About Field Sites
Pu‘u Maka‘ala Natural Area Reserve (PUUM) is a terrestrial NEON field site located in the South Hilo district on the Big Island of Hawai‘i. The 75.7 km2 (18,700 acre) reserve is managed by the Hawaii Department of Natural Resources. NEON samples 47.2 km2 (11,662.5 acres) at the reserve. Situated along an elevation gradient of 853 - 1899 m (2800 - 6230 ft.) on Mauna Loa, it features a range of habitat types, from shrubby grasslands to wet rainforest. The unique endemic diversity coupled with threats from invasive species makes Pu‘u Maka‘ala a compelling location to conduct long-term ecological research. The reserve is dedicated solely for the purpose of conservation, making the area extremely important for the protection of native species. PUUM is the only field site of the NEON Pacific Tropical Domain (D20), which includes all of the Hawaiian islands.  
Rain is frequent, as is moisture from fog, as prevailing northeast trade winds bring regular precipitation. Located on the northeast side of Mauna Loa, the reserve receives an average rainfall of 2656.8mm (104.6 in.) per year. Occasionally, large weather systems, including hurricanes, bring extremely heavy rain events. Despite Hawaii's low latitude, PUUM's elevation leads to moderate daily temperatures, ranging from near freezing to hot at the extremes. The average annual temperature is 12.7°C (54.9°F). Hotter and wetter weather occur at lower elevation zones in the reserve.   
In Pu‘u Maka‘ala Natural Area Reserve, the lava ﬂow substrate age can be as recent as 1942 to as old as 8000 BCE. Extreme geologic disturbance in the form of volcanic activity has occurred historically, the latest being in 1942, and part of the reserve is downslope of potential eruption sites on Mauna Loa. The 1984 Mauna Loa lava flow comes within 1.6 km (1 mi.) of the Reserve. The geology can be described as Pāhoehoe and ʻAʻā of the Kaʻū Basalt.  
NRCS has classified the areas within the reserve to have over 25 different soil types, ranging from very deep at lower elevation to very shallow or nonexistent at higher elevation. Soils are well drained due to the abundant precipitation. 
Soils are well drained, and there are no bodies of water aside from sparse bogs in the reserve. 
Since the reserve spans across elevational gradients with varying substrate age, there are several plants considered to be dominant in different areas. Pu‘u Maka‘ala NAR is primarily ʻōhiʻa (Metrosideros polymorpha), with a dense understory of hapu‘u tree ferns (Cibotium glaucum and Cibotium menziesii). In areas with older substrate, koa (Acacia koa) can tower up to 36 meters. In areas with younger substrate, or where there was previous grazing, the ecosystem can be classified as montane grassland, with native and non-native grasses. In the lowlands, non-native Strawberry Guava (Psidium cattleianum) encroaches upon and can dominate native ʻōhiʻa forests. Across the entire site, there are more than 160 endemic plant and fern species. 
Pu‘u Maka‘ala Natural Area Reserve provides habitat for a dozen native bird species, including 6 honeycreepers (subfamily Drepanidinae). The reserve serves as an area of significant importance for bird protection from avian malaria, since it is partially above the elevation at which mosquitoes generally are found. Feral boars are found in lowland areas of the reserve, but because Hawaii DLNR management involves fencing, trapping, and other redirection mechanisms, they are generally not found at higher elevations. Notably, in 2017, San Diego Zoo Global began managing the re-introduction of a small population of the previously extinct-in-the-wild Hawaiian Crow (Corvus hawaiiensis) in Pu‘u Maka‘ala. Also present in the reserve is Hawaii's only endemic land mammal, the Hawaiian Hoary Bat (Lasiurus cinereus semotus).    
Past Land Management and Use
Despite the lack of archaeological findings in Pu‘u Maka‘ala, cultural documents reveal a rich history of native Hawaiians using the land for bird hunting, timber harvest, and medicinal plant gathering. More recently, the reserve has been partially used for logging and ranching. In some lower elevation areas of the preserve, there is a history of military testing of chemical and biological weapons.
Various eruptions and lava flows from Mauna Loa have provided regular disturbance on the geological scale in Pu‘u Maka‘ala. Ungulate trampling, nest predation and noxious weed invasion underline the modern environmental disturbance history and ongoing threats to the reserve. Two invasive fungi pathogens, ROD canker disease (Ceratocystis huliohia) and ROD wilt disease (Ceratocystis lukuohia), have had devastating impacts to regional ʻōhiʻa forest communities, rapidly killing ʻōhiʻa trees (Metrosideros polymorpha). Yet, today most of the area in which NEON operates has been largely unimpacted by the fungi.   
