FluxLetter The Newsletter of FLUXNET Vol. 2 No. 1, March, 2009 Highlight FLUXNET sites Hinda, Kissoko and Tchizalamou flux tower sites Hinda, Kissoko and Tchizalamou by Yann Nouvellon Three main types of ecosystems UR2PI in these eucalypt planta- and the eddy-covariance system In This Issue: are found in the South-Western tions as part of a larger network and meteorological station were Republic of Congo (Central of flux tower sites in tropical then moved to a nearby savan- Africa): secondary natural for- plantations (rubber-tree, coco- nah at Tchizalamou (4°17'21.0''S, ests, savannahs, and eucalypt nut-tree, coffee and eucalypt 11°39'23.1''E), where flux meas- FLUXNET site: plantations (about 40000 ha) that plantations) managed by the urements have been carried out “Hinda, Kissoko and Tchi- have been established over sa- CIRAD “Tree-based Tropical since July 2006. The three sites zalamou ” vannahs since the 1970s for Plantation Ecosystems” research are part of the CARBOAFRICA Yann Nouvellon ……...….Pages 1-3 team (http://www.cirad.fr/ur/ flux tower site network (http:// pulpwood and charcoal produc- tion. The Hinda (4°40'52''S; 12° ecosystemes_plantations (in www.carboafrica.net; see the Editorial: 00'13''E) and Kissoko (4°47'29''S; French only). The Hinda and “Carbon cycling in Sub-Saharan Why is it so hard to sustain a Kissoko sites were operated Africa” special issue in Biogeo- 11°58'56''E) flux tower sites flux network in Africa? were established by CIRAD and successively for two years each, sciences for some early pub- Bob Scholes……….…......Pages 4-5 Celebrating the first year of FluxLetter Rodrigo Vargas and Dennis Baldoc- chi……….…...….…...............Page 6 FLUXNET graduate student : Sally Archibald ........................Page 7 FLUXNET young scientist: Agnes de Grandcourt .......Pages 8-9 Christopher Williams ….Pages 10-11 Research: Flux-measurements in a Miombo woodland in Western Zambia in relation to defores- tation and forest degradation Werner L. Kutsch, Lutz Merbold, Mukufute Mukelabai, and Maurice Muchinda…………....Pages 12-15 Figure 1: Closed-path (Li-6262+ sonic anemometer Young 81000V) and open-path(Li-7500 + 81000V) systems for flux measurements at the Hinda site (two years of measurements with the closed-path system, and one month with the two systems, for comparison) FLUXNET SITE cont. on page 2 Page 2 Hinda, Kissoko and Tchizalamou flux tower sites FLUXNET SITE cont. from page 1 lished CARBOAFRICA results) and the French network F-ORE- T (http://www.gip-ecofor.org/f- ore-t/). Measurements made at these sites aim at: i) quantifying and understanding the exchanges of water vapour (Fisher et al., 2009), CO2 and energy between the ecosystem and the atmos- phere, ii) identifying the main regulators of gross and net pri- mary production (GPP, NPP) and net ecosystem production (NEP), and iii) parameterizing/ validating ecosystem process- based models for these two types of ecosystems. The sea- sonality of net primary produc- tion (NPP), soil CO2 effluxes (Epron et al., 2004), fine root growth (Thongo et al., 2008), LAI and specific leaf area (Nouvellon et al., 2009) have Figure 2: Coarse root CO2 efflux measurement at the Kissoko site been studied at these sites. At Kissoko, NEP has been assessed At the Tchizalamou savannah soko, and Tchizalamou flux Africa surface. Another chal- in two ways: 1) from eddy- site, soil CH4 and N2O effluxes tower sites, nutrient cycling at lenge in these studies is to covariance measurements of are currently being monitored, adjacent eucalypt and savannah assess the environmental im- CO2 net ecosystem exchange as well as the seasonal dynamics ecosystems has also been stud- pact of eucalypt plantations, and (NEE), and 2) from biometric of LAI and NDVI. These data are ied: for 10 years soil water more specifically the effect of NPP measurements and hetero- being merged with data obtained content and soil solution chem- savannah afforestation on car- trophic soil respiration (Rh) at other savannah sites of the istry have been measured con- bon sequestration, water re- measurements (NEP=NPP-Rh). CARBOAFRICA flux tower site tinuously down to a depth of 5 sources, and soil fertility. At the Hinda and Kissoko sites, network (in South-Africa, Bot- m, as well as nutrient fluxes Chronosequence studies have canopy structure parameters, swana, Sudan, Mali, Niger, Benin, between the soil and the plants been carried out to assess the gap fractions, leaf gas exchange, etc.; Merbold et al., 2008) in (e.g. Laclau et al, 2005). This changes in carbon and nutrient and root CO2 efflux (Marsden et order to develop/validate provides a unique opportunity stocks in the soil (D’Annunzio al., 2008) have been measured in “process-based” models simulat- to study the interactions be- et al., 2008), and in the biomass order to parameterize canopy or ing water vapour and CO2 ex- tween the carbon, water, and (Saint-André et