Quantifying Forest Structure Parameters And Their Changes From Lidar Data And Satellite Imagery In The Sierra Nevada

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Quantifying Forest Structure Parameters and Their Changes from LiDAR Data and Satellite Imagery in the Sierra Nevada

Author : Qin Ma
Publisher :
ISBN 13 :
Total Pages : 284 pages
Book Rating : 4.:/5 (15 download)

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Book Synopsis Quantifying Forest Structure Parameters and Their Changes from LiDAR Data and Satellite Imagery in the Sierra Nevada by : Qin Ma

Download or read book Quantifying Forest Structure Parameters and Their Changes from LiDAR Data and Satellite Imagery in the Sierra Nevada written by Qin Ma and published by . This book was released on 2018 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sierra Nevada forests have provided many economic benefits and ecological services to people in California, and the rest of the world. Dramatic changes are occurring in the forests due to climate warming and long-term fire suppression. Accurate mapping and monitoring are increasingly important to understand and manage the forests. Light Detection and Range (LiDAR), an active remote sensing technique, can penetrate the canopy and provide three-dimensional estimates of forest structures. LiDAR-based forest structural estimation has been demonstrated to be more efficient than field measurements and more accurate than those from passive remote sensing, like satellite imagery. Research in this dissertation aims at mapping and monitoring structural changes in Sierra Nevada forests by taking the advantages of LiDAR. We first evaluated LiDAR and fine resolution imagery-derived canopy cover estimates using different algorithms and data acquisition parameters. We suggested that LiDAR data obtained at 1 point/m2 with a scan angle smaller than 12°were sufficient for accurate canopy cover estimation in the Sierra Nevada mix-conifer forests. Fine resolution imagery is suitable for canopy cover estimation in forests with median density but may over or underestimate canopy cover in extremely coarse or dense forests. Then, a new LiDAR-based strategy was proposed to quantify tree growth and competition at individual tree and forest stand levels. Using this strategy, we illustrated how tree growth in two Sierra Nevada forests responded to tree competition, original tree sizes, forest density, and topography conditions; and identified that the tree volume growth was determined by the original tree sizes and competitions, but tree height and crown area growth were mostly influenced by water and space availability. Then, we calculated the forest biomass disturbance in a Sierra Nevada forest induced by fuel treatments using bi-temporal LiDAR data and field measurements. Using these results as references, we found that Landsat imagery-derived vegetation indices were suitable for quantifying canopy cover changes and biomass disturbances in forests with median density. Large uncertainties existed in applying the vegetation indices to quantify disturbance in extremely dense forests or forests only disturbed in the understory. Last, we assessed vegetation losses caused by the American Fire in 2013 using a new LiDAR point based method. This method was able to quantify fire-induced forest structure changes in basal area and leaf area index with lower uncertainties, compared with traditional LiDAR metrics and satellite imagery-derived vegetation indices. The studies presented in this dissertation can provide guidance for forest management in the Sierra Nevada, and potentially serve as useful tools for forest structural change monitoring in the rest of the world.

Using Lidar in Wildfire Ecology of the California Sierra-Nevada Forests

Author : Marek K. Jakubowski
Publisher :
ISBN 13 :
Total Pages : 97 pages
Book Rating : 4.:/5 (957 download)

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Book Synopsis Using Lidar in Wildfire Ecology of the California Sierra-Nevada Forests by : Marek K. Jakubowski

Download or read book Using Lidar in Wildfire Ecology of the California Sierra-Nevada Forests written by Marek K. Jakubowski and published by . This book was released on 2012 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: California's fire suppression policy has dramatically changed Sierra Nevada forests over the last century. Forests are becoming more dense and homogenous, leading to fire regime changes that increase the potential of stand-replacing wildfires over large, continuous areas. To mitigate this problem on public lands, the US Forest Service has proposed to implement strategically placed forest fuel reduction treatments. These treatments have been proved effective in modeled and simulated environments, but their efficacy and impact in real forests is not known. The research described in this dissertation is part of a large multidisciplinary project, known as the Sierra Nevada Adaptive Management Project (SNAMP), that aims to evaluate strategically placed landscape area treatments (SPLATs) in two forests of the Sierra Nevada mountains. Specifically, in this thesis, I investigate the feasibility of using an airborne light detection and ranging (lidar) system to gain accurate information about forest structure to inform wildfire behavior models, forest management, and habitat mapping. First, I investigate the use of lidar data in predicting metrics at the landscape level, specifically to derive surface fuel models and continuous canopy metrics at the plot scale. My results in Chapter 2 indicate that using lidar to predict specific fuel models for FARSITE wildfire behavior model is challenging. However, the prediction of more general fuel models and continuous canopy metrics is feasible and reliable, especially for metrics near the top of the canopy. It is also possible to derive canopy parameters at the individual tree level. In Chapter 3, I compare the ability of two processing methods--object-based image analysis (OBIA) and 3D segmentation of the lidar point cloud--to detect and delineate individual trees. I find that while both methods delineate dominant trees and accurately predict their heights, the lidar-derived polygons more closely resemble the shape of realistic individual tree crowns. Acquiring remotely sensed data at high resolution and over large areas can be expensive, especially in the case of lidar. In Chapter 4, I investigate the ability of lidar data to reliably predict forest canopy metrics at the plot level as the data resolution declines. I show that canopy metrics can be predicted at a reasonable accuracy with data resolutions as low as one pulse per squared meter. These findings will be useful to land managers making cost benefit decisions when acquiring new lidar data. Collectively, the results of this dissertation suggest that remote sensing, and in particular lidar, can reliably and cost-effectively provide forest information across scales--from the individual tree level to the landscape level. These results will be useful for the fire and forest management community in general, as well as being key to the goals of the SNAMP program.

