The Forests of Palau: A Closer Look

Photo Credit

Seth Ayotte, USDA Forest Service.

The Rock Islands near Koror in the Republic of Palau are home to unique forest ecosystems.

The tropical islands of Palau, about 2,000 miles south of Japan in the northwestern Pacific Ocean, are known for surreal jellyfish lakes and world-class scuba diving. The forests of this archipelagic nation are less well known—but no less noteworthy.

“Palau is somewhat unique because much of the native forest is still mostly intact,” explains Julian Dendy, a natural resource specialist for the Pacific Northwest Research Station and veteran of field research projects throughout the Pacific Islands. “Across most of the rest of the Pacific, the forests have all been heavily disturbed in the recent past.”

Dendy is the lead author of a recently published report that compiles data from a 2014 survey of Palau forests by the station’s Forest Inventory and Analysis (FIA) program. To collect that data, field crews had to traverse steep, difficult terrain; consult tide charts; and contend with the dreaded poison tree (Semecarpus venenosus).

The story behind the numbers

“The hardest part was getting to the plots,” Dendy says. “The forests are really dense with mostly smaller trees and the terrain is very hilly with few trails.” Once there, another challenge presents itself. “By far the most annoying thing in the forests of Palau is an endemic species called ‘tonget’, the poison tree,” he says, adding that many Palauans are immune to its effects. “But most visitors are sensitive to it. It gets on your clothes and stays in them. It creates an oozing rash that can take a month to heal.” And it’s one of the most common trees in the country.

The crews also surveyed mangroves, which present unique challenges. Timing needs to coincide with low tide, and there’s the possibility of encountering saltwater crocodiles or sea snakes (which to be fair, generally try to avoid humans).

The famous Rock Islands also presented challenges. “They’re really picturesque” says Dendy. “But they have very steep slopes and cliffs of sharp, jagged limestone and so are quite difficult to navigate.”

Photo Credit

Seth Ayotte, USDA Forest Service

Ashley Lehman, a biological scientist with the Pacific Northwest Research Station, walks to a forest inventory plot in the Rock Islands in the Republic of Palau.

So why go through this?

The information from this survey is vital to tracking the health of Palau’s forests over time. It can be used by people studying carbon sequestration, the effects of climate change, wildlife habitat, insect and disease damages to trees, invasive species, and the effects of typhoon damage.

All forested lands in the United States and its territories are inventoried as part of the national FIA program. Although the Republic of Palau is affiliated with the United States and included in the FIA inventory, as are the Federated States of Micronesia and the Republic of Marshall Islands, they are sovereign Pacific Island nations. By revisiting plots to identify and remeasure trees and assess groundcover of dominant plant species, the FIA program tracks changes in land use, forest health and composition, and other ecological variables.

In Palau, visiting Forest Service FIA field crews collaborate with local government employees who are familiar with the flora and terrain to complete the survey work on the ground. “The local people on the crew are crucial and irreplaceable,” says Dendy.

Key findings

Field crews tallied 125 tree species and 196 dominant plant species from 56 measured forest plots in the 2014 FIA inventory. “Palau’s terrestrial diversity is relatively understudied,” says Dendy. “High species diversity and species endemism are the most interesting aspects of Palau’s forests to me.” Dendy and his coauthors found surprisingly few invasive species in the forests of Palau, especially when compared to other Pacific Island groups. They also found that FIA data is useful for estimating the effects of typhoons on Palau’s forests.

In total, Dendy and his coauthors estimated that Palau’s forests stored 8.6 million tons of live aboveground tree biomass (4.3 million tons of carbon) in 2014. FIA field crews will head back to Palau in 2025 to remeasure forest plots for the second time since this work began there in 2003. FIA analysts will then be able to assess how forest conditions have changed over the past two decades.

Coming next for forest inventories in the Pacific Islands; a similar report for the U.S. territory of The Commonwealth of the Northern Mariana Islands is in press, and crews are currently finishing field work in the U.S. territory of Guam.

Despite the hard work; hot, humid, and dense forest conditions; and steep terrain, working here is an unforgettable experience.

“It's a very beautiful place, and Palauans are wonderful people,” says Dendy. And after a challenging day of field work, it’s nice to enjoy Palau’s abundant natural wonders while sea kayaking, snorkeling, scuba-diving, or fishing.