The Importance of Old Growth

Old growth forests are forests that have grown and developed over the course of multiple human lifetimes. They have unique ecological characteristics that enable high levels of biodiversity and are one of the planet’s greatest carbon sinks. Years of rampant deforestation and unchecked agricultural expansion have annihilated the majority of the world’s old growth forests, removing their ability to store carbon and putting an unfathomable number of species at risk.

These forests are biodiversity hotspots, supporting a greater array of plants, insects and birds than any other environment in the world. The loss of these forests has had a dramatic negative impact on biodiversity around the world.

Old growth forests are also a vital component of a process called the biotic pump. Biotic pumps are marvels of evolution and the source of life for most major rainforests. Trees have microscopic pores on their leaves called stomata. These pores release water as a gas when the plant takes in carbon dioxide. When enough plants do this, the water vapor creates negative pressure pockets that drag more moist air into the area, which generates further rainfall. This can lead to a cycle that is capable of sustaining a forest over the breadth of an entire continent.

Stopping the Amazonian Dieback

The most notable example of this is the Amazon rainforest. The Amazon is sustained primarily through the biotic pump and deforestation has completely disrupted that process. The Amazon has now shifted into a new process, known as dieback. Dieback is the breakdown of the biotic pump from deforestation. As trees get cut down for fuel and land clearance, rain they would have generated does not reach other parts of the forest and they dry up and become highly vulnerable to fires, whether manmade or natural. This destroys more forest and make even more areas vulnerable to fires. This amounts to a massive chain reaction that will result in the total destruction of the Amazon rainforest, even if we stop all deforestation now.

Old growth forests play a major role within the biotic pump. They tend to have anywhere from 3 to 6 layers of vegetation, compared to non-old growth forests which usually have one. These numerous layers of vegetation in old growth allow for significantly more evapotranspiration.

Worse yet, the Amazon dieback is a climate tipping point. Climate tipping points are when natural systems are activated by human activity, and adjust their behavior to contribute to climate change. Examples of this include the accelerated loss of the Arctic ice sheets, the melting of the permafrost and the loss of glaciers.

If one of these tipping points becomes irreversably activated, then all the tipping points in the world will also become activated, regardless of what measures humans take to decarbonise. This will cause climate change to spin completely out of control. Stopping the Amazon dieback before it fully activates is crucial, as the Amazon is one of the World’s largest carbon sinks and its destruction will guarantee all of its carbon will be released into the atmosphere, activating every other tipping point. Restoring lost sections of the Amazon will be crucial to prevent this.

Sahel Restoration

The Sahel is the barrier between the Sahara and Central Africa. For thousands of years, It enjoyed regular rainfall patterns that sustained hundreds of thousands of communities across the continent of Africa as well as countless acres of forest. However, in the 1970s that began to change. Since then, rainfalls have been decreasing yearly, dust storms have become a regular occurrence and the Sahara Desert is creeping south, threatening to engulf the entire Sahel. The culprit is the introduction and widespread adoption of western agriculture and increased pastoralism. The land clearance for agriculture and the excessive consumption of leaves by pastoralists and their herds, caused the biotic pump sustaining the Sahel to rapidly collapse.

Much like the Amazon, the Sahel is experiencing a dieback. Unlike the Amazon, the Sahel is much further in the process, requiring more intensive intervention. With the Green Phoenix Project we are hoping to undo the damage done to the Sahel, restore the biotic pump in the region and stop the spread of the Sahara.