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Tropical *Dry* Forests?

Jennifer Powers gives tropical dry forests long overdue attention in her new book about these undervalued cousins of tropical rain forests.

Think “tropical.” Lush green forests full of bromeliads and dripping with water come to mind. Dry? No. But as a matter of fact, many of the world's tropical forests go for months of every year without water. These tropical dry forests contain unique plant and animal species that are adapted to annual droughts. Jennifer Powers, an ecologist at the University of Minnesota, has made it her mission to learn as much as possible about these underappreciated ecosystems.

Powers is co-editor of a book, Tropical Dry Forests in the Americas: Ecology, Conservation, and Management, published in August. The book draws together perspectives from a variety of tropical dry forests throughout the new world.

Why are tropical dry forests important?

One reason is diversity. They have unique species. They're also important from a carbon storage standpoint. They can hold significant amounts of carbon in the biomass and the soils. The tropical dry forest is considered the most endangered tropical biome, and I think the world would lose a lot if we lose the last tropical dry forests.

What does this book add to our knowledge?

Many of the chapters take a comparative approach, looking at ecological processes and patterns across the tropical dry forest from Mexico to Brazil. It also includes a number of chapters that explore the social dimensions of people's use of the dry forest. It includes the perspective of what types of natural products people derive from the dry forest and the perspective of conflicts over who owns and who has access to dry forests. Not only does this book incorporate a cross-site comparison, it also spans ecological research, remote-sensing research and social science. There's not a comparable book like this.

What are some of the social issues going on with the dry forests?

What we're seeing now are conflicts over water. In the region where I work, there's a lot of agriculture, and the agriculture is irrigated during the dry season. This use of water is likely to come into conflict with other uses, such as for tourism. A lot of these sites are beautiful places. Other conflicts that we're seeing right now in Costa Rica are with geothermal energy. The national park that I work in has been deemed suitable for geothermal energy and there are efforts to convert some of this park to a geothermal energy plant.

What do you do for your fieldwork?

I slog around! I work in the northwestern part of Costa Rica. We're interested in learning how forests recover from land use. The sites we work in were all used previously for agriculture or pasture. We're interested in how fast these forests grow back, how fast the species composition changes, how fast nutrient cycles are re-established, and how these successional processes depend on the soil characteristics.

What's the conservation outlook of these forests?

That's really hard to say. I can only speak to Costa Rica, which is the place I know best. I think conservation used to be a small, local issue, where managers were worried about fires and hunting. I think they are now worried about climate change and big things like development of geothermal energy. The pressures and threats are increasing and they’re global, not local. I don't know about the future of conservation. I'm cautiously optimistic.

— Margaret Taylor