Ageing mallee eucalypt vegetation after fire: insights for successional trajectories in semi-arid mallee ecosystems

2010 ◽  
Vol 58 (5) ◽  
pp. 363 ◽  
Author(s):  
Michael F. Clarke ◽  
Sarah C. Avitabile ◽  
Lauren Brown ◽  
Kate E. Callister ◽  
Angie Haslem ◽  
...  
Keyword(s):  
Fire History ◽  
Food Sources ◽  
Validation Data ◽  
Class Distribution ◽  
Age Class ◽  
Ecological Features ◽  
Time Since Fire ◽  
The Status ◽  
Minimum Age ◽  
Semi Arid

A critical requirement in the ecological management of fire is knowledge of the age-class distribution of the vegetation. Such knowledge is important because it underpins the distribution of ecological features important to plants and animals including retreat sites, food sources and foraging microhabitats. However, in many regions, knowledge of the age-class distribution of vegetation is severely constrained by the limited data available on fire history. Much fire-history mapping is restricted to post-1972 fires, following satellite imagery becoming widely available. To investigate fire history in the semi-arid Murray Mallee region in southern Australia, we developed regression models for six species of mallee eucalypt (Eucalyptus oleosa F.Muell. ex. Miq. subsp. oleosa, E. leptophylla F.Muell. ex. Miq., E. dumosa J. Oxley, E. costata subsp. murrayana L. A. S. Johnson & K. D. Hill, E. gracilis F.Muell. and E. socialis F.Muell. ex. Miq.) to quantify the relationship between mean stem diameter and stem age (indicated by fire-year) at sites of known time since fire. We then used these models to predict mean stem age, and thus infer fire-year, for sites where the time since fire was not known. Validation of the models with independent data revealed a highly significant correlation between the actual and predicted time since fire (r = 0.71, P < 0.001, n = 88), confirming the utility of this method for ageing stands of mallee eucalypt vegetation. Validation data suggest the models provide a conservative estimate of the age of a site (i.e. they may under-estimate the minimum age of sites >35 years since fire). Nevertheless, this approach enables examination of post-fire chronosequences in semi-arid mallee ecosystems to be extended from 35 years post-fire to over 100 years. The predicted ages identified for mallee stands imply a need for redefining what is meant by ‘old-growth’ mallee, and challenges current perceptions of an over-abundance of ‘long-unburnt’ mallee vegetation. Given the strong influence of fire on semi-arid mallee vegetation, this approach offers the potential for a better understanding of long-term successional dynamics and the status of biota in an ecosystem that encompasses more than 250 000 km2 of southern Australia.

Estimating the time since fire of long-unburnt Eucalyptus salubris (Myrtaceae) stands in the Great Western Woodlands

2013 ◽  
Vol 61 (1) ◽  
pp. 11 ◽  
Author(s):  
Carl R. Gosper ◽  
Suzanne M. Prober ◽  
Colin J. Yates ◽  
Georg Wiehl
Keyword(s):  
Plant Height ◽  
Growth Ring ◽  
Plant Size ◽  
Current Approach ◽  
Significant Advance ◽  
Growth Rings ◽  
Trunk Diameter ◽  
Class Distribution ◽  
Age Class ◽  
Time Since Fire

Establishing the time since fire in infrequently burnt, yet fire-prone, communities is a significant challenge. Until this can be resolved for >50-year timeframes, our capacity to understand important ecological processes, such as the periods required for development of habitat features, will remain limited. We characterised the relationship between observable tree growth rings, plant age and plant size in Eucalyptus salubris F.Muell. in the globally significant Great Western Woodlands in south-western Australia. In the context of recent concerns regarding high woodland fire occurrence, we then used this approach to estimate the age of long-unburnt E. salubris stands, and the age-class distribution of Eucalyptus woodlands across the region. Time since fire was strongly predicted by trunk growth rings and plant size predicted growth rings with reasonable accuracy. The best model estimating growth rings contained parameters for trunk diameter, plant height and plot location, although simple models including either trunk diameter or plant height were nearly as good. Using growth ring–size relationships to date long-unburnt stands represents a significant advance over the current approach based on satellite imagery, which substantially truncates post-fire age. However, there was significant uncertainty over the best model form for estimating the time since fire of stands last burnt over 200 years ago. The management implications of predicted age-class distributions were highly dependent on both the choice of what, if any, transformation was applied to growth rings, and the theoretical age-class distribution to which the actual age-class distribution was compared.

