Levels-of-Growing-Stock Study (LOGS)

• Levels-Of-Growing-Stock (L.O.G.S.) Cooperative Study in Douglas-fir
• About the LOGS Cooperative
• Study objectives
• LOGS partners
• Study results for the CFS-BCMOF LOGS installations
• Future potential...

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About the LOGS Cooperative

The impetus for the formation of the cooperative was the realization that, with the harvesting of the old-growth Douglas-fir stands in the Pacific Northwest region, more and more of the timber supply would be from managed second-growth stands. A common belief was that commercial thinning of second-growth stands could provide timber supplies while enhancing future stand productivity. At that time, there was very little information or experience in thinning Douglas-fir and reliable yield estimates from thinned stands were needed.

A method was developed for calculating thinning schedules and managed-stand yields based on estimated gross yield of natural stands and estimated diameter growth rates. This methodology was based on two assumptions: one, gross volume yield and periodic gross increment of a fully stocked unmanaged stand at any age represented full capacity of the site to produce wood at any age: two, approximately full increment could be produced with widely differing combination of growing stock, tree size and radial increment.

The Levels-Of-Growing-Stock (LOGS) Cooperative Study in Douglas-fir was formed in 1962 to test these assumptions and to examine the tree and stand dynamics of managed Douglas-fir stands under a number of different thinning treatments.

A comprehensive work plan was developed in 1962 to ensure standardized procedures among cooperators thus acquiring the benefits of shared costs and data. Between 1962 and 1970, nine installations were established in Oregon, Washington and British Columbia, covering the site productivity range of the region. Each agency is responsible for establishing and maintaining their installations, and the data is shared in a common data bank available to all cooperators.

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