Zone 3: The trunk

The trunk holds up the tree and supports the massive weight of its branches. Inspect the trunk thoroughly.

  • Cavities can be dangerous, depending on their size, where they're located on the tree, and how deep they are. If there is a cavity above eye level, a "climbing" inspection may be needed to find out how deep it is and if there is decay.
  • Cracks and splits in the trunk are extremely dangerous. If there is a crack or split in the trunk, the entire tree could fall or break apart at any time.
  • Missing bark (or areas where bark is falling off) usually signals a dead section. Look for places on the tree’s trunk where there is no bark, the bark is falling off, or the bark is discolored. Missing bark can also indicate a surface wound, infection, or a fungus attack.
  • A long streak of missing bark coming down the tree usually means the tree was struck by lightning. It's possible that a tree can recover from this, but if the leaves turn brown after several weeks, the tree has died.
  • When ants and beetles attack, they leave very fine, light-colored sawdust (“frass”) that is easy to see. Ants cutting into decayed wood leave coarse shavings. Pine bark beetles attacking a pine tree leave “pitch tubes” that resemble marble-sized balls of light-colored sap.
  • Trees with more than a single trunk sometimes crack and split where the trunks connect. Strong connections appear as a “U” shape; weak connections resemble a tight “V” shape. Sometimes a tree adds layers of wood over the trunk connection to strengthen a crack. After a windstorm, look at the connection in the tree where the trunks meet. Use binoculars if the connection is high up. If there is a lightly colored line that contrasts to the natural dark bark color, you are probably looking at a fresh crack. The tree may be in the process of splitting apart. Consider this situation an emergency.

If you see any of the above conditions in your tree, call a Certified Arborist immediately to determine if your tree is stable enough to leave standing or whether it should be removed.