(Press-News.org)
The regeneration of forest saplings is pivotal for maintaining biodiversity and ecosystem productivity, necessitating innovative management techniques for continuous forest coverage. Traditional 2-dimensional remote sensing struggles to accurately capture the complex, understory sapling dynamics. To address this, researchers are exploring the use of aerial laser scanning (ALS) for its potential in providing detailed 3-dimensional insights. However, despite progress in using ALS data to estimate tree metrics, accurately identifying and quantifying the phenotypic parameters of understory saplings remains a challenge. The current research gap lies in refining and applying algorithms that can effectively distinguish understory saplings within ALS datasets, a critical step towards enhancing forest management and understanding sapling regeneration processes.
In February 2024, Plant Phenomics published a research article entitled by “Identifying Regenerated Saplings by Stratifying Forest Overstory Using Airborne LiDAR Data”.
In this study, researchers developed a comprehensive methodology to extract phenotypic parameters of understory regeneration saplings using advanced high-density airborne LiDAR data. Initially, they fused data from multiple flights to generate a dense laser point cloud, which was then processed using a Nyström-based spectral clustering algorithm for segmenting upper mature trees. To address the common issues of oversegmentation and undersegmentation, a novel postprocessing method was introduced, prominently enhancing the positional accuracy of mature trees.
The results were impressive, showing a notable improvement in the detection and matching rates of tree segmentation after implementing the postprocessing steps; the detection rate for the Nyström-based spectral clustering postprocessing (NSCP) method reached 110.21%, with a matching rate of 96.69%. This optimization reduced trunk position errors, indirectly benefiting the accuracy of understory sapling detection. Utilizing the local adaptive mean shift algorithm, saplings under mature trees were successfully detected, achieving a matching rate of approximately 83% with an extraction rate between 102% to 105%, when the kernel bandwidth parameter was optimally set.
Further validation using multisource reference data confirmed the method's efficacy. Comparisons between airborne LiDAR (ALS) and terrestrial laser scanning (TLS) data revealed a strong correlation (R2 = 0.79) for tree height, demonstrating a notable improvement in RMS error after accounting for the ALS's inability to detect terminal leader shoots. This adjustment led to a more accurate representation of sapling heights, with an overall R2 of 0.71 and RMSE of 0.26 m when comparing ALS-extracted sapling heights against field measurements. Additionally, sapling crown widths estimated from ALS data, when matched against TLS measurements, yielded an acceptable R2 of 0.64 and RMSE of 0.24 m, despite the challenges posed by upper canopy obstruction.
In conclusion, the study not only demonstrated a successful application of high-density ALS data for understory sapling characterization but also highlighted the potential of this technology to enhance forest management and sapling growth studies. The proposed method distinguishes itself by accurately segmenting and measuring understory saplings offering a significant step forward in the use of remote sensing technologies for detailed forest inventory and analysis.
###
References
Authors
Liming Du1,2 and Yong Pang1,2*
Affiliations
1Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China.
2Key Laboratory of Forestry Remote Sensing and Information System, National Forestry and Grassland Administration, Beijing 100091, China.
About Yong Pang
He is currently a Professor with the Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry. His research interests include surface height and vegetation spatial structure from InSAR and LiDAR, modeling of LiDAR waveforms from forest stands, and development of algorithms for forest parameter retrieval from remote sensing data.
END
Woods Hole, Mass. (March 13, 2024) - Emperor penguin populations have been exceedingly difficult to monitor because of their remote locations, and because individuals form breeding colonies on seasonal sea ice fastened to land (known as fast ice) during the dark and cold Antarctic winter.
Now, new research that incorporates very high resolution (VHR) satellite imagery with field-based validation surveys and long-term data has provided the first multi-year time series that documents emperor penguin global population trends.
Researchers ...
Renowned cardiovascular surgeon Gilbert H. L. Tang has been named Editor-in-Chief of JACC: Case Reports, bringing a wealth of experience and expertise to the helm of one of the top cardiovascular journals published by the American College of Cardiology.
