Study Areas


Cascade Head Experimental Forest, OR (photo by Al Levno)

 

Pringle Falls Experimental Forest, OR

Warm Springs Reservation, OR (photo by Jay Sexton)

 

Logs were sampled at eight different locations in the Western U.S. (Table 1, Figure 1). The majority (5) of sites were in Oregon, but sites in Washington, Colorado and California were also examined. A range of climates are represented, with site mean annual temperatures ranging from 0.5 to 10 C, and total annual precipitation ranging from 737 to 2489 mm year-1 (Figure 2).  General characteristics of each site are described below.   

Cascade Head Experimental Forest (CHEF), Oregon

Cascade Head is located on the north-central coast of Oregon, 8km north of Lincoln City.  It lies entirely within the Hebo Ranger District of the Siuslaw National Forest.  The site is in the Oregon Coast Range region and the forests are representative of the sitka spruce-western hemlock (Picea sitchensis-Tsuga heterophylla) and Douglas-fir (Pseudotsuga menziesii) zones of the region.  Soils, derived primarily from tuffaceous siltstones, are fine textured, moderately well drained, and deep (up to 100+ cm).  Because of the Pacific Ocean influence, CHEF has a moderate and very wet climate.  Mean annual temperature is 10 C (50 F) with minimal seasonal variation.  Average yearly rainfall is 2489 mm (98 in.), although fog drip through the forest canopy can add 500 mm or more precipitation a year. 

Fraser Experimental Forest (FEF), Colorado

Fraser Experimental Forest is located in the heart of the central Rocky Mountains, about 50 air miles from Denver.  FEF includes subalpine forests typical of the area, with Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) predominating at higher elevations and lodgepole pine (Pinus contorta var. latifolia) predominating at lower elevations and on drier upper slopes.  Soils are generally derived from gneiss and schist and typically contain angular gravel and stone with very little silt or clay.  These soils are very permeable and can store considerable water during snowmelt.  Climate varies strongly with elevation.  Overall, the climate is cool and humid with long, cold winters and short, cool summers.  Mean annual temperature at the Fraser Forest headquarters is 0.5 C (34 F) and mean annual precipitation over the entire FEF is 737 mm (29 inches). 

H. J.  Andrews Experimental Forest (HJAF and FRIS), Oregon

H. J.  Andrews Experimental Forest is located approximately 5 miles east of Blue River, Oregon, within the Willamette National Forest.  The HJAF plots are primarily located in lower elevation forests that are dominated by Douglas-fir, western hemlock, and western redcedar (Thuja plicata).  The FRIS plot is located in upper elevation forest that contains noble fir (Abies procera), pacific silver fir (Abies amabilis), Douglas-fir, and western hemlock.  Throughout the experimental forest soils are mainly Inceptisols (some undoubably Andisols) with local areas of Alfisols and Spodosols.  The maritime climate has wet, mild winters and dry, cool summers. The average temperature at lower elevation is 9.5 C (49 F) and the average precipitation is 2500 mm (98 inches).  The average temperature at higher elevation is 6.7 C (44 F) and the average precipitation is 2221 mm (87 inches).  

Klamath Ranger District, Winema National Forest (KRD), Oregon

The Klamath Ranger District of the Winema National Forest is located in south-central Oregon, 35 miles northwest of Klamath Falls and south of Crater Lake National Park.  Elevations on this Ranger District range from 1,277 to 2,430 m (4,200 feet to 8,000 feet).  The topography is mountainous and dissected. Conifer forests are the dominant vegetation, and fall within the mixed conifer, white fir (Abies concolor), Shasta red fir (Abies magnifica), and mountain hemlock (Tsuga mertensiana) zones of Franklin and Dyrness (1973).  Mixtures of white fir, ponderosa pine (Pinus ponderosa), and Douglas-fir occur at the lowest elevations and red fir, mountain hemlock, western white pine (Pinus monticola) and lodgepole pine occur at the highest elevations (Hopkins 1979).  Soils are generally well-drained, gravelly and cobbly fine sandy loams to loam, with 10-75% coarse fragments (Carlson 1979).  The climate is characterized by cold, snowy winters and warm, dry summers (Carlson 1979).  The mean annual temperature is 4.4 C (40 F).  Mean annual precipitation is 1054 mm (41.5 inches).  

Pringle Falls Experimental Forest (PFEF), Oregon

Pringle Falls Experimental Forest is located in central Oregon, about 6 miles west of La Pine, within the Deschutes National Forest.  The forests are characteristic of low elevation forests within the High Cascades physiographic province and are comprised of ponderosa pine, lodgepole pine, and higher elevation mixed conifer.  Soils are derived from aerially deposited Mount Mazama pumice and ash with only a thin weathered surface layer.  Most of the soil profile is undeveloped, with low organic matter content and high porosity.  The climate at PFEF is continental, and most precipitation occurs as snowfall.  Annual precipitation averages 813 mm (32 inches) and the average temperature is 7 C (45 F). 

Sequoia National Park (SQNP), California 

Sequoia National Park is located in the Sierra Nevada mountain range of East-Central California within Tulare and Fresno Counties.  The sample plots for this study were located in the Giant Forest region of the park.  Vegetation in this region is typical for midelevation mixed conifer forests in the Sierra Nevada (Rundel et al. 1977).  The forests of this area are dominated by white fir, red fir (Abies magnifica), incense cedar (Calocedrus decurrens), sugar pine (Pinus lambertiana), Jeffrey pine (Pinus jeffreyi), and giant sequoia (Sequoiadendron giganteum) (van Mantgem et al. 2003).  Soils are primarily Pachic Xerumbrepts, derived from granodiorite (Huntington and Akeson 1987).  The climate of this area is Mediterranean, with wet, snowy winters and long, dry summers.  The mean annual precipitation is 1255 mm (49 inches), with approximately half occurring as snow.  The mean annual temperature is 8 C (46 F).

Warm Springs Reservation (WSR), Oregon.

The Warm Springs reservation plots are located in north central Oregon, approximately 8 miles from the town of Government Camp and bordering the Mt. Hood National Forest.    The forests are characteristic of mid to high elevation forests within the High Cascades physiographic province and are comprised of Douglas-fir, western hemlock, noble fir, pacific silver fir, and higher elevation mixed conifer.    The climate is characterized by cold, snowy winters and warm, dry summers.  The mean annual temperature is 8.3 C (47 F).  Mean annual precipitation is 1778 mm (70 inches).  

Wind River Experimental Forest (WREF), Washington.

The Wind River Experimental Forest is near Carson, Washington in the Gifford Pinchott National Forest.  The forest is classified as a western hemlock/salal (Gaultheria shallon) cover type, and is estimated to be ~500 years old.  Dominant tree species are Douglas-fir and western hemlock.  Dominant understory shrub species are vine maple (Acer circinatum), salal, and dwarf Oregon grape (Berberis nervosa).  Soils are of the Stabler series, coarse textured and developed on 2 to 3 meters of volcanic ejecta over basalt bedrock.  Texture ranges from shotty loam to clay with coarse particles in the top 1 m averaging 3% of the soil volume.  The climate is characteristic of a temperate winter-wet, summer-dry climate. Annual precipitation totals 2467 mm with less than 10% occurring between June and September.  Mean annual temperature is 8.7°C.

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