tailieunhanh - Báo cáo lâm nghiệp: "Photosynthesis and growth of present New Zealand forest trees relate to ancient climates"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Photosynthesis and growth of present New Zealand forest trees relate to ancient climates. | 512s Ann. Sci. For. 1989 46 suppl. 512s-514s Forest Tree Physiology E. Dreyer etal. eds. Elsevier INRA Photosynthesis and growth of present New Zealand forest trees relate to ancient climates . Hawkins and . Sweet School of Forestry University of Canterbury Christchurch New Zealand Seedlings of temperate northern hemisphere forest tree species have demonstrated optimum growing temperatures which equate closely with climates in which they presently grow Table I . The species are regarded as recent many having evolved during the cold Pleistocene climates of the last two million years replacing species of a much older tropical and subtropical flora Cox eta . 1976 . Table I. Temperate northern hemisphere forest tree seedlings a comparison from the literature of the differential between optimum growing temperatures and actual summer temperatures for different species. Species Optimum growing temp C Actual mid-summer temp C a Differential Pinus radiata b Sequoia sempervirens c Pseudotsuga menziesiid Tsuga heterophylla d Pinus rigida e Pinus taeda1 Pinus sylvestris 9 Larix decidua 9 Picea engelmanniih Mean a Mean temperature of warmest month mean maximum temperature of warmest month 2. Climatic data from meteorological tables relate specifically to the provenance used in the study. b Hellmers and Rook 1973 c Hellmers 1966 d Brix 1971 6 Good and Good 1976 1 Kramer 1957 9 Gowin etal. 1980 h Hellmers etai. 1970 . Author to whom correspondence should be addressed. 513s A series of controlled temperature experiments were carried out with seedlings of 5 species of important New Zealand forest tree genera. Conditions were a 16 h photoperiod with 10 h of full light at intensities ranging from 270 to 560 zmol-m-2-s-1 and a maximum VPD of 12 mbar. The results indicated that all species had an optimum growing temperature of 27 c .