Restoring Forest Resilience in the Sierra Nevada Mixed-conifer Zone, with a Focus on Measuring Spatial Patterns of Trees Using Airborne Lidar

Download Restoring Forest Resilience in the Sierra Nevada Mixed-conifer Zone, with a Focus on Measuring Spatial Patterns of Trees Using Airborne Lidar PDF Online Free

Author : Sean Medeiros Alexander Jeronimo
Publisher :
ISBN 13 :
Total Pages : 308 pages
Book Rating : 4.:/5 (18 download)

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Book Synopsis Restoring Forest Resilience in the Sierra Nevada Mixed-conifer Zone, with a Focus on Measuring Spatial Patterns of Trees Using Airborne Lidar by : Sean Medeiros Alexander Jeronimo

Download or read book Restoring Forest Resilience in the Sierra Nevada Mixed-conifer Zone, with a Focus on Measuring Spatial Patterns of Trees Using Airborne Lidar written by Sean Medeiros Alexander Jeronimo and published by . This book was released on 2018 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation I present three studies incorporating lidar data into different aspects of forest restoration. All studies use lidar individual tree detection as source data, in part to enable making measurements of tree spatial patterns in terms of tree clumps and canopy openings. This common focus exists because spatial patterns of trees influence fire and insect behavior, snow retention, tree regeneration, and other key ecosystem functions and services for which humans manage forests. In Chapter 1 I sought to provide this dataset by asking these questions: (1) What is the geographic and environmental distribution of restored active-fire forest patches in the Sierra Nevada mixed-conifer zone? (2) What are the ranges of variation in structure and spatial patterns across restored patches? (3) How do density, tree clumping, and canopy opening patterns vary by topography and climate in restored patches? I analyzed fire history and environmental conditions over 10.8 million ha, including 3.9 million ha in the Sierra Nevada mixed-conifer zone, and found that the 30,379 ha of restored patches were distributed throughout the range but were more abundant on National Park lands (81% of restored areas) than National Forest lands and were positively correlated with lightning strike density. Furthermore, 33% of restored areas were located in western Yosemite National Park and met our criteria for inclusion in this study only after being burned at low and moderate severity in the 2013 Rim Fire. Lidar-measured ranges of variation in reference condition structure were broad, with density ranging from 6-320 trees ha−1 (median 107 trees ha−1), basal area from 2-113 m2 ha−1 (median 21 m2 ha−1), average size of closely associated tree clumps from 1 to 207 trees (median 3.1 trees), and average percent of stand area >6 m from the nearest canopy ranging from 0% to 100% (median 5.1%). These ranges matched past studies reporting density and spatial patterns of contemporary and historical active-fire reference stands in the Sierra Nevada, except this study observed longer tails on distributions due to the spatial completeness of lidar sampling. Reference areas in middle-elevation climate zones had lower density (86 vs. 121 trees ha-1), basal area, (13.7 vs. 31 m2 ha-1), and mean clump size (2.7 vs. 4.0 trees) compared to lower- and higher-elevation classes, while ridgetops had lower density (101 vs. 115 trees ha-1), basal area (19.6 vs. 24.1 m2 ha-1), and mean clump size (3.0 vs. 3.3 trees) but more open space (7.4% vs. 5.1%) than other landforms. In Chapter 2 I developed new methods for integrating lidar data into silvicultural planning at treatment unit and project area scales, with a focus on dry forest restoration treatments. At the stand scale my objective was to delineate the decision space for prescription parameters like density, basal area, and spatial patterns given the soft constraints of reference conditions and the hard constraints of possible transitions given current structure. At the landscape scale my objective was to provide a framework for selecting from available treatment options, stand by stand, to meet different landscape-level goals. I applied the new methods to a case study area in the Lake Tahoe Basin, California and asked in this context: How do structural departures from reference conditions and associated treatment prescriptions vary with topographic position and aspect? I found that ridges and southwest-facing slopes in the study area had a greater degree of departure from the reference envelope and required more density reduction compared to valleys and northeast-facing slopes. In Chapter 3 I used pre- and post-Rim Fire data from the 25.6 ha Yosemite Forest Dynamics Plot (YFPD) to build a model of tree mortality predicted from lidar individual tree detection structural metrics. I calculated metrics at the scale of lidar-detected trees (termed tree-approximate objects, TAOs), at the scale of 0.1 ha plots centered on each TAO, and at the 90×90 m neighborhood scale. I used these to predict TAO mortality at the neighborhood scale and TAO mortality class – immediate or delayed mortality – at the TAO scale. I also tested the inclusion of a set of topoedaphic and burn weather predictors as well as a cross-scale interaction term between the TAO mortality model and the neighborhood-level mortality model. I asked these questions: (1) How does mortality progress 1-4 years post-fire in terms of rates, demographics, and agents? (2) What elements of forest structure and pattern predict immediate and delayed post-fire mortality at scales from TAOs to neighborhoods? (3) How does the prevalence of different mortality agents vary with changes in the important fine-scale predictors of fire mortality? I found that smaller trees were killed in the first year with a 40% mortality rate and the average diameter of killed trees increased each subsequent year while the mortality rate decreased. The topoedaphic and burn weather predictors as well as the cross-scale interaction improved model fit and parsimony, but that the improvement was directional, i.e., including neighborhood-level information improved the TAO-level model but not vice-versa. Important predictors fell into categories of fuel amount, fuel configuration, and burning conditions. Amounts of crown damage for immediately killed trees were higher for TAOs shorter than 51 m and in 0.1 ha areas where mean clump sizes was less than 21 TAOs. The amount of delayed mortality that was directly fire-related was higher when TAO crown base heights were less than 28 m and TAO density in 0.1 ha areas was greater than 170 TAOs ha-1. Crown base heights over 18 m and local TAO density of less than 180 TAOs ha-1 had more beetle kill and less rot. The model performed similarly well on an independent validation dataset of 48 0.25 ha plots spanning the footprint of the Rim Fire within Yosemite as on the YFDP training data, indicating that the model is widely applicable.

