Relationships among burn severity, forest canopy structure and bat activity from spring burns in oak–hickory forests

2017 ◽  
Vol 26 (11) ◽  
pp. 963 ◽  
Author(s):  
Michael J. Lacki ◽  
Luke E. Dodd ◽  
Nicholas S. Skowronski ◽  
Matthew B. Dickinson ◽  
Lynne K. Rieske
Keyword(s):  
Laser Scanning ◽  
Forest Canopy ◽  
Management Practice ◽  
Canopy Structure ◽  
Forest Stand ◽  
Burn Severity ◽  
Prescribed Fires ◽  
Insectivorous Bats ◽  
Conflicting Objectives ◽  
Stand Characteristics

The extent to which prescribed fires affect forest structure and habitats of vertebrate species is an important question for land managers tasked with balancing potentially conflicting objectives of vegetation and wildlife management. Many insectivorous bats forage for insect prey in forested habitats, serving as the primary predators of nocturnal forest insects, and are potentially affected by structural changes in forests resulting from prescribed fires. We compared forest-stand characteristics of temperate oak–hickory forests, as measured with airborne laser scanning (light detection and ranging, LiDAR), with categorical estimates of burn severity from prescribed fires as derived from Landsat data and field-based Composite Burn Indices, and used acoustic monitoring to quantify activity of insectivorous bats in association with varying degrees of burn severity (unburned habitat, low severity and medium severity). Forest-stand characteristics showed greatest separation between low-severity and medium-severity classes, with gap index, i.e. open-air space, increasing with degree of burn severity. Greater mid-storey density, over-storey density and proportion of vegetation in the understorey occurred in unburned habitat. Activity of bats did not differ with burn severity for high-frequency (clutter-adapted or closed-space foragers) or low-frequency (edge or open-space foragers) bats. Results indicate that differing degrees of burn severity from prescribed fires produced spatial variation in canopy structure within stands; however, bats demonstrated no shifts in activity levels to this variation in canopy structure, suggesting prescribed fire during the dormant season, used as a management practice targeting desired changes in vegetation, is compatible with sustaining foraging habitat of insectivorous bats.

scholarly journals Determining basic forest stand characteristics using airborne laser scanning in mixed forest stands of Central Europe

2018 ◽  
Vol 11 (1) ◽  
pp. 181-188 ◽  
Author(s):  
R Smreček ◽  
Z Michnová ◽  
I Sačkov ◽  
Z Danihelová ◽  
M Levická ◽  
...  
Keyword(s):  
Central Europe ◽  
Laser Scanning ◽  
Mixed Forest ◽  
Forest Stand ◽  
Airborne Laser Scanning ◽  
Forest Stands ◽  
Airborne Laser ◽  
Stand Characteristics

scholarly journals Effects of management thinning on CO<sub>2</sub> exchange by a plantation oak woodland in south-eastern England

2015 ◽  
Vol 12 (19) ◽  
pp. 16197-16232 ◽  
Author(s):  
M. Wilkinson ◽  
P. Crow ◽  
E. L. Eaton ◽  
J. I. L. Morison
Keyword(s):  
Carbon Balance ◽  
Forest Canopy ◽  
Ecosystem Respiration ◽  
Management Practice ◽  
Canopy Structure ◽  
Net Ecosystem Exchange ◽  
Soil Surface ◽  
Ground Vegetation ◽  
Large Pulse ◽  
Individual Trees

Abstract. Forest thinning, which removes some individual trees from a forest stand at intermediate stages of the rotation, is commonly used as a silvicultural technique and is a management practice that can substantially alter both forest canopy structure and carbon storage. Whilst a proportion of the standing biomass is removed through harvested timber, thinning also removes some of the photosynthetic leaf area and introduces a large pulse of woody residue (brash) to the soil surface which potentially can alter the balance of autotrophic and heterotrophic respiration. Using a combination of eddy covariance (EC) and aerial light detection and ranging (LiDAR) data, this study investigated the effects of management thinning on the carbon balance and canopy structure in a commercially managed oak plantation in the south-east of England. Whilst thinning had a large effect on the canopy structure, increasing canopy complexity and gap fraction, the effects of thinning on the carbon balance were not as evident. In the first year post thinning, Net Ecosystem Exchange (NEE) was unaffected by the thinning, suggesting that the better illuminated ground vegetation and shrub layer partially compensated for the removed trees. NEE was reduced in the thinned area but not until two years after the thinning had been completed (2009); initially this was associated with an increase in ecosystem respiration (Reco). In subsequent years, NEE remained lower with reduced carbon sequestration in fluxes from the thinned area, which we suggest was in part due to heavy defoliation by caterpillars in 2010 reducing GPP in both sectors of the forest, but particularly in the east.

