Trevor H. Booth

Niche analysis and tree species introduction

Abstract A method to determine the climatic requirements of tree species is outlined and related to the concept of multidimensional niche. The Bioclimate Prediction System devised by Nix, Busby and Hutchinson is used to analyse the bioclimatic component of the ‘realized niche’ of the species. The bioclimatic component of the ‘fundamental niche’ is then estimated using data from field trials outside the natural range. The method is demonstrated using the following eucalypt species: Eucalyptus citrodora, E. cladocalyx, E. fastigata, E. globulus spp. globulus, E. gomphocephala, E. grandis, E. maculata, E. paniculata, E. regnans, E. resinifera, E. robusta, E. sideroxylon and E. tereticornis . The bioclimates of their natural distributions in Australia are compared with conditions at trial sites in Africa. The method offers an explicit procedure for describing bioclimatic requirements and should assist the selection of appropriate species for trials.

Estimating monthly mean valuesof daily total solar radiation for Australia

Abstract Monthly mean values of daily total solar radiation were obtained for the widest possible network acrossAustralia. Bureau of Meteorology sources yielded 11 stations with long term records of both measured daily total solar radiation and sunshine hour values. Monthly modified Angstrom equations were developed from these data and used to estimate radiation values for a further 90 stations in the Bureau of Meteorology network that had sunshine hour data. Measured daily total solar radiation data were obtained from a variety of sources mostly outside the Bureau of Meteorology network for an additional 33 stations. Finally, estimates of solar radiation from detailed cloud cover data were used for a further 12 stations, selected because they filled in significant gaps in coverage. These various sources yielded a total of 146 sets of monthly mean values of daily total solar radiation. For each month optimal surfaces, which were functions of position only, were fitted to this network of values using Laplacian smoothing splines with generalized cross validation. Residuals from the fitted surfaces at the data points were acceptably low. Fitted surfaces which included, in addition to position variables, a cloudiness index based on a transform of mean monthly precipitation further reduced these residuals. The latter fitted surfaces permit estimation of monthly mean values of total daily solar radiation at any point on the continent with a root mean square predictive error of no more than 1.25 MJ m−2 day−1 (5.2 per cent of the network mean) in summer and 0.74 MJ m−2 day−1 (5.5 per cent of the network mean) in winter.

Mapping regions climatically suitable for particular tree species at the global scale

Abstract A microcomputer program is described which can indicate locations satisfying up to six climatic criteria important for tree species selection. Three of the worlds most important plantation species, Eucalyptus grandis, Eucalyptus tereticornis and Pinus radiata are used to demonstrate the program, with assessments being made for over 15 000 locations for each species. The program can assist in checking existing descriptions of climatic requirements. With the aid of explicit methods of analysis or expert advice it can also be used to develop improved descriptions of climatic requirements.

Mapping regions climatically suitable for particular species: an example using Africa

Abstract Data from approximately a thousand irregularly spaced meteorological stations were analysed to produce a climatic database for 10 187 points in a regular half-degree grid covering Africa. From the monthly mean values of average daily maximum temperature, average daily maximum temperature and total precipitation, six factors important for tree species selection were calculated for each point. These included measures such as mean annual temperature, maximum temperature of the hottest month, mean annual precipitation and rainfall regime. A microcomputer program was written which enables this database to be interrogated. Maps can be generated which indicate regions climatically suitable for particular species.

Grid matching: A new method for homoclime analysis

Abstract A method to assist species introductions is described. The technique compares long-term mean climatic conditions at a target location with conditions at sites in a regular grid. To illustrate the method, a location in Africa and a location in South America are compared with 2795 sites in a half-degree latitude-longitude grid across Australia. The results of trials of Australian tree species and provenances at these two locations are compared with the results of the climatic analyses. It is concluded that the identification of locations with similar climates, using the grid matching method, could assist the choice of species and provenances for trial at other target sites.

