Cankers

• Cankers are fungus-caused depressions found on tree trunks and large branches. The area around the sunken canker is usually ridged and extends beyond the trunk's normal surface. Two fungi responsible for cankers are Nectria and Eutypella. As cankers worsen, they cause girdling of branches, particularly in boxelder maple trees. Girdling effectively cuts of a portion of the branch from the tree's circulatory system, causing the branch to weaken and die. Keep your tree well watered and protect its trunk from abrasions and cuts. Open wounds allow fungus to enter the tree and cause cankers. Prevent canker growth by removing cankers early in development. This kind of tree surgery is best performed by a trained arborist. When purchasing new trees, choose saplings that are free from cankers and stem damage.
  
  

Verticillium Wilt

• Sugar maples are most susceptible to Verticillium alboatrum, a soil-borne fungus that causes verticillium wilt. The fungus travels from the soil throughout the tree and first presents itself in the form of discolored leaves that drop from the tree. In extreme cases, leaves drop from a branch's lower portion but, as the branch become infected leaves die, remain on the branch and the entire branch fails to thrive. Infected trees become stunted. Prune back infected branches. Verticillium wilt presents as light brown, dark brown or green streaks within the branch's sapwood. Pruning helps control verticillium wilt, but the condition has no cure. Severely damaged trees must be removed and replaced with resistant trees, such as birch or flowering crabapple.
  
  

Girdled Roots

• Maple trees are found in urban areas where they tolerate many detrimental conditions like pollution, compacted soils and overcrowding. Over time, however, these conditions weaken a tree, causing a condition known as maple tree decline. Trees exhibiting stunted leaves and branch dieback may suffer from root girdling, a condition caused by compacted soils. Treatment for this condition includes enlarging the tree's planting hole and removing the girdled root. Keeping your tree well watered and fertilized helps improve a tree's health and makes them more resilient to other environmental factors that may cause damage.
  
  

Considerations

• Choose the best maple species for your location. Swamp maples do well in wet soils, but sugar maples require well-draining conditions. Norway maples benefit from cool temperatures, but Southern sugar maples (Acer barbatum ) tolerate warm, humid climates. Whatever your species or location, ensure that proper pruning and maintenance schedules are performed and held to; healthy trees are better able to withstand occasional stresses, pests and disease.