improving gpp, npp, and nee predictions from space
DESCRIPTION
I R S S. Improving GPP, NPP, and NEE predictions from space. Richard Waring 1 Nicholas Coops 2 Joe Landsberg 3 1 Oregon State University 2 University of British Columbia 3 Mt Wilson, NSW 2786, Australia. Eucalyptus plantation GPP =6,000 g C m -2 yr -1. Brazilian rainforest - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/1.jpg)
Improving GPP, NPP, and NEE predictions from space
Improving GPP, NPP, and NEE predictions from space
I R S S
Richard Waring1
Nicholas Coops2
Joe Landsberg3
1 Oregon State University 2 University of British Columbia3 Mt Wilson, NSW 2786, Australia
Richard Waring1
Nicholas Coops2
Joe Landsberg3
1 Oregon State University 2 University of British Columbia3 Mt Wilson, NSW 2786, Australia
![Page 2: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/2.jpg)
Photo: Courtesy of Auro Almeida
Eucalyptus plantationGPP =6,000 g C m-2 yr-1
Brazilian rainforestGPP =3,000 g C m-2 yr-1
![Page 3: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/3.jpg)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
09/97
03/98
09/98
03/99
09/99
03/00
09/00
03/01
09/01
03/02
09/02
03/03
09/03
03/04
Date
LA
I
Eucalyptus Native forest
Brazilian plantation LAI decreases with age as trees approach 40 m in heightat 7 years when harvested. Drought reduces LAI more when stand is young than older
Drought
Auro Almeida, CSIRO Tasmania, unpublished
Drought
![Page 4: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/4.jpg)
0
50
100
150
200
250
300
08/19
99
04/20
00
12/20
00
08/20
01
04/20
02
12/20
02
08/20
03
04/20
04
Date
Av
aila
ble
so
il w
ate
r (m
m)
Eucalyptus Native forest
In the Atlantic Coastal Region of Brazil,native rainforests and eucalyptus plantations usesimilar amounts of water although LAI differs by > 2 fold.Reason: eucalypts are fertilized & have twice the photosynthetic capacity and twice the max. canopy conductance of the rainforest.
Auro Almeida, CSIRO Tasmania, unpublished
![Page 5: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/5.jpg)
Objective: to provide ecological insights to improve predictions of GPP, NPP, and NEE from space
I. GPP: set limits and identify constraints
II. NPP: allocation above and below ground
III. NEE: correlation with GPP
![Page 6: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/6.jpg)
Ecosystem Model Structure
Waring, Coops, & Landsberg 2009 For. Ecol & Mgmt (in press)
![Page 7: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/7.jpg)
Leaf chlorophyll conc. linearly related to maximum photosynthetic
capacity (link to soil fertility)
Waring et al. 1995. Plant Cell & Env. 18: 1201-1218. Zhang et al. 2009. Remote Sen. Env. 113: 880-888.
![Page 8: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/8.jpg)
Leaf conductance (g) and photosynthetic capacity (A) decrease with (relative) tree height & hydraulic conductivity
(KL)
Ambrose et al. 2009. Plant, Cell & Env. 32: 743-757.Hubbard et al. 2001. Plant, Cell & Env. 24: 113-121.
![Page 9: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/9.jpg)
Stomatal response to vpd varies by an order of
magnitude among species in boreal forests
Dang et al. 1997. Tree Physiology 17: 521-535.
![Page 10: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/10.jpg)
VPD response is a function of maximum canopy conductance
Stomatal sensitivity to vpd is a negative log function (slope =0.6) to maximum conductance at 1 kPa (r2 = 0.75).
Oren et al. 1999. Plant, Cell & Env.22:1515-1535.
![Page 11: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/11.jpg)
As the soil water deficit increases beyond a threshold, water loss through transpiration is progressively reduced below its potential as stomata close
Source: Landsberg & Gower 1997. Fig. 4.5. “Application of Physiological Ecology to Forest Management.” Academic Press, San Diego, CA
Eucalyptus maculata
![Page 12: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/12.jpg)
Root depth determines access to water
28 m
Photo: courtesy of Keith Smettem,University of Western Australia
Eucalyptus
marginata
depth that roots penetrate
Photo: courtesy of E.D. Schulze
![Page 13: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/13.jpg)
To evaluate soil water limitations, need to assess changes in canopy properties
(LAI, fPAR, PRI, & wetness)
Canadell et al. 1996. Oecologia 108:583-595
![Page 14: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/14.jpg)
Photosynthetic Reflectance Index(Gamon et al. 1992. Rem. Sen. Env. 41:35-44)
Suarez et al. 2009. Rem.Sen. Env. 113:730-744.Trotter et al. 2002. Int. J. Rem. Sen.23: 1207-1212.
8 species in New Zealand Olive trees
![Page 15: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/15.jpg)
Hall et al. 2008. Remote Sensing of Env. 112: 3201-3211
Douglas-fir (sunlite) Campbell River, B.C.
![Page 16: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/16.jpg)
Partitioning of forest NPP below ground ranges from 20% to 60% (Waring et al. (1998). When GPP 2500 g C m-2 yr-1
(respiration + NPPb) ~ minimum
Litton et al.
0.0
2.0
4.0
6.0
8.0
10.0
0 2000 4000 6000 8000
GPP, gC m-2 yr-1
Rat
io o
f bel
ow
gro
un
d c
arb
on
al
loca
tion
to a
bo
veg
rou
nd
NP
P
Litton et al. 2007. Global Change Biology 13: 2080-2109Chen et al. 2003. Oecologia 137: 405-416Stape et al. 2008. For. Ecol. & Mgmt. 255: 920-930.Waring et al. 1998. Tree Physiol. 18:129-134.
tropical savanna
young ponderosa pine
aspen
black sprucejack pineold ponderosa pine
N =38
plantations
![Page 17: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/17.jpg)
NEE varies seasonally by type of vegetation, as does GPP
After Baldocchi 2009 Aust. J. Bot. (in press)
![Page 18: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/18.jpg)
After Baldocchi 2009 Aust. J. Bot. (in press)
Predicting Ecosystem Respiration or NEE (GPP-Reco) as a function of eddy-flux measured GPP
r2 = 0.9 =0.77
=0.94
![Page 19: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/19.jpg)
To improve predictions of GPP, NPP, and NEE from space
• Chlorophyll light absorbance is better than nitrogen content to estimate max. conductance and photosynthetic capacity.
• Max. conductance and photosynthetic capacity are reduced as trees approach site & species-specific maximum height.
• PRI is a good check on modeled constraints on GPP
• GPP is more important to estimate accurately than NPP, although NPPA would be helpful to validate model predictions of growth allocation.
• Allocation of NPP (& respiration) increases below-ground if water and nutrients are not available, generally not the case if GPP 2500 g C m-2 yr-1.
• Ecosystem respiration is ~ 75% of GPP in undisturbed systems, ~ 95% in disturbed systems. Be able to distinguish disturbed systems & recovery.
![Page 20: Improving GPP, NPP, and NEE predictions from space](https://reader036.vdocuments.site/reader036/viewer/2022081801/56815735550346895dc4d4b8/html5/thumbnails/20.jpg)
Email: [email protected] Nicholas Coops [[email protected]] Joe Landsberg [[email protected]]
Waring, Coops, & Landsberg. 2009. Improving predictions of forest growth using the 3-PGS model with observations made by remote sensing. For. Ecol. & Mgmt. (in press). (RHW Pub. No. 108). www.fsl.orst.edu/~waring