scholarly journals Age structure and disturbance legacy of North American forests

2011 ◽  
Vol 8 (3) ◽  
pp. 715-732 ◽  
Author(s):  
Y. Pan ◽  
J. M. Chen ◽  
R. Birdsey ◽  
K. McCullough ◽  
L. He ◽  
...  
Keyword(s):  
Age Structure ◽  
Forest Type ◽  
Processing System ◽  
Forest Carbon ◽  
Forest Recovery ◽  
Co2 Uptake ◽  
Forest Age ◽  
Inventory Data ◽  
Disturbance Legacy ◽  
The Impact

Abstract. Most forests of the world are recovering from a past disturbance. It is well known that forest disturbances profoundly affect carbon stocks and fluxes in forest ecosystems, yet it has been a great challenge to assess disturbance impacts in estimates of forest carbon budgets. Net sequestration or loss of CO2 by forests after disturbance follows a predictable pattern with forest recovery. Forest age, which is related to time since disturbance, is a useful surrogate variable for analyses of the impact of disturbance on forest carbon. In this study, we compiled the first continental forest age map of North America by combining forest inventory data, historical fire data, optical satellite data and the dataset from NASA's Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) project. A companion map of the standard deviations for age estimates was developed for quantifying uncertainty. We discuss the significance of the disturbance legacy from the past, as represented by current forest age structure in different regions of the US and Canada, by analyzing the causes of disturbances from land management and nature over centuries and at various scales. We also show how such information can be used with inventory data for analyzing carbon management opportunities. By combining geographic information about forest age with estimated C dynamics by forest type, it is possible to conduct a simple but powerful analysis of the net CO2 uptake by forests, and the potential for increasing (or decreasing) this rate as a result of direct human intervention in the disturbance/age status. Finally, we describe how the forest age data can be used in large-scale carbon modeling, both for land-based biogeochemistry models and atmosphere-based inversion models, in order to improve the spatial accuracy of carbon cycle simulations.

scholarly journals Age structure and disturbance legacy of North American forests

2010 ◽  
Vol 7 (1) ◽  
pp. 979-1020 ◽  
Author(s):  
Y. Pan ◽  
J. M. Chen ◽  
R. Birdsey ◽  
K. McCullough ◽  
L. He ◽  
...  
Keyword(s):  
North America ◽  
Age Structure ◽  
Forest Type ◽  
Forest Carbon ◽  
Forest Recovery ◽  
Co2 Uptake ◽  
Forest Age ◽  
Inventory Data ◽  
Disturbance Legacy ◽  
The Impact

Abstract. Most forests of the world are recovering from a past disturbance. It is well known that forest disturbances profoundly affect carbon stock and fluxes in forest ecosystems, yet it has been a great challenge to assess disturbance impacts in estimates of forest carbon budgets. Net sequestration or loss of CO2 by forests after disturbance follows a predictable pattern with forest recovery. Forest age, which is related to time since disturbance, is the most available surrogate variable for various forest carbon analyses that concern the impact of disturbance. In this study, we compiled the first continental forest age map of North America by combining forest inventory data, historical fire data, optical satellite data and the dataset from NASA's LEDAPS project. Mexico and interior Alaska are excluded from this initial map due to unavailability of all required data sets, but work is underway to develop some different methodology for these areas. We discuss the significance of disturbance legacy from the past, as represented by current forest age structure in different regions of the US and Canada, tracking back disturbances caused by human and nature over centuries and at various scales. We also show how such information can be used with inventory data for analyzing carbon management opportunities, and other modeling applications. By combining geographic information about forest age with estimated C dynamics by forest type, it is possible to conduct a simple but powerful analysis of the net CO2 uptake by forests, and the potential for increasing (or decreasing) this rate as a result of direct human intervention in the disturbance/age status. The forest age map may also help address the recent concern that the terrestrial C sink from forest regrowth in North America may saturate in the next few decades. Finally, we describe how the forest age data can be used in large-scale carbon modeling, both for land-based biogeochemistry models and atmosphere-based inversion models, in order to improve the spatial accuracy of carbon cycle simulations.

scholarly journals Impact of Atmospheric Optical Properties on Net Ecosystem Productivity of Peatland in Poland

2021 ◽  
Vol 13 (11) ◽  
pp. 2124
Author(s):  
Kamila M. Harenda ◽  
Mateusz Samson ◽  
Radosław Juszczak ◽  
Krzysztof M. Markowicz ◽  
Iwona S. Stachlewska ◽  
...  
Keyword(s):  
Optical Properties ◽  
Diffuse Radiation ◽  
Co2 Uptake ◽  
High Carbon ◽  
Atmospheric Scattering ◽  
Net Productivity ◽  
Diffusion Index ◽  
Ecosystem Production ◽  
The Impact ◽  
Global Carbon

