Canopy Densities Research Articles

The Sequential Aerosol Technique: A Major Component in an Integrated Strategy of Intervention against Riverine Tsetse in Ghana

BackgroundAn integrated strategy of intervention against tsetse flies was implemented in the Upper West Region of Ghana (9.62°–11.00° N, 1.40°–2.76° W), covering an area of ≈18,000 km2 within the framework of the Pan-African Tsetse and Trypanosomosis Eradication Campaign. Two species were targeted: Glossina tachinoides and Glossina palpalis gambiensis.Methodology/Principal FindingsThe objectives were to test the potentiality of the sequential aerosol technique (SAT) to eliminate riverine tsetse species in a challenging subsection (dense tree canopy and high tsetse densities) of the total sprayed area (6,745 km2) and the subsequent efficacy of an integrated strategy including ground spraying (≈100 km2), insecticide treated targets (20,000) and insecticide treated cattle (45,000) in sustaining the results of tsetse suppression in the whole intervention area. The aerial application of low-dosage deltamethrin aerosols (0.33–0.35 g a.i/ha) was conducted along the three main rivers using five custom designed fixed-wings Turbo thrush aircraft. The impact of SAT on tsetse densities was monitored using 30 biconical traps deployed from two weeks before until two weeks after the operations. Results of the SAT monitoring indicated an overall reduction rate of 98% (from a pre-intervention mean apparent density per trap per day (ADT) of 16.7 to 0.3 at the end of the fourth and last cycle). One year after the SAT operations, a second survey using 200 biconical traps set in 20 sites during 3 weeks was conducted throughout the intervention area to measure the impact of the integrated control strategy. Both target species were still detected, albeit at very low densities (ADT of 0.27 inside sprayed blocks and 0.10 outside sprayed blocks).Conclusions/SignificanceThe SAT operations failed to achieve elimination in the monitored section, but the subsequent integrated strategy maintained high levels of suppression throughout the intervention area, which will contribute to improving animal health, increasing animal production and fostering food security.

Site-specific risk factors of white mould epidemics in bean (Phaseolus vulgaris) in Tasmania, Australia

In Tasmania, Australia, if more than 5% of bean pods are affected by white mould (Sclerotinia sclerotiorum) shipments may be rejected by the processor. This standard dictates prophylactic fungicide application over flowering, although in some instances treatment may not be warranted because of low disease risk. Surveys were conducted to identify relationships among edaphic factors, weather variables, and production practices associated with white mould. Correlations were found between disease incidence and the number of apothecia, fungicide timing, and mean minimum air temperature in the 10- and 30-day periods preceding harvest. Significant differences in disease incidence also were detected among cultivars and bean canopy densities. A nonparametric discriminant analysis model based on the predictor variables of mean minimum air temperature in the 10- and 30-day periods before harvest, cultivar, bean canopy density, and fungicide application correctly predicted presence of white mould on pods in 77% of bean fields. Several factors that can be manipulated to reduce disease risks were identified.

Comparisons of three models for vegetation canopy bi-directional reflectance distribution function

Aims With the development of quantitative remote sensing technology, multiple bi-directional reflectance dis-tribution function (BRDF) models have been developed to describe reflectance of forest canopies. Our objective is to compare the DART, 4SCALE and MGEOSAIL models for greater understanding their proper use. Methods We used the BRDF models to simulate reflectance of the scene with different canopy densities at various observation angles in red and near-infrared bands and compared the results to analyze model applicability and limitations. Important findings The MGEOSAIL model is suitable to simulate the scene reflectance with low canopy den-sity and large trees, and the hotspot is obvious. The DART and 4SCALE models are accurate and suitable to simulate the scene reflectance with various kinds of canopy density. Also, the scene reflectance simulated by 4SCALE is higher than DART's simulated first-order scattering value, but lower than DART's fifth-order scat-tering value. All three models show the "bowl" shape in the near-infrared band.

