c
c     BIODRAG combine effects of leaves and stems on wind speed
c

      real function biodrag
     i                      (lai, sai)

c
c     + + + PURPOSE + + +
c     Leaves are less effective at reducing the wind speed than
c     stems.  Thus, this function combines these effects into a single 
c     value for use by other routines.

c     + + + KEYWORDS + + +
c     biodrag, lai, sai
c
c     + + + ARGUMENT DECLARATIONS + + +

      real  lai, sai
c
c     + + + ARGUMENT DEFINITIONS + + +
c     lai   - leaf area index (m^2/m^2)
c     sai   - stem silhouette area index (m^2/m^2)
c
c     + + + PARAMETERS + + +
c
c     + + + LOCAL VARIABLES + + +
c
c     + + + END SPECIFICATIONS + + +
c

      print *, 'sai, lai: ',sai, lai
      biodrag = lai * (0.2 - 0.15*exp(-8.0*lai)) + sai
      print *, 'biodrag: ', biodrag

      return
      end