Search

To understand the potential of forests to adapt to wildfire, we studied the genetic architecture of fire-related structural, damage and recovery traits in a globally important Australian forest tree species, Eucalyptus globulus. Fourteen traits were evaluated in an outcrossed F2 population in a field trial in Tasmania, Australia, which was burnt by a wildfire 14 years after planting. The trial also included open-pollinated families of the grandparental dwarf and tall ecotypes used to produce the F2 population. We studied the phenotypic correlations within the F2 population and performed quantitative trait loci (QTL) analyses using a linkage map comprised of 472 markers. Ecotype comparisons revealed that almost all traits were under genetic control, with trees of the dwarf ecotype significantly more damaged and mainly recovering from lignotubers, whereas tall ecotype trees mainly recovered from epicormic resprouts extending for a variable height up the stem. Within the F2, tree size was negatively correlated with fire damage and positively correlated with recovery. Genetic control of fire-related traits was confirmed by the detection of 38 QTL in the F2 population. These QTL accounted for 4 to 43% of the phenotypic variation in these traits. Several QTL co-located and likely reflect pleiotropic effects. However, many independent QTL were detected, including QTL for crown consumption and trunk scorch, epicormic resprouting, resprout herbivory, and seedling establishment. The QTL detected argue that many genetically controlled mechanisms are responsible for variation in fire damage and recovery. [ABSTRACT FROM AUTHOR]

Ecosystems are influenced by multiple drivers, which shape ecosystem state and biodiversity. In some ecosystems, interactions and feedbacks among drivers can produce traps that confine an ecosystem to a particular state or condition and influence processes like succession. A range of traps has been recognized, with one of these – "a landscape trap" first proposed a decade ago for the tall, wet Mountain Ash and Alpine Ash forests of Victoria, south-eastern Australia. Under such a trap, young flammable forest is at high risk of reburning at high severity, thereby precluding stand maturation, and potentially leading to ecosystem collapse. These young forests are more common because recurrent wildfire and widespread clearcutting have transformed historical patterns of forest cover from widespread old-growth with small patches of regrowth embedded within it, to the reverse. Indeed, approximately 99% of the montane ash ecosystem is now relatively young forest. Based on new empirical insights, we argue that at least three key inter-related pre-conditions underpin the development of a landscape trap in montane ash forests. A landscape trap has been sprung in these forests because the pre-conditions for its development have been met. We show how inter-relationships among these pre-conditions, leading to frequent high-severity fire, interacts with life history attributes (e.g., time to viable seed production) to make montane ash forests (e.g., which have been highly disturbed through logging and frequent fire) vulnerable to ecosystem collapse. We conclude with the ecological and resource management implications of this landscape trap and discuss how the problems created might be rectified. [ABSTRACT FROM AUTHOR]

We present a method and case study to predict and map the likelihood of wildfires spreading to the urban interface through statistical analysis of past fire patterns using 15 000 lines from 677 fires with known ignition points and date and random potential end points on the urban interface of Sydney, Australia. A binomial regression approach was used to model whether the fire burnt to the end point of the lines as a function of measures of distance, fuel, weather and barriers to spread. Fire weather had the strongest influence on burning likelihood followed by the percentage of the line that was forested, distance and time since last fire. Fuel treatments would substantially reduce risk from fires starting 1-4 km away from the interface. The model captured 90% of variation in burning with 98% predictive accuracy on test data and was not affected by spatial autocorrelation. We apply the method to map fire risk in Sydney and discuss how the method could be expanded to estimate total risk (from ignition to impact on assets). The method has considerable promise for predicting risk, especially as a complement to simulation methods. [ABSTRACT FROM AUTHOR]

Indigenous species of actinorhizal plants of Casuarinaceae, Elaeagnaceae and Rhamnaceae are found in specific regions of Australia. Most of these plants belong to Casuarinaceae, the dominant actinorhizal family in Australia. Many of them have significant environmental and economical value. The other two families with their indigenous actinorhizal plants have only a minor presence in Australia. Most Australian actinorhizal plants have their native range only in Australia, whereas two of these plants are also found indigenously elsewhere. The nitrogen-fixing ability of these plants varies between species. This ability needs to be investigated in some of these plants. Casuarinas form a distinctive but declining part of the Australian landscape. Their potential has rarely been applied in forestry in Australia despite their well-known uses, which are being judiciously exploited elsewhere. To remedy this oversight, a programme has been proposed for increasing and improving casuarinas that would aid in greening more regions of Australia, increasing the soil fertility and the area of wild life habitat (including endangered species). Whether these improved clones would be productive with local strains of Frankia or they need an external inoculum of Frankia should be determined and the influence of mycorrhizal fungi on these clones also should be investigated. [ABSTRACT FROM AUTHOR]