Bayesian analysis of canopy transpiration models: A test of posterior parameter means against measurements

Summary Big-leaf models of transpiration are based on the hypothesis that structural heterogeneity within forest canopies can be ignored at stand or larger scales. However, the adoption of big-leaf models is de facto rather than de jure , as forests are never structurally or functionally homogeneous. We tested big-leaf models both with and without modification to include canopy gaps, in a heterogeneous quaking aspen stand having a range of canopy densities. Leaf area index ( L ) and canopy closure were obtained from biometric data, stomatal conductance parameters were obtained from sap flux measurements, while leaf gas exchange data provided photosynthetic parameters. We then rigorously tested model-data consistency by incrementally starving the models of these measured parameters and using Bayesian Markov Chain Monte Carlo simulation to retrieve the withheld parameters. Model acceptability was quantified with Deviance Information Criterion (DIC), which penalized model accuracy by the number of retrieved parameters. Big-leaf models overestimated canopy transpiration with increasing error as canopy density declined, but models that included gaps had minimal error regardless of canopy density. When models used measured L the other parameters were retrieved with minimal bias. This showed that simple canopy models could predict transpiration in data scarce regions where only L was measured. Models that had L withheld had the lowest DIC values suggesting that they were the most acceptable models. However, these models failed to retrieve unbiased parameter estimates indicating a mismatch between model structure and data. By quantifying model structure and data requirements this new approach to evaluating model-data fusion has advanced the understanding of canopy transpiration.

Development of a Variable-Rate Sprayer with Laser Scanning Sensor to Synchronize Spray Outputs to Tree Structures

Efficient and effective precision spray equipment and strategies are in high demand to reduce pesticide use in tree crop production. An experimental variable-rate air-assisted sprayer implemented with a high-speed laser scanning sensor was developed to control the spray output of individual nozzles in real time. The sprayer consisted of a laser scanning sensor control system and an air and liquid delivery system. Each nozzle in the delivery system, coupled with a pulse width modulated (PWM) solenoid valve, achieved variable-rate delivery based on occurrence, height, and width of the target tree and its foliage density. Other components of the sensor control system included a unique algorithm for variable-rate control that instantaneously processed measurements of the canopy surfaces. To determine system delay time, a high-speed video camera was used to record the time period between sensor detection of the canopy and nozzle activation. Spray deposition uniformity inside canopies was verified by quantifying spray coverage inside four ornamental nursery trees of different sizes and canopy densities at 3.2 and 6.4 km h-1 travel speeds. Test results demonstrated that differences in spray coverage inside the canopies of these four trees in the spraying direction were not statistically significant, even though these trees had different structures, canopy volumes, and foliage densities. The canopy volume and foliage density measured with the algorithm developed for the laser sensor-controlled detection system exhibited little variation between the two travel speeds. Design criteria for the sensor-controlled system in the experimental sprayer were acceptable for variable-rate application, having great potential for spray volume and drift reduction, and thus reducing environmental impact.

Image‐Assisted Gap Estimation, a Simple Method for Measuring Grapevine Leaf Canopy Density

ABSTRACTThis study compared an image analysis method of leaf canopy density measurement, image‐assisted gap estimation (ImAGE), with the commonly used point quadrat (PQ) analysis. For ImAGE, a blue background (plastic tarpaulin) was placed behind the grapevine (Vitis vinifera L.) row and digitally photographed and the image was analyzed using application‐specific software to calculate the area ratio of background to vine canopy. This was used as an estimate of the percentage area of gaps in the leaf canopy. Relationships among PQ leaf layer number (LLN), ImAGE gap area percentage (GAP), and fruit exposure were investigated in New Zealand vineyards during the 2008–2009 season in Hawke's Bay and in the 2008–2009 and 2009–2010 seasons at Pukekohe (Auckland region).. Gap area percentage was closely related (R2 = 0.87) to LLN. Significant relationships (p < 0.01) were also found between canopy density (measured by either method) and percentage severity of botrytis bunch rot at harvest. Image‐assisted gap estimation provides an alternative method to PQ analysis for measuring canopy density that is quicker, less subjective, and nondamaging. Image‐assisted gap estimation would primarily be useful as a low‐cost research tool as it could provide practical and rapid assessments without a significant investment in equipment. It may also help viticulturists achieve target leaf canopy densities for management of disease risk.

Wave dissipation by flexible vegetation

[1] Dissipation of waves propagating through natural salt marsh vegetation was about half the dissipation expected for rigid vegetation. This low dissipation was predicted by a theoretical model that accounts for bending of vegetation motions. A transect of 3 pulse-coherent Acoustic Doppler Profilers recorded water velocity and pressure (at 8 Hz) within the dense (650 stems/m2) canopy of semi-flexible single-stem vegetation (Schoenoplectus americanus). Most wave energy (56–81%) was dissipated within 19 m of the marsh edge. Two dissipation models, the first assuming rigid vegetation, and the second simulating wave-forced vegetation motion using the theory for bending of linearly-elastic beams, were tested. After choosing optimal drag coefficients, both models yielded a good fit to the observed dissipation (skill score = 0.96–0.99). However, fitted drag coefficients for the rigid model (0.58–0.78) were below the range (0.98–2.2) expected for the observed Reynolds numbers (13–450) and canopy densities (accounting for interactions between stem wakes), whereas drag coefficients for the flexible model (0.97–1.6) were nearer the expected range, indicating that prediction of wave dissipation was improved by simulating vegetation motion.

