The New Neotropical Companion

from above the base of a tree, surrounding the bole,

sometimes making cozy retreats for snakes and other

denizens of the forest. Buttresses can be impressively

large, often radiating from the bole 1.8 m (6 ft) or more

from the ground. Buttressing is particularly common

among trees of streamsides and riverbanks, as well as

among trees lacking a deep taproot (plate 3- 6).

Many plant ecologists believe that buttressing acts

principally to support major roots just below and often

on the surface of the soil. Roots generally are shallower

in tropical forests than they are in temperate forests.

Some tropical trees lack buttresses but have stilt or

prop roots, which radiate from the tree’s base, remaining

aboveground (plate 3- 7). Stilt roots are particularly

common in areas such as floodplains and mangrove

forests that become periodically inundated with water.

Other tropical trees, including the huge Brazil Nut

(Bertholletia excelsa), lack buttresses or prop roots, and

some of these have relatively deep taproots.

Finally, you will note that many tropical trees exhibit

surface roots (plates 3- 8– 9). It is rather easy to trip on

these roots as they wind across trails. The function

of surface roots is related to the rapidity of mineral

recycling in the tropics and will be discussed further

in chapter 6.

Many Patterns of Bark

It was once thought that tropical trees tend to have

light- colored bark, but in reality there is no generalized

pattern associated with bark of tropical trees.

Bark may be smooth or rough and light or dark, ranging

from almost white in some cases to almost ebony in

Plate 3- 8. Thick surface roots characterize many tropical

rain forests. Note the thin litter layer, also a characteristic of

tropical forests, where decomposition rates are high.

Photo by John Kricher.

Plate 3- 7. Stilt or prop roots are common in many tree species

along riverine, floodplain, and swampy areas. Photo by John

Kricher.

Plate 3- 9. Surface roots extend from buttresses across the

floor of the forest. Photo by John Kricher.

chapter 3 rain forest: the realm of the plants 43