When Hurricane Maria tore through Puerto Rico in September of 2017, it leveled buildings, flooded streets, and wiped out power grids and water lines across the island. According to recent reports, the Category 5 storm claimed nearly 3,000 human lives.
More than a year later, the island is slowly recovering. But much of the damage that Maria left in its wake might never be repaired—in more ways than one. According to a study published today in Nature Communications, the hurricane has wreaked unprecedented havoc on Puerto Rico’s tropical forests, decimating crucial habitats for wildlife and potentially upsetting a fragile balance that keeps carbon emissions in check.
As Hurricane Maria raged across the island with rampaging rains and winds gusting at up to 155 miles per hour, it inflicted serious damage on 20 to 40 million trees. Some species were hit harder than others, and in the aftermath of the onslaught, the makeup of Puerto Rico’s lush ecosystems has likely been permanently altered. And Maria’s destructive powers might well be a harbinger of far worse times to come: With global temperatures on the rise, the researchers forecast that similar storms will follow.
“These hurricanes are going to kill more trees...the factors that protected many trees in the past will no longer apply,” study author María Uriarte, an environmental biologist at Columbia University’s Earth Institute, said in a statement.
With her colleagues, Uriarte documented the damage Hurricane Maria had wrought on a 40-acre section of the El Yunque National Forest, near Puerto Rico’s capital of San Juan. Compared to previous storms, Maria razed twice as many trees and snapped more than three times as many trunks.
But not all species were affected in the same way. “There were winners and losers,” Uriarte told Mark Tutton at CNN. Uriarte was surprised to find that large, old hardwoods like tabonucos (candlewoods) and ausubos (bulletwoods)—thick, dense, slow-growing breeds that have traditionally showed resilience in the face of natural disasters—were among the fallen. The loss of these staple species further endangers the birds and other wildlife that typically make their homes in their branches, trunks, and leaves. Others, like the common sierra palm, which have the flexibility to sway and buckle in the gales and easily resprout after damage, fared far better.
Ultimately, these long-term shifts in composition could make for “lower saturated and less diverse forests,” Uriarte said in a statement. And that could have some serious long-term consequences.
With their lower density, palms can’t store as much carbon as hardwoods. If these forests morph into glens of short, skinny, light-bodied trees, they might not do as good a job keeping carbon out of the atmosphere. Additionally, every bout of forest destruction takes trees out of commission, compromising the ability of Earth’s ecosystems to stave off climatic changes, Yadvinder Malhi, an ecosystem scientist at the University of Oxford who was not involved in the study, told Tutton at CNN.
Emissions from the decay of felled trees could even begin to outweigh the carbon taken in by replacements, turning these forests into net carbon emitters. In other words, the landscapes of the future might end up feeding the very changes that put them at risk.
Humans will need to heed the warnings that stem from this vicious cycle, the authors say. Climate change itself isn’t causing hurricanes, but warming oceans do intensify storms on average. And if these ecosystems are further destabilized by similar events, the fates of lives outside the forests themselves could be imperiled.
In many ways, Hurricane Maria might have been the first of her kind. But she almost certainly won’t be the last.