Silvicultural considerations in established alder stands Jeff De
Silvicultural considerations in established alder stands Jeff De. Bell Washington DNR June 10, 2009
Topics • Background • Thinning in alder stands • Pruning in alder stands • Differences between natural alder stands and plantations
Alder Height Growth
Uniform early spacing is critical Alder leans toward openings in the stand Keep even spacing to keep stems straight
Thinning – growing the crown
Crowns expand by getting taller as well as wider after thinning
When should you thin? • Age 5 -10 years • Before crown ratio drops below 30% • Early gives best diameter; later gives best crown recession • Ideal at about age 6 -7 – 50% crown ratio – 25 -30 feet tall – Live crown starts about 15’ from ground
To what spacing should you thin? • Ideally, set spacing based on a relative density measure • For a simple approach, thin to a 13’ spacing
Pruning alder
Pruning: lessons from research • Time of year is not important • Small branches heal over more quickly than large ones • Decay not an issue • Epicormic branches not an issue • In young vigorous plantations, clear wood production begins in 2 -3 years
How to prune • Can start as early as age 3 • Any time of year • Wait one growing season if thinned • Remove no more than 1/3 of live crown • Leave at least 50% live crown ratio
Natural vs. Planted Stands
Advantages of planted stands • Moderate density = good growth • Even spacing = good form • Volume concentrated in fewer, larger trees • Reach target diameter sooner • Higher total volume? ?
For more reading: • Can order hard copy from USFS PNW Research Station • Ask for PNW-GTR-669 • Can download PDF at URL below http: //www. fs. fed. us/pnw/publications/gtr 669/
Streaming video presentations from “Red Alder: A State of Knowledge” • Available at University of Washington’s Rural Technology Initiative Website • Includes 45 presentations • Can order a DVD with all presentations for $10 • Watch on your computer at http: //www. ruraltech. org/video/2005/alder _symposium/index. asp
- Slides: 16