Where Wood Comes From

For most people, the phrase “tropical hardwoods” conjures up a fuzzy image of some faraway jungle-like scene, in sort of the way that we understand the origin of the food in our supermarkets (hint: it does not come prepackaged). In reality, of course, the tropics are a complex and diverse network of environments, and any specific wood that we might use comes from a similarly specific habitat. I recently returned from a trip to Peru, where I was able to photograph some of these habitats (some of the photos are from earlier trips to other areas in the New World tropics).

What I write about here is New World-specific, but is analogous in a general way to the African and Australasian tropics as well. The primary distinction is that the Neotropics are dominated by two geophysical features not found in the Old World: the Andes and the Amazon basin.

The climate of any particular region in the Neotropics is largely governed by two factors, rainfall and elevation (which in turn dictates temperatures). Rainfall generally increases from west to east, with western zones being somewhat to very dry, and with a distinct wet/dry season, and eastern zones being far more humid (and where “dry season” means “doesn’t necessarily rain every single day”). The extreme topography of the Andes creates numerous small-scale “mesohabitats,” and many species of flora and fauna are thus restricted to surprisingly small ranges. An example of this is the valley of the Río Marañon, which in some places is over twice as deep as the Grand Canyon. The valley is so deep, and the surrounding mountains create such a large rain-shadow effect, that the climate on the east slope of the valley is dramatically different from that on the west slope, only a few miles away.

Starting from the top: At the very highest elevations, above the snow line at approximately 5000m (16,000ft), there is no vegetation whatsoever. Immediately below that is the puna (dry western slopes) and páramo (wet eastern slopes). The air is always cool here, and it frequently dips below freezing at night. The temperature extremes and the lack of oxygen mean that the primary vegetation is bunchgrasses and small shrubs; the only trees are various species of Polylepis (there is no English name that I’m aware of; the most common Spanish name is queñoa, which looks like it is probably derived from a Quechua word).

Polylepis is heavily exploited for firewood and for small items like tool handles. There are reports that it has been used in furniture making, but I haven’t seen any examples. I would guess from the looks of the trees that the wood is highly twisted and contorted. Overall, the puna habitat is surprisingly similar to that of the coastal chaparral in California, with many of the same kinds of plants: bunchgrasses, Baccharis and Lupinus shrubs, but with coast live oak (Quercus agrifolia) taking the place of Polylepis there.

Below about 3700m (12,000ft), we start seeing signs of real forest. This is the beginning of the cloud forest that you’ve probably heard of. Even on the “dry” slopes the cloud forest is actually wet, but from fog more than from precipitation. Trees in the cloud forest are heavily festooned with bromeliads and lichens. The average tree is relatively small, but there are occasionally some giants. While the cloud forests are heavily exploited locally, very little of the wood is exported, and the local names are ones you’ve never heard of. I think this is because the extremely steep terrain combined with the relative sparseness of valuable trees makes any kind of commercial harvest impractical.

Woods of interest that come from the lower elevations of the cloud forests include Andean walnut (Juglans neotropica), an endangered species that is protected but still at risk because its wood is nearly indistinguishable from that of the more common Peruvian walnut (J. boliviana), and Spanish-cedar (Cedrela odorata). Some species of ipê (Hadroanthus sp., especially H. serratifolius, yellow ipê or lapacho) are also found here, although they are typically found in drier habitats.

As we move further downslope into the foothill region (below about 1500m/5000ft), we start to see some dramatic differences between the dry and wet habitats. The dry zone becomes thorn forest; everything is covered with thorns to protect against browsing by herbivores. Thorn forest is very reminiscent of the Lower Rio Grande Valley in Texas. Although the trees are small, this is where some of the most valuable highly-figured woods come from, including cocobolo (Dalbergia retusa), ziricote (Cordia dodecandra) and bocote (several Cordia species).

The wetter slopes become dominated by numerous species of fig (Ficus sp.). Unfortunately from a woodworking point of view, the wood of most figs is soft and non-durable. To top it off, the latex exuded by the bark (a defense against insects) quite literally gums up the works when it is heated by the friction of cutting. You are also likely to see balsa (Ochroma pyramidale) here, especially as a fast-growing pioneer tree in disturbed areas.

This is also where that most important of drug plants, Coffea arabica, is cultivated.

In the foothills, we begin to see many of the woods that are available commercially in quantity, although they don’t grow as large here as they do in the lowlands. The lowlands (below about 500m/1500ft) are broadly divided into terra firme (forest that normally does not flood) and várzea (forest that is flooded for a significant portion of the year). Várzea forest is generally not a source of commercial timber, but Spanish-cedar does grow there, and it is also home to that second-most-important of drug plants, Theobroma cacao. Terra firme forest is where we find the true forest giants, trees like big-leaf mahogany (Swietenia macrophylla), cumaru (Dipteryx odorata) and purpleheart (Peltogyne sp.).

Two other Neotropic habitats that don’t fall into the high-to-low elevational sequence are worthy of mention: First up is the Pantanal, a unique wetland habitat in Brazil. Flooded for much of the year, it is mostly grassland, with trees growing on small “islands,” much like the mahogany hammocks of the Florida Everglades. Here and in the adjoining cerrado (a mixed grassland/shrubland savannah) is where most of the species of Hadroanthus commercially harvested and sold as ipê are found. Second, the Atlantic coastal forest of Brazil is one of the most seriously endangered of tropical habitats, and is where two of the rarest woods, pernambuco (Caesalpinia echinata) and Brazilian rosewood (Dalbergia nigra) occur.

Is a sustainable tropical forestry possible? In principle, yes. But there are serious obstacles. As many suppliers of tropical hardwoods point out, agriculture does far more damage to tropical forests than does logging. While this is generally true, it’s also misleading. Logging, along with other non-agricultural activities such as petroleum mining, requires roads. And any road in the tropics becomes, in effect, an invitation to would-be poachers and others to exploit the land. Without controls in place to protect lands after logging has taken place, they quickly becomes yet more cattle pasture or palm oil plantations.

ADDENDUM: As you have probably guessed, I didn’t travel to Peru just to take photos of trees. The primary purpose of our trips to the tropics (22 at last count) is to see birds. The same geological forces that lead to enormous diversity of flora do the same for fauna, and many species of birds are limited to relatively tiny ranges. The Marvellous Spatuletail shown here is restricted to the eastern slope of the Río Utcubamba watershed, 2100-2900m (7000-9000ft) elevation. The theoretical range is about 600 square miles, but for whatever reason the birds occupy only a fraction of that; the total population is believed to be fewer than 1000 individuals.

– Steve Schafer

EDIT: Finally figured out how to enable comments… –SS