MC1 Dynamic Global Vegetation Model

ex. Daly et al. 2000, Bachelet et al. 2000, Conklin 2009

. Reads climate time series (spinup)

. Runs on a monthly time step

. Calculates biomass, N cycling, water

. Simulates only saturated soil water flow (bucket)

. Includes competition for light, water, N

. Includes trees and grasses (shrubs are small trees)

. Not yet calibrated for limited N

Main assumption: ecological processes (production and decomposition) are limited by soil N availability

Main assumption: ecological processes (production and decomposition) are limited by soil N availability

Tree LAI Lifeform

Lifeform

Grass LAI

% C3

% C3

Forests

Savannas Woodlands

Grasslands

Shrublands

< 2 2-3.75

> 3.75

< 1

> 1

Thresholds

C3/C4

EN DB EB High GSP Threshold

Low GSP Threshold

EB

EN EB

EN

DN

Low

MM

T Tr

esho

ld

Hig

h M

MT

Tres

hold

dry

wet

warm

cold

BIOGEOGRAPHY RULES

VEGETATION CLASSIFIER

LIFEFORM INTERPRETER

GSP: growing season ppt MMT: mean monthly temp E: evergreen, D: deciduous N: needleleaf, B: broadleaf

Includes trees (shrubs are small trees) .deciduous vs evergreen, .needle-leaf vs broadleaf

. Includes C3 and C4 grasses

LEAVES

FINE BRANCHES

LARGE WOOD

COARSE ROOTS

BIOGEOCHEMISTRY MODULE

  Modified version of CENTURY (Parton et al. CSU)

  Simulates NPP, decomposition, N & water cycling

  Simulates competition between trees and grasses for light, water, and N

FINE ROOTS

RO

OT

DE

PTH

CENTURY C CYCLE

PASSIVE SOIL C

SLOW SOIL C

ACTIVE SOIL C

STRUCTURAL C

METABOLIC C

DEAD ROOTs

STANDING DEAD

DEAD LEAVES

ROOTS FINE & COARSE BRANCHES

FINE & COARSE

LEAVES

DEAD BRANCHES

Different rooting depths between trees and grasses determine competition for water and nutrients

Deep soil moisture recharge favors woody plants

Trees shade grasses (light competition)

SOME MODEL ASSUMPTIONS

Plant parts have fixed min and max C/N, specific per lifeform (N limitation)

Fire consumes aboveground biomass (no roots), 20% of the N is returned to the system

Saturated soil water flow only (bucket)

Current Aboveground Carbon Pools

Current Vegetation

Type

Fuel Loading Crown Structure

Live and Dead Fuel Moisture

Current Weather

Current Soil Moisture

FIRE EFFECTS

Mortality Biomass Consumption Emissions Nutrient

Loss

FIRE AREA and BEHAVIOR

FIRE MODULE

MODEL LIMITATIONS

. Potential vegetation, no agriculture

. PFTs (plant functional types) not species

. no dispersal, succession (pioneer/invasive vs climax) nor migration life history traits

. There is no sub-grid cell heterogeneity

. Grazing, pests and pathogens are not included