Carbon sequestration was included as one of the values that must be considered and reported on when a timber harvest plan (THP) is submitted for timberlands managed with the “goal of maximum sustained production of high-quality timber products” under the 2010 amendments (AB 1504 Carbon Sequestration) to the Forest Practice Act. Calfire’s Greenhouse Emissions Calculator (Anonymous 2010) is one way to provide an estimate of carbon sequestration. One problem in Calfire’s calculator is that is assumes that only 38% of board feet measured in their model of a forest are actually turned into board feet of lumber. Scribner board foot measurements in the forest were designed to be an accurate estimate of historic sawmill board foot output (Dilworth 1977) so 100% of the board feet measured in the forest should come out as lumber. Changes in the size of logs and improvements in sawmill efficiency result in an overrun where more board feet are produced from the sawmill than are measured in the timber inventories (Keegan, Morgan et al. 2010). Recent sawmill surveys in California (Morgan et al. 2012) measured wood utilization rates of 99% when wood used for energy is also included. A 
recent analysis using the national GHG inventory standards for harvested products from 17,000 acres in California documents climate benefits from sustainably harvested products that are four times as large as those considered under current California accounting rules. Canadian Forest Service researchers recently published a comprehensive forest and forest products assessment that illustrates the national level potential for climate change mitigation of forests.
The Berkeley Carbon Calculator provides well documented estimates of total carbon sequestration benefits for a number of forest management approaches. The model is based on well documented publicly available data for the major forest types in California. The model has been published in the journal California Agriculture. Users can use the default 'best practices' coefficients for different management.
The take home message is that a well-managed forest will create even more carbon sequestration than a let-grow forest when the wood products are efficiently used. Efficient use of wood products is the 'best management practice' in most, but not all, cases in California.
Berkeley Carbon Calculator
Note: The calculator may be slow to load, please be patient.
References:
Dilworth, J. R. (1977). Log Scaling and Timber Cruising, Oregon State University Press.
Keegan, C. E., T. A. Morgan, K. A. Blatner and J. M. Daniels (2010). "Trends in Lumber Processing in the Western United States. Part II: Overrun and Lumber Recovery Factors." Forest Products Journal 60(2): 140-143.
Morgan, T. A., J. P. Brandt, K. E. Songster, C. E. Keegan, III and G. A. Christensen (2012). California’s forest products industry and timber harvest, 2006. . Portland, OR, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. PNW-GTR-866: 48.
Skog, K. E. (2008 ). "Sequestration of carbon in harvested wood products for the United States." Forest Products Journal 58(6): 56-72.
Smyth C. E., Stinson G., Neilson E., Lemprière T. C., Hafer M., Rampley G. J., and W.A. Kurz. 2014. Quantifying the biophysical climate change mitigation potential of Canada's forest sector. Biogeosciences 11: 3515-3529.
Stewart, W. C. and B. Sharma (2015). "Carbon calculator tracks the climate benefits of managed private forests." California Agriculture. January-March: 21-26
More Resources
2015 presenation at Five Climate Pillars - Management & Co-Benefits