The Cheapest Form of Climate Control

Plane trees found in town squares in Portugal are often 150 to 200 years old. They were planted during the 19th century - the same time when the avenues of Lisbon and the public gardens of Porto, Coimbra and Évora opened.

A plane tree of this age has a crown that can cover 400 to 600 square meters.

• It can release up to 500 liters of water a day in the middle of summer.

• It reduces the local temperature by up to 8 degrees C.

• It removes 25kg of carbon dioxide from the atmosphere per year.

• It supports more than 300 species of insects — including many butterflies and native bees.

The decision to cut down a century-old plane tree to widen a street or build a parking lot comes with a cost that never appears in the budget: the free cooling system that took 200 years to grow cannot be replaced immediately.

A new tree planted in the same location will take 50-80 years to reach the cooling effect and other benefits of the plane tree you cut. Portugal's oldest plane trees are legally protected natural monuments — but many don't have that status yet.
The coolest square in town is often the one with the oldest trees.

From Secrets of a Green Garden

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