Southern Cascades

The Southern Cascades is characterized by volcanic peaks interspersed with more gentle slopes and topographic features. Vegetation is strongly influenced by topography and substrate (Parker 1991). Open woodlands comprised of blue oak (Quercus douglasii), interior live oak (Q. wislizeni), valley oak (Q. lobata), and grey pine (Pinus sabiniana) are commonly found in the southwestern foothills. In contrast, the northwestern foothills include sagebrush (Artemisia tridentata spp. tridentata), western juniper (Juniperus occidentalis), and ponderosa pine (P. ponderosa). Mixed-conifer forests dominate the mid-montane zone of the western portion of the bioregion, but the eastern portion is dominated by dry, pine-dominated forests (Skinner et al. 2006).

Indigenous people of the bioregion used frequent, low-moderate-intensity fires to promote the production of plants for food and fiber, for ceremonial purposes, and to improve hunting conditions (Long et al. 2016). Declines in fire frequency began when Euro-American settlers entered into the region. Settlers used fire to maintain forage for livestock and reduce densities in forests, a practice that was maintained well into the beginning of the 20th century. 

Area burned by forest was reduced in the bioregion due to effective fire suppression policies. The lack of fire has led to high density forests stocked with young trees (Taylor 2000). Places where low-moderate intensity surface fires were frequent now either have fires quickly suppressed or experience high intensity fires that escape initial containment.

References

Long, J.W., M.K. Anderson, L. Quinn-Davidson, R.W. Goode, F.K. Lake, C.N. Skinner. 2016. Restoring California black oak ecosystems to promote tribal values and wildlife. USDA Forest Service General Technical Report PSW-GTR-252. Pacific Southwest Research Station, Albany, California, USA.

Parker, A.J. 1991. Forest/environment relationships in Lassen Volcanic National Park, California, USA. Journal of Biogeography 18: 543-552.

Skinner, C.N., A.H. Taylor. 2006. Southern Cascades Bioregion. Pages 195-218. In: J.W. Van Wagtendonk, N.G. Sugihara, S.L. Stephens, A.E. Thode, K.E. Shaffer, J.A. Fites-Kaufman, editors. Fire in California’s Ecosystems. University of California Press, Oakland, California, USA.

Taylor, A.H. 2000. Fire regimes and forest changes along a montane forest gradient, Lassen Volcanic National Park, southern Cascade Mountains, USA. Journal of Biogeography 27: 87-104.