Showing papers in "Australian Forestry in 2008"

Quantifying error in aerial survey data

Abstract: Aerial survey, also referred to as aerial sketchmapping, is the technique of observing symptoms of forest damage from an aircraft and transferring the information manually onto a base map. Recent high levels of bark beetle mortality across the western United States have generated greater demands for, and more disparate uses of, aerial survey data. While aerial survey data are typically considered to be qualitative in nature, the recent application of the data has driven an interest in assessing its spatial and categorical accuracies quantitatively. This paper describes methods for assessing the accuracy of aerial survey data and discusses several implications and applications related to the error results. The error matrix and kappa (κ) statistic, commonly used to assess accuracies of image classifications in remote sensing, were used to describe errors present in the aerial survey data. Field crews collected ground data that were used to validate the aerial classifications on 233 plots across 17.3 million ha. An additional 24 plots were incorporated into the validation from a complementary project, bringing the total number of plots to 257. Errors within the aerial survey data were found to be acceptable for coarse-scale analyses but excessive for use at fine spatial scales. In addition, this paper discusses the benefits of error analysis which include the quantification of errors for reporting purposes, the inclusion of error rates in the metadata, and the ability to focus training programs and technology development by highlighting classes with the highest error. Finally, the cost associated with accuracy assessment implementation is described and weighed against the benefits.

Development of a model system to predict wildfire behaviour in pine plantations

Abstract: Summary 1 We describe the development of a model system to predict fire behaviour over the full range of potential fire behaviour in the various types of fuel complexes found in exotic pine plantations in relation to environmental conditions. The proposed system integrates a series of sub-models describing surface fire characteristics and crown fire potential (e.g. onset of crowning, type of crown fire and associated rate of spread). The main inputs are wind speed, fine dead fuel moisture content and fuel complex structure (surface fuel bed characteristics, canopy base height and canopy bulk density). The detail with which the model system treats surface and crown fire behaviour allows users to quantify stand ‘flammability’ with stand age for particular silvicultural prescriptions. The application of the model to a case study of thinning treatments in a radiata pine plantation in Victoria is presented. The results highlight the complex interactions that take place between fire behaviour and attendant fuel and weather conditions. Structural changes in the fuel complex introduced by the treatments altered fire behaviour, but no definite reduction and or increase in rate of fire spread was identified. The results illustrate the role that simulation models can play in support of silvicultural and fuel management decision making.

The politics of community participation in natural resource management: lessons from community forestry in Nepal.

Abstract: Summary Australian aid to Nepal and Australian foresters' assistance to Nepalese forestry have been very influential in the recent development of forestry in Nepal, a country widely acknowledged as being at the forefront of community forestry. This paper examines the experience of three Forest Users Groups participating in the Nepalese community forestry program. Using a mix of qualitative and quantitative methods, information was obtained from 72 households, 21 key respondents, 6 focus group discussions and 3 vegetation assessments. The study demonstrates that the condition of forests has improved compared with the highly-degraded state from which most community forests started, but that community forestry may not have produced the significant biodiversity conservation outcomes expected by many of its supporters. Further, the forests were found to be underutilised, largely because powerful actors emphasise protection-oriented management to ensure forest conservation. As a result local communities, partic...

Achievements in forest tree genetic improvement in Australia and New Zealand 10: Pinus radiata in New Zealand

Abstract: Summary Pinus radiata is the subject of much the largest and longest-running tree breeding program in New Zealand. Very intensive plus-tree selection began in the early 1950s, the first seed orchard planting was in 1958, and the first orchard seed was collected in 1968. By 1985 seed orchards could meet the national planting needs, which helped prompt an innovative seed certification scheme. Selection began in local, ‘land-race’ stands. That proved appropriate, but better knowledge led to research on material from the species’ entire natural range and then to further seed importations from natural stands, mainly for future genetic resources. Initial plus-tree selection largely addressed poor tree form in the central North Island. This led to selecting a ‘short-internode’ (‘multinodal’) branching ideotype, with great improvements in general tree form and substantial gains in growth rate. A distinctive portfolio of several breeds, representing different breeding goals, has since been developed for the divers...

