scholarly journals The terrestrial laser scanning revolution in forest ecology

2018 ◽  
Vol 8 (2) ◽  
pp. 20180001 ◽  
Author(s):  
F. Mark Danson ◽  
Mathias I. Disney ◽  
Rachel Gaulton ◽  
Crystal Schaaf ◽  
Alan Strahler
Keyword(s):  
Forest Structure ◽  
Laser Scanning ◽  
Forest Ecology ◽  
Three Dimensional ◽  
Terrestrial Laser Scanning ◽  
Good Time ◽  
Ecosystem Structure ◽  
Dimensional Measurements ◽  
And Function ◽  
Ecosystem Structure And Function

New laser scanning technologies are set to revolutionize the way in which we measure and understand changes in ecosystem structure and function. Forest ecosystems present a particular challenge because of their scale, complexity and structural dynamics. Traditional forestry techniques rely on manual measurement of easy-to-measure characteristics such as tree girth and height, along with time-consuming, logistically difficult and error-prone destructive sampling. Much more detailed and accurate three-dimensional measurements of forest structure and composition are key to reducing errors in biomass estimates and carbon dynamics and to better understanding the role of forests in global ecosystem and climate change processes. Terrestrial laser scanners are now starting to be deployed in forest ecology research and, at the same time, new terrestrial laser scanning (TLS) technologies are being developed to enhance and extend the range of measurements that can be made. These new TLS measurements provide a tantalizing glimpse of a completely new way to measure and understand forest structure. It is therefore a good time to take stock, assess the state of the art and identify the immediate challenges for continued development of TLS in forest ecology.

scholarly journals Using terrestrial laser scanning to constrain forest ecosystem structure and functions in the Ecosystem Demography model (ED2.2)

2021 ◽  
Author(s):  
Félicien Meunier ◽  
Sruthi M. Krishna Moorthy ◽  
Marc Peaucelle ◽  
Kim Calders ◽  
Louise Terryn ◽  
...  
Keyword(s):  
Leaf Area ◽  
Forest Structure ◽  
Laser Scanning ◽  
Initial Conditions ◽  
Structural Parameters ◽  
Terrestrial Laser Scanning ◽  
Dimensional Structure ◽  
Forest Site ◽  
Ecosystem Structure ◽  
Area Index

Abstract. Terrestrial Biosphere Modeling (TBM) is an invaluable approach for studying plant-atmosphere interactions at multiple spatial and temporal scales, as well as the global change impacts on ecosystems. Yet, TBM projections suffer from large uncertainties that limit their usefulness. A large part of this uncertainty arises from the empirical allometric (size-tomass) relationships that are used to represent forest structure in TBMs. Forest structure actually drives a large part of TBM uncertainty as it regulates key processes such as the transfer of carbon, energy, and water between the land and atmosphere, but remains challenging to measure and reliably represent. The poor representation of forest structure in TBMs results in models that are able to reproduce observed land fluxes, but which fail to realistically represent carbon pools, forest composition, and demography. Recent advances in Terrestrial Laser Scanning (TLS) techniques offer a huge opportunity to capture the three-dimensional structure of the ecosystem and transfer this information to TBMs in order to increase their accuracy. In this study, we quantified the impacts of integrating structural observations of individual trees (namely tree height, leaf area, woody biomass, and crown area) derived from TLS into the state-of-the-art Ecosystem Demography model (ED2.2) at a temperate forest site. We assessed the relative model sensitivity to initial conditions, allometric parameters, and canopy representation by changing them in turn from default configurations to site-specific, TLS-derived values. We show that forest demography and productivity as modelled by ED2.2 are sensitive to the imposed initial state, the model structural parameters, and the way canopy is represented. In particular, we show that: 1) the imposed openness of the canopy dramatically influenced the potential vegetation, the optimal ecosystem leaf area, and the vertical distribution of light in the forest, as simulated by ED2.2; 2) TLS-derived allometric parameters increased simulated leaf area index and aboveground biomass by 57 and 75 %, respectively; 3) the choice of model structure and allometric coefficient both significantly impacted the optimal set of parameters necessary to reproduce eddy covariance flux data.

