Growth habits and crown architecture of Betula pubescens Ehrh. of seed and sprout origin

1988

S. 1603-1613

6 Abb., 44 Lit. Ang.

Unselbständiges Werk

200038793

Patterns of height increment and ramification in Betula pubescens Ehrh. of sprout and seed origin were studied at Kannus during the first few growing seasons, 1982-1985, employing trees of various ages (0-15 years(.Sprouts developed very much rapidly than seedlings during the firs three seaso ns, as a consequence of the free growth pattern and associated pronounced growth flushes. Their annual height increment declined somewhat after a few years, however, whereas that of trees of seed origin remained constant or increased slightly. The mode of height growth in birches over 10 yeas of age appeared to approach the short-duration growth model. Branches of sprouts also grew more than those of seedlings, in the first few growing seasons, with distinct differencesin branching pattern visible between the two tree forms, and also between spro uts originating from buds located above and below ground. Young sprouts used practically all buds to form branches and short shoots, giving them a bush-like appearance. In contrast, most axillary buds on seedlings remained dormant and the individuals adopted an arboreal mode of growth at an early stage. The less branched appearance of older trees of seed origin was also due in part to thedeath of a higher proportion of buds and branches.