scholarly journals STUDY ON THE EXPLAINABLE ABILITY BY USING AIRBORNE LIDAR IN STAND VALUE AND STAND COMPETITION

2016 ◽  
Vol XLI-B1 ◽  
pp. 19-23
Author(s):  
S. C. Huang ◽  
J. Y. Yeh ◽  
C. T. Chen ◽  
J. C. Chen
Keyword(s):  
Field Data ◽  
Forest Canopy ◽  
Canopy Structure ◽  
Three Dimensional ◽  
Airborne Lidar ◽  
Planting Density ◽  
Competition Index ◽  
Canopy Density ◽  
Characteristic Values ◽  
Stand Characteristics

Forest canopy structure is composed by the various species. Sun light is a main factor to affect the crown structures after tree competition. However, thinning operation is an appropriate way to control canopy density, which can adjust the competition conditions in the different crown structures. Recently, Airborne Light Detection and Ranging (LiDAR), has been established as a standard technology for high precision three dimensional forest data acquisition; it could get stand characteristics with three-dimensional information that had develop potential for the structure characteristics of forest canopy. The 65 years old, different planting density of <i>Cryptomeria japonica</i> experiment area was selected for this study in Nanytou, Taiwan. Use the LiDAR image to estimate LiDAR characteristic values by constructed CHM, voxel-based LiDAR, mu0ltiple echoes, and assess the accuracy of stand characteristics with intensity values and field data. The competition index was calculated with field data, and estimate competition index of LiDAR via multiple linear regression. The results showed that the highest accuracy with stand characteristics was stand high which estimate by LiDAR, its average accuracy of 91.03%. LiDAR raster grid size was 20 m × 20 m for the correlation was the best, however, the higher canopy density will reduce the accuracy of the LiDAR characteristic values to estimate the stand characteristics. The significantly affect canopy thickness and the degree of competition in different planting distances.

scholarly journals Correcting attenuation effects caused by interactions in the forest canopy in full-waveform airborne laser scanner data

2014 ◽  
Vol XL-3 ◽  
pp. 273-280 ◽  
Author(s):  
K. Richter ◽  
N. Stelling ◽  
H.-G. Maas
Keyword(s):  
Laser Scanning ◽  
Forest Canopy ◽  
Canopy Structure ◽  
Integral Approach ◽  
Space Representation ◽  
Real World Data ◽  
Waveform Data ◽  
Full Waveform ◽  
Airborne Laser ◽  
Lower Amplitude

Full-waveform airborne laser scanning offers a great potential for various forestry applications. Especially applications requiring information on the vertical structure of the lower canopy parts benefit from the great amount of information contained in waveform data. To enable the derivation of vertical forest canopy structure, the development of suitable voxel based data analysis methods is straightforward. Beyond extracting additional 3D points, it is very promising to derive the voxel attributes from the digitized waveform directly. For this purpose, the differential backscatter cross sections have to be projected into a Cartesian voxel structure. Thereby the voxel entries represent amplitudes of the cross section and can be interpreted as a local measure for the amount of pulse reflecting matter. However, the "history" of each laser echo pulse is characterized by attenuation effects caused by reflections in higher regions of the crown. As a result, the received waveform signals within the canopy have a lower amplitude than it would be observed for an identical structure without the previous canopy structure interactions (Romanczyk et al., 2012). If the biophysical structure is determined from the raw waveform data, material in the lower parts of the canopy is thus under-represented. <br><br> To achieve a radiometrically correct voxel space representation the loss of signal strength caused by partial reflections on the path of a laser pulse through the canopy has to be compensated. In this paper, we present an integral approach correcting the waveform at each recorded sample. The basic idea of the procedure is to enhance the waveform intensity values in lower parts of the canopy for portions of the pulse intensity, which have been reflected (and thus blocked) in higher parts of the canopy. The paper will discuss the developed correction method and show results from a validation both with synthetic and real world data.

scholarly journals Effects of management thinning on CO<sub>2</sub> exchange by a plantation oak woodland in south-eastern England

