Jerome K Vanclay
Research interests
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InterestsForestry, Forestry Research, Forest Ecology, Silviculture
Publications
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Metrics to evaluate research performance in academic institutions: A critique of ERA 2010 as applied in forestry and the indirect H2 index as a possible alternative
01/2012;
Excellence for Research in Australia (ERA) is an attempt by the Australian Research Council to rate Australian universities on a 5-point scale within 180 Fields of Research using metrics and peer evaluation by an evaluation committee. Some of the bibliometric data contributing to this ranking suffer... [more] Excellence for Research in Australia (ERA) is an attempt by the Australian Research Council to rate Australian universities on a 5-point scale within 180 Fields of Research using metrics and peer evaluation by an evaluation committee. Some of the bibliometric data contributing to this ranking suffer statistical issues associated with skewed distributions. Other data are standardised year-by-year, placing undue emphasis on the most recent publications which may not yet have reliable citation patterns. The bibliometric data offered to the evaluation committees is extensive, but lacks effective syntheses such as the h-index and its variants. The indirect H2 index is objective, can be computed automatically and efficiently, is resistant to manipulation, and a good indicator of impact to assist the ERA evaluation committees and to similar evaluations internationally.
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Impact Factor: outdated artefact or stepping-stone to journal certification?
01/2012;
A review of Garfield's journal impact factor and its specific implementation as the Thomson Reuters Impact Factor reveals several weaknesses in this commonly-used indicator of journal standing. Key limitations include the mismatch between citing and cited documents, the deceptive display of thre... [more] A review of Garfield's journal impact factor and its specific implementation as the Thomson Reuters Impact Factor reveals several weaknesses in this commonly-used indicator of journal standing. Key limitations include the mismatch between citing and cited documents, the deceptive display of three decimals that belies the real precision, and the absence of confidence intervals. These are minor issues that are easily amended and should be corrected, but more substantive improvements are needed. There are indications that the scientific community seeks and needs better certification of journal procedures to improve the quality of published science. Comprehensive certification of editorial and review procedures could help ensure adequate procedures to detect duplicate and fraudulent submissions.
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Publication patterns of award-winning forest scientists and implications for the Australian ERA journal ranking.
J. Informetrics. 01/2012; 6:19-26.
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1.95Impact points
Depth distribution of roots of Eucalyptus dunnii and Corymbia citriodora subsp. variegata in different soil conditions
Forest Ecology and Management. 01/2012; 269:249-258.
Understanding depth distribution of roots may help develop an understanding of plant productivity and the limits to productivity by indicating which parts of the soil profile are being accessed for water and nutrients. The subtropical east coast of Australia provides climatic and soil conditions tha... [more] Understanding depth distribution of roots may help develop an understanding of plant productivity and the limits to productivity by indicating which parts of the soil profile are being accessed for water and nutrients. The subtropical east coast of Australia provides climatic and soil conditions that produce some of the highest plant productivity rates in the country. This has been recognised by the hardwood plantation industry and over the last decade a substantial estate of plantations has been established with plans for further expansion. However, two of the major species used, Eucalyptus dunnii and Corymbia citriodora subsp. variegata, have had little published research directly related to root depth distribution in the area. We examined root depth distribution in established plantations of E. dunnii and C. citriodora subsp. variegata under three contrasting soil types using the techniques of soil trench profile and coring. The results showed that the fine roots of C. citriodora subsp. variegata are at lower densities in poorly structured subsoils than the roots of E. dunnii. The root densities of both species in the subsoils of a Vertosol soil (with high levels of reactive, shrink–swell clays) were lower than for the other soil types. In native vegetation Vertosols are often colonised by grasses with few, scattered trees from a limited range of species. Our findings show lower levels of root growth in the Vertosols, particularly into the subsoil and this is likely to be the reason that productivity on these, otherwise fertile soils, is restricted.
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3.13Impact points
The balance between facilitation and competition in mixtures of Eucalyptus and Acacia changes as stands develop.
Oecologia. 02/2011; 166(1):265-72.
The balance between facilitation and competition is likely to change with age due to the dynamic nature of nutrient, water and carbon cycles, and light availability during stand development. These processes have received attention in harsh, arid, semiarid and alpine ecosystems but are rarely examine... [more] The balance between facilitation and competition is likely to change with age due to the dynamic nature of nutrient, water and carbon cycles, and light availability during stand development. These processes have received attention in harsh, arid, semiarid and alpine ecosystems but are rarely examined in more productive communities, in mixed-species forest ecosystems or in long-term experiments spanning more than a decade. The aim of this study was to examine how inter- and intraspecific interactions between Eucalyptus globulus Labill. mixed with Acacia mearnsii de Wildeman trees changed with age and productivity in a field experiment in temperate south-eastern Australia. Spatially explicit neighbourhood indices were calculated to quantify tree interactions and used to develop growth models to examine how the tree interactions changed with time and stand productivity. Interspecific influences were usually less negative than intraspecific influences, and their difference increased with time for E. globulus and decreased with time for A. mearnsii. As a result, the growth advantages of being in a mixture increased with time for E. globulus and decreased with time for A. mearnsii. The growth advantage of being in a mixture also decreased for E. globulus with increasing stand productivity, showing that spatial as well as temporal dynamics in resource availability influenced the magnitude and direction of plant interactions.
