Sprouting shrub response to different seasons and fuel consumption levels of prescribed fire in Sierra Nevada mixed conifer ecosystems
1990
Kauffman, J.B. | Martin, R.E.
Virtually all shrub species present in mixed coniferforests of the Sierra Nevada have evolved specialized adaptations to survive the frequent lowintensity surface fires that characterized the fire regime of this ecosystem. In this study weexamined the variable sprouting response of broad-leaved shrubs and hardwoods following prescribed fires burned under a wide range of environmental and fuel conditions.Shrub survival was often dramatically different between treatments (i.e., fuel consumptionlevel and season of burn), species, and size classes within plant species. Of the four different burn treatments, survival of the shrubs and hardwoods was as low as 12% after earlyfall burns (high levels of fuel consumption) and as high as 79% after earlyspring burn treatments (moderate levels of fuel consumption). As much as 95% of thesmallest size of the small classes of shrubs (i.e., those less than or equal to 50 g dryweight biomass) were killed by prescribed fires. In contrast, the majority of largerindividuals survived fires of low-moderate consumption, but rates of survival declined with increasing levels of fuelconsumption. Post-fire shrub physiognomy was significantly lower in crownvolume, crown area, height, and aboveground biomass. The number of individual shrubstems per individual significantly increased after fire. Postfire biomass partitioningwas different among sprouting species; in the deciduous-leaved Quercus kelloggii, the percentage of aboveground biomass composed of leaves was lower, and the percentage composedof woody tissues was higher than that of the evergreen-leaved Lithocarpus densiflorus.
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