History of Fire

Over the past decade, Hawai‘i has experienced an average of >1,000 ignitions burning >20,000 acres (8,000 ha) each year across the main inhabited islands.  Fire response agencies are able to contain 90% of wildfire ignitions to less than one acre in size, but large fires (>1000 acres) have occurred on all islands, and happen multiple times each year across the state. 

Wildfire Threats and Impacts

Nearly all fires in Hawai‘i are human-caused and they often pose threats to communities and natural and cultural resources.  Having evolved in the absence of frequent fires, Hawai‘i’s native ecosystems are particularly vulnerable to fire disturbance, which is often associated with the spread and establishment of nonnative grass and shrub species.

Wildfire Drivers

The primary drivers of fire occurrence are: frequent, mostly human-caused ignitions; expansion of nonnative, fire-prone grasslands and shrublands over c. 25% of state land area; and strong rain shadow effects and episodic drought create which create year-round fire weather.

Statewide Wildfire Ignitions (2016)
Wildfire In Hawai‘i Fact Sheet

Recent Resources For Hawai‘i

Effects of Prescribed Grazing and Burning Treatments on Fire Regimes in Alien Grass-dominated Wildland-Urban Interface Areas, Leeward Hawaii (Castillo and McAdams, 2006)

November 7, 2006

This project was designed to evaluate at a practical scale the effectiveness and costs of a range of fine fuels management treatments in West Hawai‘i Island. The study occurred along a major inland highway from which wildfires frequently originate. We applied four major treatments that included a control (no treatment), prescribed burning, cattle grazing, and a combined burning and grazing treatment. Aerially-applied herbicide was then applied to half of each of these primary treatments resulting in a total of eight unique treatment combinations.

Moisture availability and ecological restoration limit fine fuels and modelled wildfire intensity following non-native ungulate removal in Hawaii (Zhu et al, 2021)

August 3, 2006

We measured fuels (live and dead fuel loads, type, height and continuity) and modelled potential wildfire behaviour (flame height and rate of spread) inside and outside of 13 ungulate exclosures, three of which received active ecological restoration (e.g. planting of native shrubs and trees), across a 2,740 mm mean annual rainfall (MAR) gradient on the Island of Hawaii. Differences in fuel characteristics and modelled wildfire behaviour inside versus outside of ungulate exclosures were assessed using linear mixed effects analyses.