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David B. Lindenmayer - One of the best experts on this subject based on the ideXlab platform.
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Integrating forest biodiversity conservation and restoration ecology principles to recover natural forest ecosystems
New Forests, 2019Co-Authors: David B. LindenmayerAbstract:Effective conservation of forest biodiversity and effective forest restoration are two of the biggest challenges facing forest managers globally. I present four general principles to guide strategies aimed at meeting these challenges: (1) protect and restore populations of key species and their habitats, (2) conserve and restore key attributes of stand structural complexity, (3) maintain and restore natural patterns of landscape heterogeneity, and (4) maintain and restore key ecological processes. The complexity associated with these principles is that how they will be practically implemented on the ground will invariably be ecosystem specific as what constitutes stand structural complexity or landscape heterogeneity will vary between ecosystems. Here I demonstrate the practical application of the four general principles in a detailed case study of conservation and restoration in the Mountain Ash ( Eucalyptus Regnans ) forests of the Central Highlands of Victoria, south-eastern Australia. These forests are characterized by declining species, loss of key elements of stand structural, loss of old growth forest, altered patterns of landscape heterogeneity, and altered ecosystem processes. I highlight how altered management practices in Mountain Ash forests that are guided by our four general principles can help conserve existing biodiversity and underpin effective forest restoration. Consideration of our general principles also can identify policy deficiencies that need to be addressed to enhance restoration and biodiversity conservation.
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failing to conserve leadbeater s possum and its mountain ash forest habitat
The Australian zoologist, 2018Co-Authors: David Blair, David B. Lindenmayer, Lachlan McburneyAbstract:ABSTRACT The conservation of the Critically Endangered Leadbeater's Possum Gymnobelideus leadbeateri in Victoria's Mountain Ash Eucalyptus Regnans forests is one of the most controversial native mammal conservation issues in Australia. Much of the controversy results from long-running conflicts between the demands of the native forest logging industry and associated impacts on Leadbeater's Possum and its Mountain Ash forest habitat. Here we argue that despite a legislative obligation to protect Leadbeater's Possum and some limited recent improvements in management, conservation efforts for the species have gone backwards over the past decade. The key problems we identify include that the Victorian Government has: (1) maintained levels of wood production that are too high given the amount of the forest estate that was burned in 2009, (2) failed to substitute clearfell logging practices with more ecologically-sensitive Variable Retention Harvesting Systems, (3) ignored the science (including by its own rese...
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Interacting Factors Driving a Major Loss of Large Trees with Cavities in a Forest Ecosystem
2015Co-Authors: David B. Lindenmayer, David Blair, Lachlan Mcburney, Wade Blanchard, Sam Banks, Gene E. Likens, Jerry F. Franklin, William F. Laurance, John A. R. Stein, Philip GibbonsAbstract:Large trees with cavities provide critical ecological functions in forests worldwide, including vital nesting and denning resources for many species. However, many ecosystems are experiencing increasingly rapid loss of large trees or a failure to recruit new large trees or both. We quantify this problem in a globally iconic ecosystem in southeastern Australia – forests dominated by the world’s tallest angiosperms, Mountain Ash (Eucalyptus Regnans). Tree, stand and landscape-level factors influencing the death and collapse of large living cavity trees and the decay and collapse of dead trees with cavities are documented using a suite of long-term datasets gathered between 1983 and 2011. The historical rate of tree mortality on unburned sites between 1997 and 2011 was.14 % with a mortality spike in the driest period (2006–2009). Following a major wildfire in 2009, 79 % of large living trees with cavities died and 57–100 % of large dead trees were destroyed on burned sites. Repeated measurements between 1997 and 2011 revealed no recruitment of any new large trees with cavities on any of our unburned or burned sites. Transition probability matrices of large trees with cavities through increasingly decayed condition states projects a severe shortage of large trees with cavities by 2039 that will continue until at least 2067. This large cavity tree crisis in Mountain Ash forests is a product of: (1) the prolonged time required (.120 years) for initiatio
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the use of topographic fire refuges by the greater glider petauroides volans and the mountain brushtail possum trichosurus cunninghami following a landscape scale fire
Australian Mammalogy, 2015Co-Authors: Laurence E Berry, Sam C. Banks, Don A. Driscoll, David B. LindenmayerAbstract:We examined the abundance of arboreal marsupials in topographic fire refuges after a major fire in a stand-replacing crown-fire forest ecosystem. We surveyed the abundance of arboreal marsupials across 48 sites in rainforest gullies burnt to differing extents by the 2009 fires in the mountain ash (Eucalyptus Regnans) forests of the Victorian Central Highlands, Australia. The greater glider (Petauroides volans) was less abundant within the extent of the 2009 fire. The mountain brushtail possum (Trichosurus cunninghami) was more abundant within the extent of the 2009 fire, particularly within unburnt peninsulas protruding into burnt areas from unburnt edges. Our results indicate that fire refuges may facilitate the persistence of some species within extensively burnt landscapes. Additional work should seek to clarify this finding and identify the demographic mechanisms underlying this response.
