The US Environmental Protection Agency - Western Ecology Division (EPA) has been monitoring above- and belowground climate data from 23 locations along an Oregon Cascade Mountain Crest-to-Coast transect since 1993. The start date for the sites varied over a several year period. The monitoring sites were located in old-growth and non old-growth coniferous forests (douglas fir, sitka spruce, alder, juniper, ponderosa pine), adjacent clear-cuts, and top of canopy locations. The following variables have been measured every 5-minutes with hourly averages/totals computed for each location: air temperature, relative humidity, rainfall, Photosynthetically Active Radiation (PAR), soil temperature (multiple depths), snow depth (where applicable) and volumetric soil moisture (multiple depths). In addition, wind speed, wind direction, shortwave radiation, and barometric pressure were measured at numerous field site locations. Data are provided as unprocessed raw observations; though some minimal "quality assurance" may have been applied to ensure that data contains "reasonable" values and does not exceed expected calibration thresholds.

In March 2019, incremental tree growth data (stem circumference measurements) was also submitted to the archive as additional data showing environmental conditions in the observation area. Period of record is 1997 to the present.