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Unveiling the New Alder Growth and Yield Model and a Example of the Economics of Growing Alder. David Hibbs Forest Ecosystems and Society Hardwood Silviculture Cooperative Oregon State University. Outline. Modeling RAP-ORGANON Economics.
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Unveiling the New Alder Growth and Yield Model and a Example of the Economics of Growing Alder David Hibbs Forest Ecosystems and Society Hardwood Silviculture Cooperative Oregon State University
Outline • Modeling • RAP-ORGANON • Economics
What is a growth and yield model?(and why does anyone care?) • Models predict the future • How big will the trees grow? By when? • How many trees will there be? • How much wood will those trees yield? • What is the quality of that wood? • How does management change these answers? • Models are pretty good but ……
Forest Growth and Yield Models • There are several modeling systems in the PNW and each covers several species • All have their strengths and weaknesses • Some already include a poor natural alder model • None include a managed alder model • We worked with the ORGANON system
ORGANON • Modeling system developed by David Hann at OSU • Is the modeling system used by the UW Stand Management Cooperative • Are several versions of it for different parts of the PNW (improved accuracy) • New version: RAP-ORGANON
RAP-ORGANON • Built with data from the OSU Hardwood Silviculture Cooperative and Weyerhaeuser Co. • Covers western OR and WA, southern BC • Oldest alder plantations in model are 18 years old • Model extrapolations beyond 30 or 35 years may not be wise
RAP-ORGANON • Examples of what you can get from it • There are many more kinds of questions one can ask • A pretty productive place (but not the best, SI20=83ft) in SW Washington – one ¼ ac plot of trees • Results will vary with site quality and management options • Are just beginning to explore what ORGANON can tell us
Age of thinning D I A M E T E R (in) Stand age (yrs)
Thin at age 7 to different densities(results at age 30) Trees per acre Trees per acre
Thin at 7 to 217 Thin at 7 to 178 Tree diameter (inch) Tree diameter (inch)
Economics Cost example • Site preparation: $85-135/ac • Planting: $315/ac • Thinning: $125/ac • Harvesting: $2600/ac • Trucking: $1150/ac Return example • 5” : $475/mbf • 6-7” : $550/mbf • 8-9” : $600/mbf • 10-11” : $650/mbf • 12”+ : $700/mbf
Mill-delivered valueA comparison of management choices DBH (in) Age (yrs)
Conclusions • RAP-ORGANON simulates alder plantations well • Example results will vary with: • Rotation length • Site quality • Log price structure • Discount rate • Log length • Example highlights the questions about management options and implications we need to explore and understand