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Dominant Drivers of Seedling Establishment in a Fire-Dependent Obligate Seeder: Climate or Fire Regimes?
Ecosystems, 2013Co-Authors: Annabel L. Smith, David Blair, Lachlan Mcburney, Sam C. Banks, Philip S. Barton, Wade Blanchard, Don A. Driscoll, A. Malcolm Gill, David B. LindenmayerAbstract:Climate change is causing fire regime shifts in ecosystems worldwide. Plant species with regeneration strategies strongly linked to a fire regime, such as obligate seeders, may be particularly threatened by these changes. It is unclear whether changes in fire regimes or the direct effects of climate change will be the dominant threats to obligate seeders in future. We investigated the relative importance of fire-related variables (fire return interval and fire severity) and environmental factors (climate and topography) on seedling establishment in the world’s tallest angiosperm, an obligate seeder, Eucalyptus Regnans. Throughout its range, this species dominates the wet montane forests of south-eastern Australia and plays a keystone role in forest structure. Following major wildfires, we investigated seedling establishment in E. Regnans within 1 year of fire as this is a critical stage in the regeneration niche of obligate seeders. Seedling presence and abundance were strongly related to the occurrence of fire but not to variation in fire severity (moderate vs. high severity). Seedling abundance increased with increasing fire return interval (range 26–300 years). First-year seedling establishment was also strongly associated with low temperatures and with high elevations, high precipitation and persistent soil water availability. Our results show that both climate and fire regimes are strong drivers of E. Regnans seedling establishment. The predicted warming and drying of the climate might reduce the regeneration potential for some obligate seeders in future and these threats are likely to be compounded by changes in fire regimes, particularly increases in fire frequency.
Lindenmayer, David B. - One of the best experts on this subject based on the ideXlab platform.
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Temporal fragmentation of a critically endangered forest ecosystem
'Wiley', 2020Co-Authors: Taylor Chris, Lindenmayer, David B.Abstract:Landscape change and habitat fragmentation is increasingly affecting forests worldwide. Assessments of patterns of spatial cover in forests over time can be critical as they reveal important information about landscape condition. In this study, we assessed landscape patterns across the Mountain Ash (Eucalyptus Regnans) and Alpine Ash (Eucalyptus delegatensis) forests in the Central Highlands of Victoria between 1999 and 2019. These forests have experienced major disturbance over the past 20 years through a major fire (in 2009) and extensive industrial logging. We found that around 70% and 65% of the Mountain Ash and Alpine Ash forest areas, respectively, were either disturbed or within 200 m of a disturbed area. Inclusion of planned logging increased these disturbance categories to 72% and 70%, respectively. We also found that the isolation of Mountain Ash core areas (patches of undisturbed forest > 1000 ha) increased significantly (P
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Logging and fire regimes alter plant communities
'Wiley', 2019Co-Authors: Bowd Elle, Lindenmayer, David B., Banks Samuel, Blair DavidAbstract:Disturbances are key drivers of plant community composition, structure, and function. Plant functional traits, including life forms and reproductive strategies are critical to the resilience and resistance of plant communities in the event of disturbance. Climate change and increasing anthropogenic disturbance are altering natural disturbance regimes globally. When these regimes shift beyond the adaptive resilience of plant functional traits, local populations and ecosystem functions can become compromised. We tested the influence of multiple disturbances, of varying intensity and frequency, on the composition and abundance of vascular plant communities and their respective functional traits (life forms and reproductive strategies) in the wet sclerophyll, Mountain Ash Eucalyptus Regnans forests of southeastern Australia. Specifically, we quantified the effect of the type and number of disturbances (including fires, clearcut logging, and salvage logging) on plant community composition. We found that clearcut and salvage logging and the number of fires significantly influenced plant community composition and functional traits. Specifically, multiple fires resulted in lower populations of species that depend on on‐site seeding for persistence. This includes