scholarly journals Smaller global and regional carbon emissions from gross land use change when considering sub-grid secondary land cohorts in a global dynamic vegetation model

2018 ◽  
Vol 15 (4) ◽  
pp. 1185-1201 ◽  
Author(s):  
Chao Yue ◽  
Philippe Ciais ◽  
Wei Li
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Carbon Emissions ◽  
Shifting Cultivation ◽  
Secondary Forest ◽  
Secondary Forests ◽  
Forest Age ◽  
Rotation Length ◽  
Historical Land Use ◽  
Wood Harvest

Abstract. Several modelling studies reported elevated carbon emissions from historical land use change (ELUC) by including bidirectional transitions on the sub-grid scale (termed gross land use change), dominated by shifting cultivation and other land turnover processes. However, most dynamic global vegetation models (DGVMs) that have implemented gross land use change either do not account for sub-grid secondary lands, or often have only one single secondary land tile over a model grid cell and thus cannot account for various rotation lengths in shifting cultivation and associated secondary forest age dynamics. Therefore, it remains uncertain how realistic the past ELUC estimations are and how estimated ELUC will differ between the two modelling approaches with and without multiple sub-grid secondary land cohorts – in particular secondary forest cohorts. Here we investigated historical ELUC over 1501–2005 by including sub-grid forest age dynamics in a DGVM. We run two simulations, one with no secondary forests (Sageless) and the other with sub-grid secondary forests of six age classes whose demography is driven by historical land use change (Sage). Estimated global ELUC for 1501–2005 is 176 Pg C in Sage compared to 197 Pg C in Sageless. The lower ELUC values in Sage arise mainly from shifting cultivation in the tropics under an assumed constant rotation length of 15 years, being 27 Pg C in Sage in contrast to 46 Pg C in Sageless. Estimated cumulative ELUC values from wood harvest in the Sage simulation (31 Pg C) are however slightly higher than Sageless (27 Pg C) when the model is forced by reconstructed harvested areas because secondary forests targeted in Sage for harvest priority are insufficient to meet the prescribed harvest area, leading to wood harvest being dominated by old primary forests. An alternative approach to quantify wood harvest ELUC, i.e. always harvesting the close-to-mature forests in both Sageless and Sage, yields similar values of 33 Pg C by both simulations. The lower ELUC from shifting cultivation in Sage simulations depends on the predefined forest clearing priority rules in the model and the assumed rotation length. A set of sensitivity model runs over Africa reveal that a longer rotation length over the historical period likely results in higher emissions. Our results highlight that although gross land use change as a former missing emission component is included by a growing number of DGVMs, its contribution to overall ELUC remains uncertain and tends to be overestimated when models ignore sub-grid secondary forests.

scholarly journals Smaller global and regional carbon emissions from gross land use change when considering sub-grid secondary land cohorts in a global dynamic vegetation model

2017 ◽  
Author(s):  
Chao Yue ◽  
Philippe Ciais ◽  
Wei Li
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Carbon Emissions ◽  
Shifting Cultivation ◽  
Secondary Forests ◽  
Forest Age ◽  
Priority Rules ◽  
Forest Clearing ◽  
Historical Land Use ◽  
Wood Harvest

Abstract. Several modeling studies reported elevated carbon emissions from historical land use change (LUC) by including bi-directional transitions at the sub-grid scale (termed gross land use change). This has implication on the estimation of so-called residual land CO2 sink over undisturbed lands. However, in most dynamic global vegetation models (DGVM), forests and/or other land use types are represented with a single sub-grid tile, without accounting for secondary lands that are often involved in shifting cultivation or wood harvest. As a result, land use change emissions (ELUC) are likely overestimated, because it is high-biomass mature forests instead of low-biomass secondary forests that are cleared. Here we investigated the effects of including sub-grid forest age dynamics in a DGVM on historical ELUC over 1501–2005. We run two simulations, one with no forest age (Sageless) and the other with sub-grid secondary forests of different age classes whose demography is driven by historical land use change (Sage). Estimated global ELUC for 1501–2005 are 179 Pg C in Sage compared to 199 Pg C in Sageless. The lower emissions in Sage arise mainly from shifting cultivation in the tropics, being of 27 Pg C in Sage against 46 Pg C in Sageless. Estimated cumulative ELUC from wood harvest in the Sage simulation (31 Pg C) are however slightly higher than Sageless (27 Pg C), because secondary forests simulated in Sage are insufficient to meet the prescribed harvest area, leading to the harvest of old forests. This result depends on pre-defined forest clearing priority rules given a simulated portfolio of differently aged forests in the model. Our results highlight that although gross land use change as a former missing emission component is included by a growing number of DGVMs, its contribution to overall ELUC tends to be overestimated, unless low-biomass secondary forests are properly represented.

