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Not seeing the forest for the trees: consequences of mass deforestation

Not seeing the forest for the trees: consequences of mass deforestation

If the media reports are true, the Earth is currently facing rapid and extensive deforestation, which, if unchecked, will lead to extinction of thousands of animal species, and then mankind. What is the true scale of this problem and, if possible, how can it be solved?

First, we need to ask ourselves the seemingly banal question about what forest really is. Unfortunately, the probably most common answer that it simply means a sufficiently large area with a high density of trees is not only wrong, but also harmful. A natural forest is a complex ecosystem and home to innumerable organisms interacting with each other and dependent on each other. Trees, most visible because of their size, constitute only one of many elements of the forest, The system also consists of numerous microorganisms, smaller plants, animals, soil, and a geological substratum. Hence, a pine plantation can by no means be considered equal to a primeval forest. A forest cannot be planted like a cultivated field. Similarly, it cannot be simply replanted by human hands. Ecosystems which developed for thousands of years cannot be reconstructed in one decade or even one century.

The following text is based on a recent article focusing on the problem of rapidly shrinking forest areas on our planet, authored by Dr hab. Paulina Kramarz from the Jagiellonian University Institute of Environmental Sciences.

The source of food and wood

A Carpathian mountain forest regenerating after a spruce bark beetle invasion. Photo: K. Kujawa

What was the historical relation between the forest and humans and what is it like today? Originally, it was primarily treated as a source of food. With the Neolithic revolution and the advent of agriculture (about 10 thousand years ago), it also started to be perceived as a an obstacle. Human societies, seeking areas suitable for food production, began to cut down forests to make room for farmlands and pastures. On the other hand, trees were constantly needed as the source of the most basic building material, necessary to build houses, means of transport, or furniture. Thus, trees started to be planted en masse, which led to the emergence of cultivated forests, consisting of most cost-efficient species and treated as a source of wood. At the same time, natural forests that hadn’t yet been cleared were cut by roads dismembering large ecosystems into smaller parts, and also used as a source of wood.

Five reasons to worry

And how does the situation look today?  What are the most serious global threats to forests in the 21st century?

Firstly, all over the world natural habitats, including forests, are divided into pieces by the growing network of roads. This process leads to the separation of organisms that used to coexist and interact with each other. They often find it difficult to adopt to the new circumstances, which leads to the gradual death of the forest as an ecosystem.

Secondly, tree plantations which were to become new forests tend to die very quickly. The widespread planting of trees of the same age and low genetic diversity makes them extremely vulnerable to draughts, heatwaves, gales, storms, and other adverse factors.

Thirdly, each year the Earth loses a forest area equal to the size of Great Britain. The rapid deforestation leads to higher temperatures, more severe draughts, and the degradation of soil. The drying up of Polish farmlands, which has caused large crop losses during the last few years, has largely resulted from deforestation.

Fourthly, the reforestation of burnt out areas rarely proves successful. The impoverished soil is often barely able to sustain farmlands and pastures, not to mention forests.

Fifthly, the species composition of forests in many parts of the world is becoming altered due to the climate changes. For instance, the population of Polish pines and spruces is already decreasing, due to the excessively hot and dry weather.

The threefold doom

What makes deforestation so dangerous? Contrary to the popular opinion, the problem doesn’t consist in losing a major source of oxygen. If suddenly all forests in the world disappeared, the amount of oxygen in the atmosphere would remain the same. What’s really important isn’t what the “lungs of the planet” breathe out, but what they breathe in, namely greenhouse gases. If the Earth lost this precious organ, its atmosphere would soon become filled with additional megatons of carbon dioxide. The consequences aren’t difficult to imagine.

A typical cultivated forest. Photo: K. Kujawa

Mass deforestation also leads to the disruption of the global hydrological cycle  By retaining enormous amounts of water, forests effectively inhibit the outflow of water to rivers, and then to seas and oceans. The lack of this natural buffer would lead to massive floods occurring on a regular basis.

Another huge threat is related to biodiversity. Forests are home to innumerable species. The elimination of a seemingly unspectacular element of the ecosystem, such as insects, would surely lead to human extinction. How is that possible? Without insects, plants pollinated by them will die out, along with animals which consume both the plants and insects. Large predators who eat these animas, and, finally, humans, will follow. It should be noted that, as far as pollination is concerned, the possible survival of domesticated bees wouldn’t save the mankind, due to the fact that millions of years of co-evolution of plants and insects resulted in a specific anatomy of many flowers, meaning that they can only be pollinated by certain insect species.

Lost in the woods

Can numerous tree-planting initiatives be treated as an effective remedy to the ecological and climate crisis? The answer is no. No matter how many trees we plant, they won’t be able to absorb all the carbon dioxide released to the atmosphere. They cannot replace the centuries-old natural forests, which, due to their biodiversity, perform this function much more effectively. If so, is there any hope for survival? The only chance is to both greatly reduce the emission of greenhouse gases and stop the environmental degradation, especially deforestation. This constitutes a major challenge, which isn’t made easier by the fact that the deadline to do this passed 30 years ago. Hence, the temperature is going to rise, but we can still hinder this process. The actions to address this problem must be combined with measures to adapt human societies to the ongoing and future climate changes, which won’t be possible without natural forests.

Original text: www.nauka.uj.edu.pl 

Dr hab. Paulina Kramarz from the JU Institute of Environmental Sciences has co-authored 43 publications on terrestrial invertebrates, including many papers concerning ecotoxicology and GMO farming. She is the co-author of the National Strategy to Protect Insect Pollinators. She currently focuses on evolutionary and ecological aspects of insect physiology. Her interests also include biological crop protection and agroecology. The above text is based on her article from Nauka dla Przyrody website, originally published in Krytyka Polityczna.

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