The development of static trapping systems to monitor for wood-boring insects in forestry plantations

Abstract: The effectiveness of combinations of panel and funnel static traps with lures in surveillance to detect wood-boring insects in softwood (Pinus) and hardwood (Eucalyptus) plantations was examined. Static trapping systems proved to be an effective tool for monitoring specific pest species such as the wood wasp Sirex noctilio, detecting their presence when more traditional surveillance methods did not. Traps can detect a broad range of wood-boring species, enabling detection of low (pre-outbreak) populations of pest species. The panel and funnel traps were found to be at least as effective as Malaise trapping, light trapping and insect rearing in determining the wood-boring insects present in a plantation. A strategy for the operational deployment of static traps for detecting developing outbreaks has still to be finalised - full deployment in all susceptible plantations is unlikely to be cost-effective, but sub-sampling susceptible plantations is feasible. The development of surveillance systems using static traps to detect exotic wood-borers is discussed.

Aerial detection surveys in the United States

Abstract: Summary Aerial detection survey, also known as aerial sketchmapping, involves observing forest change events from an aircraft and documenting them manually onto a map. Data from aerial surveys have become an important component of the Forest Health Monitoring program, a national program designed to determine the status, changes and trends in indicators of forest condition. Aerial surveys are an effective and economical means of monitoring and mapping common forest disturbances such as tree damage and tree mortality caused by insects and disease. Information from aerial surveys can be considered the first stage in a multi-stage or multi-phase sampling design. Aerial sketchmap surveys have been used in the United States since the 1940s. Today, the United States Department of Agriculture (USDA) Forest Service, State and Private Forestry, Forest Health Protection, together with other federal, state and county cooperators conducts annual sketchmap surveys across all land ownerships. Between 2002 and 2006 an an...

Development of hazard site surveillance programs for forest invasive species: a case study from Brisbane, Australia

Abstract: Hazard site surveillance is a system for post-border detection of new pest incursions, targeting sites that are considered potentially at high risk of such introductions. Globalisation, increased volumes of containerised freight and competition for space at domestic ports means that goods are increasingly being first opened at premises some distance from the port of entry, thus dispersing risk away from the main inspection point. Hazard site surveillance acts as a backstop to border control to ensure that new incursions are detected sufficiently early to allow the full range of management options, including eradication and containment, to be considered. This is particularly important for some of the more cryptic forest pests whose presence in a forest often is not discovered until populations are already high and the pest is well established. General requirements for a hazard site surveillance program are discussed using a program developed in Brisbane, Australia, in 2006 as a case study. Some early results from the Brisbane program are presented. In total 67 species and 5757 individuals of wood-boring beetles have been trapped and identified during the program to date. Scolytines are the most abundant taxa, making up 83% of the catch. No new exotics have been trapped but 19 of the species and 60% of all specimens caught are exotics that are already established in Australia.

Existing fire behaviour models under-predict the rate of spread of summer fires in open jarrah (Eucalyptus marginata) forest

Abstract: Fire behaviour data from Project Vesta experimental fires were used to evaluate the fire behaviour relationship on the Forest Fire Danger Meter (FFDM), the Forest Fire Behaviour Tables (FFBT) for Western Australia and the fire spread model of Burrows (1999) for predicting the rate of spread of fires in jarrah (Eucalyptus marginata) forest under dry summer conditions. Experimental fires were conducted at two sites in southwestern Australia under conditions of moderate to high forest fire danger with fine fuel moisture contents of 6-9% oven dry weight and wind speeds up to 20 km h-1 (at 10 m in the open). Fuels ranged in age from 2 to 22 y since the last fire and had understorey shrub layers from 0.5 to 2.0 m tall. Mean rates of spread for experimental fires were 392 m h-1 and 405 m h-1 at the low and tall shrub sites respectively, with the fastest fires spreading at close to 1200 m h-1. Fires spread two to three times faster than predicted by the FFDM and FFBT fire spread models, and up to five times faster than predicted by the spread model of Burrows. Both the FFDM and FFBT models predicted fire spread better at the low shrub fuel site and when wind speeds were 12.5 km h-1. We argue that existing fire behaviour models under-predict because they were developed using data from fires that had not achieved a quasi-steady rate of spread, whereas the line ignition technique used during Project Vesta experiments resulted in fires travelling at a speed closer to their potential rate of spread for the prevailing conditions. Existing guides remain valid for predicting spread during the early stages of fire growth when fires are developing from a point ignition and the headfire remains narrow.