scholarly journals Representing anthropogenic gross land use change, wood harvest and forest age dynamics in a global vegetation model ORCHIDEE-MICT (r4259)

2017 ◽  
Author(s):  
Chao Yue ◽  
Philippe Ciais ◽  
Sebastiaan Luyssaert ◽  
Wei Li ◽  
Matthew J. McGrath ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Shifting Cultivation ◽  
Agricultural Land ◽  
Traditional Approach ◽  
Grid Cell ◽  
Secondary Forests ◽  
Vegetation Model ◽  
Data Set ◽  
Wood Harvest

Abstract. Land use change (LUC) is a fundamental anthropogenic disturbance in the global carbon cycle. Here we present model developments in a global dynamic vegetation model ORCHIDEE-MICT for more realistic representation of LUC processes. First, we included gross land use change (primarily shifting cultivation) and forest wood harvest in addition to net land use change. Second, we included sub-grid even-aged land cohorts to represent secondary forests, and to keep track of the age of agricultural lands since LUC, which are associated with variable soil carbon stocks. Combination of these two features allows simulating shifting cultivation with a short rotation length involving mainly secondary forests instead of primary ones. This is in contrast with the traditional approach where a single patch is used for a given land cover type in a model grid cell and forests are thus close to primary ones. We have tested the model over Southern Africa for the period 1501–2005 forced by a historical land use change data set. Including gross land use change and wood harvest has increased LUC emissions in both simulations with (Sage) and without (Sageless) sub-grid secondary forests, but larger increase is found in Sageless (by a factor of 2) than Sage (by a factor of 1.5). Emissions from bi-directional land turnover alone are 35 % lower in Sage than Sageless, mainly because the secondary forests cleared for agricultural land have a lower aboveground biomass than primary ones. We argue that, without representing sub-grid land cohort demography, the additional emissions from land turnover/gross land use change are overestimated. In addition, our developments provide possibilities to account for continental or global forest demographic change resulting from past anthropogenic and natural disturbances.

scholarly journals Representing anthropogenic gross land use change, wood harvest, and forest age dynamics in a global vegetation model ORCHIDEE-MICT v8.4.2

2018 ◽  
Vol 11 (1) ◽  
pp. 409-428 ◽  
Author(s):  
Chao Yue ◽  
Philippe Ciais ◽  
Sebastiaan Luyssaert ◽  
Wei Li ◽  
Matthew J. McGrath ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Southern Africa ◽  
Shifting Cultivation ◽  
Forest Recovery ◽  
Secondary Forests ◽  
Miombo Woodlands ◽  
Agricultural Abandonment ◽  
Vegetation Model ◽  
Wood Harvest

Abstract. Land use change (LUC) is among the main anthropogenic disturbances in the global carbon cycle. Here we present the model developments in a global dynamic vegetation model ORCHIDEE-MICT v8.4.2 for a more realistic representation of LUC processes. First, we included gross land use change (primarily shifting cultivation) and forest wood harvest in addition to net land use change. Second, we included sub-grid evenly aged land cohorts to represent secondary forests and to keep track of the transient stage of agricultural lands since LUC. Combination of these two features allows the simulation of shifting cultivation with a rotation length involving mainly secondary forests instead of primary ones. Furthermore, a set of decision rules regarding the land cohorts to be targeted in different LUC processes have been implemented. Idealized site-scale simulation has been performed for miombo woodlands in southern Africa assuming an annual land turnover rate of 5 % grid cell area between forest and cropland. The result shows that the model can correctly represent forest recovery and cohort aging arising from agricultural abandonment. Such a land turnover process, even though without a net change in land cover, yields carbon emissions largely due to the imbalance between the fast release from forest clearing and the slow uptake from agricultural abandonment. The simulation with sub-grid land cohorts gives lower emissions than without, mainly because the cleared secondary forests have a lower biomass carbon stock than the mature forests that are otherwise cleared when sub-grid land cohorts are not considered. Over the region of southern Africa, the model is able to account for changes in different forest cohort areas along with the historical changes in different LUC activities, including regrowth of old forests when LUC area decreases. Our developments provide possibilities to account for continental or global forest demographic change resulting from past anthropogenic and natural disturbances.

scholarly journals Evaluasi Pengaruh Rehabilitasi Lahan Dan Hutan Terhadap Koefisien Aliran Tahunan Di Sub Das Krueng Meuleusong

