Assessment of the Carbon Stock in Pine Plantations in Southern Spain through ALS Data and K-Nearest Neighbor Algorithm Based Models

Accurate estimation of forest biomass to enable the mapping of forest C stocks over large areas is of considerable interest nowadays. Airborne laser scanning (ALS) systems bring a new perspective to forest inventories and subsequent biomass estimation. The objective of this research was to combine growth models used to update old inventory data to a reference year, low-density ALS data, and k-nearest neighbor (kNN) algorithm Random Forest to conduct biomass inventories aimed at estimating the C sequestration capacity in large Pinus plantations. We obtained a C stock in biomass (Wt-S) of 12.57 Mg ha−1, ranging significantly from 19.93 Mg ha−1 for P. halepensis to 49.05 Mg ha−1 for P. nigra, and a soil organic C stock of the composite soil samples (0–40 cm) ranging from 20.41 Mg ha−1 in P. sylvestris to 37.32 Mg ha−1 in P. halepensis. When generalizing these data to the whole area, we obtained an overall C-stock value of 48.01 Mg C ha−1, ranging from 23.96 Mg C ha−1 for P. halepensis to 58.09 Mg C ha−1 for P. nigra. Considering the mean value of the on-site C stock, the study area sustains 1,289,604 Mg per hectare (corresponding to 4,732,869 Mg CO2), with a net increase of 4.79 Mg ha−1 year−1. Such C cartography can help forest managers to improve forest silviculture with regard to C sequestration and, thus, climate change mitigation.

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Estimation of carbon inputs to soils from wheat in the Pampas Region, Argentina

Czech Journal of Genetics and Plant Breeding ◽

10.17221/3252-cjgpb ◽

2011 ◽

Vol 47 (Special Issue) ◽

pp. S39-S42 ◽

Cited By ~ 3

Author(s):

G. Civeira

Keyword(s):

C Sequestration ◽

Plant Production ◽

Accurate Estimation ◽

Soil Organic C ◽

Organic C ◽

Soil C ◽

C Stocks ◽

C Input ◽

Different Soils ◽

Pampas Region

Recently soils have gained more attention within the global change debate as the largest terrestrial carbon (C) pool. Different soils and vegetation types have substantial impacts on many of the processes that take place in the ecosystem functioning and thus in soil organic C stocks. An accurate estimation of vegetation C inputs to soils may aid in more precise estimation of the future release or sequestration of soil organic C. Wheat production affects C inputs and thus soil C sequestration in soils. The objective of this research was to evaluate C inputs by wheat, from 1993 to 2002 in the Pampas Region. The estimated C input rate by wheat was greater in the humid subregion than in the semiarid subregion: 0.9 and 0.75 Mg C/ha/year, correspondingly. This pattern agrees with the observation that precipitation constrains plant production in arid to subhumid ecosystems. The average organic C input by wheat into the soils throughout the period was 8.1 Mg C/ha in the humid subregion and, 6.75 Mg C/ha in the semiarid subregion.

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Use of Aerial Laser Scanning to Assess the Effect on C Sequestration of Oak (Quercus ilex L. subsp. ballota [Desf.]Samp-Q. suber L.) Afforestation on Agricultural Land

Geosciences ◽

10.3390/geosciences10020041 ◽

2020 ◽

Vol 10 (2) ◽

pp. 41

Author(s):

Miguel A. Lara-Gómez ◽

Rafael M. Navarro-Cerrillo ◽

Carlos J. Ceacero ◽

Francisco J. Ruiz-Goméz ◽

José Luis Díaz-Hernández ◽

...

Keyword(s):

