Natural reforestation of abandoned farmland: the role of soils |
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| Authors: | Zeng Liangzhong Robert J Whelan |
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| Institution: | 1. Department of Biological Sciences , University of Wollongong , Northfields Avenue, Wollongong, NSW, 2522, Australia;2. Department of Forest Science , Fujian College of Forestry , Nanping, Fujian, China, 53001 |
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| Abstract: | Natural regeneration of abandoned farmland in several areas within the catchments of the Sydney Water Board has been very slow. Several hypotheses have been put forward to explain the fact that natural reforestation has not occurred, even after up to 50 years of abandonment. This study examines regeneration in relation to substrate, soil types and soil chemistry. The abandoned farmlands occur on four main soil types: (i) eutrophic krasnozem, now occupied mainly by bracken fern (Pteridium esculentum) associated with young seedlings of Eucalyptus and Acacia; (ii) mesotro‐phic yellow earth, now occupied by blady grass (Imperata cylindrica), with few tree seedlings and scattered, dead Acacia trees; and (iii) mesotrophic alluvial soil, and (iv) oligotrophic lithosol, which both support stands of Acacia. The soil properties of the krasnozem and the yellow earth appear to be suitable for tree establishment and growth, and do not differ from similar soils in nearby areas currently under cultivation or supporting undisturbed forest. Poor forest establishment in these soils might be the result of frequent fires and biotic factors such as competition from the bracken and blady grass sward. The lack of eucalypt reforestation of the poorer soils might be explained by their poorer fertility, perhaps tolerated better by the Acacia species. |
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| Keywords: | Australian vegetation regeneration abandoned farmland soil type soil fertility fire competition |
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