Wasps

• According to the University of Delaware College of Agriculture, wasps are the most serious problem to humans among stinging insects. Wasps are much narrower than bumblebees or honeybees. Baldfaced hornets are large wasps just under 1 inch long that build nests in trees and shrubs. Paper wasps are thin insects that occasionally build paper nests in low branches of shrubs or trees. This type of wasp doesn't usually sting humans except when they are disturbed. Wasps build nests made of papery material created from chewed wood. If a wasp nest is not destroyed, the insects will continue to enlarge it until it houses hundreds of insects.
  
  

Yellowjackets

• Yellowjackets have distinctive yellow and black markings but are really a type of wasp. These insects tend to nest around people, and frequently sting humans, causing swelling and pain. Yellowjackets also build a papery nest but their nests are much smaller than other types of wasps, according to the North Carolina Cooperative Extension office. Nests can be built in shrubs, trees, below the ground or under eaves.
  
  

Honeybees

• Honey bees don't usually build their nests in trees, but a swarm of bees can cluster in an exposed location such as a tree while they are in the process of building their nest. Honey bees are more likely to build nests in the hollow of a tree or between buildings.
  
  

Other Insect Nests

• Not all insect nests in trees are created by stinging insects. Tent caterpillars build conspicuous nests in the branches of trees. Eliminating nests while they are small can help prevent the defoliation of trees that these caterpillars can cause. Some spiders build cone-like webs on low branches where they hide to lay eggs.
  
  

Control of Insect Nests

• It's often difficult to eliminate the nests of stinging insects. If the wasps or bees aren't bothering people, it might be better to wait until fall when nests are abandoned. If the bugs are a nuisance, wasp or hornet spray can be applied to the entrance of the nest after dark. Treatment should be repeated every few days until no more insects are seen. A reputable pest control company can eliminate problems with insect nests.