Age-class distribution and the forest fire cycle

1978 ◽  
Vol 8 (2) ◽  
pp. 220-227 ◽  
Author(s):  
C. E. Van Wagner
Keyword(s):  
Computer Simulation ◽  
Exponential Distribution ◽  
Forest Fire ◽  
Fire History ◽  
Class Structure ◽  
Fire Cycle ◽  
Class Distribution ◽  
Age Class ◽  
Negative Exponential Distribution ◽  
Negative Exponential

The expected age-class structure of a forest dependent on random periodic fire for disturbance and renewal is derived and presented. It is simply the negative exponential distribution, well known in probability mathematics. An important feature of this concept is that the present age-class structure of such a forest is the key to its past fire history. Its limitations are discussed, and the computer simulation of variations, including the interaction of fire and logging, is described. Three examples of its use in interpreting fire history are given.

Current plant ecological features reflect historical forest management systems in semi-arid oak forests

2021 ◽  
Vol 167 ◽  
pp. 106268
Author(s):  
Mehdi Heydari ◽  
Sina Attar Roshan ◽  
Reza Omidipour ◽  
Manuel Esteban Lucas-Borja ◽  
Bernard Prévosto
Keyword(s):  
Forest Management ◽  
Management Systems ◽  
Oak Forests ◽  
Ecological Features ◽  
Plant Ecological ◽  
Historical Forest ◽  
Semi Arid

Ecological thresholds and the status of fire-sensitive vegetation in western Arnhem Land, northern Australia: implications for management

2009 ◽  
Vol 18 (2) ◽  
pp. 127 ◽  
Author(s):  
Andrew C. Edwards ◽  
Jeremy Russell-Smith
Keyword(s):  
National Parks ◽  
Fire History ◽  
Fire Management ◽  
Fire Regime ◽  
Vegetation Types ◽  
Northern Australia ◽  
Study Region ◽  
Ecological Thresholds ◽  
Arnhem Land ◽  
The Status

The paper examines the application of the ecological thresholds concept to fire management issues concerning fire-sensitive vegetation types associated with the remote, biodiversity-rich, sandstone Arnhem Plateau, in western Arnhem Land, monsoonal northern Australia. In the absence of detailed assessments of fire regime impacts on component biota such as exist for adjoining Nitmiluk and World Heritage Kakadu National Parks, the paper builds on validated 16-year fire history and vegetation structural mapping products derived principally from Landsat-scale imagery, to apply critical ecological thresholds criteria as defined by fire regime parameters for assessing the status of fire-sensitive habitat and species elements. Assembled data indicate that the 24 000 km2 study region today experiences fire regimes characterised generally by high annual frequencies (mean = 36.6%) of large (>10 km2) fires that occur mostly in the late dry season under severe fire-weather conditions. Collectively, such conditions substantially exceed defined ecological thresholds for significant proportions of fire-sensitive indicator rain forest and heath vegetation types, and the long-lived obligate seeder conifer tree species, Callitris intratropica. Thresholds criteria are recognised as an effective tool for informing ecological fire management in a variety of geographic settings.

scholarly journals Impacts of fire history in a semi-arid woodland savanna

2018 ◽  
Vol 6 ◽  
pp. 207-218
Author(s):  
Dave F. Joubert ◽  
Caroline Stolter ◽  
Kristin M. Krewenka ◽  
Nekulilo Uunona,Vistorina Amputu ◽  
Elise Nghalipo ◽  
...  
Keyword(s):  
Fire History ◽  
Semi Arid

Timber production versus old-growth preservation with endogenous prices and forest age-classes

2004 ◽  
Vol 34 (6) ◽  
pp. 1296-1310 ◽  
Author(s):  
Olli Tahvonen
Keyword(s):  
Environmental Values ◽  
Timber Harvesting ◽  
Timber Production ◽  
Forest Age ◽  
Forest Land ◽  
Age Classes ◽  
Old Growth ◽  
Class Distribution ◽  
Age Class ◽  
Long Run

This study combines timber production and environmental values, applying a dynamic forest-level economic model with any number of forest age-classes. The model includes endogenous timber price or nonlinear harvesting costs and various possibilities to specify the dependence of environmental values (related e.g. to species persistence) on the forest age-class structure. The nonlinearities in the net benefits from timber production have the consequence that fluctuations in optimal timber harvesting may totally vanish or at least become smaller than in forest scheduling models without ad hoc even flow constraints. If environmental values are specified to depend on the fraction of forest land preserved as old growth, the optimal long run allocation between timber production and old growth is represented by an equilibrium continuum. Thus the optimal long run allocation depends on the initial age-class distribution. The continuum and the dependence of initial age-class distribution vanish when the rate of discount approaches zero. If the environmental values of age-classes increase smoothly with age, the long run equilibrium may simultaneously include multiple rotation periods. The model determines the optimality of producing timber and environmental values separately at different parts of the forest or at the same piece of forest land. Numerical computation suggests that the optimal solution always converges toward some optimal long run stationary age-class distribution.

scholarly journals Patterns of Feeding by Householders Affect Activity of Hedgehogs (Erinaceus europaeus) during the Hibernation Period

Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1344 ◽  
Author(s):  
Abigail Gazzard ◽  
Philip J. Baker
Keyword(s):  
Food Sources ◽  
Energy Deficit ◽  
Net Energy ◽  
Survey Period ◽  
Erinaceus Europaeus ◽  
Ecological Features ◽  
Hibernation Period ◽  
Negative Effect ◽  
Anthropogenic Food Sources ◽  
The Town

West European hedgehogs (Erinaceus europaeus) are likely to encounter unusual ecological features in urban habitats, such as anthropogenic food sources and artificial refugia. Quantifying how these affect hedgehog behaviour is vital for informing conservation guidelines for householders. We monitored hedgehog presence/absence in gardens in the town of Reading, UK, over the winter of 2017–2018 using a volunteer-based footprint tunnel survey, and collected data on garden characteristics, supplementary feeding (SF) habits, and local environmental conditions. Over a 20-week survey period, hedgehog presence was lowest between January and March. Occupancy analysis indicated that SF significantly affected hedgehog presence/absence before, during, and after hibernation. The number of nesting opportunities available in gardens, average temperatures, and daylength were also supported as important factors at different stages. In particular, our results suggest that SF could act to increase levels of activity during the winter when hedgehogs should be hibernating. Stimulating increased activity at this sensitive time could push hedgehogs into a net energy deficit or, conversely, help some individuals survive which might not otherwise do so. Therefore, further research is necessary to determine whether patterns of feeding by householders have a positive or negative effect on hedgehog populations during the hibernation period.

Past, current, and future fire frequencies in Quebec's commercial forests: implications for the cumulative effects of harvesting and fire on age-class structure and natural disturbance-based management

2006 ◽  
Vol 36 (11) ◽  
pp. 2737-2744 ◽  
Author(s):  
Yves Bergeron ◽  
Dominic Cyr ◽  
C Ronnie Drever ◽  
Mike Flannigan ◽  
Sylvie Gauthier ◽  
...  
Keyword(s):  
Forest Management ◽  
Sustainable Forest Management ◽  
Natural Disturbance ◽  
Fire Frequency ◽  
Ecological Functions ◽  
The Past ◽  
Class Distribution ◽  
Age Class ◽  
If Current ◽  
In Fire

The past decade has seen an increasing interest in forest management based on historical or natural disturbance dynamics. The rationale is that management that favours landscape compositions and stand structures similar to those found historically should also maintain biodiversity and essential ecological functions. In fire-dominated landscapes, this approach is feasible only if current and future fire frequencies are sufficiently low compared with the preindustrial fire frequency, so a substitution of fire by forest management can occur without elevating the overall frequency of disturbance. We address this question by comparing current and simulated future fire frequency based on 2 × CO2 and 3 × CO2 scenarios to historical reconstructions of fire frequency in the commercial forests of Quebec. For most regions, current and simulated future fire frequencies are lower than the historical fire frequency, suggesting that forest management could potentially be used to maintain or recreate the age-class distribution of fire-dominated preindustrial landscapes. Current even-aged management, however, tends to reduce forest variability by, for example, truncating the natural age-class distribution and eliminating mature and old-growth forests from the landscape. Therefore, in the context of sustainable forest management, silvicultural techniques that retain a spectrum of forest compositions and structures at different scales are necessary to maintain this variability and thereby allow a substitution of fire by harvesting.

Changes in forest fire frequency in Kootenay National Park, Canadian Rockies

1990 ◽  
Vol 68 (8) ◽  
pp. 1763-1767 ◽  
Author(s):  
Alan M. Masters
Keyword(s):  
Forest Fire ◽  
Rocky Mountains ◽  
National Park ◽  
Fire History ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Ice Age ◽  
Distribution Analysis ◽  
Fire Cycle ◽  
Time Since Fire

Time-since-fire distribution analysis is used to estimate forest fire frequency for the 1400 km2 Kootenay National Park, British Columbia, located on the west slope of the Rocky Mountains. The time-since-fire distribution indicates three periods of different fire frequency: 1988 to 1928, 1928 to 1788, and before 1788. The fire cycle for the park was > 2700 years for 1988 to 1928, 130 years between 1928 and 1788, and 60 years between 1778 and 1508. Longer fire cycles after 1788 and 1928 may be due, respectively, to cool climate associated with the Little Ice Age and a recent period of higher precipitation. Contrary to some fire history investigations in the region, neither a fire suppression policy since park establishment in 1919, nor the completion of the Windermere Highway through the park in 1923 appear to have changed the fire frequency from levels during pre-European occupation. Spatial partitioning of the time-since-fire distribution was unsuccessful. No relationship was found between elevation or aspect and fire frequency. Key words: fire cycle, Rocky Mountains, climate change.

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