Eucalyptus Nitens Plantations Research Articles

Water use and carbon assimilation respond differently to nitrogen supplementation in mid-rotation Eucalyptus nitens

ABSTRACT Large amounts of nitrogen (N) fertiliser are often applied to commercial plantations in southern Australia to obtain high growth rates. The growth response to fertiliser can be realised through increased foliar N and hence improved leaf-level photosynthetic capacity, or through increased leaf area production, which in turn increases light capture and hence canopy-level photosynthesis. While extra leaf area is beneficial to a tree in this regard, extra leaves may also incur costs in terms of both carbon (C) and water. Since canopy water use scales with total leaf area, greater leaf area could cause stomatal closure in times of water shortage, reducing the C assimilation rate. Here, we used three factorial N × phosphorus fertiliser experiments in Eucalyptus nitens plantations across Tasmania, Australia, to assess the effects of 12 fertiliser treatments on C- and water-related gas exchange, foliar N and trunk shrinkage. As prior research in this system has demonstrated an increase in leaf area in response to high N, we investigated the potential physiological costs and benefits of this extra leaf area. N application appeared to have consequences for plant water use, as evidenced by greater trunk shrinkage and lower stomatal conductance. However, this varied by site and year, indicating that the response is dependent on environmental conditions. These results highlight the importance of considering site conditions when prescribing fertiliser application regimes because adding large amounts of N could have unintended consequences for growth due to increased leaf area and hence potential water use, especially in dry conditions.

Improving spatial predictions of Eucalypt plantation growth by combining interpretable machine learning with the 3-PG model

Accurate predictions of forest plantation growth provide forest managers with improved forest inventory estimates, forest valuation, and timely harvest schedules. Forest process-based models are increasingly used for quantifying current and potential productivity, yield gaps, and factors limiting growth, such as climate variability, soil characteristics, and water deficit. Improvements in the availability and resolution of spatial and temporal data combined with advancements in machine learning algorithms provide new opportunities to improve model predictions. This study shows how interpretable machine learning (ML) can be used to independently predict site soil fertility rating (FR) and incorporate these results into the 3-PG forest process-based model to accurately predict plantation growth. Four ensemble decision tree machine learning models—random forest trees, extremely randomized trees, gradient boost, and XG boost—were trained and compared using spatial cross-validation across the study area. FR predictions were estimated in relation to the influencing soil type and terrain characteristics, and interpretable ML methods were used to show how input feature permutations may relate to the soil fertility predictions. The results show the explanatory variables are similar across the selected ML models, with the strongest influencing variables being water leaching index, site aspect, and the silt and sand soil texture properties. The extremely randomized tree models showed the overall best performance, with only a small variation in performance across the four ML models. The method was applied to Eucalyptus nitens plantations covering over 63,000 ha in north-west Tasmania, Australia. The results using the predicted FR spatial grid with 3-PG show a strong correlation with observed growth for tree diameter and stand volume (R2 tree diameter at breast height = 0.97, RMSE = 0.85 m; R2 stand volume = 0.96, RMSE = 23.1 m3 ha−1) obtained from 161 permanent sample inventory plots ranging from 3 to 31 years old. This method has practical utility for other study sites to calibrate forest plantation soil fertility rating, in both the spatial and point-scale 3-PG model, where spatial data of soil characteristics are available. The derived soil fertility grid can provide valuable insights into the spatial variability of soil fertility in unknown areas.

Do eucalypt plantations on Ferrosols in north-west Tasmania contain more or less soil carbon than native forests on the same soil type?

ABSTRACT Although studies in mainland states of Australia and overseas show that the conversion of native forests to plantations can reduce carbon (C) stocks in soils, no studies have been undertaken in Tasmania to assess how plantations affect soil C stocks. To address this knowledge gap, we compared soil C concentrations and C stocks to 30 cm depth in native ‘mixed’ eucalypt forests and adjacent Eucalyptus nitens plantations on Ferrosols in north-west Tasmania, using a factorial sampling strategy. Mean soil C and nitrogen (N) concentrations were significantly lower in plantations than in mixed forests; however, because the soils in plantations had higher bulk density, mean soil C stocks under the two treatments (114 Mg ha−1 and 116 Mg ha−1, respectively) were not significantly different. It is concluded that machine removal of 5–6 cm of topsoil into windrows during land clearing for plantations would be sufficient to explain why C concentrations were lower in plantations than in mixed forests and that, apart from this physical effect of land preparation, 17–21 years of plantation growth on Ferrosols in north-west Tasmania has not significantly affected soil C stocks in mineral soil. This result can be partly explained by the ability of Ferrosols to form stable complexes between organic matter, sesquioxides and clays.