Photo Series for Quantifying Natural Forest Residues

Author : Kenneth S. Blonski
Publisher :
ISBN 13 :
Total Pages : 222 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis Photo Series for Quantifying Natural Forest Residues by : Kenneth S. Blonski

Download or read book Photo Series for Quantifying Natural Forest Residues written by Kenneth S. Blonski and published by . This book was released on 1981 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Heterogeneity in Forest Structure Prior to Restoration by Fire

Author : Kurt Martin Menning
Publisher :
ISBN 13 :
Total Pages : 476 pages
Book Rating : 4.:/5 (34 download)

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Book Synopsis Heterogeneity in Forest Structure Prior to Restoration by Fire by : Kurt Martin Menning

Download or read book Heterogeneity in Forest Structure Prior to Restoration by Fire written by Kurt Martin Menning and published by . This book was released on 2003 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: During a century of fire suppression forest may have become more homogeneous. In many western forests fire is being reintroduced yet the effects are not well understood. The best method of reintroducing fire to forested ecosystems has been debated. To assess the effects of disturbance on structure we must quantify heterogeneity in the forest before and after disturbance. I explored means to assess heterogeneity and measured it in the mixed conifer forest and in the litter base that vectors fire. I present a new statistical metric for describing the distribution of forest structure. The metric can be used to assess forest structural heterogeneity at different spatial scales. Ground and surface fuels are essential for vectoring a contagious disturbance like fire. Fire models often assume uniform fuel characteristics for a forest community. I explored how litter bulk density could vary by dominant tree species. I modeled how variability in litter bulk density could affect fire behavior and found differences in fireline intensity and rate of spread among different dominant tree species.--Adapted from abstract.

Quantifying the Urban Forest Environment Using Dense Discrete Return LiDAR and Aerial Color Imagery for Segmentation and Object-level Biomass Assessment

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Author : Madhurima Bandyopadhyay
Publisher :
ISBN 13 :
Total Pages : 356 pages
Book Rating : 4.:/5 (914 download)

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Book Synopsis Quantifying the Urban Forest Environment Using Dense Discrete Return LiDAR and Aerial Color Imagery for Segmentation and Object-level Biomass Assessment by : Madhurima Bandyopadhyay

Download or read book Quantifying the Urban Forest Environment Using Dense Discrete Return LiDAR and Aerial Color Imagery for Segmentation and Object-level Biomass Assessment written by Madhurima Bandyopadhyay and published by . This book was released on 2015 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The urban forest is becoming increasingly important in the contexts of urban green space and recreation, carbon sequestration and emission offsets, and socio-economic impacts. In addition to aesthetic value, these green spaces remove airborne pollutants, preserve natural resources, and mitigate adverse climate changes, among other benefits. A great deal of attention recently has been paid to urban forest management. However, the comprehensive monitoring of urban vegetation for carbon sequestration and storage is an under-explored research area. Such an assessment of carbon stores often requires information at the individual tree level, necessitating the proper masking of vegetation from the built environment, as well as delineation of individual tree crowns. As an alternative to expensive and time-consuming manual surveys, remote sensing can be used effectively in characterizing the urban vegetation and man-made objects. Many studies in this field have made use of aerial and multispectral/hyperspectral imagery over cities. The emergence of light detection and ranging (LiDAR) technology, however, has provided new impetus to the effort of extracting objects and characterizing their 3D attributes - LiDAR has been used successfully to model buildings and urban trees. However, challenges remain when using such structural information only, and researchers have investigated the use of fusion-based approaches that combine LiDAR and aerial imagery to extract objects, thereby allowing the complementary characteristics of the two modalities to be utilized In this study, a fusion-based classification method was implemented between high spatial resolution aerial color (RGB) imagery and co-registered LiDAR point clouds to classify urban vegetation and buildings from other urban classes/cover types. Structural, as well as spectral features, were used in the classification method. These features included height, flatness, and the distribution of normal surface vectors from LiDAR data, along with a non-calibrated LiDAR-based vegetation index, derived from combining LiDAR intensity at 1064 nm with the red channel of the RGB imagery. This novel index was dubbed the LiDAR-infused difference vegetation index (LDVI). Classification results indicated good separation between buildings and vegetation, with an overall accuracy of 92% and a kappa statistic of 0.85. A multi-tiered delineation algorithm subsequently was developed to extract individual tree crowns from the identified tree clusters, followed by the application of species-independent biomass models based on LiDAR-derived tree attributes in regression analysis. These LiDAR-based biomass assessments were conducted for individual trees, as well as for clusters of trees, in cases where proper delineation of individual trees was impossible. The detection accuracy of the tree delineation algorithm was 70%. The LiDAR-derived biomass estimates were validated against allometry-based biomass estimates that were computed from field-measured tree data. It was found out that LiDAR-derived tree volume, area, and different distribution parameters of height (e.g., maximum height, mean of height) are important to model biomass. The best biomass model for the tree clusters and the individual trees showed an adjusted R-Squared value of 0.93 and 0.58, respectively. The results of this study showed that the developed fusion-based classification approach using LiDAR and aerial color (RGB) imagery is capable of producing good object detection accuracy. It was concluded that the LDVI can be used in vegetation detection and can act as a substitute for the normalized difference vegetation index (NDVI), when near-infrared multiband imagery is not available. Furthermore, the utility of LiDAR for characterizing the urban forest and associated biomass was proven. This work could have significant impact on the rapid and accurate assessment of urban green spaces and associated carbon monitoring and management."--Abstract.