Current Land Management and Use
In 2005, the entirety of Pu‘u Maka‘ala Natural Area Reserve was dedicated solely to conservation. Ungulate fencing, predator control, and noxious weed treatment protect the reserve from current invaders. To strengthen the forest connectivity, NARS staff also routinely conduct outplanting of koa and ʻōhiʻa trees in areas previously used for cattle ranching. Pu‘u Maka‘ala's native ecological resources have benefitted greatly from partnership with adjacent landowners, such as Three Mountain Alliance, Kamehameha Schools, and National Park Service. 
NEON Site Establishment
Plot establishment of PUUM began in 2017, and the site was reviewed for sampling readiness in 2018. Dry runs of observational sampling began in late 2018. Instrumentation systems went online and began producing data in May 2019.
 Terrestrial Observation System (TOS) Site Characterization Report: Domain 20. NEON.DOC.003903vB.
 Pu‘u Maka‘ala Natural Area Reserve (NAR) Management Plan, Pu‘u Maka‘ala Natural Area Reserve (NAR) Management Plan (2013).
 Kumu Pono Associates. (2004). HE MO‘OLELO ‘ĀINA: A CULTURAL STUDY OF THE PU‘U MAKA‘ALA NATURAL AREA RESERVE DISTRICTS OF HILO AND PUNA, ISLAND OF HAWAI‘I . HE MO‘OLELO ‘ĀINA: A CULTURAL STUDY OF THE PU‘U MAKA‘ALA NATURAL AREA RESERVE DISTRICTS OF HILO AND PUNA, ISLAND OF HAWAI‘I.
 Megapit Details - NEON Data. (n.d.). Retrieved from https://data.neonscience.org/megapit-details/tags/puum/
 HURRICANES In Hawaii. (n.d.). Retrieved from https://www.soest.hawaii.edu/MET/Faculty/businger/poster/hurricane/
 As Climate Warms Hawaiian Forest Birds Lose More Ground to Mosquitoes. (2015, July). Retrieved May 2020, from https://www.usgs.gov/news/climate-warms-hawaiian-forest-birds-lose-more…
 Swaisgood, R. (2018). Alalā Conservation: Back from the Brink. Saving Species, 2, 2–3. Retrieved from https://institute.sandiegozoo.org/sites/default/files/Saving Species 2018 Vol 2(3).pdf
 TOS Protocol and Procedure: Soil Biogeochemical and Microbial Sampling. NEON.DOC.014048vJ. https://data.neonscience.org/documents/10179/2139401/NEON.DOC.014048vJ/…
 RAPID ʻŌHIʻA DEATH. (n.d.). Retrieved May 20, 2020, from https://cms.ctahr.hawaii.edu/rod/
 ] U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. https://mrdata.usgs.gov/mrds/
 Terrestrial Instrument System (TIS, FIU) Site Characterization Supporting Data: Domain 20. NEON.DOC.011084vB
 National Oceanic and Atmospheric Administration National Centers for Environmental Information’s (NCEI) 1981-2010 climate normals (NCEI 2015).
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 32 m (105 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 Double Fence Intercomparison Reference (DFIR) near the tower, and a series of throughfalls located in the soil array.
One phenocam is attached to the top and the bottom of the tower. Here we show the images from the most recent hour. The full collection of images can be viewed on the Phenocam Gallery - click on either of the images below.
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. Please note that the small mammal sampling protocol does not take place at this field site due to endangered species requirements.
Field Site Data
Hawaii Forest Department of Land and Natural Resources
Site Access Allowed
Site Access Details
Researchers should coordinate with site manager and apply for a site research permit (3-6 months).
NEON Field Operations Office
Domain 20 Support Facility
NEON Field Operations Address
60 Nowelo Street
Hilo, Hawaii 96720
Mean Annual Temperature
Mean Annual Precipitation
Mean Canopy Height
Dominant NLCD Classes
Average number of green days
Number of Tower Levels
USGS Geology Unit
USGS Geology Name
USGS Lithologic Constituents
Lava flows; Pahoehoe and aa; Tholeiitic basalt
USGS Geology Age
250-750 years old