Effect of micro-environmental factors on natural regeneration of Sal (Shorea robusta)

Micro-environmental factors viz., soil moisture and light intensity are important factors that affect natural regeneration in forests. These factors vary spatially depending on the overhead canopy density of the forest. The present study focused on studying the effect of variation of soil moisture and light intensity on natural regeneration of sal species (Shorea robusta) under different micro-environments due to overhead canopy of varying forest density. Experimental plots of 40m× 40m size were laid under different overhead canopy densities in a small sal forested watershed in the foot hills of Himalayas in Nainital District of Uttarakhand State, India. The plots were monitored on a long term basis for soil moisture at multi depths, light intensity and natural regeneration of sal. The results of the study revealed that the natural regeneration was highest under C1 (up to-0.30) canopy followed by C2 (0.30–0.50), and C3 (0.50–0.70) canopies. The C3 canopy showed the dying back of sal shoots over 4 years of study. The highest R2 value of linear regression between incremental score of plot regeneration and average soil moisture content was obtained as 0.156 for average soil moisture content during non-monsoon months at 100 cm depth. The R2 value between incremental score of plot regeneration and annual average light intensity was obtained as 0.688 which indicated that the regeneration is largely dependent on the light intensity conditions during the year. The multiple linear regression analysis between the incremental score of regeneration and the average light intensity and average soil moisture content revealed that that about 80% of variation in regeneration is explained by both the factors.

Photosynthetic response to different irradiances of undergrowth plants in tree-herb plantation

以上海市松江不同郁闭度(低、中、高)生态公益林—— 香樟(<em>Cinnamomum camphora</em>)林下种植的红茴香(<em>Illicium henryi</em>)和大吴风草(<em>Farfugium japonicum</em>)为研究对象, 并以香樟萌生苗为对照, 分析各植物光合特性在不同生长光强下的动态变化。结果表明: 在不同郁闭度下, 红茴香和大吴风草具有较高的表观量子效率(<em>AQE</em>)、较低的光补偿点(<em>LCP</em>), 而香樟具有较高的最大净光合速率(<em>P</em>_max)和光饱和点(<em>LSP</em>)。随着郁闭度的增加,各植物AQE 逐渐增加, 且不同郁闭度处理间均存在显著差异(<em>P</em><0.05); 香樟<em>P</em>_max 表现为逐渐降低的趋势, 红茴香和大吴风草则呈先上升后降低的趋势; 香樟暗呼吸速率Rd 呈现先降低后增加的趋势, 而红茴香和大吴风草则表现为逐渐降低; 各植物的<em>LCP</em> 和<em>LSP</em> 均表现为逐渐降低的趋势以适应弱光环境。可见, 香樟通过降低自身的<em>LCP</em> 和<em>LSP</em> 逐渐适应弱光环境, 但在高郁闭度下其光合作用仍然受到胁迫; 而红茴香和大吴风草则通过降低<em>LCP</em>、<em>LSP</em> 和自身能量消耗来适应弱光环境, 且在中等郁闭度下具有最高的光合能力, 充分证明其阴生特性。

Powdery Mildew Severity as a Function of Canopy Density: Associated Impacts on Sunlight Penetration and Spray Coverage

Variable canopy densities and associated differences in sunlight distribution within the fruit zones on clusters were quantified and correlated with variable severities of powdery mildew within vineyards in the states of New York, Washington, and South Australia. Canopy density was measured with enhanced point quadrat analysis (EPQA), and the number of shading layers and the photon flux within the fruit zone of individual vines indicated that less disease developed on clusters with more exposure to sunlight. When clusters were categorized as heavily shaded (≤10% photosynthetic photon flux), moderately exposed, or well exposed (≥51% photosynthetic photon flux), vines with the least disease were also shown to have a significantly greater proportion of clusters in the well-exposed category relative to vines with the highest powdery mildew ratings. Consequently, these latter vines had significantly more heavily shaded clusters. The correlation remained strong and the relationship linear even with biweekly applications of either 2 kg/ha or 9 kg/ha of wettable sulfur during the growing season. Additionally, through the use of a fluorescent tracer and EPQA assessments, the deposit of spray materials on clusters was shown to be linearly related to their degree of exposure. Thus, canopy management practices designed to optimize sunlight exposure of grape clusters for fruit quality purposes should also significantly assist in the management of powdery mildew.

