Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Transpiration and stomatal conductance species growing in plantations (Simarouba amara and Goupia glabra) in French Guyana. | Ann Sci For 1992 49 17-24 Elsevier INRA 17 Original article Transpiration and stomatai conductance of two rain forest species growing in plantations Simarouba amara and Goupia glabra in French Guyana A Granier 1 R Hue 2 F Colin 1 INRA Centre de Nancy Champenoux F54280 Seichamps 2INRA Centre Antilles-Guyane BP 709 F97387 Kourou Guyana France Received 15 May 1991 accepted 12 August 1991 Summary Water relations of 2 tree species from the tropical rain forest of French Guyana were studied in young plantations of Simarouba amara and Goupia glabra. Experiments took place in 1988 and 1989. Sap flow was recorded continuously for several months including a dry season. On bright days sap flux densities eg sap flow per unit of conducting area exhibited high values of to . Total sap flow differed from one tree to another depending on individual sapwood areas. In spite of the increase of global radiation and of the vapour pressure deficit sap flow remained constant for Simarouba and even decreased for Goupia between 10 00 and 15 00 h as a consequence of stomatai closure. Sap flow measurements allowed the calculation of stand transpiration which for bright days represented only 50 of Penman potential evapotranspiration PET . This low transpiration level was explained by incomplete canopy closure and hence a low LAI of the plots. Canopy conductances were calculated from the Penman-Monteith equation. They demonstrated the inhibiting effect of vapour pressure deficits 4 hPa. These results confirm those of Hue and Guehl 1989 that for tropical rain forest species transpiration may be limited by stomatai closure notwithstanding a high annual rainfall. transpiration sap flow stomatai conductance air humidity tropical species canopy conductance Résumé Transpiration et conductance stomatlque de deux espèces tropicales humides en plantation Slmarouba amara et Goupla glabra en Guyane frangalse. Le fonctionnementhydri-que de 2 espèces de la foret tropicale humide a été .
