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There are more trees on Earth than stars in the Milky Way: about 3 trillion trees, against an estimated 100 to 400 billion stars.

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The tree count comes from a 2015 study in the journal Nature, led by the ecologist Thomas Crowther, then at Yale University. His team combined more than 400,000 ground measurements of forest density with satellite images and arrived at about 3.04 trillion trees, roughly 420 for every person alive. Earlier estimates, based on satellite images alone, had put the figure near 400 billion. The study also measured losses: about 15 billion trees are cut down each year, and the number of trees on Earth has fallen by around 46 per cent since the start of human civilisation.

Türkçe oku
Dünya'daki ağaç sayısı, Samanyolu'ndaki yıldızlardan fazladır: yaklaşık 3 trilyon ağaca karşılık galaksimizde tahminen 100 ila 400 milyar yıldız var.

Ağaç sayısı, ekolog Thomas Crowther'ın yönettiği ve 2015'te Nature dergisinde yayımlanan bir çalışmadan gelir. O sırada Yale Üniversitesi'nde bulunan ekip, orman yoğunluğuna ilişkin 400.000'den fazla arazi ölçümünü uydu görüntüleriyle birleştirdi ve yaklaşık 3,04 trilyon ağaç, yani yaşayan her insan için 420 kadar ağaç hesapladı. Yalnızca uydu görüntülerine dayanan önceki tahminler bu sayıyı 400 milyar dolayında gösteriyordu. Çalışma kayıpları da ortaya koydu: her yıl yaklaşık 15 milyar ağaç kesiliyor ve insan uygarlığının başlangıcından bu yana Dünya'daki ağaç sayısı yüzde 46 kadar azaldı.

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