scholarly journals Estimating aboveground carbon density and its uncertainty in Borneo’s structurally complex tropical forests using airborne laser scanning

2018 ◽  
Author(s):  
Tommaso Jucker ◽  
Gregory P. Asner ◽  
Michele Dalponte ◽  
Philip Brodrick ◽  
Christopher D. Philipson ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Laser Scanning ◽  
Canopy Cover ◽  
Carbon Stocks ◽  
Forest Carbon ◽  
Airborne Laser Scanning ◽  
Tropical Asia ◽  
Airborne Laser ◽  
Dipterocarp Forests ◽  
The Tropics

Abstract. Borneo contains some of the world’s most biodiverse and carbon dense tropical forest, but this 750 000-km2 island has lost 62 % of its old-growth forests within the last 40 years. Efforts to protect and restore the remaining forests of Borneo hinge on recognising the ecosystem services they provide, including their ability to store and sequester carbon. Airborne Laser Scanning (ALS) is a remote sensing technology that allows forest structural properties to be captured in great detail across vast geographic areas. In recent years ALS has been integrated into state-wide assessment of forest carbon in Neotropical and African regions, but not yet in Asia. For this to happen, new regional models, need to be developed for estimating carbon stocks from ALS in tropical Asia, as the forests of this region are structurally and compositionally distinct from those found elsewhere in the tropics. By combining ALS imagery with data from 173 permanent forest plots spanning the lowland rain forests of Sabah, on the island of Borneo, we develop a simple-yet-general model for estimating forest carbon stocks using ALS-derived canopy height and canopy cover as input metrics. An advanced feature of this new model is the propagation of uncertainty in both ALS- and ground-based data, allowing uncertainty in hectare-scale estimates of carbon stocks to be quantified robustly. We show that the model effectively captures variation in aboveground carbons stocks across extreme disturbance gradients spanning tall dipterocarp forests and heavily logged regions, and clearly outperforms existing ALS-based models calibrated for the tropics, as well as currently available satellite-derived products. Our model provides a simple, generalised and effective approach for mapping forest carbon stocks in Borneo, and underpins ongoing efforts to safeguard and facilitate the restoration of its unique tropical forests.

scholarly journals Estimating aboveground carbon density and its uncertainty in Borneo's structurally complex tropical forests using airborne laser scanning

2018 ◽  
Vol 15 (12) ◽  
pp. 3811-3830 ◽  
Author(s):  
Tommaso Jucker ◽  
Gregory P. Asner ◽  
Michele Dalponte ◽  
Philip G. Brodrick ◽  
Christopher D. Philipson ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Laser Scanning ◽  
Carbon Stocks ◽  
Forest Carbon ◽  
Airborne Laser Scanning ◽  
Tropical Asia ◽  
Aboveground Carbon ◽  
Airborne Laser ◽  
Dipterocarp Forests ◽  
The Tropics

Abstract. Borneo contains some of the world's most biodiverse and carbon-dense tropical forest, but this 750 000 km2 island has lost 62 % of its old-growth forests within the last 40 years. Efforts to protect and restore the remaining forests of Borneo hinge on recognizing the ecosystem services they provide, including their ability to store and sequester carbon. Airborne laser scanning (ALS) is a remote sensing technology that allows forest structural properties to be captured in great detail across vast geographic areas. In recent years ALS has been integrated into statewide assessments of forest carbon in Neotropical and African regions, but not yet in Asia. For this to happen new regional models need to be developed for estimating carbon stocks from ALS in tropical Asia, as the forests of this region are structurally and compositionally distinct from those found elsewhere in the tropics. By combining ALS imagery with data from 173 permanent forest plots spanning the lowland rainforests of Sabah on the island of Borneo, we develop a simple yet general model for estimating forest carbon stocks using ALS-derived canopy height and canopy cover as input metrics. An advanced feature of this new model is the propagation of uncertainty in both ALS- and ground-based data, allowing uncertainty in hectare-scale estimates of carbon stocks to be quantified robustly. We show that the model effectively captures variation in aboveground carbon stocks across extreme disturbance gradients spanning tall dipterocarp forests and heavily logged regions and clearly outperforms existing ALS-based models calibrated for the tropics, as well as currently available satellite-derived products. Our model provides a simple, generalized and effective approach for mapping forest carbon stocks in Borneo and underpins ongoing efforts to safeguard and facilitate the restoration of its unique tropical forests.

scholarly journals Area-based vs tree-centric approaches to mapping forest carbon in Southeast Asian forests from airborne laser scanning data

2017 ◽  
Vol 194 ◽  
pp. 77-88 ◽  
Author(s):  
David A. Coomes ◽  
Michele Dalponte ◽  
Tommaso Jucker ◽  
Gregory P. Asner ◽  
Lindsay F. Banin ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Southeast Asian ◽  
Forest Carbon ◽  
Airborne Laser Scanning ◽  
Airborne Laser

scholarly journals Single strata canopy cover estimation using airborne laser scanning data

