The Sky Oaks New site is located near the Sky Oaks Field station, owned and operated by San Diego State University. Chaparral vegetation, associated with a Mediterranean climate, covers nearly half of the rough and rocky terrain. Precipitation is almost exclusively confined to the winter months. During the summer and early fall, hot and dry Santa Ana winds from the northeast bring desert heat to the site. A high intensity natural wildfire occurred in approximately 1905. Physical characteristics prior to the 1905 burn are unknown, including stand age and canopy height. Currently, the Sky Oaks New site is an excellent representation of an old-growth chaparral ecosystem, with a canopy height of 2.3 m and chamise-dominated overstory.

The research and science objectives of the Sky Oaks New site are as follows: 1) Effects of elevated CO2 on belowground carbon dynamics in the chaparral ecosystem; 2) Investigate how elevated CO2 levels interact with a complex, patch landscape in a natural ecosystem with strong water and nutrient limitations; 3) Investigate the effects of elevated CO2 levels on root growth and on microbial biomass, activity, and community structure in a chaparral ecosystem of southern California; 4) Understand how major soil energy channels, such as bacteria-protozoa/nematodes, fungi-mites/collembola, and mycorrhizal fungi, simultaneously respond to elevated CO2 and then to examine potential interactions among these components; 5) Characterize the relationship between NEE and interannual variability in rainfall, the major limiting factor in most arid and semiarid ecosystems; 6) Examine the correlations between photosynthesis, light use efficiency, and various spectral reflectance indices over a range of timescales in a Southern California chaparral ecosystem as a basis for evaluating the light use efficiency model. (Treseder et al., 2003, Lipson et al., 2005, Allen et al., 2005, Sims et al., 2006, Luo et al., 2007)