Trees in Drought: Cooling, Storing Water, and Thriving with Care
There’s a common misconception that trees make droughts worse by competing with crops and depleting water supplies. While this can be true in certain situations—such as with dense, commercial conifer plantations or when soils are heavily drained—tree planting at low densities, in the right locations, can have the opposite effect. Thoughtfully planted trees and hedgerows help build resilience to drought, both in the countryside and our towns and cities, while also cooling the environment and supporting wildlife.
Trees Provide Natural Cooling
During hot, dry weather, trees provide invaluable benefits. Their canopies offer shade that reduces air and surface temperatures, cooling the surrounding area by as much as 5°C. In urban spaces, where concrete and asphalt trap heat, this cooling effect is even more pronounced, helping to combat the urban heat island effect and making our communities more liveable in a warming climate.
Shade from tree canopies doesn’t just benefit people—it helps wildlife too, providing protection from harmful UV rays and heat stress. Trees positioned around buildings can also help regulate indoor temperatures by blocking direct sunlight, reducing the need for artificial cooling.
However, not all trees cool the environment equally. The most effective trees for cooling tend to have wide, dense canopies and leaves that are light in colour or reflective. A tree’s cooling potential also depends on soil health, surrounding land use, water availability, and the local microclimate. Trees can only deliver their full benefits when planted in suitable conditions and given the space and resources to thrive.
Trees and Water Management
Long before a drought hits, trees play a key role in managing water. Tree roots help rainwater infiltrate the soil and subsoil, where it moves slowly towards rivers—supporting water flow during dry spells. For example, hedgerows planted on compacted pasture have been shown to increase water infiltration by up to 60 times within just a few years.
This function is more vital than ever. Modern farming and urban development have compacted or sealed soils, causing rain to run off quickly into rivers, often within minutes, and reducing water availability when droughts arrive.
Planting trees and hedgerows in the right places—whether in the countryside or within urban green spaces—can restore the soil’s ability to soak up and store water. In cities, planting trees and directing rainwater towards them can help replenish groundwater and reduce surface water runoff.
Helping Trees Survive Dry Weather with Mulch
While visiting many of our planting sites this summer, it has been remarkable how well the trees are doing, despite the extremely dry conditions. Many of our landowners have been experimenting with mulching their saplings using a range of different materials. Woodchip, wool, and grass cuttings all seem to have hugely beneficial effects. These organic materials can reduce water evaporation by around 35% and help to keep the soil around the roots cooler and wetter than elsewhere in the field.
They also reduce moisture loss from drying winds, which now appear to have become a more common feature of the Welsh summer. For many of this year’s saplings, this has made all the difference between surviving or drying out in the heat.
Sweet Chestnut coppice mulched with woodchip. Photographed July 2025 at Home Hill, Pandy, Monmouthshire. All the chestnut trees planted in January 2025 survived with no extra watering and minimal rainfall since early March.
Organic mulches bring many other benefits. They decrease erosion from heavy downpours, add nutrients to the soil as they slowly break down, and encourage better tree growth. A good mulch can reduce weeds by up to 50%, giving young trees a better chance to outcompete surrounding vegetation. Mulching also provides a wonderful habitat for helpful organisms such as earthworms, nematodes, and fungi. This not only boosts soil biodiversity but can provide food for birds, beetles, and hedgehogs too.
A newly planted cider orchard mulched with woodchip. Photographed in Crai, near Brecon, July 2025. These trees have not been hand-watered since being planted in March 2025 and are thriving. The owners have cut paths and will use the grass cuttings around the trees as a second mulch layer.
If you’d like advice on mulching your trees, get in touch with us at hello@stumpupfortrees.org. We’d love to hear about your experiences and share ideas with other landowners.
Trees are not the enemy of drought resilience—in fact, when planted thoughtfully, they’re part of the solution. Whether in fields, hedgerows, or city streets, trees can help cool the air, protect rivers, and maintain soil moisture. With the added benefits of mulching, newly planted trees stand an even better chance of surviving and thriving through dry summers.
At Stump Up for Trees, we’re committed to planting the right trees in the right places to support farmers, communities, and nature. If you’re thinking about planting trees or hedgerows on your land, get in touch—we’d love to help you find the best approach for your site.
With thanks to our experts: Trustee Bob Vaughan and Operations Manager Rachel Embury who have collaborated in writing this blog
