Effect of long-term understory prescribed burning on standing and down dead woody material in dry upland oak forests

• Published in: Forest ecology and management Vol. 291; pp. 128 - 135
• Main Authors: Polo, John A., Hallgren, Stephen W., Leslie, David M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.03.2013; Elsevier
• Subjects: Americas; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; carbon sequestration; carbon sinks; Coarse woody debris; Combustion; energy; Fine woody debris; fire suppression; Fires; food webs; forest litter; forest management; Forestry; Forests; fuels; Fundamental and applied biological sciences. Psychology; ice; landscapes; long term effects; montane forests; Oak; prescribed burning; Quercus marilandica; Quercus stellata; savannas; Snags; Stands; storms; Supports; Synecology; Terrestrial ecosystems; understory; wildlife habitats; Wildlife management; wind; woody plants; North America; Quercus marilandica; Coarse woody debris; Fine woody debris; Quercus stellata; Snags; Organic matter; Forests; Upland area; Dead tree; Snag; Forest ecology; Physical environment; Fagaceae; Long term; Controlled burning; Understory; Dicotyledones; Dead wood; Angiospermae; Forestry; Spermatophyta; Hardwood forest tree; Vegetation structure; Stump(tree)
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/j.foreco.2012.10.048

► Understory prescribed burning dry oak forests has no effect on amount of dead wood. ► Understory prescribed burning dry oak forests has no effect on density of snags. ► Dry oak forest fire suppression did not increase standing and down dead wood. ► Stand history and severe weather may affect deadwood more than prescribed fire. Dead woody material, long ignored or viewed as a nuisance for forest management, has gained appreciation for its many roles in the forest including wildlife habitat, nutrient storage and cycling, energy for trophic webs, protection of soil, fuel for fire and carbon storage. The growing interest in managing dead woody material has created strong demand for greater understanding of factors controlling amounts and turnover. Prescribed burning, an important management tool, may have strong effects of dead woody material given fire’s capacity to create and consume dead woody material. We determined effects of long-term understory prescribed burning on standing and down woody material in upland oak forests in south-central North America. We hypothesized that as frequency of fire increased in these stands the amount of deadwood would decrease and the fine woody material would decrease more rapidly than coarse woody material. The study was conducted in forests dominated by post oak (Quercus stellata) and blackjack oak (Quercus marilandica) in wildlife management areas where understory prescribed burning had been practiced for over 20years and the range of burn frequencies was 0 (unburned) fires per decade (FPD) to 4.6 FPD. The amount of deadwood was low compared with more productive forests in southeastern North America. The biomass (24.7Mgha−1) and carbon stocks (11.7Mgha−1) were distributed among standing dead (22%), coarse woody debris (CWD, dia.>7.5cm., 12%), fine woody debris (FWD, dia.⩽7.5cm., 23%), and forest floor (43%). There was no evidence that understory prescribed burning influenced the amount and size distribution of standing and down dead woody material. There were two explanations for the lack of a detectable effect. First, a high incidence of severe weather including ice storms and strong winds that produce large amounts of deadwood intermittently in an irregular pattern across the landscape may preclude detecting a strong effect of understory prescribed burning. Second, fire suppression during the first one-half of the 20th Century may have led to encroachment of woody plants into forest gaps and savannas creating a patchwork of young and old stands that produced deadwood of different sizes and at different rates.