Image d'Archive de la page 4 de la défoliation et de la mortalité dans le Connecticut. La défoliation et la mortalité dans les forêts du Connecticut defoliationmorta00étape Année : 1981 la défoliation et la mortalité, mais que la mortalité sur les sites plus humides en général se trouve en dessous de la ligne de tendance alors qu'il se situe au-dessus de sur le sites plus secs. Sur tous les sites sauf muck, la mortalité annuelle moyenne des principales espèces était d'un peu plus de 3 pour cent. Le plus haut, 3 à 5 pour cent, s'est produite sur le site humide moyen. variait de un peu moins de 2 à un peu plus de 3 p. 100 au cours de deux séries. Parce qu'apparemment, la mortalité est influencé par l'âge
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Archive image from page 4 of Defoliation and mortality in Connecticut. Defoliation and mortality in Connecticut forests defoliationmorta00step Year: 1981 Defoliation and Mortality however, that mortality on the moister sites generally lies below the trend line whereas it lies above on the drier sites. On all sites except muck, average annual mortality of major species was slightly more than 3 percent. The highest, 3-5 percent, occurred on the medium moist site. ranged from slightly less than 2 to slightly more than 3 percent over both series. Because mortality apparently is influenced by age, the trend of mortality with popula- tion size in a recent time without defolia- tion (New series, 1959-70) will be used to compare mortality on defoliated stands. 600 r 400 800 I200 I600 2000 2400 1927 TOTAL POPULATION, STEMS/A o 0 400 800 I200 I959 TOTAL POPULATION, STEMS/A Fig. 2. Periodic mortality of major species in tracts without major defoliation. The numbers are the sites: muck (1), moist (2), medium moist (3) and dry (4). The line is the straight line that best fits the observations. Upperâ Meshomasic series, 1927-37. Lowerâ Cat I in Wooa, Norfolk and Nat- chaug of the New series, 1959-70. The lower portion of Fig. 2 portrays mor- tality in three undefoliated tracts of the New series in a more recent time, 1959-70. There were no very wet or dry sites as on the Meshomasic series. Although Catlin Wood had been more than half defoliated in 1956, before the enumeration began, its mortality during 1959-70 did not differ from undefoli- ated Norfolk or Natchaug. This suggests that the effect of a prior single defoliation is short-lived. The trend line fits the observa- tions well and, despite differences in age of the stands, it is similar to that of the Meshomasic series in an earlier decade. How- ever, for a given population, mortality on the New Series during 1959-70 was less than on the Meshomasic series during 1927-37- Annual mortality of major species averaged le