Trees are prone to dropping branches in the summer months. On hot days, a tree takes in a lot of water in an effort to cool the wood via a process called evapotranspiration. The extra weight of the water in the branches can cause them to break off if they are also suffering from any of the following problems.

1. Weak Spots

Weak spots can be due to defects in the branch that forms as it grows or they can develop from outside damages. For example, a crack in the branch can form due to high winds, which will then increase the chances of the limb dropping if the tree takes in a lot of water on a hot day. Weak spots can also be a result of the growth pattern of the branch itself, such as one that is too narrow to support all of the twigs and leaves at the tip.

2. Poor Structure

Poor structure is caused by the growth pattern of the branch itself or of a neighboring branch. A wide branch crotch is one example. If the branch joins the trunk at an angle greater than 90 degrees, it is more likely to break. Another branch that rubs against the first also increases the chances of breakage due to friction stress and damage. 

3. Pest Damage

Pests include insects and animals, as well as bacterial, fungal, and viral pathogens. Insects and animals tend to damage branches by eating at the bark or boring holes. Disease pathogens can destroy a branch from the inside out if they get into the main wood. Over time the branch weakens to the point that it can support its own weight, particularly on hot days when the branch takes up a lot of water. 

4. Drought

Drought stresses a tree in many ways, which can include branches dying off which may cause them to fall down. Another drought issue occurs once wet weather returns. The tree may take up so much water during a heavy rainfall that it fills all the available water-holding structures in the branch. The weight of this much water after a prolonged dry period can cause the branch to fall. 

5. Dead Weight

A partially dead branch isn't just weak from some sort of damage, it must also support that dead weight. Whether it's the weight of a branching limb that has died or just a lot of weight from many dead twigs and leaves on an otherwise living branch, breakage is a possibility. 

Contact residential tree care services for more help if you are worried about branches dropping from your landscape trees. Regular pruning, treating possible pests, and correct irrigation can all help prevent summer branch loss.