Nitrogen fertiliser only increases leaf area in the lower crown of mid-rotation Eucalyptus nitens plantations

Nutrient supplementation can stimulate growth of plantation trees through an increase in leaf area, but this link is dependent upon how the leaves are distributed throughout the crown. Due to its effect on the light environment through the crown, vertical leaf area distribution can have important impacts on leaf function with implications for tree growth. We used large-scale fertiliser experiments in three mid-rotation Eucalyptus nitens plantations across Tasmania to investigate the effects of mid-rotation nitrogen and phosphorus fertiliser application on leaf area index (LAI), light extinction and leaf traits. Nitrogen and phosphorus application rates were 0, 300, 450, 600, 1200 and 2200 kg/ha and 0 and 200 kg/ha, respectively. We found a non-linear response of LAI to N application at all sites in the year following fertiliser application, with the greatest increases in leaf area occurring in trees grown under the intermediate N treatments. Using vertical light extinction profiles through the crown to infer leaf area distribution, we found that leaf area increase in the upper crown was relatively consistent across the range of N application levels but that leaf area increase in the lower crown increased linearly with increasing N application up to 600 kg N/ha but did not increase further with higher N application rates. The addition of phosphorus increased LAI production at all sites in the first year but had no effect on light extinction and hence the vertical distribution of foliage through the crown. Leaf traits were largely unaffected by nutrient application. These results demonstrate that nitrogen fertilisers applied mid-rotation can boost LAI in E. nitens plantations, but the extra leaf area is predominantly located lower in the crown and therefore unlikely to contribute substantially to any increase in productivity.

Modelling wood property variation among Tasmanian Eucalyptus nitens plantations

Characterisation of forest resources is increasingly focused on tree wood properties as they are important drivers of economic value. We used the Random Forests machine learning algorithm to model variability among plantations of Eucalyptus nitens in key wood properties affecting the value of solid-wood products. Using breast-height disk samples from 46 even-aged stands of different ages across the island of Tasmania, Australia, we modelled site variation in SilviScan-3TM derived estimates of wood density, microfibril angle and modulus of elasticity. Regional-scale models were developed with respect to plantation age, environmental and climatic variables. Wood density and MOE increased, and MFA decreased with age. Wood density and MOE decreased and MFA increased with elevation. Increasing elevation is associated with increasing annual precipitation and decreasing temperature, but the variation in wood properties was mainly associated with precipitation. Wood density decreased and MFA increased with annual precipitation. MOE was positively related to wood density and negatively related to MFA, thus as expected, increased with annual precipitation. Using the Random Forests climate models we demonstrate the potential for predicting and mapping wood properties relevant for solid wood products at a scale that is relevant to strategic planning by the forest industry. Such models allow quantification of the impact of different growing conditions on the wood properties of harvested logs and therefore on wood products. When coupled with genetic, growth and economic models, these wood property models have the potential to assist in characterisation of standing forest resources and future estate planning.

Characterisation of wood quality of Eucalyptus nitens plantations and predictive models of density and stiffness with site and tree characteristics

