Small-scale fire temperature patterns in upland Quercus communities

• Published in: The Journal of applied ecology 1997-06, Vol.34 (3), p.613-630
• Main Authors: FRANKLIN, S. B, ROBERTSON, P. A, FRALISH, J. S
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Conservation, protection and management of environment and wildlife; Environmental degradation: ecosystems survey and restoration; Forest and land fires; Fundamental and applied biological sciences. Psychology; Phytopathology. Animal pests. Plant and forest protection; Quercus; Weather damages. Fires
• ISSN: 0021-8901; 1365-2664
• DOI: 10.2307/2404911

Two upland Quercus sites were burned during the dormant season to assess small-scale spatial effects of fire on forest community structure. Fuel data were obtained prior to burning, fire temperatures at three heights were taken during the fire, and microtopographic and vegetation data were collected following the burn. Spatial analysis and pattern analysis were employed to examine fire temperature patterns in relation to microtopography and fuels, and fire temperature effects on vegetation. Fire temperatures at the surface, 33 cm above surface, and 75 cm above surface were light to moderate ranging from 52 to 260 degree C. These light temperature fires probably have no adverse effect on nitrogen in the system, but also have little effect on vegetation composition. Fire temperature patterns were affected by litter/duff biomass when slope steepness was low (i.e. slope < 20 degree ). Steeper slopes had a stronger effect on fire temperature patterns, thereby masking the influence of fuel biomass. Thus, the direct and indirect effects of topography on fire behaviour may be more important than fuel loading when assessing the effects of prescribed burns in eastern deciduous upland forests. Areas previously burned were found to have similar fire patterns to previously unburned areas. However, fire severity was greatest in the previously burned areas. Thus, the influence of fire on vegetation may have cumulative effects. The spatial structure of the prescribed burn influenced the patterns of vegetation response. However, all species sprouted indicating an insignificant effect of fire on vegetation composition. Different sampling designs may be required for assessing fire phenomena as slope steepness varies. For example, sampling quadrats may need to be closer together on level terrain than on sites with slopes > 20 degree . In addition, independent samples must be further apart to assess accurately the effects of fire at varying distances above the soil surface, in comparison to distances between samples assessing surface fire effects.