scholarly journals The effects of modern war and military activities on biodiversity and the environment

2015 ◽  
Vol 23 (4) ◽  
pp. 443-460 ◽  
Author(s):  
Michael J. Lawrence ◽  
Holly L.J. Stemberger ◽  
Aaron J. Zolderdo ◽  
Daniel P. Struthers ◽  
Steven J. Cooke
Keyword(s):  
Military Training ◽  
Structure And Function ◽  
Aquatic Systems ◽  
Ecosystem Structure ◽  
Population Declines ◽  
Exclusion Zone ◽  
Negative Effects ◽  
And Function ◽  
Ecosystem Structure And Function ◽  
Modern War

War is an ever-present force that has the potential to alter the biosphere. Here we review the potential consequences of modern war and military activities on ecosystem structure and function. We focus on the effects of direct conflict, nuclear weapons, military training, and military produced contaminants. Overall, the aforementioned activities were found to have overwhelmingly negative effects on ecosystem structure and function. Dramatic habitat alteration, environmental pollution, and disturbance contributed to population declines and biodiversity losses arising from both acute and chronic effects in both terrestrial and aquatic systems. In some instances, even in the face of massive alterations to ecosystem structure, recovery was possible. Interestingly, military activity was beneficial under specific conditions, such as when an exclusion zone was generated that generally resulted in population increases and (or) population recovery; an observation noted in both terrestrial and aquatic systems. Additionally, military technological advances (e.g., GPS technology, drone technology, biotelemetry) have provided conservation scientists with novel tools for research. Because of the challenges associated with conducting research in areas with military activities (e.g., restricted access, hazardous conditions), information pertaining to military impacts on the environment are relatively scarce and are often studied years after military activities have ceased and with no knowledge of baseline conditions. Additional research would help to elucidate the environmental consequences (positive and negative) and thus reveal opportunities for mitigating negative effects while informing the development of optimal strategies for rehabilitation and recovery.

scholarly journals Global patterns and climatic controls of forest structural complexity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Martin Ehbrecht ◽  
Dominik Seidel ◽  
Peter Annighöfer ◽  
Holger Kreft ◽  
Michael Köhler ◽  
...  
Keyword(s):  
Forest Structure ◽  
Laser Scanning ◽  
Structural Complexity ◽  
Terrestrial Laser Scanning ◽  
Ecosystem Functions ◽  
The Earth ◽  
Precipitation Seasonality ◽  
Latitudinal Patterns ◽  
Global Patterns ◽  
Primary Forests

AbstractThe complexity of forest structures plays a crucial role in regulating forest ecosystem functions and strongly influences biodiversity. Yet, knowledge of the global patterns and determinants of forest structural complexity remains scarce. Using a stand structural complexity index based on terrestrial laser scanning, we quantify the structural complexity of boreal, temperate, subtropical and tropical primary forests. We find that the global variation of forest structural complexity is largely explained by annual precipitation and precipitation seasonality (R² = 0.89). Using the structural complexity of primary forests as benchmark, we model the potential structural complexity across biomes and present a global map of the potential structural complexity of the earth´s forest ecoregions. Our analyses reveal distinct latitudinal patterns of forest structure and show that hotspots of high structural complexity coincide with hotspots of plant diversity. Considering the mechanistic underpinnings of forest structural complexity, our results suggest spatially contrasting changes of forest structure with climate change within and across biomes.

scholarly journals Experimental warming differentially affects vegetative and reproductive phenology of tundra plants

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Courtney G. Collins ◽  
Sarah C. Elmendorf ◽  
Robert D. Hollister ◽  
Greg H. R. Henry ◽  
Karin Clark ◽  
...  
Keyword(s):  
Growing Season ◽  
Plant Phenology ◽  
Reproductive Phenology ◽  
Ecosystem Structure ◽  
Experimental Warming ◽  
Growing Seasons ◽  
Tundra Ecosystem ◽  
Phenological Shifts ◽  
And Function ◽  
Ecosystem Structure And Function

