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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous > Basswood/Linden > Unusual woody growth on trunk

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Basswood/Linden > Trunk > Unusual woody growth on trunk

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  • Image: Burls 1
  • Image: Burls 2
  • Image: Burls 3


  • Large round to semi-circular swellings along main trunk or large branches
  • Many buds or sprouts may be present on the burl
  • Burls continue to grow as the tree grows
  • While burls do not kill trees directly they can reduce a tree's health and lifespan
  • There is no known cause for burls
  • More information on Burls
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  • Image: Perennial nectria canker 1
  • Image: Perennial nectria canker 2
  • Image: Perennial nectria canker 3

Perennial nectria canker
Neonectria galligena

  • Red to reddish orange raised cushion like bumps can occasionally be seen on the edge of the canker
  • Cankers become crater like cavities with age
  • Dead branches and twigs killed by girdling cankers
  • Sunken dark brown cankers on main trunk or branches
  • More information on Perennial nectria canker

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