the common tree species Eucalyptus Regnans, Pomaderris aspera, and Acacia dealbata. In contrast, clearcut and salvage logged sites supported abundant on‐site seeder species. However, species that depend on resprouting by surviving individuals, such as common and keystone “tree ferns” Dicksonia antarctica and Cyathea australis, declined significantly. Our data have important implications for understanding the relationship between altered disturbance regimes and plant communities and the respective effects on ecosystem function. In a period of rapid global environmental change, with disturbances predicted to increase and intensify, it is critical to address the impact of altered disturbance regimes on biodiversity.Supporting funding was provided by The Australian National University and the Paddy Pallin Foundation
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Long-term impacts of wildfire and logging on forest soils
'Springer Science and Business Media LLC', 2019Co-Authors: Bowd Elle, Banks, Samuel C., Strong, Craig L., Lindenmayer, David B.Abstract:Soils are a fundamental component of terrestrial ecosystems, and play key roles in biogeochemical cycles and the ecology of microbial, plant and animal communities. Global increases in the intensity and frequency of ecological disturbances are driving major changes in the structure and function of forest ecosystems, yet little is known about the long-term impacts of disturbance on soils. Here we show that natural disturbance (fire) and human disturbances (clearcut logging and post-fire salvage logging) can significantly alter the composition of forest soils for far longer than previously recognized. Using extensive sampling across a multi-century chronosequence in some of the tallest and most carbon-dense forests worldwide (southern Australian, mountain ash (Eucalyptus Regnans) forests), we provide compelling evidence that disturbance impacts on soils are evident up to least eight decades after disturbance, and potentially much longer. Relative to long-undisturbed forest (167 years old), sites subject to multiple fires, clearcut logging or salvage logging were characterized by soils with significantly lower values of a range of ecologically important measures at multiple depths, including available phosphorus and nitrate. Disturbance impacts on soils were most pronounced on sites subject to compounding perturbations, such as multiple fires and clearcut logging. Long-lasting impacts of disturbance on soil can have major ecological and functional implications.Thank you for the following groups for funding: the Paddy Pallin Foundation, Centre of Biodiversity Analysis, the Ecological Society of Australia and the Holsworth Wildlife Research Endowment fund
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Variable retention harvesting in Victoria’s Mountain Ash (Eucalyptus Regnans) forests (southeastern Australia)
'Springer Science and Business Media LLC', 2019Co-Authors: Lindenmayer, David B., Blair David, Mcburney LachlanAbstract:Variable retention harvesting is a silvicultural system that focuses on retaining key elements of stand structure at the time of logging and is increasingly being used worldwide. We describe the design and establishment of a variable retention harvesting experiment established in the Mountain Ash (Eucalyptus Regnans) forests of the Central Highlands of Victoria, south-eastern Australia. The experiment was instigated in 2003, and the work to date has shown that it has environmental benefits for certain groups of small mammals, birds, and vascular plants. The experiment has been integrated with an ongoing long-term monitoring program as well as other experiments such as those in post-fire salvage-logged areas. Collectively, the results of various studies suggest that the potential value of variable retention harvesting extends beyond green-tree logging to post-fire salvage logging environments. We outline some of the challenges in, and new perspectives derived from, implementing and maintaining our experiment. This included difficulties protecting islands from high-intensity post-harvest regeneration burns and threat of declining funding undermining ongoing project viability. A critically important perspective concerns the ecological and economic context in which variable retention harvesting is implemented. In the particular case of Mountain Ash forests, assessments using formal IUCN criteria classify the ecosystem as being Critically Endangered under the Red Listed Ecosystem approach. As a result, Mountain Ash forests are at a high risk of ecosystem collapse. Further logging will increase that risk, making the basis for continued harvesting questionable. In addition, economic