Grow More Trees Please: Using Nature To Beat The Heat In Summer

Some gardeners like it hot. I have friends that live farther inland than I do and adore their 90-degree plus summer weather. They definitelygrow better tomatoes^[1]and more of them than folks on the coast, but that is only one consideration. While some like it hot, I do not. I like keeping cool. Maybe it came from growing up in Alaska, but the “why” matters very little. Any temperature over 75 degrees F. (24 C.) saps my energy and makes me cranky. So, needless to say, I know some important tricks for beating the heat in summer.

Grow More Trees for Shade

Unless you live in the desert lowlands or in one of the polar zones, nature has provided wonderful and beautiful tools for avoiding the summer broil. They are called trees. All you have to do isplant some trees^[2]and keep them irrigated to enjoy a cooler summer.

Whileevergreen trees^[3]provide shade all year long,deciduous trees^[4]do not. They show off bare branches in winter, leaf out in spring, then, by hot summer days, their canopies are lush and green again. This provides refuge to anyone bent on keeping cool by reducing the amount of sun that hits your skin.

Shade Trees for Your Garden

Trees are not only perfect for sitting under on a sweltering summer day, but they can keep your home and backyard cool too. Just like trees prevent sunrays from hitting you, they can also limit the sunlight striking your home, patio and garden. This reduces the amount of energy that is absorbed and re-radiated into the air.

But that’s not all. Planting trees in your yard also provides transpiration cooling. “Transpiration” refers to the way trees release water into the atmosphere from their leaves, not unlike evaporation pads used to chill out hot greenhouses. In trees, the water moves from the soil into the tree’s roots, travels through its trunk to the branches, then into the leaves. The water is then released from the leaves in vapor form, cooling the surrounding area.

The “best” shade trees for your garden will depend on your region’s hardiness zone as well as your personal preferences. Since I split time between Southwest France’s Basque Country and San Francisco, California, I have sets of favorites for both zones.

In France, the weather dips down to freezing in the winter and shoots up into the 90s in the summers. My favorite shade trees there arebeech^[5], with their white trunks and silvery canopies. I am also fond of the fast-growingwillows^[6],paper birches^[7]andred oak^[8].

San Francisco’s frost-free climate makes these shade trees improbable. Instead, I plant trees native to the state, like evergreenMonterey cypress trees^[9]. My favorite deciduous tree in the area is the imposingCalifornia buckeye tree^[10]. Both provide excellent shade and thrive on sandy soils.