TAILIEUCHUNG - Báo cáo khoa học: "Prediction of acorn crops in three species of North American oaks: Quercus alba, Q rubra and Q velutina"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Prediction of acorn crops in three species of North American oaks: Quercus alba, Q rubra and Q velutina. | 128s Ann Sci For 1993 50 Suppl 1 128s-136s Elsevier INRA Original article Prediction of acorn crops in three species of North American oaks Quercus alba Q rubra and Q velutina VL Sork JE Bramble Department of Biology University of Missouri-St Louis st Louis MO 63121 USA Summary Many oak species show tremendous year-to-year variation in acorn production. Is this variation completely random or is there some predictable pattern Using an 8-year data set of individual trees from 3 species of oaks in central-eastern Missouri we evaluated the patterns of acorn production in order to identify critical external and internal factors. Our results showed that flower counts can be used to predict small acorn crop size but high flower counts do not always predict large acorn crops. In addition we found that each species differed in the length of the interval between large acorn crops and that acorn crop size was influenced by spring temperature and summer drought. Thus the combination of physiological constraints reflected by intermast interval and key weather factors can be used to predict future acorn crop size. Quercus alba I Q rubra I Q velutina I mast-fruiting acorn production Resume Prediction de la fructification Chez 3 chênes américains Quercus alba o rubra o velutina. De nombreux chênes manifestent de très grandes irrégularités annuelles de fructification. Quelle est la nature de ces variations est-elle purement aléatolre OU peut-elle être prédite La glandée a été observes au niveau d arbres individuals appartenant à 3 espèces differentes pendant 8 années successives au centre-est de I Etat du Missouri de manière à identifier les facteurs critiques internes et externes intervenant dans la glandée. Quand la floraison est faible la glandée peutêtre prédite à partir du comptage des fleurs par contre les floraisons importantes ne sont pas corrélées à des fructifications élevées. Des differences specifiques ont été observées dans le délai nombre d annees séparant 2 glandées

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