analyses suggest that the value of natural assets, like water production, far outweigh the value of the wood products harvested from the Mountain Ash ecosystem, again leading to questions about the viability of ongoing harvesting. We therefore conclude that whilst variable retention harvesting has the potential to contribute to biodiversity conservation in Mountain Ash forests, broader ecological and economic contextual issues (such as the values of competing resources like water yields and the heavily degraded state of the forest) may erode the case for its broader application.The work summarized in this paper has received support from the Australian Research Council, the Australian Government (National Environmental Science Program Threatened Species Recovery Hub), the Victorian Department of Environment, Land, Water and Planning, and Parks Victoria. The Myer, Poola, and Wood Foundations have supported key aspects of our work in the Variable Retention Experiment in the Mountain Ash forests of Victoria
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Data from: Logging and fire regimes alter plant communities
2018Co-Authors: Bowd, Elle J., Lindenmayer, David B., Banks, Sam C., Blair, David P.Abstract:Disturbances are key drivers of plant community composition, structure and function. Plant functional traits, including life forms and reproductive strategies are critical to the resilience and resistance of plant communities in the event of disturbance. Climate change and increasing anthropogenic disturbance are altering natural disturbance regimes, globally. When these regimes shift beyond the adaptive resilience of plant functional traits, local populations and ecosystem functions can become compromised. We tested the influence of multiple disturbances, of varying intensity and frequency, on the composition and abundance of vascular plant communities and their respective functional traits (life forms and reproductive strategies) in the wet sclerophyll, Mountain Ash Eucalyptus Regnans forests of south-eastern Australia. Specifically, we quantified the effect of the type and number of disturbances (including fires, clearcut logging and salvage logging) on plant community composition. We found that clearcut and salvage logging and the number of fires significantly influenced plant community composition and functional traits. Specifically, multiple fires resulted in lower populations of species that depend on on-site seeding for persistence. This includes the common tree species, Eucalyptus Regnans, Pomaderris aspera and Acacia dealbata. In contrast, clearcut and salvage logged sites supported abundant on-site seeder species. However, species that depend on resprouting by surviving individuals, such as common and keystone ‘tree ferns’ Dicksonia antarctica and Cyathea australis declined significantly. Our data have important implications for understanding the relationship between altered disturbance regimes and plant communities and the respective effects on ecosystem function. In a period of rapid global environmental change, with disturbances predicted to increase and intensify, it is critical to address the impact of altered disturbance regimes on biodiversity
Michael A Mccarthy - One of the best experts on this subject based on the ideXlab platform.
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fire regimes in mountain ash forest evidence from forest age structure extinction models and wildlife habitat
Forest Ecology and Management, 1999Co-Authors: Malcolm A Gill, Michael A Mccarthy, David B. LindenmayerAbstract:The mean interval between tree-killing fires in mountain ash (Eucalyptus Regnans F. Muell.) forest was inferred from information on the age structure of unlogged forest, the prevalence of mountain ash trees in the landscape, and on the abundance of live and dead hollow-bearing trees. The analyses were based on models of the local extinction and recolonization of forest patches by mountain ash trees and of the development of hollow-bearing trees in response to time since fire. The results of the analyses suggested that the mean interval between tree-killing fires was between75 and 150 years in mountain ash forest. Data on mortality of mountain ash trees suggest that approximately half the trees survive fire, making the mean interval between all fires equal to 37‐75 years. The model predicts that the proportion of the landscape occupied by mountain ash will decline sharply as the mean fire interval decreases, suggesting that changes in the fire regime may have abrupt and major effects on ecosystem properties. # 1999 Elsevier Science B.V. All rights reserved.
Lachlan Mcburney - One of the best experts on this subject based on the ideXlab platform.
