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Age Distribution in Virgin Red Spruce and Northern Hardwoods
Author(s) -
Leak W. B.
Publication year - 1975
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1934714
Subject(s) - abies balsamea , yellow birch , balsam , age structure , biology , survivorship curve , pinus contorta , ecology , betulaceae , tsuga , botany , forestry , geography , hardwood , population , demography , genetics , cancer , sociology
Age distributions are given for four species in a virgin spruce—fir stand in New Hampshire together with comparative data from virgin northern hardwoods. Three distinct forms of age distribution were found: (1) essentially linear relationships of numbers of stems (log) vs. age (log) denoting stationary populations with a power function form of survivorship; (2) concave age distributions indicative of increasing populations; and (3) convex to bell—shaped age distributions reflecting declining populations with a low birth date. Picea rubens, Abies balsamea, Betula papyrifera var. cordifolia, and Sorbus americana all exhibited stationary age distributions in the virgin spruce—fir stand. In virgin northern hardwoods, Fagus grandifolia and Acer saccharum appeared to be stationary or increasing, respectively, while P. rubens and Betula alleghaniensis had age distributions typical of declining populations.