The effect of ozone on the C sequestration potentials of European forests

Transcription

1 The effect of ozone on the C sequestration potentials of European forests Patrick Büker, Lisa Emberson, Harry Harmens, Gina Mills, et al. Carbon stocks (Mt)

2 Overview of methodology Emissions Atmospheric Chemistry Carbon stocks (Mt)

3 Species groups & sensitivity Species Flux parameterisation Response function Reference Beech/Birch Norway Spruce Northern Europe, Atlantic Central Europe, Mediterranean Northern Europe, Continental Central Europe RB = * POD 1 RB = * POD 1 Aleppo pine Mediterranean Europe BR = * POD 1.6 Temperate Oak Atlantic Central Europe BR = * POD 1.6 UNECE LRTAP, 2010 UNECE LRTAP, 2010 Karlsson et al., 2007 Karlsson et al., 2007

4 Climate regions & flux parameterisation Variation in g max (maximum stomatal conductance) by climate region UNECE LRTAP (2010)

5 Response Functions by Species Different species show different sensitivities to the same ozone dose (e.g. POD 1 ) UNECE LRTAP (2010)

6 Which means that land cover, species distribution (and associated flux parameterisation) is very important to estimate O 3 effects correctly..and is also important to determine O 3 deposition as air parcels travel over large distances

7 Previous C seq. studies have used rather crude species sensitivity groupings. Sitch et al Low sensitivity High sensitivity Can we use the information we have describing forest sensitivity by species to improve C sequestration estimates for living tree biomass?

8 Forest C sequestration estimating the effect of ozone on living C biomass but there are some limitations with these DRs UNECE Mapping Manual (2010) DRs indicate annual biomass (C) losses in relation to total C stock. OK to estimate risk but not damage.but not possible to apply these for a single year since this does not take into account ozone influence over the entire life of tree stock.

9 Ideally we need DRs that can then be used with Net Annual Increment (NAI) since this is readily available in UNFCCC databases. Forest Europe, UNECE and FAO, then we could estimate living C sequestration not present due to ozone

10 Forest C sequestration estimating the effect of ozone on living C biomass One option to re-analysise DRs to give ozone effect on net annual increment (NAI) rather than total biomass Biomass of tree at start of fumigation Biomass? Biomass and age of tree at end of experimental period (CF) Biomass and age of tree at end of fumigation (CF++) Estimate likely growth profile to estimate O 3 effect on NAI Fumigation period Here we use established forest tree growth profiles (Richards functions) for European forest trees We standardise growth to represent all European tree species

11 Min and max scenarios represent uncertainty Red dots represent actual data points We assume that O 3 has the same % effect on NAI irrespective of age

12 Re-analysed DRs NAI response UNECE Mapping Manual (2010) growth response

13 Use these NAI DRs in 3 different scenarios to investigate effect of species sensitivity and SMD on PODy: 1) Species- and climate-region specific parameterisation Norway spruce (NE, CCE) Birch (NE) Beech (ACE, CCE, ME) Scots pine (ACE) Temperate oak (ACE) Aleppo pine (ME) Remaining forest was split into needle-leaf, broad-leaf and mixed forest 2) Generic/standard parameterisation Norway spruce (NE, CCE) Beech/birch (CCE) 3) Generic/standard parameterisation, SMD module off.and also compared with AOT40

14 We know that drought will affect O 3 impacts through closure of stomates and reduced uptake of O 3 to the sites of action within the leaf...so we incorporated the Penman Monteith evapotranspiration method into the DO 3 SE model

15 Climate region specific POD y Generic/standard POD 1 Generic/standard - SMD POD 1 Some differences in spatial pattern of risk Bigger differences in spatial pattern of risk that affect magnitude of effects, especially in Mediterranean Big differences AOT40

16 Climate region specific POD y Suggest average NAI losses due to O 3 of around 20% - very high more work to do.

17 Remaining issues Understand influence of different fumigation period lengths on NAI response re-analysis Fellings these need to be included to estimate the absolute effect of O 3 on a years C laid down? Effect of SMD significant shows importance of other stressors Average relative C losses cross Europe of 19 % higher than other studies

18 Knowledge gaps in Asia?? What might be the effect of O 3 on Asian crops, cultivars and forest trees species be very variable What DRs exist, is there a threshold for O 3 response? Do these species exist in climate regions that would effect their physiology and hence flux parameterisation? Do adequate specifies-specific land cover data sets exist across Asia for this type of risk assessment study? Can new experiments be designed to capture effects on NAI as well as whole tree biomass?