Leaf 10: A New Tree List

A leaf from:

This Broken Land of Promise:

A Chronicle of Conservation in the Hispaniolan Border Country

For the first time in its eleven year history, the Tree Bank has a reasonably authoritative list of tree species native to our program area — a list that is sturdy, adaptable, and practical. It’s far from comprehensive but it’s probably representative — and we can extend it and refine it as we work.

The new list supersedes a much smaller one that was simply a record of which species we had thus far managed to propagate. The old list was not developed as a project in its own right, nor was it a tool for directing our propagation work.

We created the new list with the help of two key witnesses to our area’s forests: a professional botanist who studies the Dominican flora, and a local farmer who is both a Co-Director of the Tree Bank and a gifted naturalist. The list also draws on a small but important manual recently developed by the Dominican branch of GIZ (Deutsche Gesellschaft für Internationale Zusammenarbeit, the German equivalent to US AID).

The list was my idea — although, given the Tree Bank’s mission, this does not rank as a major intellectual achievement. I also organized the project, pushed it along, and edited the results. The first version of the list was completed on July 14.

Even though this first version is certain to undergo revision, I’m publishing it now because I see it as an important advance for the Tree Bank. I suspect also that the particulars may interest a substantial share of our members and colleagues, since so many of them are inveterate botany geeks.

But before I get to the list itself, I should explain why we need it and how we made it.

Why We Need a New List

We need the list to improve our land management. The total amount of land in our care will likely grow to at least 290 acres this year. (See Leaf 3.) All of the new area — amounting to at least 40 acres — will need to be planted with native trees. Much of the area already enrolled needs more planting as well.

So we need to scale up our native-tree production. But it’s not just a question of producing more trees; we’re going to need more kinds of trees as well — more variety. We need this variety to create plantings that more closely resemble nearby forest fragments. We also need it to accommodate the enormous variation in ecological character from one site to another — differences in vegetation, moisture, and soil. And we need it to meet differing landowner interests.

We think that the Tree Bank’s two nurseries are probably now large enough to produce an adequate volume of seedlings. We can probably grow at least 30,000 seedlings a year without putting much strain on the system.

But when it comes to native-tree stock, we aren’t collecting nearly enough seed to generate the seedling volume that we need. We don’t have enough seed for the native species already in our system, and we’ve got to get out there and shop for additional natives as well. Our meager seed harvest is now the biggest impediment to the growth of the program.

I refer specifically to native stock because, unlike our DC-area system, the Tree Bank also grows a few exotic species, primarily coffee and cacao. All of the exotics are important for agroforestry; none of them are invasive. Also unlike our DC-area system, we sometimes accept seed of native species from sources that aren’t local. Such seed comes to us from the Dominican federal Ministry of the Environment and Natural Resources. (Everyone just calls it “Medio Ambiente” — “Environment.”) I’m not happy about the outsourced seed but I think that it’s sometimes best to compromise a little just to keep things moving. As our own production improves, I’m hoping that we’ll eventually work just from local seed sources.

Thus far, we have managed our lands in our usual, improvisational way. We draw on Medio Ambiente seed; we plant lightly; we’re careful not to bash up “volunteers” (native-tree seedlings that colonize sites from nearby forest). And of course we understand that our plantings will likely gain species over time, as more and more volunteers arrive, so we don’t necessarily need to plant every species that we hope to see on a site.

But as our area in care continues to grow, such measures aren’t likely to scale very well. Too many things could go wrong. It’s not so bad to have to do some remedial planting on two acres, but on, say, 50 acres, that could be a problem. The new list is our recipe for stability. It will help us develop a nursery inventory that matches, more or less, our obligations to the land, and to our people.

How We Made the List

Producing the list involved a lot of time and talk, and quizzing of other lists and species databases. Although there are many studies of the flora of Hispaniola, this literature doesn’t provide a sound basis for the kind of list that could guide our work. Our project area only covers 25 to 30 square miles at present, and to do good restoration work there, we need precise information about the species composition of local remnant forests. Most site-specific botanical studies on Hispaniola have understandably focused on intact natural areas or areas that support unusual plant communities — and not on battered, dysfunctional landscapes like our own.

Since I couldn’t just use published sources, I had to go directly to people who know the forests. I began by approaching Brígido Peguero, a botanist at the National Botanical Garden in Santo Domingo, the Dominican Republic’s capital city. Brígido is in charge of taxonomy and botanical exploration for the Garden. In October 2016, he produced for us a native-tree list that served as the basis for our new list.

But Brígido’s list covers the entire 394-square-mile province of Dajabón, which extends from the island’s rugged central highlands, where the Tree Bank is based, down to the much warmer lowland plains to the north. There are 58 species on Brígido’s list; given the considerable variation in habitat over the province, I suspected that many of those species would not occur naturally in our program area.

The list would have to be pruned, but before attempting that, I decided to incorporate another resource. About a year before Brígido sent us his Dajabón list, Elvi Marcelino, the local GIZ representative, very kindly passed me a copy of a native-tree propagation manual that GIZ had recently produced. The manual focused on species that occur around the town of Restauración, just six miles up the road from the little municipality of Los Cerezos, where the Tree Bank is based. GIZ has an office in Restauración and the town was the center of a huge reforestation project supported by GIZ. (That project is not analogous to our own. Although it did include various native tree species, it did not aim at the restoration of natural, native forest; the species selection wasn’t tuned to the topography, and large areas were replanted in exotic pine. The project seems to have wound down in 2013.) There are 30 species in the GIZ manual; some of these are also in Brígido’s list and some are not.

To prune the list, I called up Cosme Damián Quezada, one of the Tree Bank’s Dominican Co-Directors, and quizzed him about each species. (For my conversations with Cosme, see Leaf 7.) Cosme has lived in the Tree Bank program area all his life, and the man is a walking tree encyclopedia: “No, that doesn’t grow in our area — it’s more to the north. . . . There’s a really big specimen in Manolo’s coffee parcela. . . . There are a few of those in the Reserva. . . . That big tree in front of Anhelita’s house — that’s a jagua.” Etc.

We could manage maybe 10 species per call before