Regression Models ◽

Laser Scanning ◽

Quercus Ilex ◽

Agricultural Land ◽

Tree Height ◽

Cork Oak ◽

Organic C ◽

Aerial Laser Scanning ◽

C Stocks ◽

C Stock

Conversion of agricultural lands to forest plantations to mitigate rising atmospheric carbon dioxide (CO2) has been proposed, but it depends on accurate estimation of the on-site carbon (C) stocks distribution. The use of aerial laser scanning (ALS) data is a rapidly evolving technology for the quantification of C stocks. We evaluated the use of allometric models together with high-density ALS data for the quantification of biomass and soil C stocks in a 14-year-old Quercus ilex and Q. suber plantation in Southwestern Spain. In 2010, a field survey was performed and tree dasometric and biomass variables were measured. Forty-five soil profiles (N = 180 soil samples) were taken systematically and the soil organic C content (SOC) was determined. Biomass and soil organic C values were regressed against individual dasometric variables and total tree height was used as a predictor variable. Aerial laser scanning data were acquired with a point density of 12 points m−2. Relationships among ALS metrics and tree height were determined using stepwise regression models and used in the allometric models to estimate biomass and SOC C stocks. Finally, a C stock map of the holm-cork oak cover in the study area was generated. We found a tree total biomass of 27.9 kg tree−1 for holm oak and 41.1 kg tree−1 for cork oak. In the holm oak plantation, the SOC content was 36.90 Mg ha−1 for the layer 0–40 cm (SOC40) under the tree crown and 29.26 Mg ha−1 for the inter-planted area, with significant differences from the reference agricultural land (33.35 Mg ha−1). Linear regression models were developed to predict the biomass and SOC at the tree scale, based on tree height (R2 > 0.72 for biomass, and R2 > 0.62 for SOC). The overall on-site C stock in the holm-cork oak plantation was 35.11 Mg ha−1, representing a net C stock rise of 0.47 Mg ha−1 yr−1. The ALS data allows a reliable estimation of C stocks in holm and cork oak plantations and high-resolution maps of on-site C stocks are useful for silvicultural planning. The cost of ALS data acquisition has decreased and this method can be generalised to plantations of other Mediterranean species established on agricultural lands at regional scales. However, an increase of filed data and the availability of local biomass and, in particular, SOC will improve accurate quantification of the C stocks from allometric equations, and extrapolation to large planted areas.

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Tree species richness increases ecosystem carbon storage in subtropical forests

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.1240 ◽

2018 ◽

Vol 285 (1885) ◽

pp. 20181240 ◽

Cited By ~ 40

Author(s):

Xiaojuan Liu ◽

Stefan Trogisch ◽

Jin-Sheng He ◽

Pascal A. Niklaus ◽

Helge Bruelheide ◽

...

Keyword(s):

Species Richness ◽

Tree Species ◽

C Sequestration ◽

Stand Age ◽

Southeast China ◽

Subtropical Forests ◽

C Stocks ◽

C Stock ◽

Below Ground ◽

Time Periods

Forest ecosystems are an integral component of the global carbon cycle as they take up and release large amounts of C over short time periods (C flux) or accumulate it over longer time periods (C stock). However, there remains uncertainty about whether and in which direction C fluxes and in particular C stocks may differ between forests of high versus low species richness. Based on a comprehensive dataset derived from field-based measurements, we tested the effect of species richness (3–20 tree species) and stand age (22–116 years) on six compartments of above- and below-ground C stocks and four components of C fluxes in subtropical forests in southeast China. Across forest stands, total C stock was 149 ± 12 Mg ha −1 with richness explaining 28.5% and age explaining 29.4% of variation in this measure. Species-rich stands had higher C stocks and fluxes than stands with low richness; and, in addition, old stands had higher C stocks than young ones. Overall, for each additional tree species, the total C stock increased by 6.4%. Our results provide comprehensive evidence for diversity-mediated above- and below-ground C sequestration in species-rich subtropical forests in southeast China. Therefore, afforestation policies in this region and elsewhere should consider a change from the current focus on monocultures to multi-species plantations to increase C fixation and thus slow increasing atmospheric CO 2 concentrations and global warming.

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Site-level simulations of measurable soil fractions with Millennial Version 2

10.5194/ismc2021-19 ◽

2021 ◽

Author(s):

Rose Abramoff ◽

Bertrand Guenet ◽

Haicheng Zhang ◽

Katerina Georgiou ◽

Xiaofeng Xu ◽

...

