Puccinia psidii, the causal agent of myrtle rust, was first recorded from Latin America more than 100 years ago. It occurs on many native species of Myrtaceae in Latin America and also infects non-native plantation-grown Eucalyptus species in the region. The pathogen has gradually spread to new areas including Australia and most recently South Africa. The aim of this study was to consider the susceptibility of selected Eucalyptus genotypes, particularly those of interest to South African forestry, to infection by P. psidii. In addition, risk maps were compiled based on suitable climatic conditions and the occurrence of potential susceptible tree species. This made it possible to identify the season when P. psidii would be most likely to infect and to define the geographic areas where the rust disease would be most likely to establish in South Africa. As expected, variation in susceptibility was observed between eucalypt genotypes tested. Importantly, species commonly planted in South Africa show good potential for yielding disease-tolerant material for future planting. Myrtle rust is predicted to be more common in spring and summer. Coastal areas, as well as areas in South Africa with subtropical climates, are more conducive to outbreaks of the pathogen.

PREFACE and 2.0 UPGRADE INFORMATIONAs the authors of FRAGSTATS, we are VERY concerned about the potential for misuse of this program. Like most tools, FRAGSTATS is only as "good" as the user. FRAGSTATS crunches out a lot of numbers about the input landscape. These numbers can easily become "golden" in the hands of uninformed users. Unfortunately, the "garbage in-garbage out" axiom applies here. We have done our best in the documentation to stress the importance of defining landscape, patch, matrix, and landscape context at a scale and in a manner that is relevant and meaningful to the phenomenon under consideration. Moreover, we have stressed the importance of understanding the exact meaning of each metric before it is used. These and other important considerations in any landscape structural analysis are discussed in the documentation. We strongly urge you to read the entire documentation, especially the section on Key Concepts and Terminology, before ever running FRAGSTATS.We wish to remind users that we are not in the commercial software marketing business. We are scientists who recognized the need for a tool like FRAGSTATS to assist us in our research on landscape ecological issues. Therefore, we do not wish to spend a great deal of time consulting on trivial matters concerning the use of FRAGSTATS. However, we do recognize an obligation to provide some level of information support. Of course, we welcome and encourage your criticisms and suggestions about the program at all times. We will welcome questions about how to run FRAGSTATS or interpret the output only after the user has read the entire documentation. This is only fair and will eliminate many trivial questions. Finally, we are always interested in learning about how others have applied FRAGSTATS in ecological investigations and management applications. Therefore, we encourage you to contact us and describe your application after using FRAGSTATS.This release of FRAGSTATS (version 2.0) differs from the previous version in only minor ways. Several "bugs" have been corrected. The most important change is the added option to treat a specified proportion of the landscape boundary and background edge (instead of just all or none) as true edge in the edge metrics (bound_wght option). This fraction also is used as the edge contrast weight for landscape boundary and background edge segments in the calculation of edge contrast metrics. In addition, the convention for naming the output file containing patch ID's in the raster version has been modified to comply with DOS requirements on a PC (id_image option). Similarly, the output file name extensions in the PC raster version have been shortened and renamed to comply with DOS requirements and to avoid conflicts with ERDAS conventions (out_file). The Nearest-neighbor algorithm has been modified slightly to compute actual edge-to-edge distance (previous version used cell midpoints rather than edge).We hope that FRAGSTATS is of great assistance in your work and we look forward to hearing about your applications. A...

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Plantation forests were originally established in South Africa to meet an increasing demand for solid wood products as there was a limited supply from native forests. The majority of the commercial softwood plantations were established with Mexican Pinus patula. Since growing conditions are known to impact tree growth, tree form, and wood quality of P. patula, sample plots were established over a cross-section of plantations in the Lowveld Escarpment and Highveld forestry regions of South Africa that covered an array of geologies and altitudes. Each sample plot was classified according to soil properties, rainfall, and temperature, and trees within the plots were measured for growth, form, and wood properties. Soil, growing days, and temperature were found to have little impact on tree form and wood properties. However, rainfall and specifically, spring rainfall, was found to have a highly significant impact on late wood formation, proportion of juvenile core, and wood density. In addition, tree height was found to be strongly correlated with maximum annual temperature.

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