Yes, it’s true… scientists have evidence supporting the widespread perception that trees make rain, that growing more vegetation, we get more rain.[1]

On average, 40% or more of the precipitation over land originates from evaporation and the transpiration of water from plants.[2] Forests like the Amazon don’t merely grow in wet areas; they create and maintain the conditions in which they grow.

When vegetation gets cleared, less water is available in the landscape for evaporation and transpiration, suppressing precipitation.[3]

For example, more rain used to fall on the western side of a 750 km long fence built to exclude rabbits in southwest Australia. Today, however, the land on the eastern side of the barrier gets higher rainfall. This is because, on the western side, most of the vegetation has since been removed for arable cropping.[4]

Aerial photo of rabbit proof fence and trees making rainCloud cover either side of the Rabbit-Proof Fence (©Earth Observing Laboratory)

Large-scale deforestation reduces rainfall in some areas by up to 30%, and reliable rainfall in continental interiors of Africa, Australia and elsewhere, appears to depend on maintaining relatively intact and continuous forest cover from the coast.[5] Transforming landscapes from forest to fields has at least as big an impact on regional climates as climate change.[6]

Image showing how trees make rain

The effects of Deforestation on Rainfall[7]

It’s great to know that trees make rain, but trees are being cleared at a faster rate than any time in history! How can we possibly reverse this?

>> By changing the story we tell about the value of trees

Discover how to improve rainfall in your region by drought-proofing your farm and garden.Front cover - How to Drought-Proof Your FarmFront cover drought-proof your garden

References for Trees make Rain

[1] Shukla, J and Mintz, Y, 1982. Influence of Land-Surface Evapotranspiration on the Earth’s Climate Science19 Mar 1982: 1498-1501. Vol. 215, Issue 4539, pp. 1498-1501
DOI: 10.1126/science.215.4539.1498 (https://science.sciencemag.org/content/215/4539/1498)

[2] Trees, forests and water: Cool insights for a hot world. David Ellison, Cindy E. Morris, et al. 2017. Global Environmental Change 43 (2017) 51–61 (https://www.sciencedirect.com/science/article/pii/S0959378017300134)

[3] Spracklen, D., Arnold, S. & Taylor, C. 2012, Observations of increased tropical rainfall preceded by air passage over forests. Nature 489, 282–285 doi:10.1038/nature11390 (https://www.nature.com/articles/nature11390)

[4] Nair et al-2011-Journal of Geophysical Research-Atmospheres (1984-2012) The role of land-use change on the development and evolution of the west coast trough, convective clouds, and precipitation in southwest Australia (https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2010JD014950)

[5] Charles Massey – Farming in the Middle East and Australia: lessons about a brittle climate. ABC Saturday Extra (https://www.abc.net.au/radionational/programs/saturdayextra/farming-in-the-middle-east-and-australia:-lessons-about-a-britt/10794674)

[6] Judith D. Schwartz, 2013, Clearing Forests May Transform Local—and Global—Climate, Scientific American March 4, 2013 (https://www.scientificamerican.com/article/clearing-forests-may-transform-local-and-global-climate/)

[7] Aragão, L. The rainforest’s water pump. Nature 489, 217–218 (2012) (https://www.nature.com/articles/nature11485)

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