How do trees survive droughts

In the UK although not published most years we have a number of mini droughts defined as a period of out to 40 days without rain.
Once a tree is established they have several ways to offset the effects of a drought.

Most importantly trees team up with a soil-based fungus in a symbiotic relationship in which the tree combined with the fungi to enable it to draw water from a larger area than its roots can do on their own. This is called mycorrhiza and if you are a GardenAdvice MyGardenTeam member you will have come across us speaking about it as an important part of your gardening to encourage this symbiotic relationship with your garden plants and the fungi in the soil, especially with climate change.
Next time you are in a public park have a look at the larger trees its only in very extreme weather that you will find a mature tree wilting or suffering leaf loss and this is all down to the symbiotic relationship the tree has formed with soil fungus.

Morning dew – in a hot period often a heavy early morning dew will form on large trees and the tree will have organised its leaves to allow the dew to drip down the tree transferring from one leaf to a low leaf until the drips collect on the ground directly above the main feeding roots.
Reducing the tree canopy – a tree and indeed most plants can adjust their canopy by dropping leaves to conserve water by slowing down the overall evaporation. To do this the tree will take the nutrients from the leaves back into the body of the trees and reuse them when conditions favour growing new leaves as the moisture levels improve