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Variable retention harvesting in Victoria’s Mountain Ash (Eucalyptus Regnans) forests (southeastern Australia)
Ecological Processes, 2019Co-Authors: David Lindenmayer, David Blair, Lachlan McburneyAbstract:Variable retention harvesting is a silvicultural system that focuses on retaining key elements of stand structure at the time of logging and is increasingly being used worldwide. We describe the design and establishment of a variable retention harvesting experiment established in the Mountain Ash ( Eucalyptus Regnans ) forests of the Central Highlands of Victoria, south-eastern Australia. The experiment was instigated in 2003, and the work to date has shown that it has environmental benefits for certain groups of small mammals, birds, and vascular plants. The experiment has been integrated with an ongoing long-term monitoring program as well as other experiments such as those in post-fire salvage-logged areas. Collectively, the results of various studies suggest that the potential value of variable retention harvesting extends beyond green-tree logging to post-fire salvage logging environments. We outline some of the challenges in, and new perspectives derived from, implementing and maintaining our experiment. This included difficulties protecting islands from high-intensity post-harvest regeneration burns and threat of declining funding undermining ongoing project viability. A critically important perspective concerns the ecological and economic context in which variable retention harvesting is implemented. In the particular case of Mountain Ash forests, assessments using formal IUCN criteria classify the ecosystem as being Critically Endangered under the Red Listed Ecosystem approach. As a result, Mountain Ash forests are at a high risk of ecosystem collapse. Further logging will increase that risk, making the basis for continued harvesting questionable. In addition, economic analyses suggest that the value of natural assets, like water production, far outweigh the value of the wood products harvested from the Mountain Ash ecosystem, again leading to questions about the viability of ongoing harvesting. We therefore conclude that whilst variable retention harvesting has the potential to contribute to biodiversity conservation in Mountain Ash forests, broader ecological and economic contextual issues (such as the values of competing resources like water yields and the heavily degraded state of the forest) may erode the case for its broader application.
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failing to conserve leadbeater s possum and its mountain ash forest habitat
The Australian zoologist, 2018Co-Authors: David Blair, David B. Lindenmayer, Lachlan McburneyAbstract:ABSTRACT The conservation of the Critically Endangered Leadbeater's Possum Gymnobelideus leadbeateri in Victoria's Mountain Ash Eucalyptus Regnans forests is one of the most controversial native mammal conservation issues in Australia. Much of the controversy results from long-running conflicts between the demands of the native forest logging industry and associated impacts on Leadbeater's Possum and its Mountain Ash forest habitat. Here we argue that despite a legislative obligation to protect Leadbeater's Possum and some limited recent improvements in management, conservation efforts for the species have gone backwards over the past decade. The key problems we identify include that the Victorian Government has: (1) maintained levels of wood production that are too high given the amount of the forest estate that was burned in 2009, (2) failed to substitute clearfell logging practices with more ecologically-sensitive Variable Retention Harvesting Systems, (3) ignored the science (including by its own rese...
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Interacting Factors Driving a Major Loss of Large Trees with Cavities in a Forest Ecosystem
2015Co-Authors: David B. Lindenmayer, David Blair, Lachlan Mcburney, Wade Blanchard, Sam Banks, Gene E. Likens, Jerry F. Franklin, William F. Laurance, John A. R. Stein, Philip GibbonsAbstract:Large trees with cavities provide critical ecological functions in forests worldwide, including vital nesting and denning resources for many species. However, many ecosystems are experiencing increasingly rapid loss of large trees or a failure to recruit new large trees or both. We quantify this problem in a globally iconic ecosystem in southeastern Australia – forests dominated by the world’s tallest angiosperms, Mountain Ash (Eucalyptus Regnans). Tree, stand and landscape-level factors influencing the death and collapse of large living cavity trees and the decay and collapse of dead trees with cavities are documented using a suite of long-term datasets gathered between 1983 and 2011. The historical rate of tree mortality on unburned sites between 1997 and 2011 was.14 % with a mortality spike in the driest period (2006–2009). Following a major wildfire in 2009, 79 % of large living trees with cavities died and 57–100 % of large dead trees were destroyed on burned sites. Repeated measurements between 1997 and 2011 revealed no recruitment of any new large trees with cavities on any of our unburned or burned sites. Transition probability matrices of large trees with cavities through increasingly decayed condition states projects a severe shortage of large trees with cavities by 2039 that will continue until at least 2067. This large cavity tree crisis in Mountain Ash forests is a product of: (1) the prolonged time required (.120 years) for initiatio
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Dominant Drivers of Seedling Establishment in a Fire-Dependent Obligate Seeder: Climate or Fire Regimes?