Wood density and stiffness are among the most important wood quality traits for timber products and the prediction of these traits in trees planted across large geographic areas is of increasing interest for the forest industry. This study was conducted across 65 stands of E. nitens fibre-grown plantations, the most widely planted hardwood species in Tasmania, Australia, and aimed to (i) identify the main sources of variability in density (basic density, ρb) and stiffness (dynamic modulus of elasticity, Ed) of E. nitens fibre-grown trees, (ii) identify site, climatic, environmental and geomorphological factors across the E. nitens estate and tree characteristics at the site level that influence ρb and Ed of the trees, and based on this information (iii) develop models to predict the two wood properties at the tree and site level. An extensive dataset (n = 1880) of tree ρb and Ed measures was obtained through direct tree wood sampling for basic density and non-destructive acoustic assessments for stiffness. Large variation in tree density and stiffness was found across the study sites and among trees, with basic density ranging from 0.36 g cm−3 to 0.65 g cm−3 and stiffness from 9.2 GPa to 24.7 GPa. Candidate models to predict the two properties were developed on a training dataset and validated on a separate part of the dataset. The best tree-level models describing the variation of ρb and Ed included both tree and site factors. The best model describing ρb variation on trees included tree diameter, maximum temperature of the warmest period and precipitation of the wettest period as explanatory variables, while the best Ed model for trees included tree slenderness, height and basic density and the climatic variables, elevation and site index. The predictive models explained 31% of the total variability of ρb and 59% of the total variability of Ed across the validation sites. At the site level, the best models for density and stiffness included forest structure, climatic, and geomorphological variables, as well as plot location. The model for site density explained 73% of the variability of average density, while the model for site stiffness explained 35% of the variability of average stiffness.These findings demonstrate that different site and tree factors influence the two commercially important wood quality traits, and these can be used in combination to satisfactorily predict tree basic density and stiffness across different environments both at the tree and site level. This knowledge can be employed to support the forest and wood processing industry to expand the possible uses of E. nitens fibre-grown trees, to better manage the harvest for specific products, and to develop models for planning next generation plantings.

Mass trapping of Coryphodema tristis (Lepidoptera: Cossidae) using a sex pheromone in Eucalyptus nitens compartments in Mpumalanga, South Africa

Coryphodema tristis (Lepidoptera: Cossidae) is a native wood-boring moth with a broad host range on both native and non-native vegetation and is an important pest of commercial Eucalyptus nitens plantations in South Africa. Management of C. tristis is challenging since the larvae spend the majority of their lifecycle tunnelling within the wood of host trees. Following the development of a synthetic sex pheromone for C. tristis, pheromone-based mass trapping of male moths was investigated as a tool to control the pest. More than 5 000 pheromone-baited yellow bucket funnel traps with extensions were deployed in E. nitens stands in 2016 and 2017. Evaluation of the efficacy of the mass trapping programmes was done in 2017 and 2018 through the destructive felling of infested trees and comparison of the ratio of new to old C. tristis colonies in trapped and non-trapped compartments. The results show a significant decrease in the ratio of new to old colonies in trapped compartments compared to non-trapped compartments. This study shows that the large-scale trapping of C. tristis using a synthetic sex pheromone is a viable management strategy to control C. tristis.

Why introducing a parasitoid of Paropsis charybdis Stål, 1860 (Coleoptera: Chrysomelidae) larvae is expected to enhance biological control of this Eucalyptus pest in New Zealand

AbstractParopsis charybdis (Coleoptera: Chrysomelidae) has been a major pest of Eucalyptus spp. since invading New Zealand from Australia over 100 years ago. Here, we report on the phenology, egg parasitism and defoliation levels of P. charybdis at two Eucalyptus nitens plantations in the central North Island of New Zealand and assess the establishment prospects and potential impact of a new biological control agent, the larval parasitoid Eadya daenerys. Field monitoring found that 90–100% of first generation P. charybdis eggs emerged, showing that the existing egg parasitoids Enoggera nassaui (Hymenoptera: Braconidae) and Neopolycystus insectifurax (Hymenoptera: Pteromalidae) are ineffective at controlling this generation. Further field monitoring revealed effective control of second generation eggs by E. nassaui and N. insectifurax despite the presence of Baeoanusia albifunicle (Hymenoptera: Encyrtidae), a hyperparasitoid of E. nassaui. Phenology data show that first generation P. charybdis larvae will likely be synchronous with the adult emergence of E. daenerys (Hymenoptera: Braconidae) the new larval endoparasitoid proposed to be introduced from Australia. Climate matching predicts E. daenerys could establish in all areas of New Zealand where P. charybdisimpacted Eucalyptus spp. plantations are grown. The addition of a larval endoparasitoid could significantly contribute to the suppression of P. charybdis by decreasing first generation larval survival.

