Trees stand tall and firmly anchored in the face of the blowtorch-like wind and heat radiated from hard surfaces. Driveways, rooftops, patios and sidewalks absorb sunlight and radiate that energy as the heat we all feel. When the air moves this heat over to your landscape, it's called advective heat. Advective heat means you must use your cooling power, water and shade to dissipate heat generated somewhere else. And this summer there is plenty of heat to move around.
Heat badly stresses trees in two main ways.
One is through water loss. The other, much more insidious, is through accelerated food use. Wilted foliage and drooping new twig tips are a sure sign of water shortage in the tree. The tree can take in water only from the soil. In some places, little water remains accessible to tree roots.