Impact of a moderate/high-severity prescribed eucalypt forest fire on soil phosphorous stocks and partitioning

Flame residence times and rates of weight loss of eucalypt forest fuel particles

International Journal of Wildland Fire ◽

10.1071/wf01005 ◽

2001 ◽

Vol 10 (2) ◽

pp. 137 ◽

Cited By ~ 43

Author(s):

N. D. Burrows

Keyword(s):

Weight Loss ◽

Forest Fire ◽

Size Composition ◽

Scientific Basis ◽

Residence Times ◽

Fire Behaviour ◽

Eucalypt Forest ◽

Round Wood ◽

Fine Fuels ◽

Fuel Particles

Shape, size, composition and arrangement of fuel particles within a fuel array significantly affect the way in which wildland fires behave. Australian eucalypt forest fire behaviour models characterise fine fuels according to the quantity burnt in the flaming zone, and the upper size limit for fine fuel particles is somewhat arbitrarily set at 6 mm for the McArthur Forest Fire Danger Meter and 10 mm for the Forest Fire Behaviour Tables for Western Australia. Flame residence time and rate of weight loss during combustion of dry eucalypt leaves and different dimensions of round wood were measured to provide a scientific basis for standardising litter fuel sampling in dry eucalypt forests. Eucalypt leaves burnt at a rate equivalent to a piece of 4 mm diameter round wood, with smaller diameter round wood being the most flammable component of the fuel array. Based on flame residence times of individual fuel particles measured in the laboratory, and eucalypt surface fuel arrays observed in the field, fine litter fuel sampling should be standardised to leaves and round wood less than 6 mm in diameter. This study also enables the determination of the contribution of larger fuel particles to flaming zone combustion and intensity.

Download Full-text

High severity fire promotes a more flammable eucalypt forest structure

Austral Ecology ◽

10.1111/aec.13134 ◽

2021 ◽

Author(s):

James W. Barker ◽

Owen F. Price ◽

Meaghan E. Jenkins

Keyword(s):

Forest Structure ◽

High Severity ◽

Eucalypt Forest

Download Full-text

Assessing Legacy Effects of Wildfires on the Crown Structure of Fire-Tolerant Eucalypt Trees Using Airborne Lidar Data

10.20944/preprints201910.0145.v1 ◽

2019 ◽

Author(s):

Yogendra K. Karna ◽

Trent D. Penman ◽

Cristina Aponte ◽

Lauren T. Bennett

Keyword(s):

Airborne Lidar ◽

Lidar Data ◽

Legacy Effects ◽

Individual Tree ◽

Tree Crowns ◽

High Severity ◽

Eucalypt Forest ◽

Crown Width ◽

In Fire ◽

Airborne Lidar Data

Fire-tolerant eucalypt forests of south eastern Australia are assumed to fully recover from even the most intense fires but surprisingly very few studies have quantitatively assessed that recovery. Accurate assessment of horizontal and vertical attributes of tree crowns after fire is essential to understand the fire’s legacy effects on tree growth and on forest structure. In this study, we quantitatively assessed individual tree crowns 8.5 years after a 2009 wildfire that burnt extensive areas of eucalypt forest in temperate Australia. We used airborne lidar data validated with field measurements to estimate multiple metrics that quantified the cover, density, and vertical distribution of individual-tree crowns in 51 plots of 0.05 ha in fire-tolerant eucalypt forest across four wildfire severity types (unburnt, low, moderate, high). Significant differences in the field-assessed mean height of fire scarring as a proportion of tree height, and in the proportions of trees with epicormic (stem) resprouts were consistent with the gradation in fire severity. Linear mixed-effects models indicated persistent effects of both moderate- and high-severity wildfire on tree crown architecture. Trees at high-severity sites had significantly less crown projection area and live crown width as a proportion of total crown width than those at unburnt and low-severity sites. Significant differences in lidar-based metrics (crown cover, evenness, leaf area density profiles) indicated that tree crowns at moderate- and high-severity sites were comparatively narrow and more evenly distributed down the tree stem. These conical-shaped crowns contrasted sharply with the rounded crowns of trees at unburnt and low-severity sites, and likely influenced both tree productivity and the accuracy of biomass allometric equations for nearly a decade after the fire. Our data provide a clear example of the utility of airborne lidar data for quantifying the impacts of disturbances at the scale of individual trees. Quantified effects of contrasting fire severities on the structure of resprouter tree crowns provide a strong basis for interpreting post-fire patterns in forest canopies and vegetation profiles in lidar and other remotely-sensed data at larger scales.

Download Full-text

Impact of high-severity fire in a Tasmanian dry eucalypt forest

Australian Journal of Botany ◽

10.1071/bt15259 ◽

2016 ◽

Vol 64 (3) ◽

pp. 193 ◽

Cited By ~ 17

Author(s):

Lynda D. Prior ◽

Grant J. Williamson ◽

David M. J. S. Bowman

Keyword(s):

Plant Mortality ◽

Dry Forests ◽

Obligate Seeder ◽

High Severity ◽

Fuel Loads ◽

Eucalypt Forest ◽

Whole Plant ◽

Eucalypt Forests ◽

Wet Forests

Dry eucalypt forests are believed to be highly fire tolerant, but their response to fire is not well quantified. We measured the effect of high-severity fires in dry eucalypt forest in the Tasmanian Midlands, the driest region on the island. We compared stand structures and fuel loads in long-unburnt (>15 years since fire) and recently burnt (<5 years since fire) sites that had been completely defoliated. Even in unburnt plots, 37% of eucalypt stems and 56% of acacia stems ≥5 cm in diameter were dead, possibly because of antecedent drought. The density of live eucalypt stems was 37% lower overall in burnt than in unburnt plots, compared with 78% lower for acacias. Whole-plant mortality caused by fire was estimated at 25% for eucalypt trees and 33% for acacias. Fire stimulated establishment of both eucalypt and acacia seedlings, although some seedlings and saplings were present in long-unburnt plots. The present study confirmed that eucalypts in dry forests are more tolerant of fire than the obligate seeder eucalypts in wet forests. However, there were few live mature stems remaining in some burnt plots, suggesting that dry eucalypt forests could be vulnerable to increasingly frequent, severe fires.