Developing African mahogany (Khaya senegalensis) germplasm and its management for a sustainable forest plantation industry in northern Australia: progress and needs

Abstract: The demonstrated wide adaptability, substantial yield potential and proven timber quality of African mahogany (Khaya senegalensis) from plantings of the late 1960s and early 1970s in northern Australia have led to a resurgence of interest in this high-value species. New plantations or trials have been established in several regions since the early 1990s - in four regions in north Queensland, two in the Northern Territory and one in Western Australia. Overall, more than 1500 ha had been planted by early 2007, and the national annual planting from 2007-2008 as currently planned will exceed 2400 ha. Proceedings of two workshops have summarised information available on the species in northern Australia, and suggested research and development (R and D) needs and directions. After an unsustained first phase of domestication of K. senegalensis in the late 1960s to the early 1970s, a second phase began in northern Australia in 2001 focused on conservation and tree improvement that is expected to provide improved planting stock by 2010. Work on other aspects of domestication is also described in this paper: the current estate and plans for extension; site suitability, soils and nutrition; silviculture and management; productivity; pests and diseases; and log and wood properties of a sample of superior trees from two mature plantations of unselected material near Darwin. Some constraints on sustainable plantation development in all these fields are identified and R and D needs proposed. A sustained R and D effort will require a strategic coordinated approach, cooperative implementation and extra funding. Large gains in plantation profitability can be expected to flow from such inputs.

Achievements in forest tree improvement in Australia and New Zealand 9. Genetic improvement of Eucalyptus nitens in Australia

Abstract: Summary Eucalyptus nitens is the second most widely planted eucalypt species in Australia. The species is principally grown for the production of pulpwood but substantial areas are also managed for solid-wood production. The first large-scale E. nitens progeny trials were established in the 1970s and up to two cycles of breeding have since been completed. Estimates of genetic gains achieved through breeding are not routinely published, but numerous genetic gain trials have been established. Advances in the understanding of E. nitens genetic architecture and reproductive biology have been integrated into operational breeding and deployment programs. Despite extensive research into alternative deployment strategies, improved E. nitens genotypes are almost universally deployed as seedlings derived from open-pollinated seed-orchards.

Quarantine Risks Associated with Solid Wood Packaging Materials Receiving ISPM 15 Treatments

Abstract: Surveys on solid wood packaging material (SWPM) such as crates, dunnage or pallets (pieces) displaying the ISPM 15 stamp under the International Standards for Phytosanitary Measures No. 15: Guidelines for Regulating Wood Packaging Material in International Trade (ISPM 15) were conducted by the Australian Quarantine and Inspection Service (AQIS) during 2005 and 2006 at various locations in Australia. These surveys were to evaluate the quarantine risks and or performance of SWPM receiving ISPM 15 treatments and the proportion of untreated SWPM used in air and break-bulk cargo. About 20 000 crates, dunnage or pallets (pieces) used in containerised sea cargo were inspected in Sydney, Melbourne and Brisbane. Nine percent of SWPM surveyed exhibited something of quarantine concern; of this bark represented 8.5%, fungi 5.9% and live insects, frass and soil, 3.2%, 2.8% and 1.7% respectively - these categories not being mutually exclusive. Before the introduction of mandatory treatment requirements, a large amount of SWPM entering by less-frequented routes such as air and break-bulk cargo was not ISPM 15-compliant or did not receive any treatment. Ongoing review of the ISPM 15 standard and its existing treatments, as well as auditing regimes for treatment providers, are essential to continue to improve the standard and reduce the risk of pests using SWPM as an entry pathway.

Forest health surveillance in New South Wales, Australia

Abstract: Summary It has been over a decade since Forests NSW established a forest health survey unit (FHSU), with the first formal surveys beginning in January 1996. The unit was established due to a growing need for more formal detection, delineation and recording of pest and disease outbreaks, both endemic and exotic, and to ensure continuation of forest health expertise within Forests NSW. Forest health surveys are concentrated on eucalypt and Pinns plantations. For pine plantations (predominantly Pinus radiata), aerial and follow-up ground surveys are conducted of most of the plantation estate annually. For eucalypts (Eucalyptus spp. and Corymbia spp.) ground surveys have been the predominant methodology, due to the dispersed nature of the estate, with aerial surveys becoming a regular feature only in the past few years because of the importance of a new insect pest (a psyllid, Creiis lituratus). The FHSU provides advice on management of detected health problems, and data collected during surveys are used for ...