Ecosystems, 2013Co-Authors: Annabel L. Smith, David Blair, Lachlan Mcburney, Sam C. Banks, Philip S. Barton, Wade Blanchard, Don A. Driscoll, A. Malcolm Gill, David B. LindenmayerAbstract:Climate change is causing fire regime shifts in ecosystems worldwide. Plant species with regeneration strategies strongly linked to a fire regime, such as obligate seeders, may be particularly threatened by these changes. It is unclear whether changes in fire regimes or the direct effects of climate change will be the dominant threats to obligate seeders in future. We investigated the relative importance of fire-related variables (fire return interval and fire severity) and environmental factors (climate and topography) on seedling establishment in the world’s tallest angiosperm, an obligate seeder, Eucalyptus Regnans. Throughout its range, this species dominates the wet montane forests of south-eastern Australia and plays a keystone role in forest structure. Following major wildfires, we investigated seedling establishment in E. Regnans within 1 year of fire as this is a critical stage in the regeneration niche of obligate seeders. Seedling presence and abundance were strongly related to the occurrence of fire but not to variation in fire severity (moderate vs. high severity). Seedling abundance increased with increasing fire return interval (range 26–300 years). First-year seedling establishment was also strongly associated with low temperatures and with high elevations, high precipitation and persistent soil water availability. Our results show that both climate and fire regimes are strong drivers of E. Regnans seedling establishment. The predicted warming and drying of the climate might reduce the regeneration potential for some obligate seeders in future and these threats are likely to be compounded by changes in fire regimes, particularly increases in fire frequency.
Richard G Benyon - One of the best experts on this subject based on the ideXlab platform.
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using tree detection algorithms to predict stand sapwood area basal area and stocking density in Eucalyptus Regnans forest
Remote Sensing, 2015Co-Authors: D Jaskierniak, Richard G Benyon, George Kuczera, Luke WallaceAbstract:Managers of forested water supply catchments require efficient and accurate methods to quantify changes in forest water use due to changes in forest structure and density after disturbance. Using Light Detection and Ranging (LiDAR) data with as few as 0.9 pulses m−2, we applied a local maximum filtering (LMF) method and normalised cut (NCut) algorithm to predict stocking density (SDen) of a 69-year-old Eucalyptus Regnans forest comprising 251 plots with resolution of the order of 0.04 ha. Using the NCut method we predicted basal area (BAHa) per hectare and sapwood area (SAHa) per hectare, a well-established proxy for transpiration. Sapwood area was also indirectly estimated with allometric relationships dependent on LiDAR derived SDen and BAHa using a computationally efficient procedure. The individual tree detection (ITD) rates for the LMF and NCut methods respectively had 72% and 68% of stems correctly identified, 25% and 20% of stems missed, and 2% and 12% of stems over-segmented. The significantly higher computational requirement of the NCut algorithm makes the LMF method more suitable for predicting SDen across large forested areas. Using NCut derived ITD segments, observed versus predicted stand BAHa had R2 ranging from 0.70 to 0.98 across six catchments, whereas a generalised parsimonious model applied to all sites used the portion of hits greater than 37 m in height (PH37) to explain 68% of BAHa. For extrapolating one ha resolution SAHa estimates across large forested catchments, we found that directly relating SAHa to NCut derived LiDAR indices (R2 = 0.56) was slightly more accurate but computationally more demanding than indirect estimates of SAHa using allometric relationships consisting of BAHa (R2 = 0.50) or a sapwood perimeter index, defined as (BAHaSDen)½ (R2 = 0.48).
