Ref ID: 10141
Ref Type: Confidential Report
Primary Title: Field browsing resistance of Shining Gum and Tasmanian Blue Gum seedlings raised under different nutrient regimes in the nursery
Primary Authors: Close, D. C., McArthur, C., Pietrzykowski, E., Fitzgerald, H., and Paterson, S. C.
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Periodical:
Volume: 96
Issue:
Start Page:
End Page:
Primary Date: 2002
Pub Place: Hobart, Tasmania
Publisher: CRC-SPF
Series Title: Technical Report
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Keywords: blue gum/browsing/field/gum/nursery/nutrient/report/resistance/seedling/seedlings/Technical Report/plantation/plantation establishment/establishment/cost/wood/production/scale/forestry/farm/browser/brushtail possum/possum/Trichosurus vulpecula/pademelon/Thylogale billardierii/growth/crop/1080/control/plant/species/energy/protein/secondary metabolite/metabolite/foliage/variation/leaf/chemistry/characteristic/genetic/tree/performance/induction/manipulation/variable/light/water/environment/globulus/trial/resource/affected/study/fertilizer/nitrogen/contrast/component/conventional/farm forestry/sites/site/pressure/critical/nutrition/soil/soil quality/quality/planting/effect/post-planting
Abstract: Plantation establishment involves the greatest cost in wood production, whether in broad scale forestry operations or at the relatively small farm scale. However, browsers such as brushtail possum (Trichosurus vulpecula), red-bellied pademelon (Thylogale billardierii) and Bennett's wallaby (Macropus rufogriseus) can severely impede growth of recently planted seedling crops in the absence of expensive fencing or controversial shooting and/or poisoning with sodium monofluoroacetate ('1080'). Increasing seedling resistance to browsing may contribute to a reduced need for these control measures.
Plant resistance to browsing is often observed in the field both between, and within, species. Mammalian browsers are often selective in what they choose to consume, due to the relative benefits (energy, protein) and costs (e.g. plant secondary metabolites requiring detoxification and excretion) of the foliage. Within a plant species, variation in resistance to browsing may be due to leaf chemistry characteristics owing to genetic (O'Reilly-Wapstra et al., 2002; Scott et al., 2002) or environmentally induced (Bryant et al., 1983) differences.
Tree seedlings vary in their palatability to browsers (McArthur et al., 2000), but can suffer greatly reduced growth performance as a result of severe browsing (Bulinski & McArthur, 1999). However, induction of within-species browsing resistance, through manipulation of environmental variables such as light, nutrients and water, is relatively easy in the nursery environment. Different nursery treatments have been shown to affect the resistance of E. globulus seedlings to swamp wallaby (Wallabia bicolor) browsing, although the basis of this variation was unknown (Marks & Moore, 1998). Similarly, controlled environment trials with possums and pademelons demonstrated that varying environmental resource availability in the nursery affected E. nitens seedling intake, up to two-fold, by possums and pademelons (McArthur et al., in press). A subsequent study found similar variation in browsing resistance and further quantified fertilizer regimes required to produce seedlings of defined characteristics (McArthur et al. 2002). Leaf nitrogen and toughness explained most of the variation in intake (McArthur et al. 2002). This was in contrast to studies of mature E. ovata, E. viminalis, E. polyanthemos and E. sideroxylon foliage, in which a specific and minor component of leaf secondary compounds, the formylphloroglucinol compounds (FPCs), explained variation in resistance (Lawler et al. 1998; Lawler et al. 2000).
Thus the objectives of this study were to produce 'conventional' (high-nutrient) and 'designer' (low-nutrient) E. nitens and E. globulus seedlings with careful application of liquid fertilizer and to deploy these seedlings in farm-forestry and forestry sites of varying browsing pressure. Given the critical issue of seedling nutrition, sites were chosen of varying soil quality and seedlings were either fertilized or not fertilised after planting. It was aimed to: 1) evaluate the extent and under what conditions browsing resistance of designer produced E. globulus and E. nitens seedlings to browsing is maintained and; 2) investigate the effect of post planting fertilizing on resistance.
Notes: Entered by Dugald Craig Close (7/1/2003)
Reprint: Not in File
Availability: Authors;
Address: Dugald.Close@ffp.csiro.au
Program: SPF Resource Protection
Project: C3
Deliverable: C3-2
Confidentiality: Public
Report: Annual Report 2002/3
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