Subject: Fire and Fuels Extension Update
Name:  Stephanie Rebain
Date:  11/23/2010
Variants affected: All

Description:
1) The crown shape assumption used in the canopy fuels calculations was updated for
ponderosa pine in the R1 variants (NI, IE, KT, and EM).  Specifically, the shape 
was changed from a cyclinder to a Weibull distribution to match the assumption used in the
Black Hills, as detailed in the following reference.

Keyser, Tara, and Frederick W. Smith.  2010.  Influence of Crown Biomass Estimators and 
Distribution on Canopy Fuel Characteristics in Ponderosa Pine Stands of the Black
Hills.  Forest Science 56(2):156-165.

2) The modelling of down dead wood was updated.  Specifically, this version of the code
incorporates the movement of down wood from the hard decay class to the soft decay class 
over time.  The rates are based on decay rate of that type of down wood (see the FFE variant 
documentation), which are used to estimate the amount of time it takes for that type of 
down wood to reach 64% of its original mass.

Impact on Users:
FFE users may want to obtain new variant executables.  See the FFE documentation for details.

Modified Files:
fire/cr/src/fmcrow.f - edited an incorrect comment
fire/base/src/fmpocr.f - changed the crown shape assumption for ponderosa pine in the 
                         NI, IE, KT, and EM variants
fire/base/src/fmcwd.f - added code to move wood from the "hard" decay class to "soft" annually
fire/base/src/fmdout.f - made a small change to the down wood volume table, which hasn't been
                         officially released yet.
