The New Neotropical Companion

Montane (Mountain) Forests

When visiting the Neotropics make sure you include

a segment in the magnificent Andes Mountains. Don’t

just settle for lowland rain forest. Do some climbing.

The ecology is different up in the mountains, and the

views are great. The Andes mountain chain extends

from Trinidad and Venezuela all the way down the

western part of the continent of South America to

Tierra del Fuego (plate 13- 1; fig. 13- 1). The mountains

in Central America, as well as those of islands such

as Puerto Rico, are not as tall as the Andes but are

nonetheless rich with cloud forests, and there is much

to be seen in them.

Elevational Changes: An Overview

With increasing elevation up an Andean mountainside,
temperature decreases and condensation and
precipitation both increase, conditions supporting
cooler and humid forests rich with trees often densely
laden with epiphytes. Temperature gradients can
be steep, and it is often surprisingly cool at higher
elevations. In the upper montane forests, trees are
gnarled and small in stature, forming a kind of elfin
forest. In high- elevation Andean zones, conditions
become colder and increasingly windy, too severe
for trees to survive, so only grass and shrubs prevail.
Depending upon conditions, these alpine grassy and
shrubby areas are called either páramo or puna (both
discussed below). Snow is typical at high elevations,
even in equatorial regions (plate 13- 2). Conditions
above tree line are frequently foggy and bog- like, with
extensive areas of soft peat and mossy groundcover.
As airborne moisture from the lowland tropical forest
meets the Andes it rises and cools, and mid- elevation
montane forest becomes enshrouded in dense mist
and fog— a cloud forest— for at least part of each day.
Clear morning skies yield to afternoon fog that persists
through nightfall. Cloud forests look and feel overcast
and damp, because you are literally walking in a cloud
when you traverse such areas.
Alexander von Humboldt, who explored the
Neotropics from 1799 to 1804, first described the
ecological zonation that is evident along tropical
elevation gradients (plate 13- 3). He documented how
lowland moist forests grade into cloud (or fog) forests,

Chapter 13. Scaling the Andes

NORTH

AMERICA

SOUTH

AMERICA Peru

Atacama

Desert

Chile

Pacific

Ocean

Pacific

Ocean

Tierra del Fuego

Strait of Magellan

Cape

Horn

Scotia

Sea

Falkland

Islands (UK)

Argentina

Patagonia

PAMPAS

Uruguay

Bolivia

Paraguay

Brazilian

Shield

Amazon

Basin Brazil

Brazilian Highlands

600 kilometers

600 miles

Galápagos

Islands

(Ecuador)

Colombia

Ecuador

ANDES

ANDE

S

ANDES

Caribbean Sea

Venezuela

Guyana

Suriname AtlanticOcean

Atlantic

Ocean

French

Guiana

(France)

LlanosGuiana

Highlands

Figure 13– 1. General map showing the extensive range of the

Andes Mountains. Reprinted with permission from Kricher,

John. Tropical Ecology. Princeton, NJ: Princeton University

Press, 2011.

Plate 13- 3. Alexander von Humboldt was the first to carefully

document how elevational change in the Andes Mountains

alters plant community structure; we call this the life- zone

concept. Photo by John Kricher.

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