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Factors controlling individual branch development during early growth of an experimental plantation of Eucalyptus pilularis in sub-tropical Australia
journal contribution
posted on 2023-05-20, 19:41 authored by West, PW, David RatkowskyDavid Ratkowsky, Smith, RGBDiameter at base, orientation, and height up the stem of live branches on the lower 5 m of tree stems were measured several times over 2.5–5.7 years of age in an experimental plantation of blackbutt (Eucalyptus pilularis) in sub-tropical eastern Australia. Stocking density at planting varied over 816–1667 stems ha-1 and rectangularity of planting (ratio of distance between rows to distance between trees within rows) over 1–6. Tree stem diameters, heights and crown dimensions were also measured. The height above ground at which branches emerged from the stem was a primary factor determining their growth; the higher they were, the greater was their diameter and the more vertical their orientation. This was believed to reflect both a need for newer branches to grow larger than older branches, to support greater amounts of foliage as the crowns expanded towards full size, and for branches to be better oriented to seek sunlight as the crowns of surrounding trees also expanded. Secondary factors determining branch size were tree size and spacing between trees, factors that are likely to interact with each other. Larger trees tended to have larger branches, to support more leaf weight in larger crowns. The direction of emergence of branches from stems seemed little affected by tree or stand characteristics at these early stages of tree development. The results did not suggest any need to modify existing pruning regimes that have been developed for fast-growing eucalypt plantations in Australia.
History
Publication title
TreesVolume
35Pagination
395-405ISSN
0931-1890Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
Springer-VerlagPlace of publication
175 Fifth Ave, New York, USA, Ny, 10010Rights statement
© Springer-Verlag GmbH Germany, part of Springer Nature 2020Repository Status
- Restricted