Trees Help with Water Distribution

As part of the incredible "Great Green Wall" project, China has planted so many trees – 66 BILLION since 1978 – that it has changed the entire country's water distribution, in a way that scientists are only beginning to understand. A truly amazing feat of environmental action and an example of the impact of tree-planting. The project aims to plant billions of trees around the margins of the Taklamakan and Gobi deserts by 2050! (Live Science)

Canopies prevent flash flooding by slowing down the rainwater before it reaches the ground. Up to 30% of rainwater can be evaporated back into the atmosphere directly from the canopy without ever reaching the ground, even in the winter when trees do not have their leaves. (Woodland Trust)

Following flooding across the UK in 2007, a report suggested that garden paving is a major factor in surface water movement in towns and cities. Around two thirds of all the flooding in 2007 was as a result of surface water run-off, and trees can reduce 80% of surface water run-off compared to asphalt (Woodland Trust). When people are encouraged to plant trees in their gardens, they are more likely to make choices that help to reduce the risk of flooding.

Tree-planting is considered one of the most sustainable solutions to addressing the challenges of riverbank erosion. They are an important part of riparian vegetation, stabilising riverbanks, filtering nutrients and sediment, providing shade to regulate water temperature, and offering essential wildlife habitat. (Farming & Water Scotland)

Trees are an important part of the Earth's water cycle. Leaves absorb water through "stomata" and slowly release it into the atmosphere as water vapour, contributing to local and regional rainfall cycles, among the other benefits trees provide (Plant a Million Trees). Cutting down trees disrupts evaporation levels, dries up the moisture in the air and throws off the balance of the water cycle. A continual cycle of dry air, low humidity, and decreased precipitation will inevitably lead to a drought-prone, desert-like climate (EarthDay.org).

Tree roots improve soil structure, allowing water to penetrate deeper into the soil and reducing surface runoff, therefore reducing the risk of flooding. Forest soils can absorb several times more water than compacted urban or agricultural soils.