Approach
EASTERN: Forest structure and composition may interact with longer and drier growing seasons to increase the risk of wildfire. Mortality from climate-related disturbances can lead to increases in fuel loading, which can increase the risk or severity of fire. Although some forest types are tolerant of or dependent on fire, extremely hot fires can destroy seed banks, sterilize soils, induce hydrophobic soil conditions, or cause tree mortality. Management actions to alter species composition or ecosystem structure may reduce susceptibility to these threats.
WESTERN: Forest structure and composition in many locations (e.g., dense, second growth stands with accumulations of surface and ladder fuels) may interact with longer and drier fire seasons to increase the risk, rate of spread, intensity of wildfire. Mortality from climate-related disturbances can lead to further increases in fuel loading, which can increase the risk or severity of fire. Although many forest types in California are tolerant of or dependent on fire, extremely hot fires can destroy seed banks, sterilize soils, induce hydrophobic soil conditions, or cause extensive tree mortality. These large, high-severity fires can create long-term challenges for regeneration of prior forest or shrubland conditions. Management actions to alter species composition or ecosystem structure in mixed conifer forests may reduce susceptibility to these threats.
Tactics
- Using prescribed fire and thinning to reduce surface fuels, increase height to live crown, decrease crown closure, and create a more open forest structure that is expected to be less vulnerable to severe wildfire.
- Using prescribed fire to maintain open conditions in ecosystems at lower elevations as a means of reducing fuels and the risk of wildfire in ecosystems at higher elevations.
- Promoting fire-resistant species, such as hardwoods, in buffer zones between more flammable conifers to slow the movement of wildfires.
- Physically removing dead or dying trees or other vegetation to reduce surface and ladder fuels, while minimizing exposure to invasive plants, pests, or pathogens.
- Enhancing forest structural heterogeneity by emphasizing variable inter-tree distances, varying densities based on topography, and creating a combination of individual trees, tree clusters, and canopy openings (known as the “ICO pattern”)...
- In areas of steeply rising topography, using prescribed fire to maintain open conditions in ecosystems at lower elevations as a means of reducing fuels and the risk of high severity wildfire in ecosystems at higher elevations. Also using mechanical...
- Promoting growth of large, fire-resistant species, such as hardwoods and yellow pines (such as ponderosa pine (Pinus ponderosa) and Jeffrey pine (Pinus jeffreyi)), in buffer zones between more flammable conifers (such as white fir (Abies concolor)...
Strategy
Strategy Text
Climate change is projected to continue to increase the potential for severe disturbance events, such as uncharacteristically large and severe wildfires, floods, severe and extended drought, and insect outbreaks. These disturbances have the ability to alter community composition and structure, potentially for many decades or longer, over large landscapes. Disturbances can also interact with other stressors. For example, extreme drought can cause tree damage and mortality, which increase the risk of insect outbreaks and potentially influence wildfire behavior. Even as trends continue to emerge, management will need to adjust appropriately to the changes in natural disturbance dynamics.
1. Swanston, C.W.; Janowiak, M.K.; Brandt, L.A.; Butler, P.R.; Handler, S.D.; Shannon, P.D.; Derby Lewis, A.; Hall, K.; Fahey, R.T.; Scott, L.; Kerber, A.; Miesbauer, J.W.; Darling, L.; 2016. Forest Adaptation Resources: climate change tools and approaches for land managers, 2nd ed. US Department of Agriculture, Forest Service, Northern Research Station. 161 p. http://dx.doi.org/10.2737/NRS-GTR-87-2