When trees are in their prime, basking in the warmth of the sun, seemingly healthy and strong, suddenly drop a limb or two without warning. But why does this happen? Common trees exhibiting the summer limb drop are; Oak trees (the most common), Maple trees, Raywood Ash trees, Bradford Pear trees, Modesto Ash, Redwood Ash trees, Chinese Pistache trees, and Sycamore trees.
Trees perform a process known as evapotranspiration. It is when trees draw up extreme amounts of water during the day, and then, through their leaves, they release moisture into the air. But on a hot day a sudden drop in temperature; the tree doesn’t get the opportunity to shed out the moisture it withdrew and the increased weight will cause the limb to drop. The limbs will often look like feathery cuts; healthy green and pliable with no signs of disease or pest infestations.
In some cases, a bird or another wild animal will agitate a small crack or fissure created by the moisture’s weight that didn’t completely remove the limb, and over time, their activities can make the limb fall. In any case, when the limb gets increasingly large amounts of water before it is able to expel it through the leaves; the limb will crack, or break off completely. In most cases, there aren’t any obvious signs your tree’s limbs are in distress. Occasionally, and if you know what to look for, you can see a darker spot where the water is trying to bleed out. This phenomenon can take up to 5 years or more before the limb will break, without any evidence of the coming event.
Additionally, poor pruning maintenance can make the branches unnecessarily heavier and with this bad recipe of heavy branches from poor pruning, trees gathering extra water on the hot days, and a sudden brisk wind storm, also dipping the temperatures down; the limbs will fall. You can attempt to minimize the event from occurring if you prune your trees accordingly to their species and thin out the tree crown every 7 years or so.
We hope this helps you better understand what happens when the random summer limb drop occurs!