Peatlands play an important role in the global carbon cycle due to the high carbon storage in the substrate. Ecosystem production depends, for example, on the solar energy amount that reaches the vegetation, however the diffuse component of this flux can substantially increase ecosystem net productivity. This phenomenon is observed in different ecosystems, but the study of the atmosphere optical properties on peatland production is lacking. In this paper, the presented methodology allowed us to disentangle the diffuse radiation impact on the net ecosystem production (NEP) of Rzecin peatland, Poland. It allowed us to assess the impact of the atmospheric scattering process determined by the aerosol presence in the air mass. An application of atmospheric radiation transfer (ART) and ecosystem production (EP) models showed that the increase of aerosol optical thickness from 0.09 to 0.17 caused NEP to rise by 3.4–5.7%. An increase of the diffusion index (DI) by 0.1 resulted in an NEP increase of 6.1–42.3%, while a DI decrease of 0.1 determined an NEP reduction of −49.0 to −10.5%. These results show that low peatland vegetation responds to changes in light scattering. This phenomenon should be taken into account when calculating the global CO2 uptake estimation of such ecosystems.

scholarly journals Rapid Assessment of Tree Damage Resulting from a 2020 Windstorm in Iowa, USA

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 555
Author(s):  
Thomas C. Goff ◽  
Mark D. Nelson ◽  
Greg C. Liknes ◽  
Tivon E. Feeley ◽  
Scott A. Pugh ◽  
...  
Keyword(s):  
Forest Inventory ◽  
Damage Zone ◽  
Satellite Image ◽  
Rapid Assessment ◽  
Aerial Survey ◽  
Inventory Data ◽  
Tree Damage ◽  
Forest Inventory Data ◽  
Damage Susceptibility ◽  
The Impact

A need to quantify the impact of a particular wind disturbance on forest resources may require rapid yet reliable estimates of damage. We present an approach for combining pre-disturbance forest inventory data with post-disturbance aerial survey data to produce design-based estimates of affected forest area and number and volume of trees damaged or killed. The approach borrows strength from an indirect estimator to adjust estimates from a direct estimator when post-disturbance remeasurement data are unavailable. We demonstrate this approach with an example application from a recent windstorm, known as the 2020 Midwest Derecho, which struck Iowa, USA, and adjacent states on 10–11 August 2020, delivering catastrophic damage to structures, crops, and trees. We estimate that 2.67 million trees and 1.67 million m3 of sound bole volume were damaged or killed on 23 thousand ha of Iowa forest land affected by the 2020 derecho. Damage rates for volume were slightly higher than for number of trees, and damage on live trees due to stem breakage was more prevalent than branch breakage, both likely due to higher damage probability in the dominant canopy of larger trees. The absence of post-storm observations in the damage zone limited direct estimation of storm impacts. Further analysis of forest inventory data will improve understanding of tree damage susceptibility under varying levels of storm severity. We recommend approaches for improving estimates, including increasing spatial or temporal extents of reference data used for indirect estimation, and incorporating ancillary satellite image-based products.

scholarly journals Evaluating the Potential of Commercial Forest Inventory Data to Report on Forest Carbon Stock and Forest Carbon Stock Changes for REDD+ under the UNFCCC

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Danae Maniatis ◽  
Yadvinder Malhi ◽  
Laurent Saint André ◽  
Danilo Mollicone ◽  
Nicolas Barbier ◽  
...  
Keyword(s):  
Carbon Stock ◽  
Measurement Data ◽  
Forest Carbon ◽  
Phase 2 ◽  
Inventory Data ◽  
Ecological Data ◽  
Phase 3 ◽  
Forest Carbon Stock ◽  
Commercial Logging ◽  
Commercial Forest

In the context of the adoption at the 16th Conference of the Parties in 2010 on the REDD+ mitigation mechanism, it is important to obtain reliable data on the spatiotemporal variation of forest carbon stocks and changes (called Emission Factor, EF). A re-occurring debate in estimating EF for REDD+ is the use of existing field measurement data. We provide an assessment of the use of commercial logging inventory data and ecological data to estimate a conservative EF (REDD+ phase 2) or to report on EF following IPCC Guidance and Guidelines (REDD+ phase 3). The data presented originate from five logging companies dispersed over Gabon, totalling 2,240 plots of 0.3 hectares.We distinguish three Forest Types (FTs) in the dataset based on floristic conditions. Estimated mean aboveground biomass (AGB) in the FTs ranges from 312 to 333 Mg ha−1. A 5% accuracy is reached with the number of plots put in place for the FTs and a low sampling uncertainty obtained (± 10 to 13 Mg ha−1). The data could be used to estimate a conservative EF in REDD+ phase 2 and only partially to report on EF following tier 2 requirements for a phase 3.