QUANTIFYING FOREST ABOVEGROUND CARBON POOLS AND FLUXES USING MULTI-TEMPORAL LIDAR A Report on Field Monitoring, Remote Sensing MMV, GIS Integration, and Modeling Results for Forestry Field Validation Test to Quantify Aboveground Tree Biomass and Carbon

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Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis QUANTIFYING FOREST ABOVEGROUND CARBON POOLS AND FLUXES USING MULTI-TEMPORAL LIDAR A Report on Field Monitoring, Remote Sensing MMV, GIS Integration, and Modeling Results for Forestry Field Validation Test to Quantify Aboveground Tree Biomass and Carbon by :

Download or read book QUANTIFYING FOREST ABOVEGROUND CARBON POOLS AND FLUXES USING MULTI-TEMPORAL LIDAR A Report on Field Monitoring, Remote Sensing MMV, GIS Integration, and Modeling Results for Forestry Field Validation Test to Quantify Aboveground Tree Biomass and Carbon written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Sound policy recommendations relating to the role of forest management in mitigating atmospheric carbon dioxide (CO2) depend upon establishing accurate methodologies for quantifying forest carbon pools for large tracts of land that can be dynamically updated over time. Light Detection and Ranging (LiDAR) remote sensing is a promising technology for achieving accurate estimates of aboveground biomass and thereby carbon pools; however, not much is known about the accuracy of estimating biomass change and carbon flux from repeat LiDAR acquisitions containing different data sampling characteristics. In this study, discrete return airborne LiDAR data was collected in 2003 and 2009 across H"0,000 hectares (ha) of an actively managed, mixed conifer forest landscape in northern Idaho, USA. Forest inventory plots, established via a random stratified sampling design, were established and sampled in 2003 and 2009. The Random Forest machine learning algorithm was used to establish statistical relationships between inventory data and forest structural metrics derived from the LiDAR acquisitions. Aboveground biomass maps were created for the study area based on statistical relationships developed at the plot level. Over this 6-year period, we found that the mean increase in biomass due to forest growth across the non-harvested portions of the study area was 4.8 metric ton/hectare (Mg/ha). In these non-harvested areas, we found a significant difference in biomass increase among forest successional stages, with a higher biomass increase in mature and old forest compared to stand initiation and young forest. Approximately 20% of the landscape had been disturbed by harvest activities during the six-year time period, representing a biomass loss of>70 Mg/ha in these areas. During the study period, these harvest activities outweighed growth at the landscape scale, resulting in an overall loss in aboveground carbon at this site. The 30-fold increase in sampling density between the 2003 and 2009 did not affect the biomass estimates. Overall, LiDAR data coupled with field reference data offer a powerful method for calculating pools and changes in aboveground carbon in forested systems. The results of our study suggest that multitemporal LiDAR-based approaches are likely to be useful for high quality estimates of aboveground carbon change in conifer forest systems.

Quantifying Vertical and Horizontal Stand Structure Using Terrestrial LiDAR in Pacific Northwest Forests

Author : Alexandra N. Kazakova
Publisher :
ISBN 13 :
Total Pages : 61 pages
Book Rating : 4.:/5 (89 download)

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Book Synopsis Quantifying Vertical and Horizontal Stand Structure Using Terrestrial LiDAR in Pacific Northwest Forests by : Alexandra N. Kazakova

