McRae Creek NEON / MCRA

McRae Creek (MCRA) is an aquatic NEON field site located within the H.J. Andrews Experimental Forest, 80 km (50 mi.) east of Eugene, OR in the Western Cascade Mountains. It is a third-order stream that drains a 3.93 km² (970 acre) old-growth coniferous forested watershed. H.J. Andrews is a 64 km2 (15,800 acre) ecological research site that is administered by Oregon State University, the USDA Forest Service’s Pacific Northwest Research Station, and the Willamette National Forest. It has been a part of the National Science Foundation’s Long-Term Ecological Research Program since 1980. It mainly consists of dense forests filled with cedar, hemlock, and Douglas fir trees, many of which are at least 300 years old and can grow as high as 75 m (250 ft.). MCRA 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: one additional aquatic and two terrestrial. [1] [2]

Winters in H.J. Andrews are wet and mild with warm and dry summers. Mean annual temperature at MCRA is 8.8°C (48°F) and annual precipitation is approximately 2188 mm (86 in.). Multiple winter storms are caused by low-pressure zones brought in by the polar front jet stream. They are slowed by the Coast and Cascade mountain ranges, which lower storm intensity and prolong duration. The dry, warm weather in the summer is caused by a ridge of high pressure along the coast and eastern Pacific. [7] [8]

The geology of H.J. Andrews is characterized by miocene aged undifferentiated flows and clastic rocks of basalt and andesite. The substrate within the creek is dominated by boulders, with some patches of cobble. [1] [5]

The soils at MCRA are well-drained and a mixture of medial silty loam, cobbly loam, and gravelly medial loam. [6]

The flow regime of McRae Creek is considered stable and dominated by groundwater input. Base discharge typically increases in the fall, remains high during the winter, peaks in spring due to snowmelt, and decreases to annual lows during the summer dry season. Winter storms and snowmelt create high discharge events, with very rare zero-flow days in the summer months. [1]

The Western Cascades eco-region is almost exclusively covered in dense coniferous forests, with dominant tree species changing with elevation. Below 1200 m (4000 ft.), Douglas-fir and western hemlock are the most common trees. As elevation increases, Pacific silver fir, mountain hemlock and subalpine fir begin to dominate. Above 2100 m (7000 ft.), alpine parklands and dwarf shrubs become dominant as conditions become too harsh for tree growth. The riparian area adjacent to McRae Creek consists of mature western hemlock (Tsuga heterophylla) and Douglas fir (Pseudotsuga menziesii) dominating the over-story canopy. Groundcover consists of vine maple (Acer circinatum), Pacific yew (Taxus brevifolia), dogwood (Cornus nuttallii), and alder (Alnus rubra). Most mature trees are 60-90 m (200-300 ft.) tall, while groundcover is often thick in areas adjacent to the stream. [1] [3]

The waterways of the Western Cascades are home to numerous fish, amphibians, and macroinvertebrates including coho salmon (Oncorhynchus kisutch) and rough skinned newt (Taricha granulosa). Within the streams of H.J. Andrews Experimental Forest, there are nine fish species: largescale sucker (Catostomus machrocheilus), mottled sculpin (Cottus bairdi), Paiute sculpin (Cottus beldingi), torrent sculpin (Cottus rhotheus), cutthroat trout (Oncorhyncus clarki), rainbow trout (Oncorhyncus mykiss), and Chinook salmon (Oncorhyncus tshawytscha). There are three amphibians: Cascade torrent salamander (Rhyacotriton cascadae), Pacific giant salamander (Dicamptodon tenebrosus), and tailed frog (Ascaphus truei). There are also approximately 90 species of macroinvertebrates. [2] [4]

H.J. Andrews was initially established as the Blue River Experimental Forest by the U.S. Forest Service in 1948. The name was changed in 1953 to honor Horace Justin Andrews, a U.S. Forest Service Region 6 Chief Forester, after he passed away during an automobile accident in 1951. Andrews was a strong supporter of forest research and helped select the location of the forest. H.J. Andrews was initially used to study possible improvements for forest operations, including forest regeneration and road engineering. Three experimental watersheds were created to study the effects of logging on hydrology, sediment yield, and nutrient loss. The watersheds were a clear-cut, partial cut, and an un-cut. The latter was left in its natural state as a control. In the 1970s, researchers from Oregon State University joined USFS scientists in new research topics that included nutrient fluxes, forest succession, disturbance ecology, and plant and animal diversity. Reference stands were also created for environmental monitoring. The forest became a member of the Long-term Ecological Research (LTER) Network in 1980, which led to the creation of new long-term studies that included landscape-level studies and different methods of ecosystem management. [2]

H.J. Andrews is administered cooperatively by the USDA Forest Service’s Pacific Northwest Research Station, Oregon State University and the Willamette National Forest. It has been a member of the Long-Term Ecological Research (LTER) Network since 1980. Most research at LTER sites is focused on how ecological processes change over long periods of time in relation to climate, management practices and other factors. At H.J. Andrews, research is focused on disturbance processes, landscape and water dynamics, carbon sequestration and fluxes, biological diversity, forest-stream interactions, spotted owl demography, soil and watershed processes, and cultural dimensions of forests and watersheds. [2]

Site characterization for McRae Creek began in October 2016 and establishment was completed in 2017. The aquatic observation system (AOS) began sampling in October 2017. The aquatic instrumentation system (AIS) began streaming in December 2017. The sampling strategy is based on hydrological data collected from nearby USGS hydrological monitoring locations in larger watersheds. The sampling strategy may not accurately represent the hydrologic conditions at this site and will be updated following annual data collections.