The Impact of Regional Age Structure on Entrepreneurship

2009 ◽  
Vol 85 (3) ◽  
pp. 269-287 ◽  
Author(s):  
Werner Bönte ◽  
Oliver Falck ◽  
Stephan Heblich
Keyword(s):  
Age Structure ◽  
The Impact

scholarly journals The impact of sedimentary alkalinity release on the water column CO<sub>2</sub> system in the North Sea

2016 ◽  
Vol 13 (3) ◽  
pp. 841-863 ◽  
Author(s):  
H. Brenner ◽  
U. Braeckman ◽  
M. Le Guitton ◽  
F. J. R. Meysman
Keyword(s):  
Coastal Zone ◽  
North Sea ◽  
Dissolved Inorganic Carbon ◽  
Co2 Uptake ◽  
Overlying Water ◽  
Southern North Sea ◽  
The North ◽  
Alkalinity Generation ◽  
The North Sea ◽  
The Impact

Abstract. It has been previously proposed that alkalinity release from sediments can play an important role in the carbonate dynamics on continental shelves, lowering the pCO2 of seawater and hence increasing the CO2 uptake from the atmosphere. To test this hypothesis, sedimentary alkalinity generation was quantified within cohesive and permeable sediments across the North Sea during two cruises in September 2011 (basin-wide) and June 2012 (Dutch coastal zone). Benthic fluxes of oxygen (O2), alkalinity (AT) and dissolved inorganic carbon (DIC) were determined using shipboard closed sediment incubations. Our results show that sediments can form an important source of alkalinity for the overlying water, particularly in the shallow southern North Sea, where high AT and DIC fluxes were recorded in near-shore sediments of the Belgian, Dutch and German coastal zone. In contrast, fluxes of AT and DIC are substantially lower in the deeper, seasonally stratified, northern part of the North Sea. Based on the data collected, we performed a model analysis to constrain the main pathways of alkalinity generation in the sediment, and to quantify how sedimentary alkalinity drives atmospheric CO2 uptake in the southern North Sea. Overall, our results show that sedimentary alkalinity generation should be regarded as a key component in the CO2 dynamics of shallow coastal systems.

scholarly journals The impact of rotational speed and water volume on textile translational motion in a front-loading washer

2018 ◽  
Vol 89 (16) ◽  
pp. 3401-3410 ◽  
Author(s):  
Hong Liu ◽  
R Hugh Gong ◽  
Pinghua Xu ◽  
Xuemei Ding ◽  
Xiongying Wu
Keyword(s):  
Residence Time ◽  
Rotational Speed ◽  
High Speed ◽  
Translational Motion ◽  
Processing System ◽  
Water Volume ◽  
Motion Path ◽  
Rotational Axis ◽  
Passive Region ◽  
The Impact

Textile motion in a front-loading washer has been characterized via video capturing, and a processing system developed based on image geometric moment. Textile motion significantly contributes to the mass transfer of the wash solution in porous materials, particularly in the radial direction (perpendicular to the rotational axis of the inner drum). In this paper, the velocity profiles and residence time distributions of tracer textiles have been investigated to characterize the textile dynamics in a front-loading washer. The results show that the textile motion varies significantly with the water volume and rotational speed, and that the motion path follows certain patterns. Two regions are observed in the velocity plots: a passive region where the textile moves up with low velocity and an active region where the textile falls down with relatively high speed. A stagnant area in the residence time profile is observed. This corresponds to the passive region in the velocity profile. The stagnant area affects the mechanical action, thus influencing washing efficiency and textile performance. The findings on textile dynamics will help in the development of better front-loading washers.

scholarly journals Empirical methods for the estimation of Southern Ocean CO<sub>2</sub>: support vector and random forest regression

2017 ◽  
Vol 14 (23) ◽  
pp. 5551-5569 ◽  
Author(s):  
Luke Gregor ◽  
Schalk Kok ◽  
Pedro M. S. Monteiro
Keyword(s):  
Random Forest ◽  
Southern Ocean ◽  
Synthetic Data ◽  
Good Effect ◽  
Support Vector ◽  
Co2 Uptake ◽  
Empirical Methods ◽  
Random Forest Regression ◽  
Proxy Variables ◽  
The Impact