Download or read book Quantifying Vertical and Horizontal Stand Structure Using Terrestrial LiDAR in Pacific Northwest Forests written by Alexandra N. Kazakova and published by . This book was released on 2013 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stand level spatial distribution is a fundamental part of forest structure that influences many ecological processes and ecosystem functions. Vertical and horizontal spatial structure provides key information for forest management. Although horizontal stand complexity can be measured through stem mapping and spatial analysis, vertical complexity within the stand remains a mostly visual and highly subjective process. Tools and techniques in remote sensing, specifically LiDAR, provide three dimensional datasets that can help get at three dimensional forest stand structure. Although aerial LiDAR (ALS) is the most widespread form of remote sensing for measuring forest structure, it has a high omission rate in dense and structurally complex forests. In this study we used terrestrial LiDAR (TLS) to obtain high resolution three dimensional point clouds of plots from stands that vary by density and composition in the second-growth Pacific Northwest forest ecosystem. We used point cloud slicing techniques and object-based image analysis (OBIA) to produce canopy profiles at multiple points of vertical gradient. At each height point we produced segments that represented canopies or parts of canopies for each tree within the dataset. The resulting canopy segments were further analyzed using landscape metrics to quantify vertical canopy complexity within a single stand. Based on the developed method, we have successfully created a tool that utilizes three dimensional spatial information to accurately quantify the vertical structure of forest stands. Results show significant differences in the number and the total area of the canopy segments and gap fraction between each vertical slice within and between individual forest management plots. We found a significant relationship between the stand density and composition and the vertical canopy complexity. The methods described in this research make it possible to create horizontal stand profiles at any point along the vertical gradient of forest stands with high frequency, therefore providing ecologists with measures of horizontal and vertical stand structure. Key Words: Terrestrial laser scanning, canopy structure, landscape metrics, aerial laser scanning, lidar, calibration, Pacific Northwest

Measuring Forest Structure and Biomass Using Echidna® Ground-based Lidar

Author : Tian Yao
Publisher :
ISBN 13 :
Total Pages : 328 pages
Book Rating : 4.:/5 (958 download)

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Book Synopsis Measuring Forest Structure and Biomass Using Echidna® Ground-based Lidar by : Tian Yao

Download or read book Measuring Forest Structure and Biomass Using Echidna® Ground-based Lidar written by Tian Yao and published by . This book was released on 2012 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Forest canopy structural parameters and above-ground biomass, retrieved by a ground-based, upward-scanning, near-infrared (1064 nm), full-waveform lidar, the Echidna® Validation Instrument (EVI), matched ground measurements with R2 values of 0.92 to 0.99 at six hardwood and conifer forest sites within New England in 2007 and at eight conifer forest sites in the Sierra National Forest in California in 2008. Retrieved parameters included mean diameter at breast height (DBH), stem count density, basal area, and above-ground biomass, based on five scans within each 1-ha plot. Canopy heights derived from the EVI-retrieved foliage profile closely matched those derived from the airborne Laser Vegetation Imaging Sensor (LVIS). Topographic slope can induce errors in parameter retrievals because the horizontal plane of the instrument scan, which is used to identify, measure, and count tree trunks, will intersect trunks below breast height in the uphill direction and above breast height in the downhill direction. I tested three methods of slope correction on the Sierra sites. Without correction, single-scan correlations of structural parameters with field measurements ranged from 0.53-0.86; after correction, from 0.78-0.91, 0.80-0.93 and 0,85-0.93 for the three methods respectively. These results document the importance of the slope correction in EVI structural retrievals. Three sites scanned in 2007 provided the opportunity to detect change in comparison to 2009 or 2010 scans. At a shelterwood conifer site at Howland Experimental Forest, mean DBH, above-ground biomass, and leaf area index (LAI) all increased between 2007 and 2009. An ice storm struck the Harvard Forest in December, 2008, providing the opportunity to detect damage between 2007 and 2009 or 2010 EVI scans at two sites there: hemlock and hardwood. Retrieved leaf area index (LAI) was 13 percent lower in the hemlock site in 2009 and 10 percent lower in the hardwood site in 2010. Broken tops were visible in the 2010 data. Stem density decreased and mean DBH increased at both sites, as small and weak trees were felled by the ice.

Evaluating Close Range Remote Sensing Techniques for the Retention of Biodiversity-related Forest Structures

Author : Julian Frey
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (113 download)

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Book Synopsis Evaluating Close Range Remote Sensing Techniques for the Retention of Biodiversity-related Forest Structures by : Julian Frey

Download or read book Evaluating Close Range Remote Sensing Techniques for the Retention of Biodiversity-related Forest Structures written by Julian Frey and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Forest management alters the spatial structure of forests, which directly shapes the biodiversity, processes and functioning of such ecosystems. While forest structure is commonly quantified using field-based forest management metrics, close range (distances 150m) remote sensing techniques are able to describe the distribution of material in 3D space with very high detail and precision. Since manual inventories of forest structure are labor intensive and suffer from observer biases remote sensing techniques offer new possibilities for efficient and objective quantifications of forest structure. To investigate the impacts of forest management on stand structure, new indices and metrics based on 3D point clouds have been developed and validated. This dissertation is structured in three publications (Chapters 4 - 6), starting with a methods paper on UAV flight planning optimization, followed by a comparison of tree related microhabitat inventories and close range remote sensing indices for stand structure quantification, and ending with a validation of a remote sensing index based on a forest expert survey.brFor the first paper, a technical flight planning optimization was conducted for unmanned aerial vehicles structure from motion as a basis for optimal data acquisition (Chapter 4). The image forward overlap and ground sampling distance were varied, and the parameters of the resulting geometric model completeness in 2D and 3D space that differed could be independently quantified. While finer resolutions led to a better representation of smaller forest details and a better representation of the understory, the model completeness suffered from it. A higher forward image overlap can compensate for this if the overlap is very high (95%). Tree related microhabitat (TreM) inventories are unlike remote sensing based indices but have a similar aim of quantifying forest structures, which can be accumulated to a stand level. TreMs themselves are special tree level structures such as forks, cavities and fungi. While both approaches have different perspectives on forest structure, their common goal of forest stand structure quantification make the respective insights from these methods worth comparing (Chapter 5). A significant correlation with a weak R2 (0.30) indicate that these two measures are linked but that their representation of stand structure is complementary. Foresters and other forest experts are of major relevance to the topic of implementation of retention management and the selection of retention patches, since they are the decision makers and practitioners in this sector. The judgement of those experts could be biased by additional objectives and individual preferences. In an extensive online survey (n=444), experts were asked to quantify stand structure on 360 degree panoramic images in an interactive viewer. The expert responses were compared to stand structural complexity metrics derived from terrestrial laser scans, which were taken at the same location from the same viewpoint. The standard deviation of the expert judgements were high, which indicates the necessity of objective measurements. The laser scanning based index significantly correlated with the expert judgements, which shows that neither the expert ratings nor the scanning index are random and that laser scanning is an option for more objective decision making processes. However, experts in the field might take a variety of additionally relevant criteria (e.g. rareness of the habitat in landscape, special tree features, breeding places) into account, which should not been overlooked. In summary, this dissertation validated and adapted several indices based on close range remote sensing techniques and showed their potential as monitoring tools and assistance for the forest management decision-making processes