Download Full-text

Forest fire break not a barrier to movement for a threatened rodent, the smoky mouse, Pseudomys fumeus (Rodentia : Muridae)

Australian Mammalogy ◽

10.1071/am15050 ◽

2017 ◽

Vol 39 (1) ◽

pp. 42 ◽

Cited By ~ 2

Author(s):

P. V. Macak ◽

P. W. Menkhorst

Keyword(s):

Forest Fire ◽

Threatened Species ◽

Vegetation Cover ◽

Animal Species ◽

Radio Tracking ◽

Breeding Dispersal ◽

Population Fragmentation ◽

Vegetation Communities ◽

Eucalypt Forest ◽

Eastern Australia

Linear clearings associated with roads passing through vegetation communities are known to inhibit movements of many animal species. This can reduce breeding, dispersal and foraging opportunities and lead to population fragmentation, putting further pressure on populations that are small or vulnerable, such as those of threatened species. We tested the prediction that the threatened smoky mouse, Pseudomys fumeus, would not readily cross a 30-m-wide fire break constructed along a ridgeline in eucalypt forest in Victoria, south-eastern Australia. Radio-tracking was conducted along 650 m of the fire break from October to December 2011. We recorded seven individuals that crossed the break. Five individuals fitted with transmitter collars were detected crossing at least twice on 13 of 18 tracking nights. Two animals were found to have crossed by being tracked to nests during the day and/or via trapping. A nearby narrow, unsealed vehicle track was crossed by an additional animal. Our results suggest that it is unlikely that the fire break was acting as a barrier to P. fumeus movements. The presence of fire breaks in P. fumeus habitat may, however, expose individuals to a higher rate of predation when they cross large areas unprotected by vegetation cover.

Download Full-text

Assessing Legacy Effects of Wildfires on the Crown Structure of Fire-Tolerant Eucalypt Trees Using Airborne LiDAR Data

Remote Sensing ◽

10.3390/rs11202433 ◽

2019 ◽

Vol 11 (20) ◽

pp. 2433 ◽

Cited By ~ 6

Author(s):

Yogendra K. Karna ◽

Trent D. Penman ◽

Cristina Aponte ◽

Lauren T. Bennett

Keyword(s):

Airborne Lidar ◽

Lidar Data ◽

Legacy Effects ◽

Individual Tree ◽

Tree Crowns ◽

High Severity ◽

Eucalypt Forest ◽

Crown Width ◽

In Fire ◽

Airborne Lidar Data

The fire-tolerant eucalypt forests of south eastern Australia are assumed to fully recover from even the most intense fires; however, surprisingly, very few studies have quantitatively assessed that recovery. The accurate assessment of horizontal and vertical attributes of tree crowns after fire is essential to understand the fire’s legacy effects on tree growth and on forest structure. In this study, we quantitatively assessed individual tree crowns 8.5 years after a 2009 wildfire that burnt extensive areas of eucalypt forest in temperate Australia. We used airborne LiDAR data validated with field measurements to estimate multiple metrics that quantified the cover, density, and vertical distribution of individual-tree crowns in 51 plots of 0.05 ha in fire-tolerant eucalypt forest across four wildfire severity types (unburnt, low, moderate, high). Significant differences in the field-assessed mean height of fire scarring as a proportion of tree height and in the proportions of trees with epicormic (stem) resprouts were consistent with the gradation in fire severity. Linear mixed-effects models indicated persistent effects of both moderate and high-severity wildfire on tree crown architecture. Trees at high-severity sites had significantly less crown projection area and live crown width as a proportion of total crown width than those at unburnt and low-severity sites. Significant differences in LiDAR -based metrics (crown cover, evenness, leaf area density profiles) indicated that tree crowns at moderate and high-severity sites were comparatively narrow and more evenly distributed down the tree stem. These conical-shaped crowns contrasted sharply with the rounded crowns of trees at unburnt and low-severity sites and likely influenced both tree productivity and the accuracy of biomass allometric equations for nearly a decade after the fire. Our data provide a clear example of the utility of airborne LiDAR data for quantifying the impacts of disturbances at the scale of individual trees. Quantified effects of contrasting fire severities on the structure of resprouter tree crowns provide a strong basis for interpreting post-fire patterns in forest canopies and vegetation profiles in Light Detection and Ranging (LiDAR) and other remotely-sensed data at larger scales.

Download Full-text

Forest fire

AccessScience ◽

10.1036/1097-8542.268900 ◽

2015 ◽

Keyword(s):

Forest Fire

Download Full-text

Numerical simulation of the tree higro-thermal response in forest fire environment

WEENTECH Proceedings in Energy ◽

10.32438/wpe.0220 ◽

2020 ◽

pp. 57-65

Author(s):

Eusébio Conceiçã ◽

João Gomes ◽

Maria Manuela Lúcio ◽

Jorge Raposo ◽

Domingos Xavier Viegas ◽

...

Keyword(s):

Forest Fire ◽

Numerical Study ◽

Thermal Response ◽

View Factor ◽

Tree Model ◽

Pine Tree ◽

Surface Temperatures ◽

Fire Environment ◽

Fire Front ◽

Heat Exchanges

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.

Download Full-text