Silviculture et gestion des réserves dans Orchidée (discussion) Guerric le Maire R2DS 2007

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Amanda Dean
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1 Silviculture et gestion des réserves dans Orchidée (discussion) Guerric le Maire R2DS 2007

2 Reserves management GPP Complete if necessary remaining 80%max BM_alloc_tot Rm=sink to fill Rm Reserves max. value Rm sapwood Rm falloc root Rm Leaves max. value Beginning Veg. Season : Condition on quantities

3 Reserves management GPP Complete if necessary remaining 80%max Rm=sink to fill BM_alloc_tot Reserves max. value Rm sapwood Rm falloc root Rm Leaves max. value Beginning Veg. Season : Condition on quantities

4 Orchidee modif GPP Complete if necessary GPP Castanea remaining 80%max BM_alloc_tot Rm=sink to fill Reserves max. value remaining leaves=sink to fill LAI growth LMA growth Reserves sapwood falloc Beginning Veg. Season : Condition on quantities remaining Rm=sink to fill root Leaves max. value sapwood falloc root

5 Photosynthesis and respiration Leaf respiration is calculated two times : one in Farquhar, once in stomate_resp : Use the one calculated in stomate_resp (function of temperature, biomass and nitrogen) for leaves net assimilation (Farquhar). The coupling between photosynthesis and respiration is done through leaf nitrogen (direct effect on Vc and Vj and respiration)

6 Carbon balance at Hesse (order of magnitude) gc/m²(/year): Obs (1997) sim Bleaf (sla ) Broots Baerialwood (sap/heart?) Bcoarseroots Rm sap sap Rm leaves leaves Rm+ roots (dynamics) GPP 1245/ Ra 650/

7 Forest growth and management in Orchidee One even-aged stand for the moment Closed canopy hypothesis Annual calculations Driven by DeltaB Within-stand tree distribution, no real individuals

8 General scheme: B VOL δheight i 7 circ i circ class 1 2 δvol i (tree) Tree cut rules circ i =0 6 Stand-level averages: H, D, Ind, BA + LAI max Biomass dead goes to soil or export yes 5 Trees die circ i =0 4 Self-thinning Ind=f(Dg) Ind (n. dead tr.) 3 no Management? Test on rdi δcirc i Dg=f(circ i + δcirc i ) rdi calculation

9 1 Distribution of total volume increase between trees Derived from Fagacee model (Dhote) δvol i (tree) γ Calculated so that Σ δvol i = vol σ c c c max min min c min σ c max circ i Stand Basal Area

10 2 Separation of δvol i between δheight i and δcirc i From Lindner et al. (1997), FORSKA model Tree volume increment = δvol i = fh=3.5*(1.1-exp(-0.5*lai_max_lastyear(i,j)/2))*(1-(height_ij(:))/(40)) radiation at the midle of the canopy For high LAI, fh is high more height growth Limitation of growth height by current height, with max value

11 3 Self-thinning equation: natural mortality due to space ln(ind) Mortality zone Ind ln(dg) Linear on log scale Pb for very high and low densities Species-dependent

12 4 Which trees die? Rules based on tree circumference and vigor Trees are sorted out in ascending circ i order 1) Trees that have δvol i = 0 and that have small circ i 2) If there still have trees to kill, one out of x trees die, x is a function increasing with δvol i Biomass is decreased with a proportion equal to the proportion of basal area that is dead (hyp : height is ~equal for all trees )

13 5 Management? Based on the RDI (Relative Density Index) index from Fagacée model -Standardized index -Based on self-thinning line Ln(N) Mortality zone Rdi = N / N max N max N Growth : RDI N max : RDI=1 D g Ln(D g )

14 5 Management cut? Rdi 5 parameters : -Date of first cut -RDI following first cut -Date of final cut -RDI of final cut -Band width Rdi final Rdi initial RDI target t init t fin Number of trees cut

15 6 Tree cut rules Cut rate Circ_lim circ i Nnc Circ_lim calculated so that RDI Nnc = 0.7 * RDI target

16 7 Transformation of tree circumference list to circumference class in both ways Position in list n1 n2 n3 n4 circ 2 vectors of dim(npts,npft,ncircclass) : ncircclass=20 Can be changed to 1 vector + n_constant

17 Initialisation ~ trees Circ follow a decreasing exponential with min and max values Circ calibrated so that Dg is on the self-thinning equation Should be site-dependant Problem of the self-thinning equation for high stem number Ln(Ind) Measurement zone Ln(Dg)

18 Description Equation Genericity Circ growth σ cmin =f(ba) Poor (species specific, shade cmax cmin tolerance, hard to calibrate) H and D growth separation fh=f(lai,h) Intermediate (pft specific?, hard to calibrate) Self-thinning Ind=f(Dg) Intermediate, species specific, many litterature, pb high ind RDI rules Rdi init, final, range Tree cut rules 0.7 parameter Not sensitive Can be calibrated : 4 class of std management types? Initialization fixed Should be site-dependant : how?

19 RESULTS RDI

20 H

21 Biomasse

22 Diam

23 Basal area

24 Wood increment

25 Gestion des classes d âge (à venir) Vol tot Vol âge i Vol âge i+1 Vol âge n Vol arbre i Vol arbre i+1 Biomasse âge i Vol arbre n Beaucoup de pb : Non linéarités, LAI, Biomasses, Alloc=f(H), Biomasse tot LAI tot

26 Gestion des classes d âge (à venir) NPP tot NPP âge i NPP âge i+1 NPP âge n Alloc=f(Hi) Biomasse i Vol arbre i Vol arbre n Biomass âge i LAI âge i GPPtot Rtot Pondération en f de la surface Biomasse tot LAI tot

27 Gestion des classes d âge (à venir) GPP tot Ri GPP âge i GPP âge i+1 GPP âge n NPP âge i Biomasse i Vol arbre i Vol arbre n Biomasse âge i LAI i Sert à répartir GPP tot entre classes d âges : il faut avoir une bonne relation GPP/LAI simul «à vide» par point de grille en augmentant le LAI?

Implementation and Evaluation of a Biogenic Isoprene Emissions scheme in JULES

Implementation and Evaluation of a Biogenic Isoprene Emissions scheme in JULES Federica Pacifico (1, 2, 3), Sandy Harrison (4), Chris Jones (3), Stephen Sitch (1), Gerd Folberth (3) (1) University of Exeter,