RETRACTED: Winoto-Lewin et al. Propensities of Old Growth, Mature and Regrowth Wet Eucalypt Forest, and Eucalyptus Nitens Plantation, to Burn during Wildfire and Suffer Fire-Induced Crown Death. Fire 2020, 3, 13

The authors were informed of some errors in the categorization of forest types by a colleague [...]

Propensities of Old Growth, Mature and Regrowth Wet Eucalypt Forest, and Eucalyptus nitens Plantation, to Burn During Wildfire and Suffer Fire-Induced Crown Death

There are conflicting conclusions on how the flammability of wet eucalypt forests changes in the time after disturbances such as logging or wildfire. Some conclude that forests are most flammable in the decades following disturbance, while others conclude that disturbance has no effect on flammability. The comparative flammability of Eucalyptus nitens plantations in the same environment as wet eucalypt forest is not known. We determined fire incidence and fire severity in regrowth, mature and old growth wet eucalypt forest, and E. nitens plantation, in the Huon Valley, Tasmania after the January–February 2019 wildfire. To control for topographic variation and fire weather, we randomly selected sites within the fire footprint, then randomly located a paired site for each in different forest types in the same topographic environment within 3 km. Each pair of sites was burned on the same day. Old growth forest and plantations were the least likely to burn. Old growth and mature forest exhibited scorched eucalypt crowns to a much lesser degree than regrowth forests. In a comparison of paired sites, plantation forest was less likely to burn than combined mature and old growth forests, but in all cases of detected ignition the canopy of plantation was scorched. The lower flammability of older forests, and their importance as an increasing store of carbon, suggests that a cessation of logging outside plantations might have considerable benefits.

Short-term and long-term bending properties of nail-laminated timber constructed of fast-grown plantation eucalypt

Developing higher-value structural products from fast-growing eucalypt plantations - that are currently managed for woodchip production - can create new markets for these plantation resources and ensure a sustainable supply of timber for building construction. In this study, structural nail-laminated timber (NLT) panels with different span lengths were manufactured from a 16-year-old fast-grown Eucalyptus nitens plantation using a lamination system that can maximise the use of lower-grade boards in NLT production. The short-term bending performance in the elastic region and the effects of environmental conditions and structural grade of timber on long-term bending creep deflection of the panels were evaluated. The data analysis revealed that the current visual stress-grading method is incapable of estimating the actual modulus of elasticity (MOE) of the plantation Eucalyptus nitens timber. A linear regression model was proposed using the actual MOE of the boards that can predict the MOE of NLT panels with an average accuracy of 98%. The NLT panels made with higher-grade boards showed 22.4% greater MOE values than the NLT panels made with lower-grade boards. The lamination system used resulted in NLT panels with predictable and customised MOE with a remarkable average coefficient of variance of less than 2.6%. The long-term bending creep deflection of the test panels was significantly affected by daily variations in the relative humidity of the environment and structural grade of the timber used. The results of this study can be used in the development of an appropriate NLT production system from fast-grown plantation eucalypt.

Using Sentinel-2 Multispectral Images to Map the Occurrence of the Cossid Moth (Coryphodema tristis) in Eucalyptus Nitens Plantations of Mpumalanga, South Africa

