What is a primary forest ?

Primary forests first appeared on our planet in the Devonian Period, 380 million years ago. They were very tall, magnificent and abundant with animal and plant life.

Before the appearance of the human species 40,000 years ago, all of the Earth’s forests were primary. Humans have been clearing, exploiting and deforesting them at an ever increasing rate.

A primary forest is a forest that hasn’t been exploited or cut down by man. If it has been in the past, then a sufficient amount of time has elapsed for the forest to become primary again.

In humid tropical or equatorial zones, where trees grow all year round, it takes seven centuries for a cleared area to be reclaimed by a primary forest. In temperate zones, where trees only grow five or six months a year due to winter, it takes about ten centuries.

In a lowland tropical primary forest, trees are tall (50-70 meters in height, or approximately 164-230 feet) and the undergrowth is dark because the canopy – the upper layer of trees – intercepts up to 98% of sunlight. (Light is abundant on the canopy, where 75% of the fauna is found. It is very humid because it rains during the day, and a blanket of mist covers the undergrowth at night – all year long.

The darkness of the undergrowth is sometimes cleared due to windthrow. This can affect close to a hectare (2.5 acres) of land when a large tree collapses and its vines drag the neighboring trees down with it. Windthrow is useful to the renewal of the primary forest. By bringing light back to the undergrowth, windthrow allows pioneer trees to grow in turn and the forest begins a new cycle. The gigantic fallen trunks decompose over the course of a few months, sheltering a wide variety of fauna and nourishing the soil.

Forest wildlife is often hard to see in the daytime, but it is always noisy. It is most silent at the hottest hour of the day and loudest at night. It is also easier to observe wildlife in the undergrowth at night, as different zoological groups gather on the canopy, producing a nocturnal concert: aboreal amphibians, cicadas, nocturnal birds, hyraxes, etc. The birds’ songs get very loud just before dawn.

Lowland tropical rainforests represent the maximum of the the world’s biological complexity and diversity; almost all living groups are represented there. There is also a paradox with regard to trees: rare species are ubiquitous whereas common species are scarce. In equatorial forests, one often has to travel several kilometers to find two trees of the same species, and inventories of 100 different tree species per hectare are common. It is impossible for humans to /manage/ this kind of biodiversity, and to be effective we must adopt a collective approach.

The primary forests of the equatorial plains are located in the Amazon, Indonesia, Melanesia and the Congo Basin. With 90% of its territory covered by primary forests, French Guiana is home to one of the largest regions. Another paradox is that no matter where these forests are, they all look the same – the same massive tree trunks, the same light, the same sounds and the same smells – and yet, all of their plant and animal species are different from one continent to another.

Whether it be in Africa, America or Asia, the human populations of tropical primary forests have never destroyed them or altered their primary nature. Deforestation in these regions is akin to genocide, because without their forests these populations are deprived of their daily resources, shelter, culture and often times, their lives.

Temperate lowland primary forests are found in British Columbia and along the western coast of the United States, Tasmania, New Zealand and the Southern Cone of South America. In Europe, very few lowland forests have been preserved from exploitation. Poland’s Białowieża Forest is the oldest, having formed 10,000 years ago during the last ice age. It is also is one of the last remaining primary forests in Europe and a haven for some of the continent’s last bison still alive. It is extremely beautiful.

Once a tropical or temperate primary forest has been destroyed, a secondary forest develops, with very limited biodiversity at first that increases over time, provided no predation/ occurs before it grows back into a primary forest.

According to the UNEP (United Nations Environment Programme), more than 80% of the world’s original forests have been cut down in the last century. Every year, 15 million hectares of primary tropical forest – the size of England – are deforested. Trees absorb carbon dioxide, release oxygen and purify the atmosphere. We wouldn’t be able to breathe without them because photosynthesis is our only source of oxygen. Without trees, the human species would be in grave danger.

Given these circumstances, the restoration of a primary forest in a densely populated area like Western Europe could be a way of reconnecting with a sense of time and the long life-cycles of trees, while reconciling man with unspoiled nature.

Francis Hallé, May 2020

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What is a primary forest ?

Primary forests first appeared on our planet in the Devonian Period, 380 million years ago. They were very tall, magnificent and abundant with animal and plant life.

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