf pine has failed to recruit over the past two
decades at Everwoods, and over the past half-century at Seacock Swamp, probably due to increased competition and habitat decline in the absence of fire. Boundary-line growth patterns revealed moderate and major release events for longleaf pines at both sites that we linked to anthropogenic disturbances, such as silvicultural operations (1900s to the 1930s) at both sites and logging by the landowner (early 1950s) at Seacock Swamp. We interpreted extremely low growth rates and dramatic growth-change pulses after disturbance as evidence of heavy suppression atypical for this species, which has been conceptualized as shade-intolerant. Our findings fit with other studies that have suggested that longleaf pine may be less shade tolerant than formerly thought, at least in some areas or sites. Applications of the boundary-line growth
patterns method to old-growth and second-growth longleaf pine forests throughout the southeastern U.S. could help to document possible spatial variability in disturbance histories, responses to releases, and suppression patterns.

Canopy disturbance patterns in secondary hardwood stands on the Highland Rim of Alabama

by Arvind Bhuta

Co-authored with Justin L. Hart (1st author), Department of Geography, University of Alabama, Tuscaloosa, AL and Rebecca M. Schneider (3rd author), Conservation Management Institute, Blacksburg, VA. I am second author.

Disturbance regimes of many hardwood forests of the eastern United States in the complex stage of development are... more Disturbance regimes of many hardwood forests of the eastern United States in the complex stage of development are characterized by localized canopy disturbance events
that change fine-scale biophysical conditions. Recently, research has demonstrated the importance of gap-scale disturbance processes in secondary hardwood stands of the southern Appalachian Highlands. However, information on canopy disturbance patterns during early developmental stages is required from the broader geographic region for a comprehensive understanding of stand dynamics. The goal of this study was to reconstruct canopy disturbance history for mixed hardwood stands on the Highland Rim of Alabama to elucidate disturbance patterns during early development. We analyzed radial growth from 46 Quercus individuals to reconstruct canopy disturbance history. The majority (67%) of the trees analyzed exhibited release events. In total, 42 releases were detected and some trees experienced multiple events. Of these releases, 28 (67%) were classed as minor and 14 (33%) were classed as major. Mean release duration was 4.00 years 6 0.21 (SE) and the longest release was sustained for eight years. Based on mean release duration, we speculate that most of the canopy gaps were filled by lateral crown expansion rather than subcanopy height growth. We did not document any forest-wide disturbance events; a pattern that may be a regional phenomenon or may be related to forest age. Canopy disturbances became common after ca. 40 years of development. We propose that the frequency of canopy gaps will decrease and the size and magnitude of individual gaps will increase as the stands mature.

Canopy disturbance patterns in secondary hardwood stands on the Highland Rim of Alabama

by Arvind Bhuta

Co-authored with Justin L. Hart (1st author), Department of Geography, University of Alabama, Tuscaloosa, AL and Rebecca M. Schneider (3rd author), Conservation Management Institute, Blacksburg, VA. I am second author.

Disturbance regimes of many hardwood forests of the eastern United States in the complex stage of development are... more Disturbance regimes of many hardwood forests of the eastern United States in the complex stage of development are characterized by localized canopy disturbance events
that change fine-scale biophysical conditions. Recently, research has demonstrated the importance of gap-scale disturbance processes in secondary hardwood stands of the southern Appalachian Highlands. However, information on canopy disturbance patterns during early developmental stages is required from the broader geographic region for a comprehensive understanding of stand dynamics. The goal of this study was to reconstruct canopy disturbance history for mixed hardwood stands on the Highland Rim of Alabama to elucidate disturbance patterns during early development. We analyzed radial growth from 46 Quercus individuals to reconstruct canopy disturbance history. The majority (67%) of the trees analyzed exhibited release events. In total, 42 releases were detected and some trees experienced multiple events. Of these releases, 28 (67%) were classed as minor and 14 (33%) were classed as major. Mean release duration was 4.00 years 6 0.21 (SE) and the longest release was sustained for eight years. Based on mean release duration, we speculate that most of the canopy gaps were filled by lateral crown expansion rather than subcanopy height growth. We did not document any forest-wide disturbance events; a pattern that may be a regional phenomenon or may be related to forest age. Canopy disturbances became common after ca. 40 years of development. We propose that the frequency of canopy gaps will decrease and the size and magnitude of individual gaps will increase as the stands mature.