Coryphodema tristis is a wood-boring insect, indigenous to South Africa, that has recently been identified as an emerging pest feeding on Eucalyptus nitens, resulting in extensive damage and economic loss. Eucalyptus plantations contributes over 9% to the total exported manufactured goods of South Africa which contributes significantly to the gross domestic product. Currently, the distribution extent of the Coryphodema tristis is unknown and estimated to infest Eucalyptus nitens compartments from less than 1% to nearly 80%, which is certainly a concern for the forestry sector related to the quantity and quality of yield produced. Therefore, the study sought to model the probability of occurrence of Coryphodema tristis on Eucalyptus nitens plantations in Mpumalanga, South Africa, using data from the Sentinel-2 multispectral instrument (MSI). Traditional field surveys were carried out through mass trapping in all compartments (n = 878) of Eucalyptus nitens plantations. Only 371 Eucalyptus nitens compartments were positively identified as infested and were used to generate the Coryphodema tristis presence data. Presence data and spectral features from the area were analysed using the Maxent algorithm. Model performance was evaluated using the receiver operating characteristics (ROC) curve showing the area under the curve (AUC) and True Skill Statistic (TSS) while the performance of predictors was analysed with the jack-knife. Validation of results were conducted using the test data. Using only the occurrence data and Sentinel-2 bands and derived vegetation indices, the Maxent model provided successful results, exhibiting an area under the curve (AUC) of 0.890. The Photosynthetic vigour ratio, Band 5 (Red edge 1), Band 4 (Red), Green NDVI hyper, Band 3 (Green) and Band 12 (SWIR 2) were identified as the most influential predictor variables. Results of this study suggest that remotely sensed derived vegetation indices from cost-effective platforms could play a crucial role in supporting forest pest management strategies and infestation control.

Factors influencing the production of structural plywood in Tasmania, Australia from Eucalyptus nitens rotary peeled veneer

Harvested logs supplied from five fibre-managed Eucalyptus nitens plantation coupes with different growing environments were assessed for quality and stiffness. Billets extracted from the logs were rotary peeled for veneer. When averaged across the five coupes, 30% of veneer recovered could be used directly in structural plywood production and an additional 20–25% could be used after further processing. In visual assessment most veneer was assigned an Australian/New Zealand Standard AS/NZS2269.0:2012 Quality D. Acoustic testing during processing showed veneer peeled from a drier and lower elevation coupe had significantly higher dynamic MOE values than veneer processed from logs harvested from wetter higher elevation coupes. To examine the utility of the E. nitens peeled veneer in the production of structural plywood, it was combined with veneer of a known higher stiffness, rotary peeled from regrowth forest Tasmanian oak species logs. Structural seven-ply panels were manufactured from the veneer prepared in three different ply arrangements. Mechanical testing of the panels in accordance with AS/NZS2269.0:2012 showed that an F17 target stress-grade panel product of 83% E. nitens and 17% Tasmanian oak species could be produced, if E. nitens veneer of higher stiffness were selected from veneer segregated by estimated dynamic Modulus of Elasticity value. Panels with 50% E. nitens and 50% Tasmanian oak veneer could be produced by selecting E. nitens veneer of lower stiffness after segregation. In the majority of panels tested stress-grade rating was limited by perpendicular bending strength. Outcomes from the study indicate that structural plywood can be manufactured using differing proportions of E. nitens veneer, rotary peeled from fibre-managed plantations, provided it can be segregated into stiffness categories and selected to achieve a target stress-grade.

Establishing Eucalyptus nitens plantations using controlled-release fertilisers

ABSTRACTField trials were installed in three Tasmanian Eucalyptus nitens plantations to quantify growth responses and operational factors associated with applying controlled-release fertilisers (CRF) at planting. A range of CRF products, blends and rates of application was evaluated and compared with the industry standard (di-ammonium phosphate (DAP), 100 g seedling–1). Trees treated with CRF were between 26 and 35% taller than unfertilised trees by age 2 years, with height equivalent to or greater than height using DAP. The use of CRF enabled the planting and fertilising operations to be combined, resulting in improved operational and financial efficiencies. Two suitable alternative primary CRF treatments were identified: Basacote® 9M applied at 20 g or 40 g seedling–1 (B9M20 or B9M40). The B9M20 fertiliser provided equivalent height at a lower cost than DAP, while B9M40 provided greater height than DAP but at an equivalent cost. Height response was strongest and lasted longest at the low–moderate fertility site compared to the higher fertility sites. Both CRF treatments achieved rapid early growth in height, necessary for successful establishment by age 2 years, which helped reduce the period of susceptibility to browsing mammals and overtopping from weeds. Additional benefits from using CRF include significantly reduced fertiliser inputs, lower risk of leaching and lower risk of competitive uptake by weeds. These benefits are consistent with the objectives of developing more efficient operational systems, site-specific management and reducing environmental impacts.

