Wind River Experimental Forest NEON / WREF

Wind River Experimental Forest (WREF) is a terrestrial NEON field site located 60 km (37 mi.) northeast of Vancouver, WA. The 42 km² (10,400 acre) site lies within the Wind River Experimental Forest in the south central area of the Gifford Pinchot National Forest, which is managed by the U.S. Forest Service. While best known for its old-growth Douglas fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla) stands, the forest is a mosaic of tree ages due to management practices and wildfire history. Known as the cradle of forestry in the Pacific Northwest, the Wind River Experimental Forest has a long history of ecology and silviculture studies. WREF is located in NEON's Pacific Northwest Domain (D16), which is bounded by the Pacific on the west and Canada on the north. It includes the eastern halves of Washington and Oregon and parts of northern California. The Domain hosts three other field sites: two aquatic and one additional terrestrial. It is near the MART aquatic site. [1]

The climate of WREF is significantly influenced by its close proximity to the Columbia River Gorge, with secondary orographic lifting effects from the Cascade Range. Warm, dry summers and cool, wet winters are the norm, with approximately 2225 mm (87.6 in.) of annual precipitation in the form of rain and snow and a mean annual temperature of 9.2°C (49°F). Interannual variation plays a major role in yearly precipitation levels; the El Niño Southern Oscillation is a driving force behind warmer, drier years, which lead to an increased chance of drought and wildfires. [5] [10]

The geology of the majority of plots at WREF are defined by Pleistocene-age basalt and andesite flows of the Trout Creek formation, often covered by volcanic mudflows and ejecta. The remaining plots are situated five kilometers away on steep mountain slopes formed of volcanoclastic breccias and tuffs. [3] [8]

Soils in the vast majority of plots at WREF are derived from andesite and basalt bedrock, supplemented by airborne pumice and volcanic ash. The minority originate from chemically and physically weathered volcanoclastic tuffs and breccias. Despite differences in parent material, WREF soils classify as Vitric Hapludands and are part of the Stabler or Stabler taxadjunct series. This series, as with most volcanic soils in the Pacific Northwest, displays andic properties deriving from a significant percentage of weathered volcanic glass present in the soil. [2] [3]

The two divisions of the experimental forest are named for their permanent tributaries of the Wind River: Trout Creek to the west, and Panther Creek to the east. Other small permanent and ephemeral streams drain into the creeks. The Wind River itself originates about 25 km (15 mi.) north of the forest and its watershed covers over 580 km² (225 sq. mi.), supporting a fifth-order system of streams that flow south into the Columbia River Gorge. [9]

Often more than 450 years old, older stands in Wind River Experimental Forest are dominated by Douglas fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). Canopy species throughout the rest of forest include grand fir (Abies grandis), noble fir (Abies procera), Pacific dogwood (Cornus nuttallii), Western red cedar (Thuja plicata), and red alder (Alnus rubra). The understory includes vine maple (Acer circinatum), salal (Gaultheria shallon), and Oregon grape (Mahonia aquifolium). [1]

The Wind River Experimental Forest supports many large mammals including elk (Cervus canadensis), black-tailed deer (Odocoileus hemionus columbianus), bobcat (Lynx rufus), cougar (Puma concolor), coyote (Canis latrans), black bear (Ursus americanus), marten (Martes americana), several species of weasels, and many species of small mammals including the Douglas squirrel (Tamiasciurus douglasii). Birds of all sizes inhabit the forest, including the Northern spotted owl (Strix occidentalis caurina), which is federally listed as a threatened species. [1]

Forest research began in the Wind River Valley in 1909 with the establishment of a seedling nursery aimed to repopulate local areas devastated by the severe wildfires of the early 20th century, including the 1902 Yacolt Burn. In the same year, long-term studies of Douglas-fir (Pseudotsuga menziesii) ecology were initiated by Thornton T. Munger in old-growth stands within the valley. Establishment of an arboretum and experimental station in the early 1910s and the official establishment of the Wind River Experimental Forest in 1932 solidified the area as a center of research which became the cornerstone of Douglas-fir silviculture and management in the Pacific Northwest. [4] [6]

Managed cooperatively by the U.S. Forest Service Pacific Northwest Research Station and Gifford Pinchot National Forest, the Wind River Experimental Forest has been home to silvicultural studies and forest research since 1909, with many decades-long projects continuing to this day. The 1994 installation of a 75 m (250 ft.) canopy crane allowed researchers to access over 24,000 m² (6 acres) of old-growth canopy and study tree physiology, canopy-atmosphere gas exchange, nutrient cycling, epiphyte biology, climate monitoring, and much more. The crane was removed in 2011, but the 70 m (230 ft.) tower remains, sporting sensors and data collectors used by NEON and other organizations to monitor gas exchange, carbon flux, and isotope data. Besides forest research, the experimental forest is also managed for logging and day-use recreational activities, including several kilometers of the Pacific Crest National Scenic Trail. [6]

TOS Distributed Plots were allocated at WREF according to a spatially balanced and stratified-random design. The 2006 National Land Cover Database (NLCD) was selected for stratification because of the consistent and comparable data availability across the United States. TOS Tower Plots were allocated according to a spatially balanced design in and around the NEON tower airshed. Due to increased hiking times at this site, plot allocation was constrained to areas near roads and hiking trails. TOS and TIS sampling began in June and July 2018, respectively. [1]