Growth and Carbon Sequestration Rates at Age Ten Years of Some Eucalypt Species in the Low- to Medium-rainfall Areas of New South Wales, Australia

Abstract: This paper presents the results of a study of tree growth in farm forestry eucalypt plantations in the low -to medium-rainfall (450-700 mm y-1) regions of New South Wales, Australia, in an attempt to estimate the productivity of the plantations. The species measured include Eucalyptus camaldulensis, E. botryoides, E. globulus, E. albens, E. polyanthemos, E. microcarpa, E. melliodora, E. sideroxylon, E. crebra and Corymbia maculata. At age 10 y, mean dominant height (100 tallest trees per hectare) ranged from 7.5 to 18.8 m, mean top basal area (thickest 100 stems ha-1) from 1.5 to 9.2 m2 ha-1, volume from 9.5 to 125.9 m3 ha-1, total above-ground biomass from 12.5 to 105.8 t ha-1, and mean carbon density (above ground) from 11.2 to 35.2 t ha-1.

Population Differentiation within Eucalyptus Obliqua: Implications for Regeneration Success and Genetic Conservation in Production Forests

Abstract: Genetic differentiation at the site level was investigated within Eucalyptus obliqua L'Herit. by comparing the progeny of ecologically distinct populations from two contrasting sites on topographic gradients at each of two localities, Lune and Forestier, in southern Tasmania. Progeny from all four sites of seed collection were planted together in trials at or near each collection site. At the Lune locality there were significant differences in growth rates and susceptibility to leafspotting fungi between progeny grown from seed collected from midslope and plain populations respectively. At the Forestier locality, there were no differences between progeny from gully and ridge populations for growth rate and frost resistance. The gully population, however, had lower susceptibility to infection by leaf spotting fungi and browsing by native mammals than the ridge population. The results indicated that differential selection forces may result in genetic differences between populations of E. obliqua over the scale of hundreds of metres, in addition to the tens or hundreds of kilometres normally associated with broad geographic variation at the ecotypic or provenance level. Variation at the site level has important implications for the conservation of genetic diversity and for the probability of successful regeneration and long-term adaptation and growth within the typically heterogeneous native forest coupes in production forests.

Forest canopy health and stand structure associated with bell miners (Manorina melanophrys) on the central coast of New South Wales

Abstract: Forest attributes including canopy health and stand structure were visually assessed to identify features commonly associated with the bell miner (Manorina melanophrys, Meliphagidae), a cooperatively breeding, insectivorous honeyeater endemic to south-eastern Australia. A stratified random sampling methodology, using a combination of SPOT5 satellite imagery and a 25-m pixel digital altitude model, was used to establish 130 circular plots 40 m in diameter within a 12 800 ha study area in the Watagan mountain range, central coast of New South Wales (NSW). In this study site, the presence of bell miners was significantly associated with unhealthy eucalypt crowns. This supports the proposition that a dieback syndrome known as bell-miner-associated dieback (BMAD) exists in central coastal forests of NSW. Our results also demonstrate a strong association of a sparse eucalypt canopy over a dense lower midstorey with the presence of bell miners. Altitude and fire frequency were negatively correlated with bell miners while the topographical wetness index was positively correlated with bell miners. Logistic regression was used to quantify the effects of a series of explanatory variables including tree species, forest structure variables and selected topographic variables. Although there were significant differences in the ranking of crown condition between eucalypt species, tree species was not selected in the final model. The final variables identified by the logistic regression for the presence of bell miners included sparse eucalypt overstorey cover, dense lower midstorey cover, the absence of young vigorous regrowth trees and higher values of the topographic wetness index. Based on the results of our survey we discuss practical options for managing the forest dieback syndrome associated with bell miners in the central coast region of NSW and an approach to mapping forests at risk from BMAD.

An estimate of the potential economic impact of pine pitch canker in Australia

Abstract: Summary This paper estimates the economic benefits Australian pine plantations can expect to enjoy if the pine pitch canker fungus can be prevented from entering the country at any time over the next 30 years. It presents a stochastic bioeconomic model that estimates the additional costs imposed by producer behavioural changes as the pathogen enters the country and begins to spread. The avoidance of these large cost and revenue effects can be interpreted as the benefits of exclusion. Our results indicate that delaying the process of entry and spread by as little as two to three years will produce economic benefits of almost $13 million over time.

