PnET tree plantation model

Table of Contents

• Model options
  • Branch fraction
  • Crown length
  • Competition

The PNET module respresents mechanisms of the PNET2 Model [2], which is a monthly-timestep plantation model (monspecific, evenly structured forests) based on daily photosynthesis calculations [1]. General descriptions can be found at http://www.pnet.sr.unh.edu. The functions are taken from the Download of PNET_VERSION 4.1, Oct. 12, 2001.

Note

Water balance and soil respiration calculations in the orginil model have been deleted and the water and nitrogen availability is now provided by other modules of LandscapeDNDC.

Model options

Branch fraction

Available options (default options are marked with bold letters):

• Branch fraction ("branchfraction" = diameter / volume)
  Branch fraction is either estimated from parameterized tree diameter relationship (option: diameter) or from crown volume (option: volume).

Crown length

• Crown length ("crownlength" = height / volume)
  Crown length is either estimated from parameterized height relationship (option: height, see: _crown-length_parameter) or from crown volume (option: volume).

Competition

• Competition ("competition" = true / false)
  The Competition effect for stand density on height/diameter ratios is either neglected (option: false) or considered (option: true).

Calculates allocation to the different plant parts CHANGED: The parameter of root growth has been made dependend on physiological parameter describing fine root demand

C-Allocation out of roots (respiration and senescence)