Comparison of automatic and interactive thresholding of hemispherical photography

This study presents the effects of operator bias and variation in interactive thresholding on the estimation of light environment using hemispherical photography. Twenty-one hemispherical photographs taken beneath a wide range of canopy densities were visually converted to binary images twice by 21 operators, and then the gap fraction was computed from the images. The interactive threshold varied greatly among the different operators and within a single operator, which resulted in a considerable operator bias and variation in the gap fraction. This study also compared three widely used automatic thresholding algorithms, which were installed in freely available software LIA for Win32 for analyzing hemispherical photography, with interactive thresholding using the same photographs. The median of the interactive threshold by repetitive interactive thresholdings from 21 operators was assumed to be correct for the comparison. The results indicated that MINIMUM was considered to be a better algorithm than the other ones installed in LIA32 when the gap fraction was over 10%. However, VARIANCE seemed to be superior to MINIMUM under the low gap fraction and the cloudy sky condition with dark and white clouds. This implied that MINIMUM or VARIANCE should be used for analyzing hemispherical photographs with LIA32. In conclusion, we need to pay attention to the selection of the automatic thresholding algorithm and the sky condition when taking hemispherical photographs.

Aeolian sediment transport over vegetation canopies: A wind tunnel study with live plants

Abstract This wind tunnel study examines aeolian sediment transport in live plant canopies, whereas most previous studies have used model plants for this purpose. Experiments were performed with three canopy densities of Perennial Ryegrass ( Lolium perenne ) and with bare sand surfaces. The results suggest that both total sediment mass flux Q and PM 10 concentration in the air decreased exponentially with increasing canopy density. In the large-density canopy (frontal area index λ = 0.58), Q and PM 10 concentration were reduced to 0.01% and 0.4%, respectively, compared to the unplanted configuration. In the medium-density canopy ( λ = 0.16), Q and PM 10 concentration were reduced to 6.6% and 48.5%. In the small-density canopy ( λ = 0.03), however, Q and PM 10 concentration were increased to 117.5% and 145.6%. This is attributed to elevated shear stress on the sand bed caused by flow acceleration around the tussocks and vortical structures in their lee. Furthermore, the grasses were observed to trigger erosion by oscillating movements at the ground surface. It was also found that the vertical profiles of sediment mass flux in the medium- and large-density canopy strongly deviated from the exponential decay curve of the unplanted configuration, showing a local maximum at approximately twice the canopy height.

Atmospheric Stability Effects on Wind Fields and Scalar Mixing Within and Just Above a Subalpine Forest in Sloping Terrain

Air temperature T a , specific humidity q, CO2 mole fraction χ c , and three-dimensional winds were measured in mountainous terrain from five tall towers within a 1 km region encompassing a wide range of canopy densities. The measurements were sorted by a bulk Richardson number Ri b . For stable conditions, we found vertical scalar differences developed over a “transition” region between 0.05 < Ri b < 0.5. For strongly stable conditions (Ri b > 1), the vertical scalar differences reached a maximum and remained fairly constant with increasing stability. The relationships q and χ c have with Ri b are explained by considering their sources and sinks. For winds, the strong momentum absorption in the upper canopy allows the canopy sublayer to be influenced by pressure gradient forces and terrain effects that lead to complex subcanopy flow patterns. At the dense-canopy sites, soil respiration coupled with wind-sheltering resulted in CO2 near the ground being 5–7 μmol mol−1 larger than aloft, even with strong above-canopy winds (near-neutral conditions). We found Ri b -binning to be a useful tool for evaluating vertical scalar mixing; however, additional information (e.g., pressure gradients, detailed vegetation/topography, etc.) is needed to fully explain the subcanopy wind patterns. Implications of our results for CO2 advection over heterogenous, complex terrain are discussed.