Mapping Forest Structure, Species Gradients and Growth in an Urban Area Using Lidar and Hyperspectral Imagery

Author :
Publisher :
ISBN 13 :
Total Pages : 292 pages
Book Rating : 4.:/5 (934 download)

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Book Synopsis Mapping Forest Structure, Species Gradients and Growth in an Urban Area Using Lidar and Hyperspectral Imagery by :

Download or read book Mapping Forest Structure, Species Gradients and Growth in an Urban Area Using Lidar and Hyperspectral Imagery written by and published by . This book was released on 2015 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Urban forests play an important role in the urban ecosystem by providing a range of ecosystem services. Characterization of forest structure, species variation and growth in urban forests is critical for understanding the status, function and process of urban ecosystems, and helping maximize the benefits of urban ecosystems through management. The development of methods and applications to quantify urban forests using remote sensing data has lagged the study of natural forests due to the heterogeneity and complexity of urban ecosystems. In this dissertation, I quantify and map forest structure, species gradients and forest growth in an urban area using discrete-return lidar, airborne imaging spectroscopy and thermal infrared data. Specific objectives are: (1) to demonstrate the utility of leaf-off lidar originally collected for topographic mapping to characterize and map forest structure and associated uncertainties, including aboveground biomass, basal area, diameter, height and crown size; (2) to map species gradients using forest structural variables estimated from lidar and foliar functional traits, vegetation indices derived from AVIRIS hyperspectral imagery in conjunction with field-measured species data; and (3) to identify factors related to relative growth rates in aboveground biomass in the urban forests, and assess forest growth patterns across areas with varying degree of human interactions. The findings from this dissertation are: (1) leaf-off lidar originally acquired for topographic mapping provides a robust, potentially low-cost approach to quantify spatial patterns of forest structure and carbon stock in urban areas; (2) foliar functional traits and vegetation indices from hyperspectral data capture gradients of species distributions in the heterogeneous urban landscape; (3) species gradients, stand structure, foliar functional traits and temperature are strongly related to forest growth in the urban forests; and (4) high uncertainties in our ability to map forest structure, species gradient and growth rate occur in residential neighborhoods and along forest edges. Maps generated from this dissertation provide estimates of broad-scale spatial variations in forest structure, species distributions and growth to the city forest managers. The associated maps of uncertainty help managers understand the limitations of the maps and identify locations where the maps are more reliable and where more data are needed.

Quantifying and Monitoring Forest Fragmentation Using Satellite Imagery and Forest Inventory and Analysis Plot Data

Author : Dacia Marie Meneguzzo
Publisher :
ISBN 13 :
Total Pages : 196 pages
Book Rating : 4.:/5 (351 download)

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Book Synopsis Quantifying and Monitoring Forest Fragmentation Using Satellite Imagery and Forest Inventory and Analysis Plot Data by : Dacia Marie Meneguzzo

Download or read book Quantifying and Monitoring Forest Fragmentation Using Satellite Imagery and Forest Inventory and Analysis Plot Data written by Dacia Marie Meneguzzo and published by . This book was released on 2008 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Not Seeing the Forest for the Points

Author : Heather Anuhea Kramer
Publisher :
ISBN 13 :
Total Pages : 84 pages
Book Rating : 4.:/5 (957 download)

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Book Synopsis Not Seeing the Forest for the Points by : Heather Anuhea Kramer

