Sub-tropical exotic pine taxa, growth, form and wood properties comparisons across multiple sites in coastal Queensland in: thinning and clearfall age trials; in family and clonal hybrid pine trials and in a genetics x fertiliser x weed control trial.

This project supports improved management and deployment of sub-tropical pines for solid wood products. It had three major objectives, in respect of both growth rate and standing tree wood properties: 1) to compare major and potential pine species and hybrids for south-east Queensland; 2) to investigate selection strategies for identifying improved families and clones, and make selections; and, 3) to evaluate both the separate and combined effects of fertiliser application, weed control and genetic improvement in a young hybrid pine trial

Teleparallel Gravity and Dimensional Reductions of Noncommutative Gauge Theory

We study dimensional reductions of noncommutative electrodynamics on flat space which lead to gauge theories of gravitation. For a general class of such reductions, we show that the noncommutative gauge fields naturally yield a Weitzenbock geometry on spacetime and that the induced diffeomorphism invariant field theory can be made equivalent to a teleparallel formulation of gravity which macroscopically describes general relativity. The Planck length is determined in this setting by the Yang-Mills coupling constant and the noncommutativity scale. The effective field theory can also contain higher-curvature and non-local terms which are characteristic of string theory. Some applications to D-brane dynamics and generalizations to include the coupling of ordinary Yang-Mills theory to gravity are also described.Comment: 31 pages LaTeX; References adde

Decision support software tools for pine plantations

Software tools that link silviculture, wood quality and grading of structural timber are being developed to support the managers of Queensland's commercial pine estate. The tools allow the evaluation of alternative silvicultural scenarios, in terms of internal rate of return and net present value. This paper describes the decision support project that will bring together software tools that grade sawn timber outputs from a conversion model, assign revenues, link to costs associated with a specific silvicultural scenario, and finally generate internal rates of return and net present values. These software tools provide a powerful decision support system that will pass on significant benefits to plantation managers. They will capture several decades of research to maximise the benefits to forest growers and processors by linking silviculture, wood quality and grading of structural timber

Predicting wood value in Queensland Caribbean pine plantations using a decision support system

A decision support system has been developed in Queensland to evaluate how changes in silvicultural regimes affect wood quality, and specifically the graded recovery of structural timber. Models of tree growth, branch architecture and wood properties were developed from data collected in routine Caribbean pine plantations and specific silvicultural experiments. These models were incorporated in software that simulates the conversion of standing trees into logs, and the logs into boards, and generates detailed data on knot location and basic density distribution. The structural grade of each board was determined by simulating the machine stress-grading process, and the predicted graded recovery provided an indicator of wood value. The decision support system improves the basis of decision-making by simulating the performance of elite genetic material under specified silvicultural regimes and by predicting links between wood quality and general stand attributes such as stocking and length of rotation

The effect of initial spacing and thinning on wood quality and graded sawn recovery of mature Caribbean pine grown in Queensland.

A mature Caribbean pine (Pinus caribaea var. hondurensis) silviculture experiment provided initial square spacing treatments of 1.8 m2, 2.4 m2, 3.0 m2 and 3.6 m2 (equal to 3088, 1737, 1111 and 772 stems/ha) that were thinned at age 10 years to 600, 400 and 200 stems/ha, retaining an unthinned control for each initial spacing. The trial was destructively sampled at age of 28 years and discs taken along 8 various stem heights were analysed for variation in basic density and SilviScan wood properties. In addition, the logs from ten stocking × thinning treatments were processed in a sawing study. Results indicate thinning effects were generally more pronounced than initial spacing effects. Fast growing trees produced wood with significantly higher average wood densities and higher average stiffness values. Detailed SilviScan densitometry results obtained radially and at various stem heights enabled construction of tree maps for wood properties, providing insights into the variation in juvenile to mature wood proportion across the initial and post-thinning stocking treatments studied. Dried dressed recovery was strongly related to tree size, and log value decreased consistently from butt to top logs across all treatments. The estimated value per hectare was highest in unthinned plots due to values being multiplied by high stem numbers per hectare. However, a complete economic analysis considering all cost structures is required to investigate the optimal silviculture to maximise economic returns to growers and processors. Improved understanding of the relationship between initial spacing, post-thinning stocking and wood and end-product quality should help to customize future forest management strategies required to produce better quality wood and wood products

Information theory and hypothesis testing: a call for pluralism

Summary 1. A major paradigm shift is occurring in the approach of ecologists to statistical analysis. The use of the traditional approach of null-hypothesis testing has been questioned and an alternative, model selection by information–theoretic methods, has been strongly promoted and is now widely used. For certain types of analysis, information–theoretic approaches offer powerful and compelling advantages over null-hypothesis testing. 2. The benefits of information–theoretic methods are often framed as criticisms of null-hypothesis testing. We argue that many of these criticisms are neither irremediable nor always fair. Many are criticisms of the paradigm's application, rather than of its formulation. Information–theoretic methods are equally vulnerable to many such misuses. Care must be taken in the use of either approach but users of null-hypothesis tests, in particular, must greatly improve standards of reporting and interpretation. 3. Recent critiques have suggested that the distinction between experimental and observational studies defines the limits of the utility of null-hypothesis testing (with the paradigm being applicable to the former but not the latter). However, we believe that there are many situations in which observational data are collected that lend themselves to analysis under the null-hypothesis testing paradigm. We suggest that the applicability of the two analytical paradigms is more accurately defined by studies that assess univariate causality (when null-hypothesis testing is adequate) and those that assess multivariate patterns of causality (when information–theoretic methods are more suitable). 4. Synthesis and applications. Many ecologists are confused about the circumstances under which different inferential paradigms might apply. We address some of the major criticisms of the null-hypothesis testing paradigm, assess those criticisms in relation to the information–theoretic paradigm, propose methods for improving the use of null-hypothesis testing, and discuss situations in which the use of null-hypothesis testing would be appropriate. We urge instructors and practitioners of statistical methods to heighten awareness of the limitations of null-hypothesis testing and to use information–theoretic methods whenever prior evidence suggests that multiple research hypotheses are plausible. We contend, however, that by marginalizing the use of null-hypothesis testing, ecologists risk rejecting a powerful, informative and well-established analytical tool