2016 ◽  
Vol 13 (8) ◽  
pp. 2367-2378 ◽  
Author(s):  
Matthew Wilkinson ◽  
Peter Crow ◽  
Edward L. Eaton ◽  
James I. L. Morison
Keyword(s):  
Photosynthetic Rate ◽  
Carbon Balance ◽  
Forest Canopy ◽  
Ecosystem Respiration ◽  
Management Practice ◽  
Canopy Structure ◽  
Soil Surface ◽  
Ground Vegetation ◽  
Significant Difference ◽  
Peak Summer

Abstract. Forest thinning, which removes some individual trees from a forest stand at intermediate stages of the rotation, is commonly used as a silvicultural technique and is a management practice that can substantially alter both forest canopy structure and carbon storage. Whilst a proportion of the standing biomass is removed through harvested timber, thinning also removes some of the photosynthetic leaf area and introduces a large pulse of woody residue (brash) to the soil surface, which potentially can alter the balance of autotrophic and heterotrophic respiration. Using a combination of eddy covariance (EC) and aerial light detection and ranging (lidar) data, this study investigated the effects of management thinning on the carbon balance and canopy structure in a commercially managed oak plantation in the south-east of England. Whilst thinning had a large effect on the canopy structure, increasing canopy complexity and gap fraction, the effects of thinning on the carbon balance were not as evident. In the first year post thinning, the peak summer photosynthetic rate was unaffected by the thinning, suggesting that the better illuminated ground vegetation and shrub layer compensated for the removed trees. Peak summer photosynthetic rate was reduced in the thinned area between 2009 and 2011, but there was no significant difference between sectors. Ecosystem respiration fluxes increased in the thinned relative to the unthinned area in the post-thinning phase.

scholarly journals STUDY ON THE EXPLAINABLE ABILITY BY USING AIRBORNE LIDAR IN STAND VALUE AND STAND COMPETITION

2016 ◽  
Vol XLI-B1 ◽  
pp. 19-23
Author(s):  
S. C. Huang ◽  
J. Y. Yeh ◽  
C. T. Chen ◽  
J. C. Chen
Keyword(s):  
Field Data ◽  
Forest Canopy ◽  
Canopy Structure ◽  
Three Dimensional ◽  
Airborne Lidar ◽  
Planting Density ◽  
Competition Index ◽  
Canopy Density ◽  
Characteristic Values ◽  
Stand Characteristics

Forest canopy structure is composed by the various species. Sun light is a main factor to affect the crown structures after tree competition. However, thinning operation is an appropriate way to control canopy density, which can adjust the competition conditions in the different crown structures. Recently, Airborne Light Detection and Ranging (LiDAR), has been established as a standard technology for high precision three dimensional forest data acquisition; it could get stand characteristics with three-dimensional information that had develop potential for the structure characteristics of forest canopy. The 65 years old, different planting density of &lt;i&gt;Cryptomeria japonica&lt;/i&gt; experiment area was selected for this study in Nanytou, Taiwan. Use the LiDAR image to estimate LiDAR characteristic values by constructed CHM, voxel-based LiDAR, mu0ltiple echoes, and assess the accuracy of stand characteristics with intensity values and field data. The competition index was calculated with field data, and estimate competition index of LiDAR via multiple linear regression. The results showed that the highest accuracy with stand characteristics was stand high which estimate by LiDAR, its average accuracy of 91.03%. LiDAR raster grid size was 20 m × 20 m for the correlation was the best, however, the higher canopy density will reduce the accuracy of the LiDAR characteristic values to estimate the stand characteristics. The significantly affect canopy thickness and the degree of competition in different planting distances.

scholarly journals Radiative Transfer Modeling of a Coniferous Canopy Characterized by Airborne Remote Sensing

2008 ◽  
Vol 9 (2) ◽  
pp. 228-241 ◽  
Author(s):  
Richard Essery ◽  
Peter Bunting ◽  
Aled Rowlands ◽  
Nick Rutter ◽  
Janet Hardy ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Laser Scanning ◽  
Large Scale ◽  
Forest Canopy ◽  
Canopy Structure ◽  
Spatial Variations ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Temporal Averaging ◽  
Radiative Transfer Modeling

