About Field Sites
Soaproot Saddle (SOAP) is a terrestrial NEON field site located in the middle elevations of the Sierra National Forest, 56 km (35 mi.) northeast of Fresno near Auberry, CA. The 5.82 km2 (1440 acre) site is hosted by the U.S. Forest Service and is part of the U.S. Forest Service’s Major Land Resource Area (MRLA) 22A – Sierra Nevada mountains. The site is located in a mixed conifer forest that sits at the lower rain-snow transition line of the Sierras. It has complex terrain of coarse, steep hills and narrow drainages ranging from 1000 - 1400 m (3300 - 4600 ft.) in elevation. It is part of the Pacific Southwest Domain (D17), which is bounded by the Pacific Ocean on the west and the Sierra Nevada Mountains on the east, and encompasses most of California. There are four other NEON field sites in D17, including two additional terrestrial sites and two aquatic sites. It is colocated with the BIGC aquatic field site.   
SOAP has a typical Mediterranean, mid-montane climate. Located on the rain-snow transition line of the Sierras, the site is strongly seasonal with cool wet winters and warm dry summers. While higher elevations are snow dominated, SOAP receives winter snow that melts rapidly between weather events and a mean annual precipitation of 900.35 mm (35.4 in.). Mean annual temperature is 13.4°C (56°F), and winters are relatively mild with 212 frost free days per year. Drought and a warming climate have led to pine die-off caused by an outbreak of pine bark beetles, leaving the site at high fire risk due to large areas of dry, dead wood.    
The geology of SOAP is granodiorite and quartz monzonite. 
Major soil series that are mapped at the SOAP site are Holland (Fine-loamy, mixed, semi-active, mesic Ultic Haploxeralfs), Chaix (Coarse-loamy, mixed, superactive, mesic Typic Dystroxerepts), Chawanakee (Loamy, mixed, active, mesic, shallow Typic Dystroxerepts), and Tollhouse (Loamy, mixed, superactive, mesic, shallow Entic Haploxerolls).  
Ponderosa pine (Pinus ponderosa) and incense cedar (Calocedrus decurrens) dominate the overstory, with co-dominant canyon live oak (Quercus chrysolepis) and California black oak (Quercus kelloggii). However, the interaction of long-term drought and warming has exacerbated the outbreak of pine bark beetles, leading to high Ponderosa pine mortality and a potential shift in the forest community. Mariposa manzanita (Arctostaphylos viscida ssp. Mariposa) are interspersed throughout the understory and often form dense thickets in open areas, whereas deerbrush (Ceanothus integerrimus) and poison oak (Toxicodendron diversilobum) are common in the shaded understory. Mountain misery (Chamaebatia foliolosa) provides dense groundcover throughout much of the site. 
Current Land Management and Use
Soaproot Saddle is part of the U.S. Forest Service’s Major Land Resource Area (MRLA) 22A – Sierra Nevada mountains. The area is used for logging, grazing, and recreation - this includes quail, mule deer, and black bear hunting. Soaproot is managed by the High Sierra Ranger Station and Blue Canyon work station, which conduct controlled burns, logging, and herbicide application to manage the forest for timber and livestock production, as well as fire suppression.
The Critical Zone Observatory maintains an eddy-covariance flux tower and hydrological monitoring instruments to analyze the carbon and water balance and other atmospheric properties of the forest.  
NEON Site Establishment
NEON plot establishment at SOAP began in 2015 and was largely complete by the fall of 2016. The site transitioned to full operations in August 2018, and terrestrial sampling and observations began. The site’s 52 m (171 ft.) flux tower came online and began streaming data in September 2017.
 Kunch,Theresa. (2019). NEON Site-Level Plot Summary, Soaproot Saddle (SOAP), May 2019. https://data.neonscience.org/documents/10179/2361410/SOAP_Soil_SiteSumm…
 Terrestrial Observation System (TOS) Site Characterization Report: Domain 17. NEON.DOC.003900vB
 O'Geen et Al. 2018. Southern Sierra Critical Zone Observatory and Kings River Experimental Watersheds: A Synthesis of Measurements, New Insights, and Future Directions
 U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. https://mrdata.usgs.gov/mrds/
 PRISM Climate Group., Oregon State University, http://prism.oregonstate.edu, created 4 Feb 2004.
 Giger and Schmitt (1983) Soil Survey of Sierra National Forest Area, California. https://www.blogs.nrcs.usda.gov/Internet/FSE_MANUSCRIPTS/california/sie…
 Aquatic Instrument System (AIS) Site Characterization Report: Domain 17. NEON.DOC.003536vA.
 NEON RTE Endangered Species List
Remote sensing surveys of this field site collect lidar, spectrometer and high-resolution RGB camera data.
This site has a flux/meteorological tower that is 52 m (171 ft) tall with six measurement levels. The tower top extends above the vegetation canopy to allow sensors mounted at the top and along the tower to capture the full profile of atmospheric conditions from the top of the vegetation canopy to the ground. The tower collects physical and chemical properties of atmosphere-related processes, such as humidity, wind, and net ecosystem gas exchange. Precipitation data are collected by a tipping bucket at the top of the tower and a series of throughfalls located in the soil array.
Soil Sensor Measurements
This site has five soil plots placed in an array within the airshed of the flux tower. Photosynthetically Active Radiation (PAR) at soil surface, soil heat flux, solar radiation, and throughfall are measured at the soil surface in each soil plot. Soil moisture, soil temperature, and CO2 concentration are measured at multiple depths in each soil plot.
At terrestrial sites, field ecologists observe birds and plants, and sample ground beetles, mosquitoes, small mammals, soil microbes, and ticks. Lab analyses are carried out to provide further data on DNA sequences, pathogens, soils, sediments, and biogeochemistry. Learn more about terrestrial observations or explore this site's data products.
Field Site Data
US Forest Service
Site Access Allowed
Site Access Details
Researchers should coordinate directly with the US Forest Service for permitting and approval.
NEON Field Operations Office
Domain 17 Support Facility
NEON Field Operations Address
4727 West Shaw Avenue
Fresno, CA 93722
NEON Field Operations Phone
Mean Annual Temperature
Mean Annual Precipitation
Dominant Wind Direction
Mean Canopy Height
Dominant NLCD Classes
Evergreen Forest, Shrub/Scrub
Average number of green days
Average first greenness increase date
Average peak green date
Average first greenness decrease date
Average minimum greenness date
Number of Tower Levels
USGS Geology Unit
USGS Geology Name
Mesozoic granitic rocks, unit 3 (Sierra Nevada, Death Valley area, Northern Mojave Desert and Transverse Ranges)
USGS Lithologic Constituents
Primarily granodiorite, tonalite, quartz monzonite, and granite
USGS Geology Age
Permian to Tertiary; most Mesozoic
Megapit Soil Family
Fine, loamy, mixed, semiactive, mesic. Ultic Haploxeralfs.
Related Field Sites
Other Domain D17 Field Sites
Other Field Sites in CA