al., 2005) after individual tree-based models changes between savannas and nutrient cycles. This is impor- savannah afforestation. Soil CO2 (CANOAK, G’DAY and the atmosphere, that will further tant since the response of Afri- effluxes after savannah affore- MAESTRA). Leaf gas exchanges be applied at the regional and can savannas to climate change station (Nouvellon et al., 2008) measurements, and eddy- continental scales, using remote is likely to be determined by and changes in the isotopic covariance measurements have sensing data, soil and vegetation the complex interactions be- composition of soil C and of both shown marked differences cover maps, and meteorological tween these three major cycles, soil CO2 effluxes have also been in the water-use efficiencies of data. and since savannas cover about measured in order to investi- the two studied eucalypt clones. In the vicinity of the Hinda, Kis- two thirds of the sub-Saharan gate the dynamics of savannah- FLUXNET SITE cont. on page 3 Page 3 Hinda, Kissoko and Tchizalamou flux tower sites FLUXNET SITE cont. from page 2 PI contact information: trenched-plot technique. New Phy- Yann Nouvellon : tologist, 177:676-687. Merbold, L., Ardo, J., Arneth, A., [email protected] Scholes, R.J., Nouvellon, Y., de Grand- Agnès de Grandcourt : court, A., Archibald, S., Bonnefond, [email protected] J.M., Boulain, N., Bruemmer, C., Brueggemann, N., Cappelaere, B., Ceschia, E., El-Khidir, H.A.M., El-Tahir, B.A., Falk, U., Lloyd, J., Kergoat, L., Le Further Reading Dantec, V., Mougin, E., Muchinda, M., D’Annunzio R., Conche S., Landais D., Mukelabai, M.M., Ramier, D., Roup- Saint-André L., Joffre R., Barthes B., sard, O., Timouk, F., Veenendaal, E.M., 2008. Pairwise comparison of soil and Kutsch, W. L., 2008. Precipitation organic particle-size distributions in as driver of carbon fluxes in 11 African native savannas and Eucalyptus planta- ecosystems. Biogeosciences Discuss., tions in Congo. Forest Ecology and 5, 4071–4105. Management 255:1050-1056. Nouvellon, Y., Epron D., Laclau, J-P., Epron, D., Nouvellon, Y., Roupsard, Kinana, A., Mabiala, A., D’Annunzio, R., O., Mouvondy, W., Mabiala, A., Saint- Deleporte, P., Saint-André, L., Mars- André, L., Joffre, R., Jourdan, C., den, C., Roupsard, O., Bouillet, J-P., Bonnefond, J.M., Berbigier, P., Hamel, and Hamel, 0., 2008. Soil CO2 efflux O., 2004. Spatial and temporal varia- and soil carbon balance following tions of soil respiration in a Eucalyptus savannah afforestation in Congo: plantation in Congo. Forest Ecology comparison of two site preparation and Management, 202 :149-160. treatments. Forest Ecology and Man- Epron, D., Marsden, C., Thongo agement, 255: 1926-1936. m’bou, A., Saint-andré, L., D’Annunzio, Nouvellon, Y., Laclau, J-P., Epron, D., R., Nouvellon, Y., 2009. Soil carbon Kinana, A., Mabiala, A., Roupsard, O., dynamics following afforestation of a Bonnefond, J-M., Le Maire, G., Mars- tropical savannah with Eucalyptus in den, C., Saint-André, L., 2009. Within- Congo. Plant and Soil (in press). stand and seasonal variations of spe- Fisher, J.B., Malhi,Y., de Araújo, A.C., cific leaf area in a clonal Eucalyptus Bonal, D., Gamo, M., Goulden, M.L., plantation in the Republic of Congo. Hirano, T., Huete, A.R., Kondo, H., Figure 3: Soil CO2 effluxes measurements at the Tchizalamou savannah site Forest Ecology and Management Kumagai, T., Loescher, H.W., Miller, (submitted) S., Nobre, A.D., Nouvellon, Y., Ober- derived, and newly eucalypt- CSIR, B. Scholes; DISAFRI, R. Saint-André L., Thongo M’Bou A., bauer, S.F., Panuthai, S., von Randow, Mabiala A., Mouvondy W., Jourdan C., derived soil C after savannah Valentini, etc.). C., Rocha, H.R., Roupsard, O., Saleska, Roupsard O., Deleporte Ph., Hamel afforestation (Epron et al., 2009). S., Tanaka, K., Tanaka, N., and Tu, O., Nouvellon Y. 2005. Age-Related New research (planned but not Research team: K.P., 2009. The land-atmosphere equations for above- and below- water flux in the tropics. Global yet funded) will focus on carbon, CIRAD: L. Saint-André, Y. Nou- ground biomass of a Eucalyptus hybrid Change Biology (in Press). water, and nutrient cycles in the vellon, A. de Grandcourt, O. in Congo. Forest Ecology and Manage- Laclau J-P., Ranger J., Deleporte Ph., ment 205:199-214. secondary natural forests. Hamel, O. Roupsard, JP Laclau, Nouvellon Y., Saint-André L., Marle S., Thongo M’Bou, A., Jourdan, C., Dele- Our research is carried out in C. Jourdan, JP. Bouillet, C. Mars- Bouillet J-P. 2005. Nutrient cycling in a porte, P., Nouvellon, Y., Saint-André, collaboration with scientists den, P. Deleporte, L. Mareschal, clonal stand of Eucalyptus and an A., Bouillet, J-P., Mialoundama, F., adjacent savanna ecosystem in Congo. from INRA, University of Nancy, G. Le Maire Mabiala, A., Epron, D., 2008. Root 3. Input-output budgets and conse- elongation in tropical Eucalyptus planta- CNRS (ESE and CEFE), Second UR2PI: A.