AbstractRapid climate warming is altering Arctic and alpine tundra ecosystem structure and function, including shifts in plant phenology. While the advancement of green up and flowering are well-documented, it remains unclear whether all phenophases, particularly those later in the season, will shift in unison or respond divergently to warming. Here, we present the largest synthesis to our knowledge of experimental warming effects on tundra plant phenology from the International Tundra Experiment. We examine the effect of warming on a suite of season-wide plant phenophases. Results challenge the expectation that all phenophases will advance in unison to warming. Instead, we find that experimental warming caused: (1) larger phenological shifts in reproductive versus vegetative phenophases and (2) advanced reproductive phenophases and green up but delayed leaf senescence which translated to a lengthening of the growing season by approximately 3%. Patterns were consistent across sites, plant species and over time. The advancement of reproductive seasons and lengthening of growing seasons may have significant consequences for trophic interactions and ecosystem function across the tundra.

THE USING OF TERRESTRIAL LASER (POINT CLOUD) SCANNING TECHNOLOGIES ON URBAN SCALE: EXAMPLE OF THE HISTORICAL URBAN TEXTURE OF LAPSEKİ

2021 ◽  
Vol 0 (23) ◽  
pp. 0-0
Author(s):  
Hatice Çiğdem ZAĞRA ◽  
Sibel ÖZDEN
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Terrestrial Laser Scanning ◽  
Traditional Methods ◽  
Life Project ◽  
Three Dimensional Models ◽  
Architectural Restoration ◽  
Cloud Technologies ◽  
Orthophoto Images

Aim: This study aims to comparatively evaluate the use potential of orthophoto images obtained by terrestrial laser scanning technologies on an urban scale through the "Old Lapseki Finds Life Project" prepared using terrestrial laser scanning technologies and the "Enez Historical City Square Project" prepared using traditional methods. Method: In the study, street improvement projects of 29.210 m2 Lapseki and 29.214 m2 Enez city designed on an urban scale were evaluated and compared with descriptive statistics based on different parameters. Results: In the study, it has been determined that terrestrial laser (point cloud) technologies are 99,9% accurate when compared to traditional methods, save time by 83,08% and reduce workforce by 80%. In addition, it has been determined that terrestrial laser scanning technologies accelerate project processes compared to traditional methods. Conclusion: In this study, the use of laser scanning technologies, which are basically reverse engineering applications, in architectural restoration projects, determination of the current situation and damage, architectural documentation of structures and preparation of three-dimensional models, in terms of efficiency in survey studies are evaluated. It has been observed that orthophoto images obtained by terrestrial laser scanning technologies in architectural relief-restoration-restitution projects have potentials' worth using in different stages of the project.

scholarly journals Network method for deformation analysis of three-dimensional point cloud with terrestrial laser scanning sensor

2018 ◽  
Vol 14 (11) ◽  
pp. 155014771881413 ◽  
Author(s):  
Xiangyang Xu ◽  
Hao Yang
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Terrestrial Laser Scanning ◽  
Deformation Analysis ◽  
Transverse Displacement ◽  
Displacement Analysis ◽  
Accuracy Measurement ◽  
Network Method ◽  
Displacement Information

The complexity of structural materials is increasing the importance of the technology for high accuracy measurement. How to obtain the displacement information of structural feature points accurately and efficiently is the key issue of deformation analysis. In this article, displacement analysis of a composite arched structure is investigated based on the terrestrial laser scanning technique. A new method based on the measured point cloud is proposed to analyze the displacement of surficial points, resulting in not only the displacement size but also the displacement direction. The innovation lies in extracting the displacement information with a network and remapped point cloud, which is called the network method. The displacement map obtained demonstrates that the transverse displacement in the experiment plays an important role in the safety of the structure, which could not be observed and obtained by the surface approximation method. Therefore, the panorama- and pointwise displacement analysis technologies contribute to ensure the safety of increasingly complex constructions.

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