2021 ◽  
Vol 14 (2) ◽  
pp. 10-18
Author(s):  
Herry Andrisa ◽  
Hairul Basri ◽  
Muhammad Rusdi
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Satellite Imagery ◽  
Catchment Area ◽  
Secondary Forest ◽  
Flow Coefficient ◽  
Secondary Forests ◽  
Water Catchment Area ◽  
Water Catchment ◽  
Forest Rehabilitation

Abstrak. Penelitian ini bertujuan untuk mengetahui pengaruh rehabilitasi lahan dan hutan (RHL) terhadap nilai koefisien aliran tahunan (KAT) di sub-DAS Krueng Meulesong. Pelaksanaan RHL di Desa Riting Kecamatan Indrapuri Kabupaten Aceh Besar yang termasuk dalam DAS Krueng Meuleusong dikategorikan tidak berhasil berdasarkan citra satelit perubahan tata guna lahan tahun 2009, 2014, 2017 dan 2019. Hasil interpretasi citra satelit menunjukkan penurunan luasan hutan sekunder, namun luas perdu dan sabana meningkat. Berdasarkan hasil uji korelasi menunjukkan bahwa pelaksanaan kegiatan RHL tidak berpengaruh terhadap perubahan penggunaan lahan menjadi hutan sekunder dan kegiatan RHL tidak berpengaruh terhadap nilai koefisien aliran tahunan (KAT) di Sub-DAS Krueng Meuleusong.Evaluation Of The Effect Of Land And Forest Rehabilitation On Annual Flow Coefficient In Krueng Meuleusong Sub-WatershedAbstract. This study aims to determine the effect of land and forest rehabilitation (RHL) on the value of the annual flow coefficient (KAT) in the Krueng Meulesong sub-watershed. The implementation of RHL in Riting Village, Indrapuri District, Aceh Besar District which is included in the water catchment area of the Krueng Meuleusong sub-watershed is categorized as unsuccessful based on satellite imagery of 2009, 2014, 2017 and, 2019 of land-use change. The results of satellite imagery interpretation showed a decrease in the area of secondary forest, but shrubs and savanna area had increased. Based on the results of the correlation test, shows that the implementation of RHL activities has no effect on changes in land use to secondary forests and RHL activities have no effect on the value of annual flow coefficient (KAT) in the Krueng Krueng Meuleusong sub-watershed.

scholarly journals Contributions of secondary forest and nitrogen dynamics to terrestrial carbon uptake

2010 ◽  
Vol 7 (2) ◽  
pp. 2739-2765 ◽  
Author(s):  
X. Yang ◽  
T. K. Richardson ◽  
A. K. Jain
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Secondary Forest ◽  
Nitrogen Dynamics ◽  
Carbon Uptake ◽  
Secondary Forests ◽  
Terrestrial Carbon ◽  
Tropical Regions ◽  
Forest Regrowth ◽  
Limiting Nutrient

Abstract. We use a terrestrial carbon-nitrogen cycle component of the Integrated Science Assessment Model (ISAM) to investigate the impacts of nitrogen dynamics on regrowing secondary forests over the 20th century. We further examine what the impacts of nitrogen deposition and land use change history are on terrestrial carbon uptake since preindustrial time. Our results suggest that global total net land use emissions for the 1990s associated with changes in cropland, pastureland, and wood harvest are 1.22 GtC/yr. Without considering the secondary forest regrowth, the estimated net global total land use emissions are 1.58 GtC/yr or about 0.36 GtC/yr higher than if secondary forest regrowth is considered. Results also show that without considering the nitrogen dynamics and deposition, the estimated global total secondary forest sink for the 1990s is 0.90 GtC/yr or about 0.54 GtC/yr higher than estimates that include the impacts of nitrogen dynamics and deposition. Nitrogen deposition alone is responsible for about 0.13 GtC/yr of the total secondary forest sink. While nitrogen is not a limiting nutrient in the intact primary forests in tropical regions, our study suggests that nitrogen becomes a limiting nutrient for regrowing secondary forests of the tropical regions, in particular Latin America and Tropical Africa. This is because land use change activities, especially wood harvest, removes large amounts of nitrogen from the system when slash is burnt or wood is removed for harvest. However, our model results show that carbon uptake is enhanced in the tropical secondary forests of the Indian region. We argue that this may be due to enhanced nitrogen mineralization and increased nitrogen availability following land use change in the Indian tropical forest ecosystems. Results also demonstrate that there is a significant amount of carbon accumulating in the Northern Hemisphere where most land use changes and forest regrowth has occurred in recent decades. This study indicates the significance of secondary forests to terrestrial carbon sinks, the importance of nitrogen dynamics to the magnitude of secondary forests carbon uptake, and therefore the need to include both primary and secondary forests and nitrogen dynamics in terrestrial ecosystem models.

