September 11, 2023 – We’ve discussed soil, water, and sun in terms of their effects on our gardens. It would be shortsighted, however, to ignore the effect of these items on our trees which, under our current conditions, are little effected by the soil itself, as they were born, grew, and currently survive in the same soil. On the other hand, they’re affected by the sun, associated temperatures, and especially by water availability.
Trees have varying abilities to store food-energy (sugars) in the root system but have only a limited ability to conserve energy. Triple digit temperatures combine with severe drought wreaks havoc on the available water supply. Trees do what they can to cope, but coping doesn’t alleviate the need for water.
Leaves can curl to save water, stomates can close, leaves can wilt, turn yellow or brown, and without further relief, drop from the tree. Basically, the trees pretend it’s winter and live off stored sugars. Doing this once may have little long-term effect on mature trees, but when it recurs for several years, trees are left in worsening health each fall, because they haven’t had time to replace sugars lost from previous years’ drought(s). Further, young trees and saplings started with only a few sugars to fall back on. You can also get sudden limb drop where a large limb suddenly snaps in two with no warning.
Urban yard trees need additional water as well as our gardens. Providing 1-2” of Water weekly out to the drip line will provide great relief to soil cracking and root nourishment.
Current conditions which have existed for at least four years show no signs of abating. Rather than being the exception, summer drought in NETSEO appears to be the norm. Further, weakened/stressed trees in a cold winter do not make for a long life.