“I am both honored and humbled to be a cardiac surgeon among the Editor-in-Chiefs in the JACC family of journals,” Tang said. “It is going to be an exciting time for JACC: Case Reports to build on a team of multidisciplinary cardiovascular practitioners with diverse backgrounds and experiences, and at different stages of their professional careers, to enhance the journal’s academic and educational impact globally.”
Tang ...
Recent advancements in hyperspectral imaging and machine learning have revolutionized the non-destructive monitoring of crop nutritional status, enabling accurate prediction of plant element concentrations. Despite successes, the single-target regression method, which predicts concentrations individually, faces accuracy limitations for certain elements. Traditional methods offer accuracy but at the cost of being destructive and inefficient for large-scale use. Current research highlights the potential of multi-target ...
Woods Hole, Mass. – A healthy coral reef is noisy, full of the croaks, purrs, and grunts of various fishes and the crackling of snapping shrimp. Research suggests that larval animals use this symphony of sounds to help them determine where they should live and grow.
Researchers at the Woods Hole Oceanographic Institution (WHOI) recently demonstrated that replaying healthy reef sounds could potentially be used to encourage coral larvae to recolonize damaged or degraded reefs. A reef that has been ...
The University of Warwick has been awarded £11m to train PhD students in computational modelling.
The new centre will train 50 PhD students to use computational modelling to tackle pressing global sustainability challenges from accessing clean fusion energy, controlling infectious diseases, to designing energy-efficient devices such as new battery electrolytes.
The Centre for Doctoral Training in Modelling of Heterogeneous Systems (HetSys II), led by Professor James Kermode from the School of Engineering, Dr Livia Bartok-Partay from Chemistry and Professor Nicholas Hine from Physics, will train ...
Researchers have published a simple trick that improves the accuracy of techniques that help us understand how external variables – such as temperature – affect gene activity in plants.
“There are really two contributions here,” says Colleen Doherty, corresponding author of a paper on the work and an associate professor of molecular and structural biochemistry at North Carolina State University. “First, we’re raising the visibility of a problem that many of us in the ...
The root system is crucial for plants to absorb water and nutrients, with in situ root research providing insights into root phenotypes and dynamics. While deep-learning-based root segmentation methods have advanced the analysis of root systems, they require extensive manually labeled datasets, which are labor-intensive and time-consuming to produce. Current methods of in situ root observation vary in their effectiveness. Moreover, traditional root image recognition methods face challenges such as subjectivity and ...
About The Study: In this randomized clinical trial of 345 patients with mild-to-moderate COVID-19, viral load rebound and symptom rebound were both common after a standard 5-day course of antiviral treatment with either VV116 or nirmatrelvir-ritonavir. Prolongation of treatment duration might be investigated to reduce COVID-19 rebound.
Authors: Yufang Bi, M.D., and Yiping Xu, M.Sc., of the Shanghai Jiao Tong University School of Medicine in Shanghai, China, are the corresponding authors.
To access the embargoed study: Visit our For ...
About The Study: The findings of this study of 4,515 adolescents suggest that in-person schooling and several coping behaviors (caring for one’s body, exercising, and engaging in healthy behaviors) were associated with significantly higher positive affect and lower perceived stress during the COVID-19 pandemic among adolescents with high adverse childhood experiences (ACEs). Adolescents with high ACEs demonstrated especially greater mental health scores when they reported in-person schooling. Future studies should build on these findings to identify clinical and school-based mental health protective ...
Chlorophyll a fluorescence (ChlF) has been a pivotal tool in understanding plant photochemistry, offering insights into the energy transfer processes within chloroplasts and the efficiency of Photosystem II (PSII). Researchers have relied on quantifying ChlF through specific measures such as F0, Fm, and Fv under various lighting conditions to assess photosynthetic activities. Nonetheless, the technique encounters obstacles owing to the intrinsic uncertainties in gauging the absolute magnitude of ChlF and the fluctuation in baseline levels affected by environmental conditions. This complicates the interpretation of ...