2013 ◽  
Author(s):  
Antonio Ferraz ◽  
Clement Mallet ◽  
Gil Goncalves ◽  
Margarida Tome ◽  
Paula Soares ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Canopy Cover ◽  
Airborne Laser Scanning ◽  
Airborne Laser

Simple approach to improving the extraction of canopy metrics from airborne laser scanning data for tropical forests

2016 ◽  
Vol 10 (1) ◽  
pp. 016019
Author(s):  
Zhengyang Hou ◽  
Qing Xu ◽  
Chao Zhang ◽  
Matti Maltamo ◽  
Timo Tokola
Keyword(s):  
Tropical Forests ◽  
Laser Scanning ◽  
Simple Approach ◽  
Airborne Laser Scanning ◽  
Airborne Laser

scholarly journals Puittaimestiku kaardistamine aerolidari andmete põhjal metsana lisanduvatel aladel/ Estimation of fractional forest cover from airborne laser scanning data in abandoned agricultural land

2013 ◽  
Vol 59 (1) ◽  
pp. 45-58
Author(s):  
Marta Mõistus ◽  
Mait Lang ◽  
Allan Sims
Keyword(s):  
Laser Scanning ◽  
Agricultural Land ◽  
Canopy Cover ◽  
Airborne Laser Scanning ◽  
Tree Canopy ◽  
Maximum Height ◽  
Plant Canopy ◽  
Actual Problem ◽  
Airborne Laser ◽  
The Impact

Abstract The abandonment of agricultural land is an actual problem in Estonia due to significant impact on landscape ecology and structure. Abandoned agricultural fields are usually converting into forest. Mapping of agricultural land use is a strategic interest of each country. Airborne laser scanning (ALS) is used in many countries for topographical mapping and the laser pulse return positions are promising datasets for mapping the abandonment of agricultural land. We used ALS data based woody plant canopy cover estimates made at certain reference height unachievable for field crops to map abandoned agricultural land in nine test sites in Tartumaa, Estonia. The maximum height of trees in test sites ranged from 6.5 m to 13.4 m. The lidar pulse returns based canopy cover estimate was assessed 1) by using ortophoto based digitized maps of tree canopy, 2) repeated measurements made with plant canopy analyzer LAI-2000 and 3) by using allometric crown radius models and repeated tree measurements from sample plots. The interpretation of canopy boundaries and separation of small spaces between tree crowns from ortophotos is a challenging task for an operator. The relationship between ALS based canopy cover and ortophoto based canopy cover was linear in all test sites except when ALS data from beginning of June were used. It the beginning of June foliage is not fully developed on trees. An increase in the woody canopy cover was detected from repeated LAI-2000 measurements and also from repeated tree measurements-based simulated crowns. The impact of reference height change from 2.0 m to 1.3 m on canopy cover estimations was not significant and much smaller compared to the tree growth induced increase in canopy cover, indicating that similar errors originating from e.g. digital elevation model are not problematic for the proposed method in practical applications.

scholarly journals Airborne laser scanning proxies of canopy light transmission in forests

2021 ◽  
Author(s):  
Adam Erickson ◽  
Nicholas Coops
Keyword(s):  
Laser Scanning ◽  
Light Transmission ◽  
Canopy Cover ◽  
Field Measurements ◽  
Airborne Laser Scanning ◽  
Validation Data ◽  
Cloud Models ◽  
Airborne Laser ◽  
Gap Fraction ◽  
And Function

Reliable estimates of canopy light transmission are critical to understanding the structure and function of vegetation communities but are difficult and costly to attain by traditional field inventory methods. Airborne laser scanning (ALS) data uniquely provide multi-angular vertically resolved representation of canopy geometry across large geographic areas. While previous studies have proposed ALS indices of canopy light transmission, new algorithms based on theoretical advancements may improve existing models. Herein, we propose two new models of canopy light transmission (i.e., gap fraction, or Po, the inverse of angular canopy closure). We demonstrate the models against a suite of existing models and ancillary metrics, validated against convex spherical densiometer measurements for 950 field plots in the foothills of Alberta, Canada. We also tested the effects of synthetic hemispherical lens models on the performance of the proposed hemispherical Voronoi gap fraction (Phv) index. While vertical canopy cover metrics showed the best overall fit to field measurements, one new metric, point-density-normalized gap fraction (Ppdn), outperformed all other gap fraction metrics by two-fold. We provide suggestions for further algorithm enhancements based on validation data improvements. We argue that traditional field measurements are no longer appropriate for ‘ground-truthing’ modern LiDAR or SfM point cloud models, as the latter provide orders of magnitude greater sampling and coverage. We discuss the implications of this finding for LiDAR applications in forestry.