Keyword(s):

Meta Analysis ◽

C Sequestration ◽

Current Understanding ◽

Century Model ◽

Mineral Association ◽

Microbial Decomposition ◽

Organic C ◽

Soil C ◽

Soil Fractions ◽

C Stocks

Soil carbon (C) models are used to predict C sequestration responses to climate and land use change. Yet, the soil models embedded in Earth system models typically do not represent processes that reflect our current understanding of soil C cycling, such as microbial decomposition, mineral association, and aggregation. Rather, they rely on conceptual pools with turnover times that are fit to bulk C stocks and/or fluxes. As measurements of soil fractions become increasingly available, soil C models that represent these measurable quantities can be evaluated more accurately. Here we present Version 2 (V2) of the Millennial model, a soil model developed to simulate C pools that can be measured by extraction or fractionation, including particulate organic C, mineral-associated organic C, aggregate C, microbial biomass, and dissolved organic C. Model processes have been updated to reflect the current understanding of mineral-association, temperature sensitivity and reaction kinetics, and different model structures were tested within an open-source framework. We evaluated the ability of Millennial V2 to simulate total soil organic C (SOC), as well as the mineral-associated and particulate fractions, using three soil fractionation data sets spanning a range of climate and geochemistry in Australia (N=495), Europe (N=176), and across the globe (N=730). Millennial V2 (RMSE = 1.98 &#8211; 4.76 kg, AIC = 597 &#8211; 1755) generally predicts SOC content better than the widely-used Century model (RMSE = 2.23 &#8211; 4.8 kg, AIC = 584 &#8211; 2271), despite an increase in process complexity and number of parameters. Millennial V2 reproduces between-site variation in SOC across a gradient of plant productivity, and predicts SOC turnover times similar to those of a global meta-analysis. Millennial V2 updates the conceptual Century model pools and processes and represents our current understanding of the roles that microbial activity, mineral association and aggregation play in soil C sequestration.

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The transferability of airborne laser scanning based tree-level models between different inventory areas

Canadian Journal of Forest Research ◽

10.1139/cjfr-2018-0128 ◽

2019 ◽

Vol 49 (3) ◽

pp. 228-236 ◽

Cited By ~ 4

Author(s):

Tomi Karjalainen ◽

Lauri Korhonen ◽

Petteri Packalen ◽

Matti Maltamo

Keyword(s):

Laser Scanning ◽

Nearest Neighbor ◽

Airborne Laser Scanning ◽

Tree Level ◽

Stem Volume ◽

K Nearest Neighbor ◽

Individual Tree ◽

Tree Detection ◽

Airborne Laser ◽

Crown Base Height

In this paper, we examine the transferability of airborne laser scanning (ALS) based models for individual-tree detection (ITD) from one ALS inventory area (A1) to two other areas (A2 and A3). All areas were located in eastern Finland less than 100 km from each other and were scanned using different ALS devices and parameters. The tree attributes of interest were diameter at breast height (Dbh), height (H), crown base height (Cbh), stem volume (V), and theoretical sawlog volume (Vlog) of Scots pine (Pinus sylvestris L.) with Dbh ≥ 16 cm. All trees were first segmented from the canopy height models, and various ALS metrics were derived for each segment. Then only the segments covering correctly detected pines were chosen for further inspection. The tree attributes were predicted using the k-nearest neighbor (k-NN) imputation. The results showed that the relative root mean square error (RMSE%) values increased for each attribute after the transfers. The RMSE% values were, for A1, A2, and A3, respectively: Dbh, 13.5%, 14.8%, and 18.1%; H, 3.2%, 5.9%, and 6.2%; Cbh, 13.3%, 15.3%, and 18.3%; V, 29.3%, 35.4%, and 39.1%; and Vlog, 38.2%, 54.4% and 51.8%. The observed values indicate that it may be possible to employ ALS-based tree-level k-NN models over different inventory areas without excessive reduction in accuracy, assuming that the tree species are known to be similar.

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Biochar from sugarcane residues: An overview of its sequestration potential in Sao Paulo, Brazil

10.5194/egusphere-egu2020-2880 ◽

2020 ◽

Author(s):

David Lefebvre ◽

Jeroen Meersmans ◽

Guy Kirk ◽

Adrian Williams

Keyword(s):

