Image Tabebuia aurea at forest edgeThe forest of Guiana is part of the Amazonian forest, which means deep jungle, uninhabited large areas of pristine forest, myriads of amazing species in both vegetal and animal reigns, and an undisputed paradise for any serious naturalist. Over 90% of the whole territory of French Guiana is covered by forest - roughly 8 million hectares. On this comparatively tiny portion of the whole Amazonian forest (550 million hectares) some 440.000 species of both plants and animals have been estimated. There are about 1300 trees species with something like 80 to 200 different species within a single hectare (10000 square meters or a square of 100m by 100m)! Nothing like woods and forests of the temperate areas of Europe or Northern America where there would be only 3 to 6 trees species per hectare...And this estimates accounts only for the tree speciies; equatorial forests are characterized by lushs and prodigious diversity so there is also an incredible number of smaller plants from bushes to ferns, climbers, mosses, a stunning number of epiphytic species, palm trees, heliconias and many more. And of course we have to add all the animals, visible and invisible, which live, propagate and die within this life-buzzing biotope. Actually the scientists have figured that the Amazonian forest hosts 20% of the whole water reserves of the Earth as well as more than 30% of both animal and vegetal species.

Image Typically buttressed tree Then there is the topography: on the hilltops and slopes we will see the development of high forest while low parts will host smaller species where one will encounter the ‘pinotières' where the ‘pinot palm' (Euterpe oleracea) makes compact habitats. Some trees such as ‘river cocoa' (Pachira aquatica) or ‘moutouchi' (Pterocarpus officinalis) are completely pledged to river banks. The ‘low forest' does not grow higher than 25m (75 feet). Higher growth is quite rare and found in the vicinity of inselberg (a geological formation of hard rock such as granite, rising in the middle of the forest, from the German ‘insel' (island) and ‘berg' (mountain).) The liana forests can be found either in higher or lower elevations and are very special as they look more like a total tangle than a proper forest. They supposedly form after a large storm which breaks down most trees and allows for the rapid growth of climbers, vines and other creepers which grow faster than trees and take over. It is nearly impossible to move through such vegetal formations though they only develop between 1 and 20m (3 to 60 feet) high. Cloud forests (also called fog forests) grow only at elevations over 400/500m (1200/1500 feet) which is quite rare in Guiana but still can be found; the extremely high humidity level allows the prodigious growth of epiphytics, trunks and branches are covered with lichens, mosses, orchids, bromeliads, usneas etc. A strange kind of plants formation is known under the local name of ‘cambrouze' and consists in almost monospecific large areas covered by Guadua latifolia, a spiny and climbing bamboo. The stems are about 3cm in diameter and grow to several meters. It seems like this bamboo inhibits the growth of other species, and its rhizomes grow as deep as 60cm (2 feet) deep hence giving it a high resistance. This ‘cambrouze' is found all over Amazonia and remains still quite mysterious; some researchers think that they could be the traces of former Indian villages as this bamboo is widely used to make arrows, another idea is that they are relics of dry periods of the ice ages which have survived until today. Trying to move through a cambrouze would be like going across a mass of barbed wire--not what anybody would want to do!
Image Tityra cayana (male) Image Well armed Ceiba pentandra trunk!

For today we will stay safely away from cambrouzes and liana forests and keep to the high forest. The high forest is what makes the most part of Guiana and the Amazonia; it consists of large trees growing up to 15 to 45m (45 to 135 feet) high which form the ‘canopy' or forest sky topped by the emerging trees, 50 to 60m (150 to 180 feet) high. The undergrowth which is where the ordinary walker will go through is rather dark as only one percent of the light will reach it, the compact mass of leaves, branches, lianas and various plants blocking most of the sunlight. This undergrowth is therefore easy to travel through as the lack of light impedes the anarchic growth, so the image of impenetrable jungle than most people have is quite false. At this level one will see many species adapted to very low light levels such as ferns, begonias, gingers, heliconias, and small palm trees. Every once in a while, especially after heavy rains, one will hear tremendous cracking and wood breaking, vines snapping and branch fallings, a very impressive event and probably one of the worst dangers: a falling tree. An estimated one percent of the trees fall each year, usually very large ones. This is caused either by uprooting as the ground is quite shallow or from the trunk breaking, most often caused by the added weight of the tree itself and the numerous vines and epiphytic plants which grow over it; mosses and bromeliads can add several hundreds of pounds to a single branch. When falling, a large tree will often break and smash smaller ones around producing a large clearing called a "chablis.".

Image Heavy butterfly resting on the ground.
As the hole in the canopy now allows the light to reach the ground there will be a large number of seeds germinating, mostly species needing light and which produce a great number of tiny seeds which will remain dormant until the required conditions are offered. They will grow fast, taking advantage of the sudden availability of light. A smaller ‘light hole' can be produced by a single falling branch, called a ‘volis' which may sound like a joke but remember that a tropical or equatorial tree can have branches as big as a whole tree! While strolling through this understory we have to watch for spiny palms which may very well drive a hole through clothes and skin and in case you stop to admire a strange mushroom or a giant vine make sure you are not an ant trail. There are many different species of ants in the forest and some can be pretty nasty--they will sting, bite and take food from where it is either your feet or legs! The ‘legionare ants' known in Spanish as ‘marabunta' roam the forest in quest of food, can number between 100,000 and one million insects which is enough to overtake large animals including tourists. Do not become too anxious though, you will hear and see more birds than anything; lizards, some snakes, butterflies, monkeys, frogs but most animals will move away from you, just beware of wasps which may build a nest underneath large leaves and welcome you with a burning sting. I will not admonish you about the various parasites such as leeches, ticks, leshmania, amphlistomes and other annoyances as you would not stay long on the trail!
Image Flooded understory

Hopefully this short trip was enjoyable. For the courageous and fit among you, our next excursion might consist of tree climbing, the main reason I went to Guiana, but do not worry; I am a qualified arborist and tree-climbing instructor, we will go up and come back down safe or maybe you will choose to stay up there and set a hammock for the night!