Abstract Solar radiation beneath a forest canopy can have large spatial variations, but this is frequently neglected in radiative transfer models for large-scale applications. To explicitly model spatial variations in subcanopy radiation, maps of canopy structure are required. Aerial photography and airborne laser scanning are used to map tree locations, heights, and crown diameters for a lodgepole pine forest in Colorado as inputs to a spatially explicit radiative transfer model. Statistics of subcanopy radiation simulated by the model are compared with measurements from radiometer arrays, and scaling of spatial statistics with temporal averaging and array size is discussed. Efficient parameterizations for spatial averages and standard deviations of subcanopy radiation are developed using parameters that can be obtained from the model or hemispherical photography.

scholarly journals Estimation of forest structure metrics relevant to hydrologic modeling using coordinate transformation of airborne laser scanning data

2012 ◽  
Vol 9 (4) ◽  
pp. 5531-5573 ◽  
Author(s):  
A. Varhola ◽  
G. W. Frazer ◽  
P. Teti ◽  
N. C. Coops
Keyword(s):  
Solar Radiation ◽  
Forest Structure ◽  
Laser Scanning ◽  
Forest Canopy ◽  
Canopy Structure ◽  
Airborne Laser Scanning ◽  
Water Dynamics ◽  
Hydrologic Models ◽  
Airborne Laser ◽  
Structure Metrics

Abstract. Accurate characterizations of the complex and heterogeneous forest architecture are necessary to parameterize physically-based hydrologic models that simulate precipitation interception, energy fluxes and water dynamics. While hemispherical photography has become a popular method to obtain a number of forest canopy structure metrics relevant to these processes, image acquisition is field-intensive and therefore difficult to apply across the landscape. In contrast, airborne laser scanning (ALS) is a remote sensing technique increasingly used to acquire detailed information on the spatial structure of forest canopies over large, continuous areas. This study presents a novel methodology to calibrate ALS data with in-situ optical hemispherical camera images to obtain traditional forest structure and solar radiation metrics. The approach minimizes geometrical differences between these two techniques by transforming the Cartesian coordinates of ALS data to generate synthetic images with a polar projection directly comparable to optical photography. We demonstrate how these new coordinate-transformed ALS metrics, along with additional standard ALS variables, can be used as predictors in multiple linear regression to estimate forest structure and solar radiation indices at any individual location within the extent of an ALS transect. This approach is expected to substantially reduce fieldwork costs, broaden sampling design possibilities, and improve the spatial representation of forest structure metrics directly relevant to parameterize hydrologic models.

Modelling growing stock volume of forest stands with various ALS area-based approaches

2021 ◽  
Author(s):  
Karolina Parkitna ◽  
Grzegorz Krok ◽  
Stanisław Miścicki ◽  
Krzysztof Ukalski ◽  
Marek Lisańczuk ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Mean Squared Error ◽  
Prediction Method ◽  
Forest Stand ◽  
Boosted Regression Trees ◽  
Forest Stands ◽  
Individual Tree ◽  
Growing Stock ◽  
Modelling Techniques ◽  
Stock Volume

Abstract Airborne laser scanning (ALS) is one of the most innovative remote sensing tools with a recognized important utility for characterizing forest stands. Currently, the most common ALS-based method applied in the estimation of forest stand characteristics is the area-based approach (ABA). The aim of this study was to analyse how three ABA methods affect growing stock volume (GSV) estimates at the sample plot and forest stand levels. We examined (1) an ABA with point cloud metrics, (2) an ABA with canopy height model (CHM) metrics and (3) an ABA with aggregated individual tree CHM-based metrics. What is more, three different modelling techniques: multiple linear regression, boosted regression trees and random forest, were applied to all ABA methods, which yielded a total of nine combinations to report. An important element of this work is also the empirical verification of the methods for estimating the GSV error for individual forest stand. All nine combinations of the ABA methods and different modelling techniques yielded very similar predictions of GSV for both sample plots and forest stands. The root mean squared error (RMSE) of estimated GSV ranged from 75 to 85 m3 ha−1 (RMSE% = 20.5–23.4 per cent) and from 57 to 64 m3 ha−1 (RMSE% = 16.4–18.3 per cent) for plots and stands, respectively. As a result of the research, it can be concluded that GSV modelling with the use of different ALS processing approaches and statistical methods leads to very similar results. Therefore, the choice of a GSV prediction method may be more determined by the availability of data and competences than by the requirement to use a particular method.

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