Home Course Map Resources Help Back 2 of 7 Next
Lesson 5Lesson 5


Edge Feathering and Crown Modification

Edge Feathering:

  • Edge feathering is thinning within the first tree length of the stand edge.
  • Where possible, retain the most windfirm trees.
  • Don’t feather edges in dense stands of slender trees.
  • Feathering mimics the pattern of partial damage that develops along moderate risk boundaries.
  • During salvage, leave standing and leaning trees in place if possible.
Show Larger Image

Crown Modification:

  • Crown modification includes: topping, top-pruning, sailing, spiral pruning.
  • Removing the top 1/3 of the crown reduces wind loading by 50%.
  • Topping and top pruning can reduce tree vigour and cause trees to produce multiple leaders.
  • There are helicopter-based techniques for topping and top pruning.
  • Heli-saw productivity ranges from 12–44 trees/hour, costing $19–68/tree. It is best suited to mature stands.
Show Larger Image
Show Larger Image
Show Larger Image
Show Larger Image
  • Heli-shear productivity ranges from 9–37 trees/hour, costing $23–91/tree. It is best suited to 2nd growth stands.
Show Larger Image
Show Larger Image
  • Manual topping productivity ranges from 1.3–1.9 trees/hour, costing $46–54/tree.
Show Larger Image
  • Sailing and spiral pruning are manual arboricultural techniques that preserve the top of the tree.
  • In sailing, windward branches are removed from the lower 2/3 of the crown.
  • In spiral pruning, branches are removed throughout the crown.
  • Productivity for sailing and spiral pruning treatments is lower than topping.
Show Larger Image



Forest Service BC
Forest Renewal BC