Integrating plantation health surveillance and wood resource inventory systems using remote sensing

Abstract: Commercial softwood growers in Australia are keen to improve the efficiency and precision of resource inventory underpinning their timber supply commitments. At the same time, they also need to implement forest health strategies which contribute to their environmental management systems and certification process. For example, the Australian Forestry Standard requires forest managers to identify, assess and prioritise any potential damage agents that may impact on forest ecosystem health and vitality. These health programs, however, are often run parallel with, and independently of, resource inventory programs. While most large growers maintain a health surveillance program, their capacity to quantify the impact of damaging agents on stand productivity and wood volume is often limited. Quantification of productivity losses due to biotic and abiotic agents would significantly improve decisions associated with resource scheduling and allocation of resources for pest control and stand amelioration. This paper discusses how remote sensing technologies can provide spatially-explicit data that permit the integration of plantation inventory and health assessments. The emerging diversity of sensor capabilities on both satellite and airborne platforms enables the development of hierarchical monitoring programs that can be customised for individual regions. For example, the coarse-scale sensor MODIS can provide very cheap coverage suitable for frequent temporal condition monitoring (thus identifying areas requiring more detailed attention in a timely manner), whereas the new generation of high-resolution sensors are facilitating a shift from manually mapped stand polygons (e.g. those from aerial sketchmapping and aerial photographic interpretation (API)) to pixel and object-based digital analysis techniques suitable for both crown and stand-level inventory and canopy health assessment on a continuous, broad-scale basis. The application of these new technologies and associated spatial analyses permits the integration of plantation inventory and health assessment, thus providing forest managers with a holistic and cost-effective approach to timber production.

Pest detection surveys on high-risk sites in New Zealand

Abstract: A need for a surveillance system in New Zealand dedicated to early detection of newly-introduced pests has been recognised since the 1950s. Surveys around ports and high-risk sites started in earnest in the 1970s, taking the form of a 'walk in the park'. It was not until the late 1980s that a formal and structured survey system was developed. Data on the efficacy of pest detection surveys were collected from field trials carried out in 1995 and 1999, and based on the latter study a new surveillance system of intensive surveys in small plots was developed. The need for further development of the system was emphasised with the growth in numbers of import transitional facilities in the mid-2000s that spread biosecurity risk far wider than ports. The improvement process is ongoing.

Mountain Ash in Victoria's State Forests Silviculture Reference Manual No. 1 [Book Review]

Abstract: Review(s) of: Mountain Ash in Victoria's State Forests Silviculture Reference Manual No. 1, by Andrew Flint and Peter Fagg, Department of Sustainability and Environment, Melbourne, 2007, 97 Pages, Paperback, ISBN 1 74146 571 0, $22.

Forest health monitoring in the United States: a program overview

Abstract: Summary The Forest Health Monitoring Program in the United States is a science-based, comprehensive monitoring system that provides statistically precise and accurate baseline and forest health trend information to determine detrimental changes or improvements that occur in our forests overtime. This program, initiated in 1990 to provide information on forest health and sustainability, consists of four separate, interrelated activities, including detection monitoring, evaluation monitoring, research on monitoring techniques, and intensive site monitoring. Descriptions and examples are provided for each activity.

Estimating the accuracy of tree ageing methods in mature Eucalyptus obliqua forest, Tasmania

Abstract: Summary Estimates of tree age are important for making management decisions on the tree hollow resource because hollows suitable for fauna occur with greater frequency in older trees. The methods used to age trees vary with the practicalities of obtaining wood samples and the quality of the wood samples available. Ring counting is commonly used on smaller sample sizes when complete wood samples are available. When wood samples are incomplete, a combination of ring counting and extrapolation is often used. When no wood samples are obtained, growth models are generally used to estimate tree age. This paper uses all three methods, including three different growth models, to examine the accuracy of ageing trees. Simple regressions between tree age and diameter at breast height (over bark, dbh) provided the most accurate growth models at a site. Age estimates obtained from such models, however, had unacceptably large errors when few trees were used or when variable growth rates occurred. Under these circumstan...

