From forest inventories to carbon balance at the plot scale

Transcription

1 From forest inventories to carbon balance at the plot scale November 19, 2015

2 Why study the carbon balance? Carbon budget and environmental policies Indirect data : field data, remote sensing Modeling approach : Understanding post-logging processes Create dynamic models Estimate parameters Assess the plot carbon balance

3 From field data to biomass Evolution of AGB stocks Modeling carbon fluxes Logging and carbon stocks From field data to biomass Evolution of AGB stocks Modeling carbon fluxes

4 From field data to biomass Evolution of AGB stocks Modeling carbon fluxes From DBH to biomass stocks All live trees : DBHi (H i ) botanical identification WSG i Allometric equations AGB i AGB tot = AGB i

5 From field data to biomass Evolution of AGB stocks Modeling carbon fluxes At the plot scale AGB (Mg/ha) T = 29 yr trt 0 trt 1 trt 2 trt year

6 From field data to biomass Evolution of AGB stocks Modeling carbon fluxes Defining some variables

7 From field data to biomass Evolution of AGB stocks Modeling carbon fluxes

8 From field data to biomass Evolution of AGB stocks Modeling carbon fluxes Uncertainty propagation Parameters = uncertain quantities Parameters distribution 1 iteration : Take parameters in their distribution Run the model Stock the results Repeat n times Calculate statistics : mean, 95% confidence intervals

9 Extracted biomass Infrastructure Biomass decay Logging and carbon stocks Extracted biomass Infrastructure Biomass decay

10 Extracted biomass Infrastructure Biomass decay

11 Extracted biomass Infrastructure Biomass decay The fate of extracted logs Ext p = Vext p dext (1) Log transformation 0.33 = Sawnwood 0.67 = Sawdust Keller et al. 2003

12 Extracted biomass Infrastructure Biomass decay

13 Extracted biomass Infrastructure Biomass decay Biomass loss from damages Dam p = dagb p Ext p Dam p = f (Vext p ) Dam (Mg/ha) Sites Jari Paracou Tapajos Tortue Prediction 95% confidence interval Extracted volumes (m 3 /ha)

14 Extracted biomass Infrastructure Biomass decay

15 Extracted biomass Infrastructure Biomass decay Biomass loss from infrastructure Deforested area = roads + skid trails (+ logging decks) Defor p = Sdef p AGB0 p (2)

16 Extracted biomass Infrastructure Biomass decay

17 Extracted biomass Infrastructure Biomass decay Fine and Large Woody Biomass Large (or Coarse) Woody Biomass : diameter 10 cm LWB i = DBH i (3) Paracou : f LWB = 0.85 f LWBp = p LWB i p AGB i Chambers et al (4)

18 Extracted biomass Infrastructure Biomass decay Exponential decay C(t t 0 ) = C(t 0 ) exp( λ (t t 0 )) (5) Half-life time t 0.5 : y(t 0.5 ) = 0.5

19 Extracted biomass Infrastructure Biomass decay Parameters value λ t 0.5 Source Sawnwood IPCC 2006 FWB Chambers 2004 LWB Paracou

20 Logging and carbon stocks

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22 The hypothesis of a linear recovery t rec = t min + dagb RR

23 The hypothesis of a linear recovery ( Recov t = min dagb ; (t t0) dagb ) t rec

24 Logging and carbon stocks

25 MgC/ha Net Balance 95% confidence interval Vext: 1.1 m 3 /ha Vext: 33.0 m 3 /ha MgC/ha Recovery Sawmill Road and skid trail opening Regrowth on skid trails 95% confidence interval

26 MgC/ha Net Balance 95% confidence interval Vext: 1.1 m 3 /ha Vext: 33.0 m 3 /ha MgC/ha Recovery Sawmill Road and skid trail opening Regrowth on skid trails 95% confidence interval

27 Conclusion Field data carbon fluxes at the plot scale Mechanistic model, conservative approach Carbon balance at the regional scale?