Puerto Rico has many unique -- and many imperiled -- natural resources. In fact, one of its most distinctive trees is also one of its most endangered trees.
Named for the red hue of its heartwood, the Palo de Rosa faces many threats. But, even the strongest storms in the island's recent history cannot destroy the efforts to conserve the plant at Fort Buchanan, an Army Reserve-funded Installation in San Juan.
Fort Buchanan is one of the few places on Puerto Rico where the Palo de Rosa thrives, and the trees at the Installation are some of the only trees on the island that are producing viable seeds.
According to Victor Rodriguez Cruz, an environmental protection specialist at Fort Buchanan, the Palo de Rosa's decline could be attributed to many factors.
Deforestation has decimated the Palo de Rosa's natural habitat.
In addition, the Palo de Rosa's reproduction cycles are erratic, at best. Biological studies indicate that the tree may be a "mast flowering" species, or one that produces an abundance of fruits in some seasons but no fruits in other seasons.
Seed dispersal is also a challenge for the Palo de Rosa. The Palo de Rosa may be an "outcrossing" species, requiring the cross pollination of individual trees. Since its populations are so limited, the pollination process can be very difficult. Furthermore, the fruits of the Palo de Rosa resemble the fruits of trees pollinated and dispersed by bats. The absence of bats, or other pollinators, can contribute to the tree's demise.
Last fall, the Palo de Rosa encountered a different enemy: hurricane season.
Hurricanes Irma and Maria devastated Puerto Rico in September of 2017. Despite the destruction, the Palo de Rosa's future is promising at Fort Buchanan.
On May 2, Rodriguez Cruz -- with personnel from the Puerto Rico Department of Natural and Environmental Resources and the United States Fish and Wildlife Service -- conducted a post hurricane assessment of the Palo de Rosa at the Installation.
"When we first climbed the hill to assess the population, we were a bit concerned because at least 40 percent of the tree cover had fallen, and we suspected that the Palo de Rosa might have also suffered the same fate," said Rodriguez Cruz. "Fortunately, all the mature trees were still standing."
"Despite severe defoliation [loss of leaves] and damage to the crowns of the trees, the population is recovering," said Omar Monsegur Rivera, a biologist with the United States Fish and Wildlife Service.
Rodriguez Cruz said that, as a tropical tree, the Palo de Rosa is a resilient species. "They were already resprouting, and we could see a lot of new growth on them," he added.
"All trees have an innate capability of resprouting, but tropical species resprout at a much faster rate because their biome receives plenty of sunlight and water, and the soils have sufficient nutrients," he explained.
As part of its Memorandum of Understanding with the Puerto Rico Department of Natural and Environmental Resources and the United States Fish and Wildlife Service, Fort Buchanan will continue to monitor the Palo de Rosa population, especially as the saplings and seedlings respond to the newly open forest canopy.
"We have seen an abundant germination of new seedlings in the forest floor and saplings with abundant amounts of new growth," Rodriguez Cruz said, addressing the benefits of the open forest canopy.
On June 23, Fort Buchanan welcomed the city of Ponce's Boy Scout Troop 514, who planted 20 Palo de Rosa seedlings that were propagated at the Puerto Rico Department of Natural and Environmental Resources' Cambalache Nursery from seed material collected at Fort Buchanan.
The Scouts planted the seedlings near forested habitat to connect the new trees with the known population of Palo de Rosa, providing opportunities for cross pollination and long-term monitoring.
Rodriguez Cruz said that the partnerships between the Puerto Rico Department of Natural and Environmental Resources, the United States Fish and Wildlife Service and the Boy Scouts benefit Fort Buchanan in many ways.
"We receive technical expertise from the agencies in order to be more effective in our conservation measures, and they also participate in the monitoring process," he remarked.
And, as Fort Buchanan cultivates the Palo de Rosa, the Installation also cultivates a caring, conservation-minded community -- particularly among the children, who feel that they are contributing to the protection of a species unique to the island.
"We are creating conscious environmental stewards at an early age, which is key to long-term commitment," said Rodriguez Cruz.