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Then…

Then…. ….and Now. 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). influences.

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Then…

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  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. influences determines determines influences ForestryManagementOptions TreeGrowth WoodProperties TechnicalPerformance AcceptanceFor End Use influences influences Size Cost of managementand 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) Note: Data is not from 2012

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

  8. * Growth rate effect on ring structure Rapid grown Slow grown Softwoods Diffuse poroushardwoods Ring poroushardwoods

  9. Wide spacing (400-750 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 * Effects of initial spacing distance at time of planting

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

  11. How to overcome disadvantagesof wide spacing • Plant genetically selected stock • Chemical or mechanical brush control • Plant close together initially, then thin • Prune

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

  13. Thinning Before After Loblolly pine plantation – 20% stem removal http://www.forestryforum.com/board/index.php?topic=39179.0%3Ball

  14. Thinning Skidder with grapple full of thinnings Take-out row for skidder access http://www.forestryforum.com/board/index.php?topic=39179.0%3Ball

  15. * Thinning Schematic sizes and ring width patterns of Douglas-fir logs (sections at 4.5 feet) grown under different regimes (each concentric circle represents six annual rings). Note on a good site, the plantation wood (B) produces wood with large rings at the centre and faster diameter growth than from a natural stand (A). Poor sites will produce narrow rings (C) but still juvenile wood (formed while the cambium is still within the live crown) in both natural stands and plantations. If plantations (B) are not thinned when young, many of them will probably slow down abruptly in growth and appear as D, so that primarily small diameter wood will be available in the future. If they are thinned by removing some of the trees when young (at B), they can produce logs as in E or F, depending on the intensity of the thinning. Future logs such as E or F will be produced primarily if the forest products industry can develop a market for logs such as B, so that such stands can be thinned instead of developing into logs with characteristics such as D. (Oliver)

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

  17. Pruning http://trimblefoundation.org.nz/images/trimble_trees.jpg http://www.country-works.co.uk/weblog.aspx

  18. Pruning

  19. Pruning

  20. * Maximum knot sizes allowed on the edge and the centre-line of 2x4, 2x8 and 2x12 lumber Old-growth log quality zones and products value • Clear $1,250-4,000/Mbfm • Near Clear $ 600-1,000/Mbfm • Appearance merch. $ 450-800/Mbfm • Structural lumber $ 350-500/Mbfm • Low grade $ 200-350/Mbfm (Josza)

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

  22. Effect of fertilization on wood density

  23. 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

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