Contribuições do solo e dossel em modelo de estimativa de biomassa aérea no Bioma Pampa

O objetivo deste trabalho foi avaliar o desempenho preditivo do submodelo espectral do modelo JONG, com a inserção de variáveis espectrais que considerassem a densidade de biomassa do dossel e as contribuições dos diferentes solos subjacentes. Índices calculados pela diferença e razão simples - entre as bandas 4 e 3, 4 e 5, 4 e 7, do sensor orbital ETM+/Landsat 7 - foram sugeridos para representar a contribuição espectral dos solos subjacentes e a influência das diferenças estruturais dos dosséis. A parametrização da componente espectral foi implementada por regressão linear múltipla e, em seguida, foi comparada aos dados de biomassa obtidos em campo. As variáveis espectrais que melhor expressaram as variações da disponibilidade inicial de forragem foram a fração solo (modelo linear de mistura espectral) e a razão entre as bandas 4 e 7. A componente espectral do modelo JONG, com a nova parametrização, apresenta sensibilidade para eliminar as influências do solo e dossel na disponibilidade inicial de biomassa e facilita a interpretação dos resultados, em razão da relação entre as variáveis espectrais selecionadas.

Canopy effects on vegetation caused by harvesting and regeneration treatments

This paper reviews the primary effects of canopy on understorey vegetation to provide insight into the management of the canopy space to benefit tree regeneration. Site conditions, like nutrient and water availability, overstorey conditions, e.g. tree species, and canopy density, are important determinants of ground vegetation. An investigation of canopy effects is concerned about how the canopy trees modify site conditions. As canopy density may be deliberately modified during regeneration treatments, the effect of canopy density on individual species in the herbaceous layer and tree regeneration is important. This autecological perspective focuses on the successional traits of species to help understand species differences in fecundity, survival, density and growth. From a synecological perspective, the importance of successional traits for the outcome of competition between species arising from differences in canopy densities is highlighted. This review shows that moderately dense canopies may favour tree regeneration over aggressive shade-intolerant graminoids or forbs. This is particularly true for shade-tolerant and intermediate shade-tolerant tree species. To better understand and utilise this phenomenon, research should try to identify and isolate different canopy effects.

Embedded‐sensor network design for snow cover measurements around snow pillow and snow course sites in the Sierra Nevada of California

The design of sensor networks for measuring the mean and spatial distribution of snow depth at the scale of 1–16 km2 was evaluated by deploying an embedded‐sensor network consisting of ultrasonic snow depth sensors to capture the variable physiographic features around an operational snow course in Yosemite National Park in the Sierra Nevada of California. Manual snow surveys were also carried out during accumulation and ablation periods. Four years of continuous data from the embedded‐sensor network showed that snow depths during both accumulation and ablation periods can vary as much as 50% based on variability in topography and vegetation across a 0.4 ha study area. Spatial snow surveys showed that such a sensor network can be deployed so as to capture both the variability and mean for accumulation and ablation periods across a 1 km2 area surrounding the sensor network, with a broader network required to extend this to 4 and 16 km2 areas. In forested areas, higher canopy densities, greater than 60% closure, were associated with the lowest snow depths. Analysis of historical snow course records from 14 sites in Yosemite, including the 10 spatial measurements made during each monthly snow course survey, showed snow depths across the 300 m snow course transects to be relatively uniform, with 68% of all monthly values having standard deviations no more than 10% of the mean. Although existing snow courses do little to help define the spatial patterns of snow distribution at the 1–16 km2 scales, it is feasible to extend the representativeness of current operational networks by deploying low‐cost embedded‐sensor networks nearby. Such networks should be strategically located to also capture elevational differences in snow accumulation and melt, as well as local‐scale variability in canopy cover and aspect.

Estimation of stand mean crown diameter from high-spatial-resolution imagery based on a geostatistical method

Using the panchromatic band of QuickBird high-spatial-resolution satellite images as a data source, we estimated the mean crown diameters of different stands and of stands with different canopy densities by applying the semivariogram methodology used in geostatistics. The results indicated that relatively accurate estimates of the mean crown diameters of stands with a relatively high canopy density could be obtained. The estimated errors increased proportionally with decreasing canopy density. The whole-stand-image (matrix) method we used provided fairly accurate estimates of stand structural parameters, but would not readily permit the evaluation of patterns in stand structure. The transect method exhibited periodicity as a function of distance and, although it permits the detection of directional patterns, it does not depict stand structural parameters as accurately as the matrix method. Our results suggest that this approach could provide a new reference method for solving the problem of automated estimation of mean crown diameter at the stand level.

