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

      real function biodrag (lai, sai)

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

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

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

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

      return
      end