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A new method for measuring stand sapwood area in forests
Ecohydrology, 2014Co-Authors: D Jaskierniak, Richard G Benyon, George Kuczera, Andrew P. RobinsonAbstract:We introduce a novel methodology for measuring stand sapwood area (SA), which provides a useful indicator of evapotranspiration from forest stands. The method is demonstrated in a 73-year-old Eucalyptus Regnans forest comprising 784 stems over a 5 ha area. We used photos of stump cross-sections to differentiate sapwood from heartwood and found 90% of stump segments to have a visible transition boundary. The digital images were corrected for lens distortion and scaled to an actual cross-sectional area, with resulting stump perimeters corresponding well with field-measured perimeters traced using string (root-mean-square error = 4 cm, R² = 0.99). Calculated SA and basal area (BA) at stump height were coupled with tree and sapwood taper data to predict the SA:BA ratio at 1.3 m height (̂R1.3). Tree taper data were coupled with stump dimensions data in a mixed-effects model to predict each stump's BA at 1.3 m, and sapwood taper data from buttress logs were used to improve each stems ̂R1.3. Using this procedure, we found our study site to have an ̂R1.3 of 0.21 and total stand SA at 1.3 m height of 9.3 m² ha⁻¹. We quantified the bias in traditional ̂R1.3 estimates that use cores to measure sapwood thickness and diameter tape to calculate SA. We show traditional methods underestimate inline image that increases with tree diameter and decreases with stem circularity, whereas our methodology gave more accurate measures of SA in large buttressing trees. Our methodology also provides a more efficient way of generating maps of SA variation across large forested catchments
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long term growth and water balance predictions for a mountain ash Eucalyptus Regnans forest catchment subject to clear felling and regeneration
Tree Physiology, 1996Co-Authors: Robert A. Vertessy, Richard G Benyon, T J Hatton, Warrick DawesAbstract:We used a physically based ecohydrological model to predict the water balance and growth responses of a mountain ash (Eucalyptus Regnans F. Muell.) forest catchment to clear-felling and regeneration. The model, Topog-IRM, was applied to a 0.53 km(2) catchment for a 3-year pretreatment period, and a 20-year period following clear-felling and reseeding of 78% of the catchment area. Simulations were evaluated by comparing observed and predicted streamflows, rainfall interception and soil water values. The model faithfully simulated observed temporal patterns of overstory live stem carbon gain and produced a leaf area trajectory consistent with field observations. Cumulative throughfall was predicted within 1% of observations over an 18-year period. Over a 4-year period, predicted soil water storage in the upper 1.5 m of soil agreed well with field observations. There was fair correspondence between observed and predicted daily streamflows, and the model explained 76% of the variation in monthly flows. Over the 23-year simulation period, the model overpredicted cumulative streamflow by 6%. We argue that there is a useful role for physically based ecohydrological models in the management of mountain ash forest catchments that cannot be satisfied by simple empirical approaches.
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relationships between stem diameter sapwood area leaf area and transpiration in a young mountain ash forest
Tree Physiology, 1995Co-Authors: Robert A. Vertessy, Richard G Benyon, S K Osullivan, P R GribbenAbstract:: We examined relationships between stem diameter, sapwood area, leaf area and transpiration in a 15-year-old mountain ash (Eucalyptus Regnans F. Muell.) forest containing silver wattle (Acacia dealbata Link.) as a suppressed overstory species and mountain hickory (Acacia frigescens J.H. Willis) as an understory species. Stem diameter explained 93% of the variation in leaf area, 96% of the variation in sapwood area and 88% of the variation in mean daily spring transpiration in 19 mountain ash trees. In seven silver wattle trees, stem diameter explained 87% of the variation in sapwood area but was a poor predictor of the other variables. When transpiration measurements from individual trees were scaled up to a plot basis, using stem diameter values for 164 mountain ash trees and 124 silver wattle trees, mean daily spring transpiration rates of the two species were 2.3 and 0.6 mm day(-1), respectively. The leaf area index of the plot was estimated directly by destructive sampling, and indirectly with an LAI-2000 plant canopy analyzer and by hemispherical canopy photography. All three methods gave similar results.