Potential protease activity and organic nitrogen concentration are rapid tests and accurate indicators of N-availability in Tasmanian Eucalyptus nitens plantations

There are a variety of soil-based tests used to gauge the availability of N, with some of the more common tests being based on pools of inorganic N and/or N mineralization. Implicit assumptions of these tests are: 1) plants take up inorganic nitrogen compounds only, and 2) mineralisation is the rate-limiting step in producing available N. However, there is mounting evidence that 1) plants can take up organic nitrogen and 2) the rate-limiting step of nitrogen availability is more likely depolymerisation. The aim of this study was to test if pools of amino acids and potential protease activity could be used to predict nutrient limitation. To test this idea we set up nine experimental field sites with widely divergent nutrient availability. Sites were planted with the plantation tree species Eucalyptus nitens and we measured growth response to fertiliser to gauge the extent of nutrient limitation.Among the nine sites the size of growth responses to fertiliser were strongly correlated with potential protease activity and amino acid concentration. Data were consistent with the notion that depolymerisation (as indicated by protease activity) could be the rate-limiting step in generating available forms of N. We suggest that potential protease activity may be a useful indicator of nitrogen availability and could be used to tailor fertiliser supply to demand.

Optimization of Pheromone Traps for Coryphodema tristis (Lepidoptera: Cossidae).

The Coryphodema tristis (Drury) is an important pest of Eucalyptus nitens (Deane and Maiden) plantations in South Africa. The gregarious larvae of this pest cause damage by feeding on the tree sapwood, and adults emerge in spring each year. The aim of this study was to optimize pheromone traps for operational use in management programs. This was achieved by investigating different pheromone blend combinations and trap types for efficacy under field conditions. Our results confirm that the cross vane bucket funnel trap baited with a 95:2.5:2.5 volumetric blend of Z9-14:OAc, Z9-14:OH, and 14Ac was superior to similarly baited standard bucket funnel and delta traps. We also estimated the release rate and ratios of the pheromone compounds loaded into an artificial permeation dispenser through solid-phase microextraction sampling. Results showed that the released blend of pheromone compounds mirrored the dispensed ratios relatively accurately and that release rates are affected by temperature.

The threat to Eucalyptus plantations from an emerging Tasmanian leaf beetle pest: Paropsisterna selmani (Coleoptera: Chrysomelidae)

ABSTRACTA newly described eucalypt leaf beetle, Paropsisterna selmani Reid and de Little, endemic to Tasmania, Australia, required management in Tasmania for the first time in 2011 to protect Eucalyptus nitens plantations from severe defoliation. This species was discovered following its incursion and subsequent establishment in southern Ireland in 2007.Field monitoring using sticky traps in eight E. nitens plantations around Tasmania was performed to compare the spatial and temporal population distributions of adult P. selmani with adult P. bimaculata and P. agricola over two summer seasons, 2009–2010 and 2010–2011. Populations of all three species were extremely variable between sites and between and within the two seasons. While P. bimaculata dominated at six of the eight sites throughout Tasmania, P. agricola had high populations at the three most northerly sites. Adult P. selmani were trapped at all sites but were the dominant leaf beetles at one site and were relatively common at two other northerly sites.During the longer trapping period in the second season, all three species showed two population peaks: one in spring (November–December) following emergence of adults from overwintering, and a second in late January–February of a second generation of adults. Heavy egg-laying followed the first but not the second adult population peak. At the two sites with the largest P. selmani populations, the peak spring flight of P. selmani adults occurred at least two weeks earlier than that of P. bimaculata and P. agricola, and the second flight peak was at least two weeks later than that of these species.A new pest with a population phenology that differs from that of existing plantation pests could have important implications for the success of an Integrated Pest Management program designed to protect plantations from defoliation. Field records of P. selmani since it was first recorded in 1979 suggest that this species is increasing in abundance in Tasmania. Management of this species has been required since 2011 to prevent economic damage to plantations. This newly emerging plantation pest feeds on a range of Eucalyptus hosts, including the adult-phase foliage of the plantation species E. nitens, and poses new problems for plantation management in Australia, as well as increasing the threat of invasion into overseas eucalypt plantations, as already demonstrated in Ireland.