Download or read book Not Seeing the Forest for the Points written by Heather Anuhea Kramer and published by . This book was released on 2016 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Forest and fire ecology have long utilized remote sensing datasets to learn more about landscapes. Advances in gps spatial accuracy, GIS software capabilities, computing power, and remote sensing technology and software, as well as increases in the spatial and temporal resolution of remote sensing products, have made remote sensing a critical component of forest and fire ecology. Aerial light detection and ranging (LiDAR) is a fast-growing active remote-sensing technology that can be mined for detailed structural information about forests. These data are utilized in the fields of hydrology, forest ecology, silviculture, wildland fire ecology, wildlife ecology, and habitat modeling. LiDAR coverage has also become increasingly common, yet still contains much untapped potential. Despite widespread research that derived copious valuable metrics from aerial LiDAR, few of these metrics are available to managers due to a significant knowledge and software barrier for LiDAR processing. Even when LiDAR is utilized to derive more complex metrics by scientists and LiDAR experts, metrics are often predictions of plot-based data across the landscape. While these metrics are useful, LiDAR can offer so much more. Because it holds information about forest structure in 3 dimensions, new metrics can be derived that capture the full complexity of forest structure. I explore ways in which managers can use the plot network and data layers already available to them to derive large tree density, a metric that is critical for habitat modeling for many species, including the California spotted owl. I also explore the utility of LiDAR for estimating ladder fuels that carry fire from the ground into the canopy. Because there was no reliable method for quantifying these fuels, I also developed a plot-based methodology to collect these data. My dissertation work aims to increase LiDAR accessibility to managers and to develop new ways to use LiDAR to solve old problems. While there is much more work to be done, I am excited to share my work with LiDAR experts and forest managers, and hope that my findings improve the way we use LiDAR, the way we manage forests, and the way that we model and manage for wildland fire.

Determining Allometric Relationships Within Tree Species for a Quantitative Understanding of Forest-atmosphere Water Fluxes Coupled with Remote-sensing-based Methods for Determining Forest Structure at an Individual-tree Scale

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Author : Kevin A. Meyer
Publisher :
ISBN 13 :
Total Pages : 47 pages
Book Rating : 4.:/5 (785 download)

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Book Synopsis Determining Allometric Relationships Within Tree Species for a Quantitative Understanding of Forest-atmosphere Water Fluxes Coupled with Remote-sensing-based Methods for Determining Forest Structure at an Individual-tree Scale by : Kevin A. Meyer

Download or read book Determining Allometric Relationships Within Tree Species for a Quantitative Understanding of Forest-atmosphere Water Fluxes Coupled with Remote-sensing-based Methods for Determining Forest Structure at an Individual-tree Scale written by Kevin A. Meyer and published by . This book was released on 2011 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Chapter 1 Abstract Transpiration from forests contributes to both regional and global hydrological cycles. Rates of transpiration depend on a tree's physiology and its surrounding environmental factors. Many of these factors control water stress levels that in turn affect transpiration rates. By studying tree architecture and allometric relationships within that architecture, we can begin to quantify the 'pipe network' of a tree (i.e. its branching network). These relationships can produce parameters that define the hydrodynamic framework of a specific tree species. The framework can help further define the water stresses a tree experiences within its 'pipe network'. This information can be incorporated into hydrological models to enhance their predictive capabilities of forest-level transpiration. The models can consider changes in forest composition because each tree will have a different representative hydrodynamic framework. As forests change, the corresponding change in transpiration will be better incorporated into the models. Our results support that such hydrodynamic models can be developed. Virtual trees can be created that accurately depict a specific tree species. This is possible because many allometric relationships exist within a single tree, between trees of the same species, and between trees of different species. Chapter 2 Abstract Atmosphere-biosphere interactions involve exchanges of water, heat and carbon dioxide between the atmosphere and forest ecosystems. This exchange is important in contributing to weather and climate change. Current land-surface models do not resolve the effects of canopy structure change or incorporate 'real' forest heterogeneity as input parameters. The primary goal of this work is to provide a remote-sensing-based method to determine forest structure at an individual-tree scale. This will be done by: (1) parameterization of empirical allometric relationships that govern the scaling of tree-crown hydraulic structure with tree size, species, and relative location in the canopy, and (2) tree-type classification of high-resolution airborne images combining visible and LIDAR. To determine allometric relationships, measurements of structural-hydraulic characteristics of trees, such as stem diameter and taper, branch diameter, splitting patterns, and leaf distribution were taken at existing experimental plots. 2010 census data containing tree species, location, and diameter at breast height (DBH) was obtained to provide additional forest composition information. Remote sensing data was provided by the National Agricultural Imagery Program. Aerial LIDAR data supplemented these images. Species-specific allometric equations were generated relating tree height and crown diameter to DBH, which will be input parameters to existing hydrological models. Using ENVI 4.5, an image analysis program, we will visually attempt to classify the heterogeneity of a forest. This will be coupled with the LIDAR data to provide additional classification schemes. The validity of our ENVI results will be compared to the 2010 census. Combining remote-sensing-determined composition with allometric relationships will allow simulations using new generation hydraulic models, which simulate water flow through the forest at the individual-tree scale and strengthen the predictive capabilities of existing hydrological models, and thus producing better predictions of atmosphere-biosphere interactions.

Measurements and Estimations of Forest Stand Parameters Using Remote Sensing

Author : Donald A. Stellingwerf
Publisher : VSP
ISBN 13 : 9789067642514
Total Pages : 292 pages
Book Rating : 4.6/5 (425 download)

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Book Synopsis Measurements and Estimations of Forest Stand Parameters Using Remote Sensing by : Donald A. Stellingwerf

Download or read book Measurements and Estimations of Forest Stand Parameters Using Remote Sensing written by Donald A. Stellingwerf and published by VSP. This book was released on 1997-08 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Generally speaking, the use of remote sensing imagery will reduce field work. Remote sensing imagery gives an overall view of the forest in addition to more detailed information, the extent of which depends mainly on scale and film used in case of analogue data, and mainly on pixel size in case of digital data. This book deals with measurements and estimations of forest stand parameters using aerial photographic, aircraft and satellite scanning data, radar and laser imagery. It includes technical and statistical information of practical examples from both temperate and tropical forests. Statistical analysis of measurement data and sampling techniques are given when required. The obtained results are compared with those from other techniques, showing their relative advantage or disadvantage.

