Everyone’s familiar with the story of “Chicken Little”, the pint-sized poultry who proclaimed “the sky is falling.” Well, he needs to get to work prognosticating about tree-limb failure. Most summers are complete with sporadic limb failure, but an added effect of this historically hot and dry summer has been an increase in what is often termed “sudden limb drop”. The cause of this dramatic event is complicated and contested among arborists, however, two general factors are at play: preexisting structural defects in the broken limb and excessive evapotranspiration as a result of high temperatures.
These two factors account for an apparent spike in “sudden limb drop” this summer. The extreme cold and heavy snow and ice we experienced during February provided the structural defect by causing micro fractures in the limbs. This summer’s record-breaking string of 100-degree-plus days in the Southern Plains provided the extreme transpiration. While predicting these events is virtually impossible, reducing the amount of damage could be possible by thinning the weight of the branches, especially on nut-bearing trees whose limbs get heavier as the nuts mature late in the summer.