Eucalypts and Their Potential for Invasiveness Particularly in Frost-Prone Regions

Eucalypts are being considered for biofuel production in the Lower Coastal Plain of the United States. The evolution of eucalypts in Australia has equipped some species to be successful in plantations and has also influenced their potential as invasive species. More than 200 eucalypt species have been evaluated in many countries around the world. Generally eucalypts have proved to have limited invasive potential for a number of reasons, including their poor dispersal capabilities. Two regions with climates similar to the Lower Coastal Plain of the United States are identified in Argentina and China. Frosts, particularly sudden frosts, are an important limitation for eucalypts in these regions, so existing plantations are very limited. However, invasive eucalypts do not appear to be a major problem in other regions of either country. The use of carefully selected frost-tolerant species and the development of genetically modified eucalypts may now open up more frost-affected areas for eucalypt plantations. Some control actions may be necessary and research needs are outlined, but it is concluded that experience in other regions around the world suggests that eucalypts are likely to be a relatively low risk as invasive species in the Lower Coastal Plain.

Identifying climatically suitable areas for growing particular trees in Latin America

Abstract Six climatic factors important for tree species selection were calculated from monthly mean values of maximum temperature, minimum temperature and precipitation estimated for 66,688 locations in a 10-min (18.5 km approx.) grid across Latin America. These included measures such as mean annual temperature, mean maximum temperature of the hottest month, mean annual precipitation and rainfall regime. Three microcomputer programs were written to enable the database to be interrogated for Latin America as a whole, and also for the northern and southern regions. The use of the programs is demonstrated with Acacia mearnsii, Eucalyptus camaldulensis (northern provenances) and Pinus radiata. It is concluded that the programs can assist identifying climatically suitable areas for these trees and also assist developing improved descriptions of climatic requirements for other species and provenances.

Assessing possible impacts of climate change on species important for forestry in Vietnam

The likely effects on two tree species of a range of scenarios of climatic and atmospheric change expected by the year 2050 are investigated using a climatic mapping program, a simple simulation model and a process-based simulation model. Styrax tonkinensis is a native species for which relatively little information is available. Acacia mangium is an introduced species, which is important for pulp production in several other countries, and for which there is considerable information for growth and utilization. A climatic mapping program is used to show areas which may be suitable for these species under present and predicted conditions. Two simulation models are used to investigate likely effects on productivity of the two species for a range of climatic change scenarios for Hanoi and Ho Chi Minh City. The estimated changes in production are predicted to be relatively small, though uncertainities associated with the simulations are quite high. However, the models highlight areas where more data are needed and also suggest some key regions in Vietnam which would be worth monitoring to detect early signs of the effects of climatic and atmospheric change.

Incorporation of indices of annual climatic variation into growth models for Pinus radiata

Abstract Data for Pinus radiata D. Don grown in the Australian Capital Territory (ACT) are used to show that annual indices of growth potential can be successfully incorporated into Schumacher projection models of stand basal area growth. Significant reductions in the error mean squares of the models can be obtained by including a simple index such as annual rainfall, but best results were obtained by incorporating estimates of photosynthesis simulated with a detailed process-based model: BIOMASS. In the ACT it was sufficient to estimate the growth index at a single location within the forest estate. Reductions in error mean squares due to the incorporation of temporal variables were about twice as large as those obtained by incorporating spatial variables such as geological substrate, site index or indices of soil development. The gains due to the two classes of variables were approximately additive. The new models improve the descriptive power of the Schumacher model. Short-term predictions made with the models should be more accurate than those obtained with the traditional model and should be particularly useful for updating stand inventories. The new models would be most applicable to regions where there is substantial variation in climatic factors between growing seasons and where the object species is responsive to those factors. A key result is that the temporal variation in the growth indices need not be assessed at each sample plot used to calibrate the model nor each inventory plot to which the model is applied. The temporal variation is regional in nature; consequently, it can be characterised by studies at a relatively few number of sites. This leads the way to new avenues for forest modelling.

Assessing vulnerable areas for Puccinia psidii (eucalyptus rust) in Australia

This research note describes a model prepared before the arrival of Puccinia psidii in Australia that identifies areas where the rust disease may be most likely to occur. The initial spread of P. psidii since April 2010 has corresponded well with the highly vulnerable areas identified in eastern coastal Australia.