Forest Health Surveillance in Victoria

Abstract: Forest health surveillance (FHS) has been undertaken in Victorian native forests and plantations on an ad hoc basis since the early 1960s in response to incursions and outbreaks of native and introduced insect pests and plant pathogens, such as sirex wood wasp, Monterey pine aphid, Phytophthora dieback, phasmatids and other defoliators. The purpose of surveillance is to provide a broad overview of forest health and data for land managers to allow them to take appropriate strategic decisions and manage risks to their estate. Early targeted FHS in Victoria consisted mainly of drive-through surveys with aerial surveillance where required to determine the extent of a particular damaging agent. In 1991, a plot-based surveillance system targeting high-risk sites was developed to monitor levels of Dothistroma disease. These plots were used to trigger more intensive surveillance (e.g. aerial) to enable early management intervention once the levels reached predetermined thresholds. In 2001, a broader plot-based monitoring system was implemented for HVP Plantations as part of its risk management program to determine the status, changes and trends in tree health on an annual basis, and provide data for management decisions to control outbreaks threatening the health of plantations. This paper describes the establishment of a plot-based monitoring system, combined with supplementary surveys to provide information on the extent and damage potential of pest agents in the HVP Plantations estate, and its possible application in native forests.

Forest Health Surveillance in Western Australia: A Summary of Major Activities from 1997 to 2006

Abstract: Summary In Western Australia (WA), no formal forest health surveillance program is in place, but individual programs within the Department of Environment and Conservation undertake surveys to monitor major pathogens and pests associated with native jarrah and karri forest. Recently the Tuart Health Research Group and the Wandoo Recovery Group were established to undertake monitoring and to coordinate research into the cause of tuart and wandoo decline. For blue gum plantations, Murdoch University has an extensive pathogen research program and private industry has an Integrated Pest Management program to undertake pest surveillance. The Forest Products Commission carries out regular surveys for sirex wasp in pine plantations. Not all the results of surveillance and associated forest health research in WA are formally reported, but they are compiled and evaluated annually and presented in the Annual Pest and Disease Status Report for Australia and New Zealand by Research Working Group 7 (Forest Health).

Effectiveness of repellents for reducing damage to eucalypt seedlings by browsing mammals

Abstract: Marsupial herbivores cause significant damage to seedlings in forestry operations. Damage can lead to changes in tree form, reduced growth rates and seedling death. Non-lethal tactics, as a component of an integrated browsing management strategy, are currently sought to assist in reducing this damage. One such tactic involves making seedlings deterrent or unpalatable through the application of chemical repellents. We investigated the effect of three chemical repellents, Plant Plus, Sentree and Hot Shot, upon browsing of Eucalyptus nitens seedlings by two marsupial herbivores known to browse newly established plantations in Tasmania: the common brushtail possum and the red-bellied pademelon. One repellent was designed to deter herbivores through an unpleasant odour (Plant Plus), one to be unpalatable (Hot Shot), and the third to be both deterrent and unpalatable (Sentree). We ran a combination of paired feeding trials (one repellent + control) and cafeteria trials (all three repellents at once with no control) with captive possums and pademelons, for three nights per trial. Both species consumed significantly more foliage from control seedlings than those treated with Plant Plus or Sentree repellents. Pademelons also preferred controls to Hot Shot treated seedlings but, interestingly, possums consumed significantly more foliage from seedlings treated with Hot Shot than from control seedlings. The most effective repellent against both herbivores was Sentree, and the marked reduction in browsing indicates that further testing in the field is warranted.

A review of the outcomes of a decade of forest health surveillance of state forests in Tasmania

Abstract: Forest health surveillance, involving annual inspection of pine and eucalypti plantations by trained health observers, commenced in Tasmania in 1997. In the ten years since its introduction, forest health surveillance has become fully integrated into Forestry Tasmania's plantation management program. Importantly, forest health surveillance has provided value extending beyond the detection of pest and disease problems and has become a key element of the solutions for the management of health problems. The use of forest health surveillance to assist in the management of health problems at strategic, tactical and operational levels is discussed and illustrated with examples including establishing priorities for research, informing deployment strategies for managing pests or diseases, incursion responses and management in direct response to detection of pests or diseases.

