Subject: MORTMSB Mature Stand Boundary Keyword
Name: R. Havis
Date: November 13, 2008
Variants affected: AK, BM, CA, CR, CS_NEW, EC, EM, LS_NEW, NC, NE_NEW,
                   SN, SO, TT, UT, and WS

Description:

1) New MORTMSB Keyword

   MORTMSB (MORTality Mature Stand Boundary)
   AK, BM, CA, CR, CS_NEW, EC, EM, LS_NEW, NC, NE_NEW, SN, SO, TT, UT, and WS

   The MORTMSB (MSB) Keyword has been added to the variants that use the
   Maximum Stand Density Index (SDImax) based mortality method. The keyword
   is based on work by Shaw and Long (in press), and DeRose et al. (in press).
   The MSB concept is implemented in FVS using the following
   equation on a ln-ln plot of tpa versus QMD.
   
   ln(tpa) = C0 - S*ln(QMD)
   
   where
   tpa = number of trees per acre
   CO  = constant
   S   = slope
   QMD = stand quadratic mean diameter
   
   field 1: the value of the stand quadratic mean diameter where the
            MSB equation (above) intersects the line representing
            .85*SDImax (this value is required)
   field 2: the value of the slope (S) term in the MSB equation must
            satisfy the inequality  -3.0 < S < -1.605

   The SDI-based mortality algorithm in FVS limits stand development to .85*SDImax.
   The MSB equation intersects the .85*SDImax line at the QMD value specified in
   the MORTMSB keyword. Stand mortality follows the .85*SDImax line until the user-
   defined QMD value is reached. Stand mortality will then follow the MSB equation
   trajectory.

References
  DeRose, R. Justin; Shaw, John, D.;Vacchiano, Giorgio; Long, James, N. (in press)
  Improving log leaf pine mortality predictions in the Southern Variant of the
  Forest Vegetation Simulator. Proceedings of the Third Forest Vegetation Simulator
  Conference, February 15-17, 2007, Fort Collins, Colorado.
  
  Shaw, John, D.; Long, James, D. (in press) A density management for longleaf
  pine stands with application to Red-Cockaded Woodpecker Habitat. Southern Journal
  for Applied Forestry.

2) The default dead fuel loading values (tons/acre) have been updated in the SN
   variant.  The new default fuel loading values are based on FIA data collected
   in the southern region and vary based on forest type.  Details can be found in
   the FFE addendum document.
  
3) Several problems were corrected. A numerical error was avoided when using the
   volume equation 500DVEW631 for Species No. 8, TANOAK (TO) in the Klamath 
   Mountains (NC) variant. A problem with the machine readable header for the 
   Dead Tree List Table was corrected.
  
Impact on users: Users should obtain new executables. Users interested in the
                 MORTMSB keyword should obtain new executables, and users of
                 the SN-FFE model should obtain new executables.

Files:
GRINIT - initialized Mature Stand Boundary (MSB) variables QMDMSB, SLPMSB and CEPMSB
MORTS - added MSB logic

./ak/src/grinit.f
./ak/src/morts.f
./base/src/initre.f - changed DBHMSB to QMDMSB
./base/src/prtrls.f - corrected printing of machine readable header for dead tree list
./base/src/revise.f
./bm/src/grinit.f
./bm/src/morts.f
./ca/src/grinit.f
./ca/src/morts.f
./ci/src/grinit.f
./common/VARCOM.F77 - changed DBHMSB to QMDMSB
./cr/src/grinit.f
./cr/src/morts.f
./cs/src/grinit.f
./cs_new/src/grinit.f
./ec/src/grinit.f
./em/src/grinit.f
./em/src/morts.f
./ie/src/grinit.f
./kt/src/grinit.f
./ls/src/grinit.f
./ls_new/src/grinit.f
./ls_new/src/morts.f
./nc/src/grinit.f
./nc/src/morts.f
./ne/src/grinit.f
./ne_new/src/grinit.f
./ni/src/grinit.f
./pn/src/grinit.f
./sn/src/grinit.f
./sn/src/morts.f
./so/src/grinit.f
./so/src/morts.f
./so33/src/grinit.f
./so33/src/morts.f
./tt/src/grinit.f
./tt/src/morts.f
./ut/src/grinit.f
./ut/src/morts.f
./wc/src/grinit.f
./ws/src/grinit.f
./ws/src/morts.f
./fire/sn/scr/fmcba.f - added new default fuel loading values
./volume/src/voleqdef.f - Corrected error in volume equation number at line 656.
                          Changed 500DVE631 to 500DVEW631