Modelling the hydrological response of a Mediterranean medium-sized headwater basin subject to land cover change: The Cardener River basin (NE Spain)

Summary Abandonment of old agricultural fields is one of the main land cover changes over the second half of the XX century in Pyrenean headwater catchments, resulting in a natural succession from old crop fields and meadows towards shrub and forested covers, as well as an increase in forest canopy densities. In this situation, important changes in hydrological processes, water balance and, in consequence, water resources have been identified in the records and are expected for the future. The HYLUC model [Calder, I.R., 2003. Assessing the water use of short vegetation and forests: development of the Hydrological Land Use Change (HYLUC) model. Water Resources Research, 39(11), 1318] was tested for simulating the daily flows and water balance of the River Cardener (NE Spain) as well as for estimating the hydrological consequences of changes in land cover under operational conditions, i.e., with limited input data and parameter requirements. HYLUC successfully simulated the historical daily flows, flow duration curve and annual water balances in the catchment. It had several advantages over the hydrological model currently used for operational purposes in this catchment, although a snow cover sub-model should be added if it is to be applied to the main headwater catchments in the same Pyrenean region. When the model was used to simulate the consequences of land cover changes, the differences in water balance were larger than those predicted with an annual water balance equation. However, similar results were obtained from the analysis of historical data from headwater catchments of the Ebro River basin, and the decrease in low flows simulated under forest cover was comparable to that observed under Mediterranean climate elsewhere.

‘Quantifying the effects of forest canopy cover on net snow accumulation at a continental, mid‐latitude site’

AbstractAlthough many studies have investigated the effects of forest cover on streamflow and runoff, and several have examined the effects of canopy density on snowpack accumulation, the impacts of forest canopy density on spatial patterns of snowmelt input to catchments remain relatively underquantified. We performed an intensive snow depth and density survey during maximum accumulation in a mid‐latitude montane environment in northern New Mexico, taking 900 snow depth measurements and excavating six snow pits across a continuum of canopy densities. Snow water equivalent (SWE) data are correlated with forest canopy density (R2 = 0·21, p &lt; 0·0001), with maximum snow accumulation in forests with density between 25 and 40%. Forest edges are shown to be highly influential on patterns of snow depth, with unforested areas shaded by forest to their immediate south holding approximately 25% deeper snow than either large open areas or densely forested areas. This indicates that the combination of canopy influences on throughfall and snowpack shading are key processes underlying snow distribution in the high solar load environments typical of mountainous, mid‐latitude areas. We further show that statistical models of snow distribution are improved with the addition of remotely sensed forest canopy information (R2 increased in 10 of 11 cases, deviance lowered in 9 of 11 cases), making these findings broadly relevant for improving estimation of water resources, predicting the ecohydrological implications of vegetation and climate change, and informing integrated forest and water resources management. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Mapping burned areas and burn severity patterns in SW Australian eucalypt forest using remotely-sensed changes in leaf area index

Remote sensing is the most practical method available to managers of fire-prone forests for quantifying and mapping fire impacts. Differenced Normalised Burn Ratio (ΔNBR) is among the most widely used spectral indices for the mapping of burn severity but is difficult to interpret in terms of fire-related changes in key biophysical attributes and processes. We propose to quantify burn severity as a change in the leaf area index (ΔLAI) of a stand. LAI is a key biophysical attribute of forests, and is central to understanding their water and carbon cycles. Previous studies have suggested that changes in canopy LAI may be a major contributor to ΔNBR and to the composite burn index (CBI) that is frequently used in combination with the NBR to assess burn severity on the ground. We applied remotely-sensed ΔLAI to map burn severity in jarrah ( Eucalyptus marginata) forest in south-western Australia burnt during the January 2005 Perth Hills wildfires. Ground-based digital photography was used to measure LAI in typical stands representing the full range of canopy densities present in the study area as well as variation in the time since the last fire. Regression models for the prediction of LAI were developed using NBR, the Normalised Difference Vegetation Index (NDVI) or the Simple Ratio (SR) as the independent variable. All three LAI models had equally high coefficients of determination ( R 2: 0.87) and small root mean squared errors (RMSE: 0.27–0.28). ΔLAI was calculated as the difference between pre- and post-fire LAI, predicted using imagery from January 2004 and February 2005, respectively. The area affected by the January 2005 fire and the burn severity patterns within that area were mapped using ΔLAI and ΔNBR. Landscape patterns of burn severity obtained from differencing pre- and post-fire LAI were similar to those mapped by ΔNBR. We conclude that fire-affected areas and burn severity patterns in the northern jarrah forest can be objectively mapped using remotely-sensed changes in LAI, while offering the important advantage over NBR of being readily interpretable in the wider context of ecological forest management.