Plant Trees! – They say… but which ones?

Everywhere around the world people at large are planting trees. India planted 66 million trees in 12 hours in the region of Madhya Pradesh on July 2nd. Yacouba Sawadogo in Africa began planting trees in 1980 to save North Burkina Faso from desertification. In Niger farmers are turning to Gao trees, considered magical and extremely useful to growing crops (unlike other trees), moreover its fallen branches give wood for fire and its pods feed the animals. Italy’s current most ambitious project is called ForestaMi, which aims at planting 3 Million trees (one for each person who lives in Milan) by 2030. 
Among the multiple reforestation campaigns I am observing around the world, one has caught my attention (also the news are not covering it too much, perhaps it’s one of those things that has the potential to bring immense change): The Great Green Wall in Africa. As a matter of fact The Guardian wrote a piece over 8 years ago. All began as a conversation started by Richard St. Barbe Baker – professional forester and pioneer in environmental activism – back in 1952. He suggested a bold solution to the problem of desertification: plant a barrier of trees wide 50 km that cuts in two Africa, from coast to coast. In 2002, during the World Day to Combat Desertification & Drought, the ex Nigerian president Olusegun Obasanjo launched The Great Green Wall project. Five years later, in 2007 the African Union officially approves the grandiose project. What is it? In brief, it’s a wall of trees covering Africa from side to side in the region of Sahel, right below the Sahara desert, extending for 8000 km and 15 km wide. The symbol of such extraordinary project is more than just combat desertification. It’s a wall symbol of life and unity. It has the potential to decrease, if not stop, wars between African tribes/States. People come together for a bigger cause. It will give shelter to animals, feed people, and show the world that Africa can be united beyond profit. However in 2012 the project changed its vision to adapt more to the countries’ morphology, as planting solely trees was going to be unrealistic: The wall is no longer seen as a narrow band of trees along the southern edge of the Sahara. The vision is now to surround the Sahara with a wide belt of vegetation – trees and bushes greening and protecting an agricultural landscape. The new vision engages all the countries surrounding it, including Algeria and others in North Africa, not just the 11 original sub-Saharan countries of the Sahel – The Conversation
It’s not an easy task! It needs a lot of effort and especially cooperation and flexibility: The sub-Saharan countries are not all the same and the techniques (and plants/trees) must be adapted accordingly. Though lets not despair! 🙂

Why are trees important?
Trees eat CO2. … CO2 is carbon dioxide, a colourless gas we find naturally in Earth’s atmosphere. It’s produced by all aerobic organisms when they metabolise carbohydrates and lipids to produce energy by respiration – hence we humans too. Carbon dioxide in the atmosphere is the primary carbon source for life on Earth and its concentration in Earth’s pre-industrial atmosphere since late in the earliest part of Earth history has been regulated by photosynthetic organisms (plants, algae and cyanobacteria) and geological phenomena. The “problem” with CO2 is that it absorbs and emits infrared radiation at wavelengths of 4.26 µm and 14.99 µm and consequently is a greenhouse gas that plays a significant role in influencing Earth’s surface temperature through the greenhouse effect. The increase of CO2 in the atmosphere has been attributed to human activity, particularly deforestation and the burning of fossil fuels. This increase and other long-lived greenhouse gases in Earth’s atmosphere has produced the current episode of global warming. Between 30% and 40% of the CO2 released by humans into the atmosphere dissolves into the oceans, wherein it forms carbonic acid and effects changes in the oceanic pH balance (causing among other things coral bleaching, and also threatens the future food chains linked with the oceans). – You can deepen your basic understanding of the carbon cycle on wikipedia 😉
Last but not least, Alejandro Jodorowsky proposes a psychomagic act to heal the planet: plant a tree on the 7th of September.
I asked Giorgio Vacchiano, researcher in forest management and planning at the State University of Milan, if planting trees helps:
Planting trees to sequester carbon works IF those trees survive and grow well after being planted, IF they are replaced with others at the end of their cycle, and IF their plant does not affect other important services such as food production or flora habitat or fauna. T
hose trees will absorb carbon as they grow, so over time their usefulness will increase (if they are maintained and not eliminated, not even by fires or insect attacks). Forests have a different time than ours … but starting now is better than nothing.”

On Tropical and Boreal Forests
Most tropical rainforest plants are considered to be evergreens, replacing their leaves gradually throughout the year as the leaves age and fall, whereas species growing in seasonally arid climates may be either evergreen or deciduous. Most warm temperate climate plants are also evergreen. In cool temperate climates, fewer plants are evergreen, with a predominance of conifers, as few evergreen broadleaf plants can tolerate severe cold below about −26 °C. E
vergreens don’t photosynthesise all year round. In cold areas, winter temperatures are too low and photosynthesis takes place minimally or not at all. In the Mediterranean areas, the evergreens close the stomata (the “hatches” of the leaves) during the summer to avoid losing water by evaporation, so even here photosynthesis stops.
Boreal coniferous forests are the second most important carbon reservoir after the tropical ones. FYI, two thirds of the Boreal forests are located in Siberia.
What makes these forests so important it’s the fact that they are the ones that contain more biomass, therefore more tissues capable of storing carbon.

The Family of 5 Primary Forests (National Geographic2015)


So today we hear excessively about needing to plant new forests (as if it were that easy… few people are aware of the fact that forests need management) since we see them as carbon tanks. Because humanity emits more CO2 into the atmosphere than plants and oceans can accumulate, forests are ecosystems that can potentially help reduce the impact by storing carbon in its biomass. However they can also emit more CO2 than their storing capacity, hence why management and planning is needed. 

And the question is, any tree is good or some are better than others?

My Conclusions

If you want to plant a tree make a research about the area that you live in and choose an evergreen possibly. If you have enough land to plant more trees, I would advice you contact a forest management expert in your area or at a University. In Italy I would like to indicate Mosaico Verde, based in Rome they operate in the entire country even for just a quick consultancy. Something I really like about the job they do is the fact that if, for example, you live in a city and don’t have a garden nor yard whereto plant a tree don’t despair! 😀 Mosaico Verde has multiple projects you can support by simply buying a tree: you choose the area and also the tree that is good for that specific area.

To plant a tree (or trees) to clean your conscience is not ideal as the tree won’t be enough to clean the air you pollute by your lifestyle.

Take care as much as you can of the local forests: we are so used to looking at the Amazon and giving money to protect the Amazon while forgetting about our home and our country.
I asked Mr. Vacchiano about the present situation of European forests, “There is a forest expansion of 800’000 hectares every year – of which 50-70’000 ha in Italy – mainly spontaneous on abandoned fields and pastures. Means good news for carbon sequestration and hydrogeological instability, even if all that glitters is not gold – in some places, it also means an increase of fire hazard. At the same time, the very few virgin forests remaining in Europe are actually getting smaller and smaller, especially in Romania and Ukraine, due to illegal cuts to obtain valuable wood and, in part, energy biomass. At last, climate change risks stressing forests (especially in Italy) with more frequent droughts, storms and fires. I would say this is the biggest problem, which we must learn to face.”
Europe’s virgin forests are fundamental treasures of biodiversity and unique places able to make us understand how nature works without human intervention. 

Plant trees for the sake of planting them and as a gift to Mother Earth. And remember the best tree to plant is the one that grows better in your area. 

900 wild bisons live in Bialowieza (© Tomasz Kaminski)

Scienza in rete
National Geographic

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