Angel Island Fires: A Case Study in Eucalyptus Removal
A case study in Eucalyptus tree removal
"Restored" Angel Island plants burned uncontrollably, while trees didn't ignite.
by Georgia Wright, HCN Boardmember
The trees the California Department of Parks & Recreation (aka, California State Parks) targeted were so-called “non-native” eucalyptus (Eucalyptus globulus), planted decades earlier, by the military to function as windbreaks, erosion control, for beautification, and for construction timber. By the mid-1980s, the eucalyptus had grown to cover 86 acres of the island. Experts from UC Berkeley were called in to calculate the effect that "converting" forest into grassland — cutting down thousands of trees — would have on wildlife and its habitat.
They tested the soil and noted that the last controlled fire in the forest, used to clear bark and undergrowth, had been set four years earlier. Finally, in 1996, the project was approved. Thousands of trees were cut down, leaving only those few growing near historic buildings on the periphery of the island. In addition, herbicides were sprayed on plants including Italian thistle (Carduus pycnocephalus), Ice plant (Carpobrotus edulis) and French broom (Genista monspessulana). Hand clearing was done by prisoners.
Scrub oak and bay trees, some planted, grew, starting from the northern tip of the island, delighting the Park Service. But in 2004, eight years after the removal of the eucalyptus forests, the first wildfire occurred, burning 1.5 acres. One year later, in 2005, twenty-five additional acres burned. Finally, on October 12, 2008, a third and much larger fire, driven by fierce north winds, swept flames from the grasses into the new oak/bay woods—and in two days incinerated 380 acres of vegetation. This was over half the island’s 740 acres. The six acres of eucalyptus trees left standing around the buildings survived the fire.
Without the fog drip created by the former 100-year-old eucalyptus forest, the oak/bay scrub had dried out. During the fire, winds fueled the wildfire’s flames without the windbreak created by the trees. Massive efforts by firefighters from fire boats, and air drops of water and fire retardant were ineffective in extinguishing the fire until the winds subsided. This same reality occurred in the devastating 1991 Oakland Hills Fire; high winds rendered firefighters efforts useless. Only after strong winds dropped could the massive wildfire be contained and eventually extinguished.
What was billed in part as a “native plant restoration” project became instead a demonstration of how forests suppress wildfire. All this inadvertantly became a demonstration that, regardless of tree species, forests are much less easily ignited than the fast-burning grasslands favored by “native” plant advocates. Even eucalyptus trees — often labeled “flammable” by “native” plant advocates — provide substantially greater resistance to wildfire than various “native” vegetation that grows or is planted in the place of felled mature trees.
"Native" plant "restoration" and fire danger mitigation are two entirely different and separate agendas. Angel Island, for those who study its history, demonstrates the very real dangers of mistaking or conflating one with the other.
At HCN, we favor "species-neutral" fire danger mitigation strategies — as do all the major, respected fire science agencies like the National Fire Protection Association (NFPA), its Firewise program, and the U.S. Forest Service.
The California Dept. of Parks & Recreation tried to “restore” Angel Island to its “native” flora — and reduce fire danger — by cutting down thousands of trees.
But the project became an unintended demonstration of how forests suppress wildfire.