From our field reconnaissance of the Central Oregon site, we estimated litter depth was 0.5 inch with 90% cover and duff depth was 1 inch with 70% cover.  The Notes to Users section of the PNW Interior Mixed-Conifer photo series contains bulk density values used for calculating litter and duff loading.  Similar values may be back-calculated using the data provided in each of the Lodgepole Pine site datasets.

Using a litter bulk density estimate of 3 tons/acre-inch and duff bulk density estimate of 12.1 tons/acre-inch, we estimated the following:

Litter loading (tons/acre) = 0.5 inch x 3 tons/acre-inch x 0.9 (cover) = 1.35 tons/acre

Duff loading (tons/acre) = 1 inch x 12.1 tons/acre-inch x 0.7 (cover) = 8.47 tons/acre