NEON's PUUM field site is located in the Pu'u Maka'ala Natural Area Reserve (NAR) on the eastern side of Hawaii's Big Island, managed by the Hawaii Division of Forestry and Wildlife (DOFAW). More than 18,000 acres in size, the NAR is home to a rainforest with many native species, some of them endangered. It was established to protect some of the Big Island's best wet native forest and unique geologic features. Part of the reserve is fenced to reduce damage from feral ungulates making the area extremely important for the protection of native species. Due to the unique mix of soil conditions, flora and fauna on the island, researchers at PUUM will need to make a number of modifications to the sampling and measurement protocols used at most other NEON field sites. Because the island is volcanic and soil depths average just 4 inches, soil measurement methods have been modified for the site. Field sampling schedules have been modified to minimize traffic through ecologically sensitive areas and accommodate Hawaii's year-round growing season. Small mammal sampling has been eliminated, as Hawaii has only one native terrestrial mammal (the Hawaiian Hoary Bat), an endangered species which is already being monitored by other research programs. Tick sampling has also been eliminated. Tree tagging methods have been modified to avoid creating entry points for ROD in ohia trees. The flux/meteorological tower at this site is 105’ with 6 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 Double Fence Intercomparison Reference (DFIR) near the tower, and a series of throughfalls located in the soil array. This site has one phenocam on the top of the flux tower and one near the bottom of the tower. This site has five soil plots placed in an array within the airshed of the flux tower. Biogeochemical data, and soil data is also collected. Total data products planned for this site: 116.