1. Strengthening our Community Tree Canopy Through Education
Module #3:
Pruning Young Trees in the Urban Landscape
Laura Sanagorski, Environmental Horticulture Extension Faculty

2. Strengthening Our Community Tree Canopy
2012 Urban Forestry Series
This series is a part of a project titled “Strengthening Our Community Tree Canopy Through Education”.
This project is made possible by  a grant through the 2011 National Urban and Community Forestry Grant Program and the Florida Department of Agriculture and Consumer Services, and the Florida Forest Service.

3. Pruning Young Trees in the Urban Landscape

4. STRUCTURALLY SOUND TREES
Straight, single leader
Evenly spaced branches and full, even canopy
Free of pests, disease, and injury
Roots grow away from the trunk; do not circle or girdle
Photo: UF Laura Sanagorski

5. EFFECTS OF PRUNING Creates potential entry points for decay organisms
Every pruning cut:
Creates potential entry points for decay organisms
Promotes shoot elongation
Reduces photosynthesis
Causes consumption of stored carbohydrates
Photo: UF Laura Sanagorski

6. EFFECTS OF PRUNING May create or enhance structural defects
Improper pruning cuts: Cause the above negative impacts, plus
May create or enhance structural defects
May increase insect and disease problems
May increase maintenance needs
Could reduce tree longevity
Could injure or kill you
Photo: UF Laura Sanagorski

7. EFFECTS OF PRUNING - CODIT
CODIT: Compartmentalization of decay in trees
Compartmentalization ~ trees don’t heal
Xylem cells form 6-sided compartment with four walls
Wall (s) 1 : plugging of xylem vessels above and below wound
Wall 2: Thick cell growth on ring
Wall(s) 3: Cell growth on radial xylem rays
Wall 4: New xylem formation
Photo: UF Laura Sanagorski

8. Compartmentalization Of Decay In Trees (CODIT)
Wall (s) 1 : plugging of xylem vessels above and below wound
Wall 2: Thick cell growth on ring
Wall(s) 3: Cell growth on radial xylem rays
Wall 4: New xylem formation
USDA Forest Service - Northeastern Area Archive, USDA Forest Service, Bugwood.org

9. TREES DO NOT HEAL The tree will either:
Seal off the wounded area, preventing the decay from spreading to the healthy, uninjured parts of the tree, allowing the tree to survive
Not seal off the wounded area, allowing the decay to spread throughout the tree. Trees with excessive decay are prone to branch failure and may have shortened life spans
Photo: UF Laura Sanagorski

10. PRUNING OBJECTIVES Remove dead and diseased branches
Maintain proper structure and tree health
Central Leader
Strong Branch Connections
Balanced Canopy
Keep Branches < ½ Trunk Diameter
Improve and maintain tree appearance
Provide clearance beneath tree
Reduce weight of stressed limbs
Increase safety of landscape environment
Photo: UF Laura Sanagorski

11. Photos: UF Laura Sanagorski

12. Photos: UF Laura Sanagorski

13. WHEN ASSESSING PRUNING NEEDS, CONSIDER
Species’ form
Tree’s age
Tree’s reaction to pruning and strength of compartmentalization
Photos: UF Laura Sanagorski

14. Angle of Cuts Make cut at a slight slant ¼” above healthy bud.
Proper pruning cuts should be made above a bud growing in the direction desired
Photos: Stephen Davis

15. Photo: Stephen Davis

16. Reduction Cut Leader Branch bark ridge Imaginary line
Final Cut should be at a 45 degree angle
Drawing: Stephen Davis

17. Pruning Tools 3/4”=Hand Pruners ¾”-1 ¾”=Lopping Shears
Up to 2 ½”=Fine Toothed Hand Saw
3”-10”=Coarsely Textured Hand Saw
3”-10”=Chainsaw
Pole Pruners=Up to 2”
Photos: Stephen Davis

18. PROPER CUTS Remain just outside a tree’s branch bark collar
Should not leave a stub
Should not be flush with the trunk or adjacent branch
Photo: UF Laura Sanagorski

19. Larger angles = stronger attachments
Branch bark collar or included bark??
Photo: UF Laura Sanagorski

20. FLUSH CUT VS PROPER CUT Natural Target Pruning (NTP)
USDA Forest Service - Northeastern Area Archive, USDA Forest Service, Bugwood.org

21. Healthy Wound Closure
Photo: Stephen Davis

22. STRUCTURAL DEFECTS THAT MAY LEAD
TO TREE FAILURE
Co dominant stems
Included bark
Cavities
Multiple attachments
Cross branching
Girdling roots
Leaning
Decay
Splits or cracks
Fungus
Loose or cracked bark
Previous failure
Deadwood, stubs
Termites, ants, other
Insects
Wounds
Over pruned palms, trunk constrictions
Nesting holes
Laura Sanagorski

23. Before
Photo: Roy Cuellar

24. After
Photo: Roy Cuellar

25. …remove harmful synthetic materials!
While you’re at it…
…remove harmful synthetic materials!
Photos: UF Laura Sanagorski

26. Strengthening our Community Tree Canopy Through Education
Module #3:
Pruning Young Trees in the Urban Landscape
Laura Sanagorski, Environmental Horticulture Extension Faculty