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Studies on the phenotypic variation in growth stress intensity and its association with tree and wood properties of South African grown Eucalyptus grandis (Hill ex Maiden)
Thesis (PhD)--University of Stellenbosch, 1984.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2012
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| _version_ | 1867613770826645504 |
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| access_status_str | Open Access |
| author | Malan, F. S. |
| author2 | Gerischer, G. F. R. |
| author_browse | Gerischer, G. F. R. Malan, F. S. |
| author_facet | Gerischer, G. F. R. Malan, F. S. |
| author_sort | Malan, F. S. |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--University of Stellenbosch, 1984. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/64868 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:41:25.747Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2012 |
| publishDateRange | 2012 |
| publishDateSort | 2012 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/64868 Studies on the phenotypic variation in growth stress intensity and its association with tree and wood properties of South African grown Eucalyptus grandis (Hill ex Maiden) Malan, F. S. Gerischer, G. F. R. Stellenbosch University. Faculty of AgriSciences. Dept. of Forest and Wood Science. Eucalyptus grandis Trees -- Growth Phenotypic plasticity Thesis (PhD)--University of Stellenbosch, 1984. ENGLISH ABSTRACT: The level of growth stress in the stems of Eucalyptus grandis trees is apparently not determined by environmental factors to any great extent. A significant positive relationship was found between level of growth stress and rate of growth, but the latter accounted for only a small proportion of the enormous variation that characteristically exists among plantation grown trees. It may, however, explain to some extent why trees on poor quality sites tend to develop less end-splitting in their logs as compared to those from better quality sites. Seasonal fluctuations in the level of growth stress were observed. Attempts to explain these fluctuations in terms of weather patterns and soil moisture content yielded contradictory results. Although not quantitatively there was some evidence to suggest that the level of proved, growth stress is intensified in actively growing trees during periods of severe soil moisture deficit. Studies on open- and control-pollinated material indicated a very definite genetic variation among families. A narrow-sense heritability estimate of 0,56 was obtained. The genetic manipulation of growth stress therefore seems to const1tute the most promising means of growth stress reduction in trees of this species, and it can be done irrespective of tree characteristics. Since a poor relationship was found between growth stress intensity and rate of growth, the selection for reduced level of growth stress and increased volume growth can be employed simultaneously. Marked differences in a wood density were found growth stress intensities. number of anatomical features and among trees of widely different Results suggested that the genetic reduction of the level of growth stress in a tree improvement programme would result in a reduction in the pith-to-bark wood density and fibre length gradients, causing lower values in the outer parts of the stem for both these properties. Since these properties are the most widely used this implies that the selection for indices for wood quality, reduced level of growth stress would, apart for a reduction in splitting, result in reduced within-tree variability in wood quality. Furthermore, characteristics stress suggest the observed between trees that anatomical differences in anatomical of different levels of growth determinations could be used as an effective means to separate low-stressed trees from high-stressed trees. Results indicated that the inherent potential of a tree to generate growth stress of a particular level may even be assessed at a fairly young age from the anatomical characteristics of the wood. However, further research is needed to quantify this in more exact terms before they can be used for predicting level o.f growth stress with sufficient precision. Doctoral 2012-08-27T12:08:35Z 2012-08-27T12:08:35Z 1984 Thesis http://hdl.handle.net/10019.1/64868 en_ZA Stellenbosch University 258 leaves : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Eucalyptus grandis Trees -- Growth Phenotypic plasticity Malan, F. S. Studies on the phenotypic variation in growth stress intensity and its association with tree and wood properties of South African grown Eucalyptus grandis (Hill ex Maiden) |
| title | Studies on the phenotypic variation in growth stress intensity and its association with tree and wood properties of South African grown Eucalyptus grandis (Hill ex Maiden) |
| title_full | Studies on the phenotypic variation in growth stress intensity and its association with tree and wood properties of South African grown Eucalyptus grandis (Hill ex Maiden) |
| title_fullStr | Studies on the phenotypic variation in growth stress intensity and its association with tree and wood properties of South African grown Eucalyptus grandis (Hill ex Maiden) |
| title_full_unstemmed | Studies on the phenotypic variation in growth stress intensity and its association with tree and wood properties of South African grown Eucalyptus grandis (Hill ex Maiden) |
| title_short | Studies on the phenotypic variation in growth stress intensity and its association with tree and wood properties of South African grown Eucalyptus grandis (Hill ex Maiden) |
| title_sort | studies on the phenotypic variation in growth stress intensity and its association with tree and wood properties of south african grown eucalyptus grandis hill ex maiden |
| topic | Eucalyptus grandis Trees -- Growth Phenotypic plasticity |
| url | http://hdl.handle.net/10019.1/64868 |
| work_keys_str_mv | AT malanfs studiesonthephenotypicvariationingrowthstressintensityanditsassociationwithtreeandwoodpropertiesofsouthafricangrowneucalyptusgrandishillexmaiden |