Common Sickness Symptoms in Trees Leaves - these symptoms are usually easy to spot. The leaves may be an indicator of sickness if they fall earlier than they should. If you take a closer look, you might also see change in color, small dots or insect damage. All of these are sure signs that the condition of the tree has deteriorated. Branches - falling branches might also be a bad sign. It means that the tree is not capable of supporting them and certain parts...