Biology of Creiis lituratus Froggatt: (Hemiptera: Psyllidae), pest on Eucalyptus dunnii Maiden in plantations: morphology, life cycle and parasitism

Abstract: The psyllid Creiis lituratus Froggatt is the most significant defoliating pest of young Eucalyptus dunnii Maiden plantations growing in north-eastern New South Wales This paper describes aspects of the life history of C lituratus, information required to monitor psyllid populations and develop management strategies The psyllid has five nymphal instars Feeding by these nymphs causes considerable damage to the foliage of host trees The different nymphal instars are distinguishable on the basis of body and lerp dimensions, colouration and wing bud morphology Mean fecundity in captive populations was 95 eggs per female (observed range 130-148) Egg and juvenile development had threshold temperatures of 3 C and 10 C respectively, and the relationship between development rate and temperature was determined for both stages Adult longevity was reduced at high temperatures, which affected fecundity and may account for the low psyllid population densities observed in plantations over summer Parasitism of the nymphal instars by two species of Psyllaephagus wasps was observed While parasitism may exceed 90% in field surveys it is uncertain what role it plays in regulating populations No specialised parasitism or predation of eggs or adults was observed

Deep weathering profile and groundwater characteristics within a low-lying coastal pine plantation, southern Queensland - relationship to water-logging and salinisation

Abstract: Summary Exotic pine plantations are a major landuse within the coastal lowlands of southern Queensland Seasonal water-logging and the potential for salinity are of significant concern to forest managers In the northern Tuan State Forest, a typical deep weathering profile is characterised by soils at the top, ferricrete (discontinuous), mottled saprolite, fine saprolite and coarse saprolite at the base This zonation exerts a major control on the occurrence and geochemical character of groundwaters within the profile Three groundwater zones are identified: (1) shallow groundwater (fresh) perched on top of the ferricrete or mottled saprolite; (2) intermediate groundwater (brackish) on top of the fine saprolite, and (3) a deep confined groundwater (fresh) aquifer within the coarse saprolite Water-logging is caused by the perched shallow groundwater and the risk is largely controlled by the depth of restrictive layer that is related to geology Discharge of the intermediate groundwater at breaks in slope

Effect of Fertiliser and Water Supply on the Growth, Nutrient Status and Photochemical Efficiency of Eucalyptus pilularis Seedlings in a Phosphorus-deficient Soil

Abstract: A factorial pot trial, using a clay loam P-deficient soil, was conducted with two fertiliser rates (a) unfertilised and (b) fertilised with N, P, K and Mg, and with water supply within the range of 20% to 95% field-capacity (FC). Within the growth period of 180 days, plants of Eucalyptus pilularis Smith were exposed to increasing drought. Growth and photochemical efficiency were measured under these conditions and leaves and stems were analysed for biomass and nutrients. As judged by photochemical efficiency, fertilised plants were more stressed than unfertilised plants, where exposed to severe drought. As pre-conditioned plants displayed greater tolerance to drought than non-conditioned plants, it is recommended that where seedlings are to be planted in drought-prone areas, fertiliser application should be reduced and drought periods imposed during the nursery stage. Both stem and leaf nutrient concentrations increased with fertiliser application. On the other hand, leaf nutrient concentration decreased with increasing water supply, but stem concentration did not. It follows that the stem nutrient concentration may be the better indicator of the nutrient status of E. pilularis seedlings and this should be subject to further investigation.

Post-wildfire seedling colonisation patterns in a Eucalyptus delegatensis (Myrtaceae) windthrow site at Snowy River National Park, Victoria

Abstract: During June 1998, a severe windstorm caused significant damage to a sub-alpine stand of Eucalyptus delegatensis (Myrtaceae) at the Snowy River National Park. In 2002, about 4.5 y after the windstorm, a study documented the effects on E. delegatensis and early understorey succession. In February 2003, wildfire burnt across the windthrow site and we examined the seedling recruitment patterns at windthrow-burn and burn-only sites. Our aim was to document the regeneration of the canopy-dominant E. delegatensis and to confirm that Acacia dealbata is a pioneer species that potentially interferes with or prevents regeneration of E. delegatensis. Permanent transects were established within the windthrow-burn and burn-only sites. The data suggest that the heavily disturbed (mounded) soil at the windthrow site had a strong positive influence on regeneration of both species. By providing favourable growing conditions, the disturbed soil appears to have assisted seedling survival and subsequent growth of the E. delegatensis, despite competition from dense, concurrently established A. dealbata.