Dale D. Wade

Potential fire behavior in pine flatwood forests following three different fuel reduction techniques

Abstract A computer modeling study to determine the potential fire behavior in pine flatwood forests following three fuel hazard reduction treatments: herbicide, prescribed fire and thinning was conducted in Florida following the 1998 wildfire season. Prescribed fire provided immediate protection but this protection quickly disappeared as the rough recovered. Thinning had a similar effect on fireline intensity. Herbicides produced a dramatic decrease in fireline intensity from year 2 to 6 but had little effect on fire severity, thus increasing the likehood of root kill resulting in tree death if wildfire occurs during drought conditions. Treatment combinations, such as thinning and herbicide may provide immediate and long-term fireline intensity reductions as long as forest managers take into account each alternative’s strengths and weaknesses.

Influence of long-term dormant-season burning and fire exclusion on ground-dwelling arthropod populations in longleaf pine flatwoods ecosystems

Abstract Frequent dormant-season prescribed burns were applied at 1-, 2- and 4-year intervals to longleaf pine stands, Pinus palustris , for over 40 years on the Osceola National Forest in Baker County, Florida. Control plots were unburned for the same period of time. Pitfall traps were operated from November 1994 to October 1999 to measure the short- and long-term effects of prescribed burning frequency on the relative abundance and diversity of ground-dwelling macroarthropods. We also measured dead and live plant biomass to determine how long-term frequent fires affected the structure of the forest floor. The average total dead plus live plant biomass was significantly higher on plots where fire had been excluded. Annual and biennial burning resulted in about the same amount of total plant biomass (dead and live plant material combined) which was significantly less than the quadrennially burned plots. Shannon diversity ( H ′) and evenness of ground-dwelling arthropods were reduced by burning. Annually burned plots had the lowest diversity and evenness while biennially and quadrennially burned plots also were significantly lower than unburned control plots. Dormant-season burning did not increase the number of rare genera regardless of frequency. Percent similarity of arthropod communities was highest for comparisons between plots that had been burned (60–68%) and lowest for the comparison of annually burned plots to unburned controls (37%). Examination of diversity and similarity through time showed that changes were due to short-term effects caused by the application of fire and not long-term changes in the ground-dwelling arthropod community. Burning significantly reduced the numbers of predators regardless of fire frequency and resulted in an increased number of detritivores. A total of 42 genera were reduced by prescribed burning; 32 genera were captured in greater numbers on annually burned plots, and 11 genera had higher numbers in one or both of the intermediate burn frequencies (biennial or quadrennial). Twenty-six genera were captured in equal numbers on quadrennially and annually burned plots, but in significantly lower numbers than on unburned plots, demonstrating that 4 years was insufficient time for their populations to recover from mild dormant-season fires. Arthropod response to burning appeared to be species specific so attempts to generalize how arthropods will respond based on a few species or groups should be avoided. The slow recovery rate of so many species suggests that management oriented toward conservation of biodiversity in longleaf pine flatwoods should include areas of fire exclusion.

Wildland Fire in Ecosystems Effects of Fire on Flora

____________________________________ Brown, James K.; Smith, Jane Kapler, eds. 2000. Wildland fire in ecosystems: effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 257 p. This state-of-knowledge review about the effects of fire on flora and fuels can assist land managers with ecosystem and fire management planning and in their efforts to inform others about the ecological role of fire. Chapter topics include fire regime classification, autecological effects of fire, fire regime characteristics and postfire plant community developments in ecosystems throughout the United States and Canada, global climate change, ecological principles of fire regimes, and practical considerations for managing fire in an ecosytem context.

Ground-Dwelling Arthropod Association with Coarse Woody Debris Following Long-Term Dormant Season Prescribed Burning in the Longleaf Pine Flatwoods of North Florida

ABSTRACT A 5-year study of long-term (40 years) study plots was conducted on the Osceola National Forest in northern Florida to determine how dormant-season fire frequency (annual, biennial, quadrennial, or unburned) affects ground-dwelling macroarthropod use of coarse woody debris in longleaf pine (Pinus palustris Mill.) forests. Pitfall traps were used to sample arthropods near logs or metal drift fences of equal length. Samples were identified to genus or the lowest practical taxonomic level. Overall, significantly more arthropods and more arthropod biomass were captured near drift fences than near logs. Similarity of arthropods captured near logs or drift fences ranged from 64.4% in annually burned plots to 69.2% in quadrennially burned plots, with no significant differences noted. Likewise, Shannon diversity, evenness, richness, and number of rare genera were the same for traps regardless of the trap location. Interaction between fires and trap location were observed in 31 of 932 arthropod taxa. Of those, 10 taxa had significantly higher numbers captured in traps near logs in some burn treatments but there was no consistent pattern between log use and fire frequency. In most cases, more were captured in log pitfalls in frequently burned plots but that was not the case for at least 4 taxa. Where interactions between trap location and fire frequency were not significant, arthropods in an additional 101 taxa were captured in higher numbers at 1 trap location or the other. Of those, 73 were captured in higher numbers in pitfalls near drift fences and 28 were captured in higher numbers near logs. Results showed no increase in log usage by general or more mobile ground-dwelling arthropods as more frequent burning reduced the herbaceous and woody under story. However, logs were clearly important to a wide variety of arthropods regardless of burn frequency.

Fire exclusion as a disturbance in the temperate forests of the USA : Examples from longleaf pine forests

Abstract Forest fires are a disturbance where the effects can range from benign to extreme devastation within a given ecosystem. The stage of stand development coupled with prior management dictates the amount and composition of potential fuels. Thus, fire policy exerts a strong influence on fire effects. Changes in cultural acceptance and use of fire typically drive fire policy. This linkage is perhaps exemplified by Americas 300 year love/hate relationship with this powerful natural force. This article uses the four stages of stand development (stand initiation, stem exclusion, understory reinitiation and old-growth), as described by Oliver and Larson (1996), to present opportunities and constraints to fire use, and management options are suggested. Using a selective review of research in the USA that emphasizes the longleaf pine ecosystem in the south-east, the focus is on three themes presented from the viewpoint of a resource manager trying to attain a specific result. First, some high points in the history of fire in America and its ecological ramifications on the landscape are outlined, using examples to illustrate key concepts of behavior, intensity and periodicity. Secondly, examples are given of how people have sought to exclude fire from the landscape, often with disastrous consequences. Thirdly, the topic of prescribed fire in an ecosystem maintenance and restoration role is touched on. Some challenges associated with reintroducing fire into areas where past fire policy dictated its exclusion are also related.