Palo de Rosa
Ottoschulzia rhodoxylon, commonly known as palo de rosa due to its pink colored wood, was first listed as endangered under the Endangered Species Act (ESA) in 1990. An evergreen tree native to Puerto Rico, this tree can reach up to 49 feet in height.
Ottoschulzia rhodoxylon, commonly known as palo de rosa due to its pink colored wood, reaches up to approximately 49 feet (14 meters) in height. Its trunk can reach 16 inches (41 cm) in diameter. The leaves are alternate, elliptical or ovate, coriaceous and glossy with a slightly white margin. The flowers of this genus are small and composed of 5 sepals united at the base, and a corolla with a short tube in the shape of a cup and 5 lobes. The fruit is about 0.98 inches (2.5 cm) long and 0.86 inches (2.2 cm) wide, smooth and with a thin cover that turns dark purple when ripe.
The flowering and fruiting of this species is infrequent and, therefore, difficult to describe. Available data suggests that palo de rosa relies on scattered flowering events, the events are not synchronized among subpopulations, and depend on seasonal rain events. Due to current population locations on the top of limestone hills, it has been suggested that the seeds were once dispersed by an animal. However, none have been currently identified. Some have suggested that seeds could be dispersed by bats, but clustering of seeds around the plants suggest seeds are not being dispersed by any mechanisms other than gravity.
In general, palo de rosa trees are limited to rocky, alkaline soils and serpentine derivatives along the southwestern coast of Puerto Rico, from the municipality of Cabo Rojo to the municipality of Guayanilla; and along the northern coast of Puerto Rico, from the municipality of Aguadilla to the municipality of Fajardo.
When listed in 1990 only 10 individuals were known from few localities in Puerto Rico.
Currently, there are about 1,146 individuals from 66 subpopulations in Puerto Rico. In Hispaniola, there is little information of the population’s current status and location.
Although limited species distribution is no longer considered an imminent threat, palo de rosa still faces threats related to habitat destruction and modification in privately-owned lands (particularly along the northern coast of Puerto Rico), and other natural or manmade factors such as hurricanes, climate change, and habitat encroachment by invasive plant species. There are also biological and ecological limiting factors for the species, such as populations consisting of isolated trees and the requirement of cross-pollination (transfer of pollen from the flowers of one individual to neighboring trees) to maintain viable populations.
This is exacerbated by slow growth of the species seedlings, and the species’ sporadic flowering and fruit production, which results in a low recruitment rate. Nonetheless, the slow growth of this tree and its reproductive biology suggest that palo de rosa is a late successional species, whose sapling stage might be prolonged under closed canopy conditions until a natural disturbance induces favorable conditions for their development to adulthood.
Partnerships, research and projects
The Service in collaboration with several partners has been successfully implementing recovery actions for palo de rosa. Among these conservation efforts is the propagation of the species in nurseries, the protection of the species on private lands, and the incorporation of protective measures for the species in public forests.
How you can help
To recover palo de rosa from a landscape perspective, there is a need for increased collaboration and partnership efforts with private landowners. The Service is working with the Puerto Rico Department of Natural and Environmental Resources on developing conservation strategies and recommendations when evaluating urban and infrastructure development projects that could affect subpopulations of palo de rosa. Such conservation measures should include the maintenance and enhancement of effective forested buffer areas and corridors to provide connectivity between subpopulations and to secure the microhabitat conditions necessary to sustain a viable population (e.g., maintaining recruitment).
Subject matter experts
- Omar Monsegur, Fish and Wildlife Biologist, firstname.lastname@example.org, 787.851.7297 x 217
Designated critical habitat
Critical habitat has not been designated for this species.
Federal register notices
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