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0.54Impact points
Forestry at Southern Cross University: Fifteen years in review
International Forestry Review. 01/2011; 13:500-510.
After 15 years, it is timely to review the 4-year bachelor degree in forestry offered by Southern Cross University (SCU), now the only remaining such 4-year degree in Australia. The SCU program is characterised by innovative teaching, a strong fieldwork component, emphasis on research, and strong li... [more] After 15 years, it is timely to review the 4-year bachelor degree in forestry offered by Southern Cross University (SCU), now the only remaining such 4-year degree in Australia. The SCU program is characterised by innovative teaching, a strong fieldwork component, emphasis on research, and strong links with local interest groups (both environmental and industrial). The progressive introduction of two-site delivery and on-line lectures has maintained the viability of the course despite modest student demand.
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Publication patterns of award-winning forest scientists and implications for the ERA journal ranking
CoRR. 01/2011; abs/1108.4828.
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An evaluation of the Australian Research Council's journal ranking
09/2010;
As part of its program of 'Excellence in Research for Australia' (ERA), the Australian Research Council ranked journals into four categories (A*, A, B, C) in preparation for their performance evaluation of Australian universities. The ranking is important because it likely to have a major im... [more] As part of its program of 'Excellence in Research for Australia' (ERA), the Australian Research Council ranked journals into four categories (A*, A, B, C) in preparation for their performance evaluation of Australian universities. The ranking is important because it likely to have a major impact on publication choices and research dissemination in Australia. The ranking is problematic because it is evident that some disciplines have been treated very differently than others. This paper reveals weaknesses in the ERA journal ranking and highlights the poor correlation between ERA rankings and other acknowledged metrics of journal standing. It highlights the need for a reasonable representation of journals ranked as A* in each scientific discipline.
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Calibrating the self-thinning frontier
09/2009;
Calibration of the self-thinning frontier in even-aged monocultures is hampered by scarce data and by subjective decisions about the proximity of data to the frontier. We present a simple model that applies to observations of the full trajectory of stand mean diameter across a range of densities not... [more] Calibration of the self-thinning frontier in even-aged monocultures is hampered by scarce data and by subjective decisions about the proximity of data to the frontier. We present a simple model that applies to observations of the full trajectory of stand mean diameter across a range of densities not close to the frontier. Development of the model is based on a consideration of the slope s=ln(Nt/Nt 1)/ln(Dt/Dt 1) of a log-transformed plot of stocking Nt and mean stem diameter Dt at time t. This avoids the need for subjective decisions about limiting density and allows the use of abundant data further from the self-thinning frontier. The model can be solved analytically and yields equations for the stocking and the stand basal area as an explicit function of stem diameter. It predicts that self-thinning may be regulated by the maximum basal area with a slope of -2. The significance of other predictor variables offers an effective test of competing self-thinning theories such Yoda's -3/2 power rule and Reineke's stand density index. Comment: Typos corrected, missing reference added
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Tree diameter, height and stocking in even-aged forests
04/2009;
Empirical observations suggest that in pure even-aged forests, the mean diameter of forest trees (D, diameter at breast height, 1.3 m above ground) tends to remain a constant proportion of stand height (H, average height of the largest trees in a stand) divided by the logarithm of stand density (N, ... [more] Empirical observations suggest that in pure even-aged forests, the mean diameter of forest trees (D, diameter at breast height, 1.3 m above ground) tends to remain a constant proportion of stand height (H, average height of the largest trees in a stand) divided by the logarithm of stand density (N, number of trees per hectare): D = beta (H-1.3)/Ln(N). Thinning causes a relatively small and temporary change in the slope beta, the magnitude and duration of which depends on the nature of the thinning. This relationship may provide a robust predictor of growth in situations where scarce data and resources preclude more sophisticated modelling approaches. Comment: 15 pages, 8 figures. Annals of Forest Science, in press
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Resource inventory for conversion modelling
Forest growth and timber quality: Crown models and simulation methods for sustainable forest management; 01/2009
Foresters routinely estimate the economic potential of a standing forest resource as lumber. It is usual to consider the straightness and size of a tree to estimate gross recovery and the range of lumber products that might be produced. However, such estimates are usually subjective and depend on th... [more] Foresters routinely estimate the economic potential of a standing forest resource as lumber. It is usual to consider the straightness and size of a tree to estimate gross recovery and the range of lumber products that might be produced. However, such estimates are usually subjective and depend on the knowledge and experience of the assessor. Several conversion modeling packages are available to assist with such appraisals, but these require an established library of log data, or require detailed and expensive log measurements. Fortunately, many tree attributes that influence lumber out-turn can be easily and objectively appraised, and these easy-to-measure attributes can be used to infer a larger suite of log characteristics. This paper briefly describes a computer-based conversion modelling system that emulates components of a wood-processing system and enables users to create a custom wood-processing facility producing lumber, veneer, or other products. It examines the attributes of trees that need to be quantified for such simulation to proceed, describes how routine timber cruising can record these details, and discusses how a user may modify these attributes to reflect different silvicultural regimes. It also describes the accounting module which enables detailed financial analysis of conversion strategies, and of the whole value chain. The system challenges forest managers to examine silvicultural options in a broader context, focusing not on a “better log”, but on creating more value in the lumber marketplace.
