A carbon-balance, process-based growth model was developed to simulate
the growth of young red pine (Pinus resinosa Ait.). The dry weights o
f current, 1-year-old, 2-year-old, 3-year-old needles, stems and branc
hes, and roots of individual trees were considered as state variables.
The hourly rate of photosynthesis was calculated with solar radiation
, air temperature, leaf water potential, and leaf age as driving varia
bles by assuming that the needles experience the same incident light d
ensity. Maintenance respiration rate was assumed to be a function of s
urrounding temperature. The seasonal allocation of assimilates to each
compartment was determined by the activity of each compartment and wa
s regulated by soilwater potential. The translocation of carbohydrate
reserves, litter fall, and root turnover were incorporated in the mode
l. The simulated results fit well with observed values from three plan
tations in the central Upper Peninsula of Michigan.