Abstract. The Southern Ocean accounts for 40 % of oceanic CO2 uptake, but the estimates are bound by large uncertainties due to a paucity in observations. Gap-filling empirical methods have been used to good effect to approximate pCO2 from satellite observable variables in other parts of the ocean, but many of these methods are not in agreement in the Southern Ocean. In this study we propose two additional methods that perform well in the Southern Ocean: support vector regression (SVR) and random forest regression (RFR). The methods are used to estimate ΔpCO2 in the Southern Ocean based on SOCAT v3, achieving similar trends to the SOM-FFN method by Landschützer et al. (2014). Results show that the SOM-FFN and RFR approaches have RMSEs of similar magnitude (14.84 and 16.45 µatm, where 1 atm  =  101 325 Pa) where the SVR method has a larger RMSE (24.40 µatm). However, the larger errors for SVR and RFR are, in part, due to an increase in coastal observations from SOCAT v2 to v3, where the SOM-FFN method used v2 data. The success of both SOM-FFN and RFR depends on the ability to adapt to different modes of variability. The SOM-FFN achieves this by having independent regression models for each cluster, while this flexibility is intrinsic to the RFR method. Analyses of the estimates shows that the SVR and RFR's respective sensitivity and robustness to outliers define the outcome significantly. Further analyses on the methods were performed by using a synthetic dataset to assess the following: which method (RFR or SVR) has the best performance? What is the effect of using time, latitude and longitude as proxy variables on ΔpCO2? What is the impact of the sampling bias in the SOCAT v3 dataset on the estimates? We find that while RFR is indeed better than SVR, the ensemble of the two methods outperforms either one, due to complementary strengths and weaknesses of the methods. Results also show that for the RFR and SVR implementations, it is better to include coordinates as proxy variables as RMSE scores are lowered and the phasing of the seasonal cycle is more accurate. Lastly, we show that there is only a weak bias due to undersampling. The synthetic data provide a useful framework to test methods in regions of sparse data coverage and show potential as a useful tool to evaluate methods in future studies.

scholarly journals CO2 uptake decreased and CH4 emissions increased in first two years of peatland seismic line restoration

2021 ◽  
Author(s):  
Megan Schmidt ◽  
Scott J. Davidson ◽  
Maria Strack
Keyword(s):  
Oil And Gas ◽  
Ecosystem Respiration ◽  
Tree Seedlings ◽  
Co2 Uptake ◽  
Seismic Line ◽  
Oil And Gas Exploration ◽  
Net Productivity ◽  
The Impact ◽  
Seismic Lines ◽  
Reference Areas

Abstract Oil and gas exploration has resulted in over 300,000 km of linear disturbances known as seismic lines, throughout boreal peatlands across Canada. Sites are left with altered hydrologic and topographic conditions that prevent tree re-establishment. Restoration efforts have concentrated on tree recovery through mechanical mounding to re-create microtopography and support planted tree seedlings to block sightlines and deter predator use, but little is known about the impact of seismic line disturbance or restoration on peatland carbon cycling. This study looked at two mounding treatments and compared carbon dioxide and methane fluxes to untreated lines and natural reference areas in the first two years post-restoration. We found no significant differences in net ecosystem CO2 exchange, but untreated seismic lines were slightly more productive than natural reference areas and mounding treatments. Both restoration treatments increased ecosystem respiration, decreased net productivity by 6–21 gCO2m− 2d− 1, and created areas of increased methane emissions, including an increase in the contribution of ebullition, of up to 2000 mgCH4m− 2d− 1. Further research on this site to assess the longer-term impacts of restoration, as well as application on other sites with varied conditions, will help determine if these restoration practices are effective.

The Impact of the Transformation of Age Structure on Economic Growth

2016 ◽  
Vol 04 (04) ◽  
pp. 1650031 ◽  
Author(s):  
Wen ZHAO ◽  
Xuyang ZHU
Keyword(s):  
Economic Growth ◽  
Age Structure ◽  
Capital Accumulation ◽  
Technological Progress ◽  
Participation Rate ◽  
Market Mechanisms ◽  
Economic Growth Rate ◽  
Intergenerational Redistribution ◽  
Labor Remuneration ◽  
The Impact

The impact of the transformation of the age structure of the population on economic growth is governed by a strict law. In 12 economies under the authors’ observation, the contribution from the rejuvenation of the population to economic growth is basically 6% — the Chinese Mainland makes a contribution of 6.3%. The rejuvenation of the population has stimulated economic growth, but its contribution is very small compared with the contributions from capital accumulation and technological progress. According to international experience, in the case of addressing the transformation of the age structure of the population, relying on intergenerational redistribution will exert a great negative economic impact, while reducing the intensity of that redistribution and relying on market mechanisms to adjust the level of labor remuneration can increase the employment rate and the labor participation rate, thus raising the economic growth rate to the greatest extent.

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