Remote Sensing of Forest Biomass Dynamics Using Landsat-derived Disturbance and Recovery History and Lidar Data

Author : Dirk Pflugmacher
Publisher :
ISBN 13 :
Total Pages : 182 pages
Book Rating : 4.:/5 (764 download)

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Book Synopsis Remote Sensing of Forest Biomass Dynamics Using Landsat-derived Disturbance and Recovery History and Lidar Data by : Dirk Pflugmacher

Download or read book Remote Sensing of Forest Biomass Dynamics Using Landsat-derived Disturbance and Recovery History and Lidar Data written by Dirk Pflugmacher and published by . This book was released on 2011 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improved monitoring of forest biomass is needed to quantify natural and anthropogenic effects on the terrestrial carbon cycle. Landsat's temporal and spatial coverage, fine spatial grain, and long history of earth observations provide a unique opportunity for measuring biophysical properties of vegetation across large areas and long time scales. However, like other multi-spectral data, the relationship between single-date reflectance and forest biomass weakens under certain canopy conditions. Because the structure and composition of a forest stand at any point in time is linked to the stand's disturbance history, one potential means of enhancing Landsat's spectral relationships with biomass is by including information on vegetation trends prior to the date for which estimates are desired. The purpose of this research was to develop and assess a method that links field data, airborne lidar, and Landsat-derived disturbance and recovery history for mapping of forest biomass and biomass change. Our study area is located in eastern Oregon (US), an area dominated by mixed conifer and single species forests. In Chapter 2, we test and demonstrate the utility of Landsat-derived disturbance and recovery metrics to predict current forest structure (live and dead biomass, basal area, and stand height) for 51 field plots, and compare the results with estimates from airborne lidar and single-date Landsat imagery. To characterize the complex nature of long-term (insect, growth) and short-term (fire, harvest) vegetation changes found in this area, we use annual Landsat time series between 1972 and 2010. This required integrating Landsat data from MSS (1972-1992) and TM/ETM+ (1982-present) sensors. In Chapter 2, we describe a method to bridge spectral differences between Landsat sensors, and therefore extent Landsat time-series analyses back to 1972. In Chapter 3, we extend and automate our approach and develop maps of current (2009) and historic (1993-2009) live forest biomass. We use lidar data for model training and evaluate the results with forest inventory data. We further conduct a sensitivity analysis to determine the effects of forest structure, time-series length, terrain and sampling design on model predictions. Our research showed that including disturbance and recovery trends in empirical models significantly improved predictions of forest biomass, and that the approach can be applied across a larger landscape and across time for estimating biomass change.

Lidar Remote Sensing Of Forest Canopy Structure

Author : Christopher Felix Hansen
Publisher :
ISBN 13 :
Total Pages : 240 pages
Book Rating : 4.:/5 (18 download)

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Book Synopsis Lidar Remote Sensing Of Forest Canopy Structure by : Christopher Felix Hansen

Download or read book Lidar Remote Sensing Of Forest Canopy Structure written by Christopher Felix Hansen and published by . This book was released on 2015 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light detection and ranging (LiDAR) data can provide detailed information about three-dimensional forest horizontal and vertical structure that is important to forest productivity and wildlife habitat. Indeed, LiDAR data have been shown to provide accurate estimates to forest structural parameters and measures of higher trophic levels (e.g., avian abundance and diversity). However, links between forest structure and tree function have not been evaluated using LiDAR. This study was designed and scaled to assess the relationship of LiDAR to multiple aspects of forest structure and higher trophic levels (arthropod and bird populations), which included the ground-based collection of percent crown and understory closure, as well as arthropod and avian abundance and diversity data. Additional plot-based measures were added to assess the relationship of LiDAR to forest health and productivity. High-resolution discrete-return LiDAR data (flown summer of 2009) were acquired for the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, USA. LiDAR data were classified into four canopy structural categories: 1) high crown and high understory closure, 2) high crown and low understory closure, 3) low crown and high understory closure, and 4) low crown and low understory closure. Nearby plots from each of the four LiDAR categories were grouped into "blocks" to assess the spatial consistency of data. Ground-based measures of forest canopy structure, site, stand and individual tree measures were collected on nine 50 m-plots from each LiDAR category (36 plots total), during summer of 2012. Analysis of variance was used to assess the relationships between LiDAR and a suite of tree function measures. Our results show the novel ability of LiDAR to assess forest health and productivity at the stand and individual tree level. We found significant correspondence between LiDAR categories and our ground-based measures of tree function, including xylem increment growth, foliar nutrition, crown health, and stand mortality. Furthermore, we found consistent reductions in xylem increment growth, decreases in foliar nutrition and crown health, and increases in stand mortality related to high understory closure. This suggests that LiDAR measures can reflect competitive interactions, not just among overstory trees for light, but also interactions between overstory trees and understory vegetation for resources other than light (e.g., nutrients). High-resolution LiDAR data show promise in the assessment of forest health and productivity related to tree function.