USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Hawaiʻi Experimental Tropical Forest

A phoot of the dry forest of the Puu Waawaa Unit. The vegetation is primarily dry grass.
Hawaii Experimental Tropical Forest, Puʻu Waʻawaʻa, Island of Hawaiʻi. (Forest Service)

Puʻu Waʻawaʻa Dry Forest

The Puʻu Waʻawaʻa Experimental Forest Unit is located on the North Kona coast on the Island of Hawaiʻi. This 38,885 acre (15,743 ha) unit lies on the northern flank of Hualalai volcano, extending from sea level to within 1 mile (1.6 km) of the mountain summit.

The landscape consists of exotic-dominated grasslands, tropical dry and moist forests. Tropical dry forests are among the most endangered forest types in the world and in Hawaii the few remaining remnants are severely threatened by wildfire, invasive species, and land cover changes. There are no tropical dry forests represented on any forest experiment station in the United States of America and very few across the world, even athough they are the most widespread of tropical ecosystems.

A Biological Assessment completed in 2003 listed 189 native vascular plants, 36 land snails (two introduced), 264 native arthropods, 35 cave arthropods, 104 non-native arthropods, 15 native birds, and 38 non-native bird species. At least 40 rare plant taxa have been reported from the area. Of these, 17 are Federally-listed endangered species. Also listed are 11 endangered bird species and one insect. Botanical surveys reveal that a great number of plants have been extirpated at Puʻu Waʻawaʻa in recent years.

The watershed (Ahupuaʻa) has an elevational range from sea level to 6,400 feet (1,951 m). It covers the gradient of the major dry and mesic forest types in Hawaii (five Holdridge life zones). It contains examples of highly degraded as well as intact forests. Much of the mesic forests at the upper elevations are dominated by the ecologically and economically important koa. Rainfall ranges from an average of 11 inches (279 mm) on the coast to about 49 inches (1,250 mm) at the highest elevations. An infrastructure of roads, houses, and water exists on the unit. It is located about one hour from the Kona Airport and about 1.5 hours from Hilo. Because the forests extend from almost 6,500 feet (2,000 m) to sea level, the potential to do watershed level studies and links of forests to marine environments are great.

Additional Resources