Skin artefacts due to post-mortem damage caused by Notiothauma reedi: A insect of forensic importance in forest communities of Chile

We selected four types of forestal areas with different botanical compositions and an anthropised prairie in a region of Chile to identify insects that participate in the decomposition of pig carcasses and that can be used as bioindicators in Chilean forensic entomology and to identify the post-mortem artefacts caused by them. We observed the presence of Notiothauma reedi (Mecoptera: Eomeropidae), an endemic insect of Chile, on carcasses only in the forested environment that characterised the deciduous forests, evergreen forest, Eucalyptus nitens plantation and Pinus radiata plantation from the third day of the post-mortem interval (PMI) and throughout the decomposition process. This species was not found on carcasses located in a prairie near Temuco city. Additionally, N. reedi caused skin lesions that had morphological similarities with ante-mortem injuries caused by cigarette burns, which change as the carcass decomposes. This study provides preliminary results on the role of this species in the decomposition of carcasses in native forests and exotic plantations in southern Chile and on the skin lesions that it causes, which should be taken into account when cadavers are found under conditions similar to those described above. In light of these findings, N. reedi could be a new bioindicator of forensic utility in the forest communities of southern Chile.

An economic analysis of biochar production using residues from Eucalypt plantations

Producing biochar from organic residues is a potential method to integrate carbon sequestration and residue management costs while enhancing conventional agricultural and forestry production systems. Plantation forestry is an important industry in Tasmania, and is based on large scale plantations of Pinus radiata and Eucalyptus (Eucalyptus globulus and E. nitens). The area covered by forestry plantations in Tasmania (on State land) exceeds 100 000 ha, while plantations on private land double this number. Eucalypt plantations are managed primarily for the production of high-value pruned logs for industry; however, unpruned saw logs, peelers, poles, posts and pulp are also produced, and significant quantities of residue are produced as a byproduct. This study was an economic analysis that considered on-site biochar production system using post-harvest forestry residues, with biochar being utilized within the system, or sold as a product. The financial analysis was based on previous experimental outcomes on the use of Macadamia shell biochar in Eucalyptus nitens plantations, and the local operating environment in Tasmania; including current forestry procedures used for managing plantations. A number of assumptions were considered concerning a) production costs, b) savings enjoyed by traditional operations, following biochar scenario implementation, and c) biochar sales. The analysis revealed a potential annual income of over 179 k$ (2014 value) and the sensitivity analysis identified the crucial factors responsible for scenario profitability, namely biochar price and final product distribution.

Productivity and cost of whole‑tree harvesting without debarking in a Eucalyptus nitens plantation in Tasmania, Australia

There is increasing interest worldwide in using tree harvesting biomass as an energy source. Bark retained on logs is commonly used as an energy source, but is generally removed from eucalypt logs during harvest. In order to evaluate the potential use of eucalypt bark as fuel, there is a need for information on the productivity and cost implications of retaining eucalypt bark during harvest operations. The study examined the impact of retaining bark on logs on the productivity and costs of a whole‑tree to roadside harvesting system in a short‑rotation Eucalyptus nitens plantation in Australia being harvested for pulp logs. Trees were felled and bunched with a feller‑buncher in spring, then left infield for four weeks to promote bark adhesion and reduce bark loss. A skidder extracted the trees to roadside where a processor processed them to predominantly 10 m logs. Machine productivities were calculated from estimated tree and log volumes and cycle times recorded from video recordings. The feller‑buncher's productivity (65 m3 PMH0−1) was less than expected as it appeared to be underpowered to handle the larger trees on the study site. The skidder's productivity (56 m3 PMH0−1) was comparable to those reported in studies under similar conditions and with bark retained. The roadside processor's productivity (25 m3 PMH0−1) was lower than expected. This was believed to result from the operator separately stacking 10 m and 5 m logs, and the lower feed speed resulting from slippage due to the reduced feed roller pressure used in the study to reduce bark loss. Future research could identify feed rollers that increase feed speed while retaining bark. Harvest system costs (AUD18 GMt−1) were similar to those reported for a eucalypt roadside processing trial where bark was removed. These results suggest that retaining bark on the logs at roadside did not affect the harvesting system's productivity or costs.