Then… ….and Now

2 Old growth Second growth

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)

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

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

Softwood Lumber Pricing ($/MBF) ProductLength (ft) x x x x Note: Prices are not from 2015

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

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 Ring porous hardwoods Diffuse porous hardwoods Softwoods Rapid grown 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 Rapid grown Slow grown

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

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 Juvenile wood Mature wood Narrow spacing Wide spacing Effect of tree spacing on juvenile wood production

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

Thinning 18 BeforeAfter Loblolly pine plantation – 20% stem removal

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

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

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

Pruning

Pruning

25 Old-growth log quality zones and products value 1.Clear $1,250-4,000/Mbfm 2.Near Clear $ 600-1,000/Mbfm 3.Appearance merch. $ /Mbfm 4.Structural lumber $ /Mbfm 5.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)

Effect of fertilization on wood density

29 Practical consideration 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