Planting trees and restoring existing forests to combat both the causes and impacts of climate change has been growing in popularity. Forests are constantly in flux and our understanding of them relies on studies that take place over long timescales.
One such living laboratory exists on St Croix, the Estate Thomas Experimental Forest. The 150-acre site is in the interior of the island, situated a short distance from Christiansted, as well as the Virgin Islands Agricultural Experiment Station, a high school, and the University of the Virgin Islands’ St. Croix campus. However, few residents or visitors are aware of the experimental forest, its history, or the island’s role in forest research and management.
Long-term studies require longstanding laboratories. Since 1908, the U.S. Forest Service has owned and managed a network of experimental forests and ranges that serve this purpose. It is the largest and longest-lived ecological research network in the U.S., with over 84 sites designated to date.
Experimental forests play an important role in our understanding of long-term impacts to forest ecosystems, providing practical guidance to natural resource policymakers and managers.
Roots in the past
European settlement of St. Croix began around 1625 and resulted in the steady replacement of the island’s native forest with agricultural estates. In 1749, the property’s namesake, William Thomas, laid claim to Estate Thomas as part of the Danish colonization of the island.
The property cycled through the hands of several individuals and government entities until present day ownership by the U.S. Forest Service. Prior to its use for forestry research, the land was put into sugar production and used for subsistence agriculture. For a period of time, people enslaved at the adjacent Sion Farm Estate sourced charcoal and grew provisions for themselves at Estate Thomas.
In 1963, the U.S. Forest Service purchased the Estate Thomas forest for $5,616.48 with the explicit goal of acquiring a subtropical dry forest to conduct research on timber growing practices. The acquisition of the property was also a strategic complement to the Forest Service’s subtropical humid forest research at the Luquillo Experimental Forest, a part of the more widely known El Yunque National Forest on the neighboring island of Puerto Rico. Both of these forests are managed by the International Institute of Tropical Forestry, a program of the U.S. Forest Service headquartered in Puerto Rico.
For most of its history, Estate Thomas’s function has been explicitly for the purpose of research. The site is not distinguished as a U.S. National Forest nor is it a part of the Caribbean National Forest, perhaps in part explaining its obscurity to the public.
Historically, the Estate Thomas Experimental Forest had been used to study suitability and adaptability of new timber species, with a focus on the commercially desirable hardwood mahogany. Rows of single-species plantings of trees, known as tree plantations, characterized the site.
“A visit to the site today provides a sense of discovery of the rich past of land use and disturbance and the effects that such history has had in what we are currently seeing both above and below ground,” said Grizelle Gonzalez, the Forest Service scientist who oversees research activities at Estate Thomas.
If you look closely, you can still see remnant rows of these planted trees in sections of the property along with weathered signposts indicating the sites of forestry studies. However, the forest of trees and shrubs, or “bush” as it is referred to locally, have grown underneath planted trees as a result of natural regeneration.
This process of regeneration has become a focal point for research activities at Estate Thomas. And while human disturbances at Estate Thomas are minimal today, the forest is far from static. Natural disturbances, such as hurricanes or periods of drought, continue to make their mark on the site, adding to the appeal and importance of the experimental forest to scientists and natural resource managers.
University of Wisconsin-Madison Professor Erika Marin-Spiotta and former doctoral student Emily Atkinson studied how different forest plots at Estate Thomas regenerated over a period of time to better understand how the historical use of a piece of land influences the structure and function of the forest that regrows on it.
They found that decades after the abandonment of timber trials on the site, the forest at Estate Thomas had regrown unaided with a diversity of species, many of which were not originally planted on the site. It appears that the rows of planted trees created a nursery effect of sorts that helped the growth of shade-tolerant native trees that were not found in similar-aged forests regrowing post-agricultural.
The benefits of doing this work at Estate Thomas? An abundance of historical data thanks to the Forest Service.
“Often when studying forest regrowth, we use forests of different known ages and shared similar histories to predict what a site might have looked like in the past,” explained professor Marin-Spiotta, “because we often do not have historical data for a particular site.”
A public good
Estate Thomas’s importance goes beyond its scientific contributions. The environmental functions that attract scientists to study are the same ones that provide crucial services for both humans and wildlife. An island within an island, the relatively large contiguous block of undeveloped land in a sea of development, allows rainwater to replenish nature’s underground water storage systems. This represents an important service given the island’s dependence on well water in some parts, especially for agriculture. The forest is also a refuge for local birds and migratory bird species travelling long distances.
Moreover, Estate Thomas is an educational and cultural resource. The Forest Service is actively looking for ways to partner with the local community in an effort to promote active use of the forest by students and the general public. Basic infrastructure and a covered pavilion were installed in 2012 using funds received from the American Economic Recovery and Reinvestment Act of 2009. Like much of the island, the site sustained significant damage from the 2017 hurricanes. The International Institute of Tropical Forestry is committed to restoring the damaged facilities and infrastructure, while also expanding its use.
Questions about educational efforts and opportunities at Estate Thomas Experimental Forest can be directed to U.S. Forest Service staff person Magaly Figueroa through the U.S. Forest Service website.