scholarly journals Past and future carbon fluxes from land use change, shifting cultivation and wood harvest

Tellus B ◽  
2014 ◽  
Vol 66 (1) ◽  
pp. 23188 ◽  
Author(s):  
Benjamin D. Stocker ◽  
Fabian Feissli ◽  
Kuno M. Strassmann ◽  
Renato Spahni ◽  
Fortunat Joos
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Shifting Cultivation ◽  
Carbon Fluxes ◽  
Wood Harvest

scholarly journals Contributions of secondary forest and nitrogen dynamics to terrestrial carbon uptake

2010 ◽  
Vol 7 (10) ◽  
pp. 3041-3050 ◽  
Author(s):  
X. Yang ◽  
T. K. Richardson ◽  
A. K. Jain
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Secondary Forest ◽  
Nitrogen Dynamics ◽  
Carbon Uptake ◽  
Secondary Forests ◽  
Terrestrial Carbon ◽  
Tropical Regions ◽  
Forest Regrowth ◽  
Limiting Nutrient

Abstract. We use a terrestrial carbon-nitrogen cycle component of the Integrated Science Assessment Model (ISAM) to investigate the impacts of nitrogen dynamics on regrowing secondary forests over the 20th century. We further examine what the impacts of nitrogen deposition and land use change history are on terrestrial carbon uptake since preindustrial time. Our results suggest that global total net land use emissions for the 1990s associated with changes in cropland, pastureland, and wood harvest are 1.22 GtC/yr. Without considering the secondary forest regrowth, the estimated net global total land use emissions are 1.58 GtC/yr or about 0.36 GtC/yr higher than if secondary forest regrowth is considered. Results also show that without considering the nitrogen dynamics and deposition, the estimated global total secondary forest sink for the 1990s is 0.90 GtC/yr or about 0.54 GtC/yr higher than estimates that include the impacts of nitrogen dynamics and deposition. Nitrogen deposition alone is responsible for about 0.13 GtC/yr of the total secondary forest sink. While nitrogen is not a limiting nutrient in the intact primary forests in tropical regions, our study suggests that nitrogen becomes a limiting nutrient for regrowing secondary forests of the tropical regions, in particular Latin America and Tropical Africa. This is because land use change activities, especially wood harvest, removes large amounts of nitrogen from the system when slash is burnt or wood is removed for harvest. However, our model results show that carbon uptake is enhanced in the tropical secondary forests of the Indian region. We argue that this may be due to enhanced nitrogen mineralization and increased nitrogen availability following land use change in the Indian tropical forest ecosystems. Results also demonstrate that there is a significant amount of carbon accumulating in the Northern Hemisphere where most land use changes and forest regrowth has occurred in recent decades. This study indicates the significance of secondary forests to terrestrial carbon sinks, the importance of nitrogen dynamics to the magnitude of secondary forests carbon uptake, and therefore the need to include both primary and secondary forests and nitrogen dynamics in terrestrial ecosystem models.

Historical land use change and associated carbon emissions in Brazil from 1940 to 1995

2012 ◽  
Vol 26 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Christiane Cavalcante Leite ◽  
Marcos Heil Costa ◽  
Britaldo Silveira Soares-Filho ◽  
Letícia de Barros Viana Hissa
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Carbon Emissions ◽  
Historical Land Use

Bewirtschaftung von tropischen Sekundärwäldern

2002 ◽  
Vol 46 (1) ◽  
Author(s):  
Dietrich Schmidt-Vogt
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Stand Structure ◽  
Secondary Forest ◽  
Secondary Forests ◽  
Tropical Asia ◽  
Land Use Systems ◽  
The Future ◽  
The Tropics ◽  
Primary Forests

AbstractManagement of secondary tropical forests: a new perspective for sustainable use of forests in Asia. The decline of primary forests in the tropics is leading to a reassessment of the role secondary forests might play within the context of tropical forest management. Recent research has shown that secondary forests in the tropics can be both rich in species and complex in terms of stand structure. There is, moreover, a growing recognition of the importance of secondary forests for traditional subsistence economies in the tropics and of their economic potential for land use systems in the future. Management of secondary forests in Asia as an alternative to the extraction of timber from primary forests but also as one among other options to intensify traditional land use systems has a potential for the future especially because of the existence of vast tracts of valuable secondary forest cover, and because of the store of traditional knowledge that can still be found in tropical Asia.

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