4.                            C A S C A D E S                                                                                                                                                                                                                                                                                                                                                                             

      Level IV Ecoregion                                   Physiography                                                              Geology                                                                          Soil                                                                        Climate                                            Potential Natural                         Land Use and Land Cover    
                                Area                                                           Elevation /                  Surficial material and bedrock                Order (Great Groups)                             Common Soil Series                Temperature  /     Precipitation     Frost Free      Mean Temperature                       Vegetation                                                       
                               (square                                                        Local Relief                                                                                                                                                  Moisture Regimes    Mean annual       Mean annual      January min/max;
                               miles)                                                             (feet)                                                                                                                                                                          (inches)            (days)      July min/max, ( F)                                                                                      

4b. Western Cascades  4557 Steep, glaciated, dissected mountains and                          2800-5900 Oligocene-Miocene andesitic and basaltic                    Inceptisols (Haplumbrepts),              Keel, Hummington, Aschoff, Bull                    Frigid,           70-120           80-120              26/37;           Pacific silver fir, western hemlock,           Extensive Pacific silver fir/western hemlock/
                                           ridges with high to medium gradient streams              /          lava flows and breccia.                              Andisols (Hapludands,                    Run, Illahee, Mellowmoon. Very deep                 Cryic/                                                44/75            mountain hemlock, Douglas-fir; some  Douglas-fir/mountain hemlock/noble fir/sub-  
      Montane                                                                                                                                                                                                                                                                                                                                                                                                             
                                           and glacial rock-basin lakes.                      2000-3100                                                             Fulvicryands, Haplocryands)              to moderately deep, silt loam, gravelly              Udic                                                                  noble fir. Ecoregion 4b is higher in           alpine fir/grand fir/white fir forests. Common
      Highlands                                                                                                                                                                                              silt loam, gravelly loam, cobbly loam.                                                                                     elevation than Ecoregion 4a and is             land uses include forestry and recreation. Eco-
                                                                                                                                                                                                                                                                                                                                        snow influenced.                               region 4b is an important regional water source.