scholarly journals Carbon Dynamics in a Human-Modified Tropical Forest: A Case Study Using Multi-Temporal LiDAR Data

2020 ◽  
Vol 12 (3) ◽  
pp. 430 ◽  
Author(s):  
Yhasmin Mendes de Moura ◽  
Heiko Balzter ◽  
Lênio S. Galvão ◽  
Ricardo Dalagnol ◽  
Fernando Espírito-Santo ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Tropical Forests ◽  
Carbon Dynamics ◽  
Carbon Stocks ◽  
Forest Carbon ◽  
Selective Logging ◽  
Carbon Accounting ◽  
Lidar Data ◽  
Multi Temporal ◽  
The Tropics

Tropical forests hold significant amounts of carbon and play a critical role on Earth´s climate system. To date, carbon dynamics over tropical forests have been poorly assessed, especially over vast areas of the tropics that have been affected by some type of disturbance (e.g., selective logging, understory fires, and fragmentation). Understanding the multi-temporal dynamics of carbon stocks over human-modified tropical forests (HMTF) is crucial to close the carbon cycle balance in the tropics. Here, we used multi-temporal and high-spatial resolution airborne LiDAR data to quantify rates of carbon dynamics over a large patch of HMTF in eastern Amazon, Brazil. We described a robust approach to monitor changes in aboveground forest carbon stocks between 2012 and 2018. Our results showed that this particular HMTF lost 0.57 m·yr−1 in mean forest canopy height and 1.38 Mg·C·ha−1·yr−1 of forest carbon between 2012 and 2018. LiDAR-based estimates of Aboveground Carbon Density (ACD) showed progressive loss through the years, from 77.9 Mg·C·ha−1 in 2012 to 53.1 Mg·C·ha−1 in 2018, thus a decrease of 31.8%. Rates of carbon stock changes were negative for all time intervals analyzed, yielding average annual carbon loss rates of −1.34 Mg·C·ha−1·yr−1. This suggests that this HMTF is acting more as a source of carbon than a sink, having great negative implications for carbon emission scenarios in tropical forests. Although more studies of forest dynamics in HMTFs are necessary to reduce the current remaining uncertainties in the carbon cycle, our results highlight the persistent effects of carbon losses for the study area. HMTFs are likely to expand across the Amazon in the near future. The resultant carbon source conditions, directly associated with disturbances, may be essential when considering climate projections and carbon accounting methods.

scholarly journals Quantification of Lichen Cover and Biomass Using Field Data, Airborne Laser Scanning and High Spatial Resolution Optical Data—A Case Study from a Canadian Boreal Pine Forest

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 682
Author(s):  
Ashley C. Hillman ◽  
Scott E. Nielsen
Keyword(s):  
High Resolution ◽  
Spectral Data ◽  
Laser Scanning ◽  
Canopy Cover ◽  
Jack Pine ◽  
Pine Forest ◽  
Airborne Laser Scanning ◽  
Woodland Caribou ◽  
Airborne Laser ◽  
Pine Stands

Ground-dwelling macrolichens dominate the forest floor of mature upland pine stands in the boreal forest. Understanding patterns of lichen abundance, as well as environmental characteristics associated with lichen growth, is key to managing lichens as a forage resource for threatened woodland caribou (Rangifer tarandus caribou). The spectral signature of light-coloured lichen distinguishes it from green vegetation, potentially allowing for mapping of lichen abundance using multi-spectral imagery, while canopy structure measured from airborne laser scanning (ALS) of forest openings can indirectly map lichen habitat. Here, we test the use of high-resolution KOMPSAT (Korea Multi-Purpose Satellite-3) imagery (280 cm resolution) and forest structural characteristics derived from ALS to predict lichen biomass in an upland jack pine forest in Northeastern Alberta, Canada. We quantified in the field lichen abundance (cover and biomass) in mature jack pine stands across low, moderate, and high canopy cover. We then used generalized linear models to relate lichen abundance to spectral data from KOMPSAT and structural metrics from ALS. Model selection suggested that lichen abundance was best predicted by canopy cover (ALS points > 1.37 m) and to a lesser extent blue spectral data from KOMPSAT. Lichen biomass was low at plots with high canopy cover (98.96 g/m2), while almost doubling for plots with low canopy cover (186.30 g/m2). Overall the model fit predicting lichen biomass was good (R2 c = 0.35), with maps predicting lichen biomass from spectral and structural data illustrating strong spatial variations. High-resolution mapping of ground lichen can provide information on lichen abundance that can be of value for management of forage resources for woodland caribou. We suggest that this approach could be used to map lichen biomass for other regions.

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