The ‘ōhi’a lehua tree doesn’t care about your expectations. It sprouts from fresh lava flows while the rock is still warm enough to make you reconsider your life choices, sending roots into cracks that didn’t exist five minutes ago. This is how forests begin on Hawaiian volcanoes—not gently, not gradually, but with the botanical equivalent of showing up uninvited to a disaster zone and thriving.
When Lava Meets Life and Nobody Wins Gracefully
Kilauea has been erupting almost continuously since 1983, and what’s remarkable isn’t just the persistence—it’s what happens after. The 2018 eruption alone destroyed over 700 homes and added 875 acres of new land to Hawaii’s Big Island. Within months, ferns were already colonizing the cooled basalt. The ‘ama’u fern, specifically, which has the audacity to be bright red when young, as if announcing its arrival to a landscape that’s literally still smoking.
Here’s the thing about Hawaiian volcanic forests: they exist in states of permanent revolution.
The soil isn’t soil in any conventional sense—it’s pulverized rock with the nutritional value of, well, rock. Yet somehow the ‘ōhi’a forests on Mauna Loa’s slopes host over 90 endemic species of birds, insects, and plants that exist nowhere else on Earth. The trees themselves are evolutionary shapeshifters, appearing as shrubs at high elevations and towering 100-foot giants in wetter zones. Same species, completely different survival strategy depending on whether they’re dealing with altitude, lava fields, or the wettest spot in the United States (Mount Waialeale gets 460 inches of rain annually, if you’re keeping score).
The Nitrogen Problem That Shouldn’t Have a Solution But Does
Fresh lava contains approximately zero nitrogen, which is problematic when you’re a plant trying to, you know, live. Most ecosystems take centuries to build up nitrogen through decomposition and bacterial action. Hawaiian forests cheat. They use nitrogen-fixing bacteria housed in the roots of certain pioneers like the ‘ōhi’a, essentially importing fertilizer from the atmosphere while standing on geological infant rock that can’t offer them anything except a place to stand.
Turns out biological desperation breeds innovation.
By the time the forest is 150 years old—basically an infant in forest years—nitrogen levels have increased twentyfold. Scientists studying the 1959 Kilauea Iki eruption site found that within 50 years, full forest cover had returned with soil depths reaching 10 centimeters. That’s not succession; that’s biological impatience.
Why Everything Keeps Dying in the Most Fascinating Way
Rapid ‘Ōhi’a Death is killing these forests faster than we can study them, and yes, that’s the actual scientific name—ROD. Since 2014, it’s killed hundreds of thousands of ‘ōhi’a trees across Hawaii. Two fungal pathogens, Ceratocystis lukuohia and C. huliohia, basically clog the trees’ vascular systems until they die of thirst while standing in one of the rainiest places on the planet. The cruel irony is that these trees survived millennia of lava flows, hurricane-force winds, and the extinction of most of their pollinators, only to be taken out by microscopic fungi that probably arrived on someone’s muddy hiking boots.
Wait—maybe that’s the actual story here.
The Forest That Builds Itself From Nothing Every Century
The 1790 eruption of Kilauea killed at least 80 people (possibly 400, depending on which historical account you trust) and buried entire villages under tephra. Today, that same area hosts thriving ‘ōhi’a forests with understories of hapu’u tree ferns that can live 500 years. The forest doesn’t remember the catastophe; it simply archives it in layers of vegetation built on top of death.
Every tree is a gravestone that decided to become something else.
When the Ground Itself Becomes the Villain and the Nursery
Volcanic soils age weirdly. Young flows are hostile black deserts where surface temperatures can hit 140°F. Intermediate-age flows (300-1,400 years old) host the most biodiverse forests—the sweet spot where there’s enough soil but not so much weathering that nutrients have leached away. Ancient flows, paradoxically, become nutrient-poor again as millions of years of rain wash away everything useful, leaving behind oxidized iron and aluminum that plants struggle to use. So the timeline isn’t linear—it’s a bell curve where “middle-aged” lava supports more life than either extreme.
The Big Island has lava flows ranging from yesterday to 700,000 years old, all supporting different forest types, creating a landscape that functions as a natural experiment in ecological succession stretched across geological time. You can literally walk through evolutionary stages in an afternoon hike.
These forests don’t wait for permission to exist, they don’t follow textbook succession models, and they certainly don’t care that they’re growing on rock that was liquid last Tuesday. They’re ecological opportunists in the most beautiful sense—thriving not despite catastrophe, but becuase of it.
