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Carbon fluxes in a managed Northern Wisconsin landscape (Chequamegon National Forest, Washburn Ranger District). Stands: MHW, MRP, PB, CC/YHW, YMP Data coverage: May 1, 2002 - April 30, 2003 Asko Noormets, Jiquan Chen. Stand characteristics. Site 1: Mature hardwood. Site 2: Mature red pine.
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Carbon fluxes in a managed Northern Wisconsin landscape (Chequamegon National Forest, Washburn Ranger District) Stands: MHW, MRP, PB, CC/YHW, YMP Data coverage: May 1, 2002 - April 30, 2003 Asko Noormets, Jiquan Chen
0.5 0.4 MHW 0.3 MRP NEE, mg CO2 m-2 s-1 PB CC 0.2 YRP 0.1 0.0 0 10 20 30 40 Ta, °C Night NEE-Ta relationships MHW: y = 0.1361 e0.0111x, R2yr=0.1507, R2s=0.0292 MRP: y = 0.1869 e0.0214x, R2yr=0.1355, R2s=0.0603 PB: y = 0.0784 e0.05x, R2yr=0.0873, R2s=0.0077 CC/YHW: y = 0.1703 e0.0298x, R2yr=0.2301, R2s=0.1088 YMP: y = 0.2265 e0.0156x, R2yr=0.1130, R2s=0.1063
Storage term calculations IF (PB or CC or YMP) THEN FcSTOR=FcWPL Fc Li800 FcWPL Li800WPL IF ((MHW or MRP) AND Li800 ne .) THEN FcSTOR=FcWPL+Li800WPL 7-day mean of Li800WPL=lagli800 Li800WPL = f (Tref) CO2STOR IF ((MHW or MRP) AND (before or after Li800)); IF (Li800WPL<-0.05 or Li800WPL= .) AND CO2STOR>0 THEN FcSTOR=FcWPL+CO2STOR IF Li800WPL<-0.05 AND CO2STOR<0 THEN FcSTOR=FcWPL+lagli800 IF (MHW or CC or PB) AND month>10 THEN FcSTOR>0 ELSE .; IF (MRP or YMP) AND month>10 AND TAir<10 THEN FcSTOR>0 ELSE .;
Partial R2 for residual analysis Fc_resid = f {VPD, Rn} R2VPD (MHW)=0.063, R2Rn (MHW)=0.161 R2VPD (MRP)=0.105, R2Rn (MRP)=0.149 Fc_resid = f {Rn, VPD} R2Rn (PB)=0.055, R2Rn (PB)=0.056 R2Rn (CC)=0.203, R2Rn (CC)=0.130 R2Rn (YMP)=0.123, R2Rn (YMP)=0.275
Remaining uncertainties • Accuracy of net radiometers • Independent criteria for quantifying storage • Absence of direct storage data in winter • Midday NEE negative in winter (w/o leaves)
1.2 1 0.8 Pmax 0.6 0.4 0.2 Nov.-Dec. October September 0 July-Aug. May-June MHW MRP PB YHW YRP A-Q response, Pmax
0.007 0.006 0.005 0.004 Quantum yield 0.003 0.002 Nov.-Dec. 0.001 October September 0 July-Aug. MHW May-June MRP PB YHW YRP A-Q response, Q
200 180 160 140 120 Light comp. point 100 80 60 40 Nov.-Dec. October 20 September 0 July-Aug. MHW May-June MRP PB YHW YRP A-Q response, L