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Fire and Fire Risk in the Umpqua Basin

Most of the Umpqua Basin's landscape and climate favor conifer forests, especially Douglas-fir.  In the Coast Range region, mild temperatures and wet winters result in lush, dense forests.  Sitka spruce and western hemlock forests are common along the Pacific coast.  Moving further inland, forests are dominated by Douglas-fir and include other species such as western hemlock, bigleaf maple, and incense cedar.  Red alder is commonly found along stream corridors. 

In the Klamath Mountains region, vegetation in the lowlands and valleys is very diverse.  Pastures and agricultural crops such as vineyards, row crops, and orchards are intermixed with oak savannas, oak woodlands, and forests of Douglas-fir and Ponderosa pine.  In higher elevations, forests are a mixture of conifers and hardwoods.  Douglas-fir is still the dominant tree species but other species such as Ponderosa pine, incense cedar, golden chinquapin, and Pacific madrone are common.  Throughout this region, invasive species such as Himalayan blackberry and Scotch broom are abundant. 

In the lower elevations of the Cascades region, forests are a mixture of Douglas-fir, grand fir, white fir, and western hemlock.  At the highest elevations, mixed conifer forests include species such as mountain hemlock, noble fir, grand fir, white fir, Engelmann spruce, and lodgepole pine.  As with the Coast Range region, hardwoods are found within conifer-dominated stands and along streams. 

In all three regions, fire has played an important role in shaping forest composition and structure.  In the western portion of the Coast Range region, fires have historically been infrequent.  However, when they do occur, they are generally large, stand-replacing fires.  Lightning fires were once common in Douglas-fir/western hemlock forests, especially in the late summer and fall.  Historically, these stand-replacing fires were smaller than in the Coast Range.  Fire suppression has eliminated many of the natural wildfires; now, wildfires that do occur are often high-severity fires.  In the low valleys of the Klamath Mountains region, annual burning by Native Americans historically resulted in open oak savannas and lush, vast prairies.  Since burning stopped, the savannas and prairies have been replaced by oak woodlands and conifer forests intermixed with cities and rural residential developments.

Authored by Jay Walters, private consultant, Barnes and Associates (2006)

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