1. Then…
….and Now

2. Old growth
Second growth

3. Stand age vs. percent of juvenile wood
When trees grow rapidly so that they are of harvestable size when relatively young, the percentage of juvenile wood increases dramatically (data shown for Loblolly pine).
(Zobel & van Buijtenen)

4. Forestry Management Options Tree Growth Wood Properties
influences
determines
determines
influences
Forestry Management Options
Tree Growth
Wood Properties
Technical Performance
Acceptance For End Use
influences
influences
Size
Cost of management and silviculture
influences
influences
Price

5. Forest Management/Silvicultural options – effects on Wood Quality
Objective
To maximize the value of a plantation over a short rotation.
Value of logs and lumber depend upon:
Logs - large diameters
- long lengths
- clear faces
Lumber - premium lengths and widths
- absence of knots and other defects

6. Softwood Lumber Pricing ($/MBF)
Product
Length (ft) 8 10 12 14 16 18 20
2 x 4
215
245
240
270
260
2 x 6
235
265
2 x 8
220
255
275
290
2 x 10
195
200
300
315
Note: Prices are not from 2018

7. Forest management/silvicultural options and wood quality
Foresters’ options
Improve site
Cultivate
Irrigate
Fertilize
Manipulate crop
Planting stock
Planting distance
Juvenile space
Thin
Prune
Rotation age (harvest)

8. These actions influence the growth of the crown and roots which in turn influence:
Stem size and form
Ring structure (relative ew/lw proportions)
Branch size and number
Juvenile wood (amount and proportion)

9. Growth rate effect on ring structure
Rapid grown
Ring porous hardwoods
Diffuse porous hardwoods
Softwoods
Slow grown

10. Growth rate effect on ring structure
Ring porous hardwoods
Rapid grown
Slow grown

11. Growth rate effect on ring structure
Diffuse porous hardwoods
Rapid grown
Slow grown

12. Growth rate effect on ring structure
Softwoods
Slow grown
Rapid grown

13. Forest management/silvicultural options and wood quality
Foresters’ options
Improve site
Cultivate
Irrigate
fertilize
Manipulate crop
Planting stock
Planting distance
Juvenile space
Thin
Prune
Rotation age

14. Effects of initial spacing distance at time of planting
Wide spacing
( stems/ha)
Increased vegetative competition
Trunk with large branches
Maximize piece size
Encourage lower density of mature wood
Lower % of juvenile wood
Narrow spacing
(1500 stems/ha)
Maximize stand volume
Fewer and smaller branches
Encourage higher density of mature wood
Higher % of juvenile wood

15. Effect of tree spacing on juvenile wood production
Mature
wood
Narrow spacing
Wide spacing

16. How to overcome disadvantages of wide spacing
Plant genetically selected stock
Chemical or mechanical brush control
Plant close together initially, then thin
Prune

17. Tree improvement programs
Select high volume producers
Reject low wood density selections
Select straight trees
Select small branches (perpendicular)
Reject extreme spiral grain

18. Thinning Before After Loblolly pine plantation – 20% stem removal

19. Thinning Take-out row for skidder access
Skidder with grapple full of thinnings

20. A B C Effect of Thinning on Stem Development at Breast Height 10 in.
18 yrs. No
Thin
Light
Thin
Heavy
Thin
13 in.
16 in.
24 in.
48 yrs. A
48 yrs. B
48 yrs. C

21. Pruning Reduces number of branches (knots)
Reduces juvenile wood formation
Reduces taper
Possibly reduces growth rate

22. Pruning http://trimblefoundation.org.nz/images/trimble_trees.jpg

23. Pruning

24. Pruning

25. Old-growth log quality zones and products value
Clear $ 1,250-4,000/Mbfm
Near Clear $ ,000/Mbfm
Appearance $ /Mbfm merchantable
Structural $ /Mbfm lumber
Low grade $ /Mbfm
(Josza)

26. Maximum knot sizes allowed on the edge and the centre-line of 2x4, 2x8 and 2x12 lumber
(Josza)

27. Fertilizing Increase growth rate Reduce wood density
Even out earlywood-latewood differences in wood density
Relatively short term effect (3-5 years)

28. Effect of fertilization on wood density

29. Practical considerations for wood quality control
Economics of clear wood, high wood density, large log diameter
Tree improvement programs
Control of juvenile wood
Spacing (planting, juvenile spacing, thinning)
Rotation age
Develop clear wood by pruning