NPP - APRSAF

Net Primary Production of
Tropical Forest: A modeling
approach
Tania June
SEAMEO BIOTROP, BOGOR INDONESIA
taniajune@biotrop.org

Increasing atmospheric CO 2 and
Global warming
• Demand for more accurate ecosystems
carbon budgets for projecting how these
ecosystems will be affected by climatic and
atmospheric change
• Better modelling of canopy photosynthesis is
needed An extrapolation of result from point
modeling to become spatial information is
needed
• Challenging research area

CENTRAL KALIMANTAN
Study Site
Palangkaraya
• 3 million ha peatlands
(Mega rice project
started in 1995)
• Drainage of peatsoil
through channel
development of 4000
km long
• Very vulnerable to fire
The area is Abandoned in 1999
Source: Parish (1995)
Source: Landsat ETM+ 118/062
Date: 2004-06-25

CHANNELS DEVELOPMENT
FROM THE MRP
(MEGA RICE PROJECT)
• Illegal logging occurs all over
the area:
1991-1997 = 1.9% per year
1997-2000 = 6.5% per year
1991-2001 = 3.3% per year
• Disturb hydrology of the peat land
• Drought and low water tables
(Boehm et al, 2003)
INCREASING FIRE RISK

PEATLAND FOREST FIRES IN
INDONESIA
• 1982-1983 : 500.000
ha burned
• 1988: 1.5 million ha
burned
• 1997 forest fire: 60% of
haze-SE Asia
• > 500 million t CO 2
emitted

HUGE AMOUNT OF CARBON
(CO2) INTO THE ATMOSPHERE
FOREST FIRE
1997 AND 2002
CONTRIBUTES TO GLOBAL
WARMING
TRANSBOUNDARY POLLUTION
LOSS OF FOREST AS CARBON SINK
LOSS OF BIODIVERSITY
NEED TO ESTIMATE HOW MUCH CARBON IS ABSORB BY
THE REMAINING VEGETATION AND BY VEGETATION
REGROWTH AFTER FIRE

Tower
site
Study Site:
Kalampangan Area
Channels development from the MRP
(Mega Rice Project) = 4,000 km

Continous measurement of
CO2, H2O and microclimate
in Central Kalimantan
Height 50 m
Lat.: 2 o 20’41.6”
Long.: 114 o 02’11.3”

Method to estimate CO 2
sequestration by vegetation
Remote sensing
NPP
=
365
∑
i=
1
e*
fAPAR*
PAR
Meteorology
station
Semi-mechanistic
modelling
NPP = net CO2 assimilation rate per year (g m -2 year -1 )
e = radiation use efficiency (g MJ -1 )
fAPAR = fraction of absorbed PAR
PAR = Photosynthetically active
radiation

Definitions for CO 2 Release/uptake by
Vegetation
• Gross Primary Production (GPP):
Uptake of C by plants
• Net Primary Production (NPP):
NPP=GPP-R
• Net Ecosystem Production (NEP):
NEP=NPP- R H
• Net Biosphere Production (NBP):
NBP=NEP-D
• R: Plant respiration
• R H
: Heterotrophic respiration
• D: Disturbance effects

The Model
c a
Temperature
I. H 2 O g supply
II. N
k
c i
V
J
demand
Light
reduced
carbon
temperature

Outline of the C3 Photosynthesis Model to estimate canopy efficiency, e and NPP: Equations (1) and (2) showing
the effect CO2 concentration on leaf assimilation rate; Equations (3) showing the light effect; Equations (4)
showing the temperature effects on model parameters.; Equation (5) showing supply of CO2 and Equations (6)
and (7) showing e and NPP.

Light use efficiency (e)
• Light use efficiency, or canopy efficiency, in this simulation
is defined as mol CO 2
assimilated per mol of absorbed light,
i.e A c
divided by I c
.
e =
A
I
c
c
NPP
=
365
∑
e*
fAPAR
*
PAR
i=
1

Software used and Data Input for NetPro v. 1.0
Sofware used are:
• Visual Basic 6.0
• ERMapper 6.4
• ArcView 3.3
• MapObject 2.1.
Data input includes:
• Shapefile of NDVI class
• Daily averaged climate
data (Global radiation,
maximum and minimum
temperature).

NDVI ANALYSIS
(NIR – R)
(NIR + R)
LANDSAT
ORIGINAL IMAGE
LANDSAT
NDVI IMAGE

Calculation of NPP

LAI - NDVI
LandSat TM
LAI = NDVI*1.71+ 0.4(Asrar et al,
1985 for grass-land)
LAI= (NDVI / 0.31)0.2 (Spancer et al,
1990 for conifer/needle-leaf)
LAI= (NDVI / 0.26)2 (Priece et al, 1993
for broad leaf)
NOAA AVHRR

f APAR -NDVI
Ochi and Shibasaki (1999) for some
type of asian vegetation ;
fAPAR = - 0.08 +1.075 NDVI
(r2 = 0.75) using NOAA/AVHRR
Knorr, et al. (1999)

LAI,f APAR, and NPP

Study site

Flux Measurement
LoreLindu National
Park, Central
Sulawesi
Height 70 m
Lat. 1 o 39′-1 o 42′ S
Long. 120 o 10′-120 o 12′ E

Model Output
3000
NPP (gC m -2 year -1 )
2900
2800
2700
2600
2500
2400
2300
CO 2
700,
0 o C temp. increase
CO 2
700,
6 o C temp. increase
2200
CO 2
350,
0 o C temp. increase
2100
110 115 120 125 130 135 140 145 150 155
Leaf Nitrogen (mmol m -2 )

Model Output
2900
2800
2700
LowN
CO 2
700
3000
2900
2800
High N
CO 2
350
NPP (gCm -2 year -1 )
2600
2500
2400
2300
2200
2100
2000
1900
1800
LowN
CO 2
350
0 1 2 3 4 5 6
NPP (gCm -2 year -1 )
2700
2600
2500
2400
2300
2200
2100
2000
1900
High N
CO 2
700
0 1 2 3 4 5 6
Increase in Temperature ( o C)
Increase in Temperature ( o C)

RESEARCH NEEDED
• Site specific parameterisation
–Vcmax
• Site variable measurement and estimation
– Leaf Nitrogen, LAI, f APAR
• Climate data: diurnal global radiation, min
and max temperature, diffuse radiation.
•CO 2 flux data and e from tower for
validation of model
• Develop specific site equations for
NDVI-LAI and NDVI-f APAR