Sudden Tree Limb Drop

Published on August 07, 2023

With this year’s intense summer weather, some trees around the City are experiencing sudden limb drop. Sudden limb drop occurs when a branch unexpectedly breaks off a tree, often during the summertime. It most frequently occurs in mature trees that are otherwise healthy.

There are many theories about the cause of sudden branch drop. A few of the main contributing factors include internal cracking and shrinkage of tissue due to heat and dryness, presence of over-extended, end-heavy branches, and evapotranspiration needs exceeding vascular capabilities leading to an accumulation of excess internal moisture and weakened structure.

While sudden limb drop can be difficult to predict, there are steps one can take to reduce the likelihood of occurrence.

These steps include scheduling regular inspections and maintenance pruning. To help reduce the occurrence of tree failures, the City of Menlo Park’s tree crew and its contractor West Coast Arborists, Inc. inspect and conduct maintenance pruning on street and park trees on a five-year cycle. Of particular relevance to sudden limb drop is reduction pruning of end-heavy horizontal branches that extend beyond a tree’s dripline and pruning to balance a tree’s crown to help distribute weight and vascular flow evenly. Appropriate mulching, fertilizing, and watering during hot summer months can also help increase tree resiliency.

To report a tree branch down or to request inspection and maintenance for a City tree in your neighborhood, send a work request to the City.