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A robust growth model for smallholder tree plantations
End-of-Project Workshop, ACIAR ASEM/2003/052 Improving Financial Returns to Smallholder Tree Farmers in the Philippines, Sabin Resort Hotel, Ormoc City, Leyte; 01/2009
Information is a prerequisite for wise forest management decisions, but is inadequate in many situations, especially in the context of small non-industrial forest growers. This paper presents a series of robust functions able be calibrated with sparse data, and integrated into a simple spreadsheet-b... [more] Information is a prerequisite for wise forest management decisions, but is inadequate in many situations, especially in the context of small non-industrial forest growers. This paper presents a series of robust functions able be calibrated with sparse data, and integrated into a simple spreadsheet-based smallholder plantation growth model designed to assist silvicultural decisions in smallholder plantations. A case study with Gmelina arborea is presented.
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12.92Impact points
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Ranking forestry journals using the h-index
01/2008;
An expert ranking of forestry journals was compared with journal impact factors and h-indices computed from the ISI Web of Science and internet-based data. Citations reported by Google Scholar appear to offer the most efficient way to rank all journals objectively, in a manner consistent with other ... [more] An expert ranking of forestry journals was compared with journal impact factors and h-indices computed from the ISI Web of Science and internet-based data. Citations reported by Google Scholar appear to offer the most efficient way to rank all journals objectively, in a manner consistent with other indicators. This h-index exhibited a high correlation with the journal impact factor (r=0.92), but is not confined to journals selected by any particular commercial provider. A ranking of 180 forestry journals is presented, on the basis of this index.
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On the robustness of the h-index
02/2007;
The h-index (Hirsch, 2005) is robust, remaining relatively unaffected by errors in the long tails of the citations-rank distribution, such as typographic errors that short-change frequently-cited papers and create bogus additional records. This robustness, and the ease with which h-indices can be ve... [more] The h-index (Hirsch, 2005) is robust, remaining relatively unaffected by errors in the long tails of the citations-rank distribution, such as typographic errors that short-change frequently-cited papers and create bogus additional records. This robustness, and the ease with which h-indices can be verified, support the use of a Hirsch-type index over alternatives such as the journal impact factor. These merits of the h-index apply to both individuals and to journals.
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Bias in the journal impact factor
01/2007;
The ISI journal impact factor (JIF) is based on a sample that may represent half the whole-of-life citations to some journals, but a small fraction (<10%) of the citations accruing to other journals. This disproportionate sampling means that the JIF provides a misleading indication of the true im... [more] The ISI journal impact factor (JIF) is based on a sample that may represent half the whole-of-life citations to some journals, but a small fraction (<10%) of the citations accruing to other journals. This disproportionate sampling means that the JIF provides a misleading indication of the true impact of journals, biased in favour of journals that have a rapid rather than a prolonged impact. Many journals exhibit a consistent pattern of citation accrual from year to year, so it may be possible to adjust the JIF to provide a more reliable indication of a journal's impact.
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Effects of Selection Logging on Rainforest Productivity
01/2007;
An analysis of data from 212 permanent sample plots provided no evidence of any decline in rainforest productivity after three cycles of selection logging in the tropical rainforests of north Queensland. Relative productivity was determined as the difference between observed diameter increments and ... [more] An analysis of data from 212 permanent sample plots provided no evidence of any decline in rainforest productivity after three cycles of selection logging in the tropical rainforests of north Queensland. Relative productivity was determined as the difference between observed diameter increments and increments predicted from a diameter increment function which incorporated tree size, stand density and site quality. Analyses of variance and regression analyses revealed no significant decline in productivity after repeated harvesting. There is evidence to support the assertion that if any permanent productivity decline exists, it does not exceed six per cent per harvest.
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Improved timber inventory and strategic forest planning in Papua New Guinea
01/2005; Bureau of Rural Sciences, Canberra, and Forest Research Institute, Lae.
Following (13)
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Pieter Zuidema
Wageningen University -
Mila Bristow
Charles Darwin University -
Adrian Miller
Southern Cross University -
Rafael Repiso
ESCO - University of Granada -
Sisira Ediriweera
Southern Cross University
Topics (1)
