Subject: Crown ratio dubbing for LM, PY, AS, MM, and PB trees less than
         1.0" in diameter.

Name: Gary Dixon
Date: 06/22/2010

Variants affected: Inland Empire (IE)

Description: Stand MAI is an independent variable in the equation used to dub 
             crown ratio values missing in the input data for limber pine, 
Pacific yew, quaking aspen, mountain maple, and paper birch less than 1.0" in
dbh, and for dead trees of all sizes for these species. Stand MAI is estimated
from the site index of the site species for the stand. In the IE variant, 
site species is mapped by habitat type to 1 of the original 11 species for all 
habitat types except 1 (habitat type 850 is mapped to whitebark pine).
There is no default site index for the original 11 North Idaho (NI) species, or 
for whitebark pine, since site index is not used in any of the model's equations
for these species. As a result, if users did not provide site index values  or
designate a site species using the SITECODE keyword then a default site index of 
140 was being used for whatever site species is assigned by habitat type in the
calculation of MAI. 
Default site index values by habitat type, provided by Regional personnel, range from 
22 to 41 for limber pine and Pacific yew, and 33 to 60 for aspen, mountain maple, and 
paper birch. So, the site value of 140 being used in the calculation of MAI was not
representative of stands in Region 1.
     This problem has been corrected. If users do not enter site index information, the 
model now uses the default site index by habitat type provided by Regional personnel in
the calculation of MAI for limber pine, Pacific yew, quaking aspen, mountain maple, and 
paper birch. This results in better crown ratio estimates and slightly different growth 
predictions for affected trees.
     To reiterate, this problem only affected crown ratio values missing in the input data 
for limber pine, Pacific yew, quaking aspen, mountain maple, and paper birch less than 1.0" 
in dbh, and for dead trees of all sizes for these species.

Impact on users: The highest impact would be in stands where all trees in
                 the inventory were less than 1.0" in dbh and were one of
the species listed above. In this extreme case, the impact on a 100-year
simulation for a medium high site would be about a 10% reduction in volume.
In general, the impact will be far less than 10% and in most cases negligible. 
However, users of this variant should obtain a new executable.

Files:
ie/src    crown.f   changed the date of revision; defined new variables RMAIAS 
                    and RMAILM to represent the MAI of the stand if the stand 
                    was either classified as AS/MM/PB  or LM/PY; computed these
                    new values with calls to function ADJMAI. Used these values
                    in dubbing crowns on tree less than 1.0" dbh and cycle 0 dead
                    trees instead of the regular MAI value computed in CRATET.
                    
          dubscr.f  changed the date of revision; renamed the local variable RMAI
                    to TMAI to avoid potential confusion with the RMAI variable in
                    the PLOT common.
                    
          maical.f  changed the date of revision; reset values of the ISPNUM array
                    for hardwood species since hardwoods use a different equation
                    in ADJMAI than do conifers.            