Soil Carbon ◽

C Sequestration ◽

Sao Paulo ◽

São Paulo ◽

Soil C ◽

Paulo State ◽

Sequestration Potential ◽

C Stocks ◽

C Stock ◽

Soil C Stock

Harvesting sugarcane (Saccharum officinarum) produces large quantities of biomass residues. We investigated the potential for converting these residues into biochar (recalcitrant carbon rich material) for soil carbon (C) sequestration. We modified a version of the RothC soil carbon model to follow changes in soil C stocks considering different amounts of fresh sugarcane residues and biochar (including recalcitrant and labile biochar fractions). We used Sao Paulo State (Brazil) as a case study due to its large sugarcane production and associated soil C sequestration potential.Mechanical harvesting of sugarcane fields leaves behind > 10 t dry matter of trash (leaves) ha-1 year-1. Although trash blanketing increases soil fertility, an excessive amount is detrimental and reduces the subsequent crop yield. After the optimal trash blanketing amount, sugarcane cultivation still produces 5.9 t C ha-1 year-1 of excess trash and bagasse (processing residues) which are available for subsequent use.The available residues could produce 2.5 t of slow-pyrolysis (550&#176;C) biochar C ha-1 year-1. The model predicts this could increase sugarcane field soil C stock on average by 2.4 &#177; 0.4 t C ha&#8209;1 year&#8209;1, after accounting for the climate and soil type variability across the State. Comparing different scenarios, we found that applying fresh residues into the field results in a smaller increase in soil C stock compared to the biochar because the soil C approaches a new equilibrium. For instance, adding 1.2 t of biochar C ha&#8209;1 year&#8209;1 along with 3.2 t of fresh residue C ha&#8209;1 year&#8209;1 increased the soil C stock by 1.8 t C ha&#8209;1 year&#8209;1 after 10 years of repeated applications. In contrast, adding 0.62 t of biochar C ha&#8209;1 year&#8209;1 with 4.5 t of fresh sugarcane residues C ha&#8209;1 year&#8209;1 increased the soil carbon soil stock by 1.4 t C ha&#8209;1 year&#8209;1 after 10 years of application. These are reductions 25% and 40% of the potential soil C accumulation rates compared with applying available residues as biochar.&#160; &#160;We also tested the sensitivity of the model to biochar-induced positive priming (i.e. increased mineralization of soil organic C) using published values. This showed that the C sequestration balance remains positive over the long term, even considering an extremely high positive-priming factor. Upscaling our results to the total 5 Mha of sugarcane in Sao Paulo State, biochar application could sequester up to 50 Mt of CO2 equivalent per year, representing 31% of the emissions attributed to the State in 2016.This study provides first insights into the sequestration potential of biochar application on sugarcane fields. Measurements of changes in soil C stocks in sugarcane field experiments are needed to further validate the model, and the emissions to implement the practice at large scale need to be taken into account. As the climate crisis grows, the need for greenhouse gas removal technologies becomes crucial. Assessing the net effectiveness of readily available technologies is essential to guide policy makers.&#160;&#160;

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Biogeochemical factors contributing to enhanced carbon storage following afforestation of a semi-arid shrubland

Biogeosciences Discussions ◽

10.5194/bgd-4-2111-2007 ◽

2007 ◽

Vol 4 (4) ◽

pp. 2111-2145 ◽

Cited By ~ 13

Author(s):

J. M. Grünzweig ◽

I. Gelfand ◽

D. Yakir

Keyword(s):

Pinus Halepensis ◽

Accumulation Rate ◽

C Sequestration ◽

Decay Rates ◽

Organic C ◽

C Storage ◽

Land Use Types ◽

C Stock ◽

Significant Addition ◽

Semi Arid

Abstract. Ecosystems in dry regions are generally low in productivity and carbon (C) storage. We report, however, large increases in C sequestration following afforestation of a semi-arid shrubland with Pinus halepensis trees. Using C and nitrogen (N) inventories, based in part on site-specific allometric equations, we measured an increase in the standing ecosystem C stock from 2380 g C m−2 in the shrubland to 5840 g C m−2 in the forest after 35 years, with no significant change in N stocks. The total amount of C produced by the forest was estimated as 6250 g C m−2. Carbon sequestration following afforestation was associated with increased N use efficiency as reflected by an overall increase in C/N ratio from 7.6 in the shrubland to 16.6 in the forest. The C accumulation rate in the forest was particularly high for soil organic C (SOC; increase of 1760 g C m−2 or 50 g C m−2 yr−1), which was associated with the following factors: 1) Analysis of a small 13C signal within this pure C3 system combined with size fractionation of soil organic matter indicated a significant addition of new SOC derived from forest vegetation (68% of total forest SOC) and a considerable portion of the old original shrubland SOC (53%) still remaining in the forest. 2) A large part of both new and old SOC appeared to be protected from decomposition as about 60% of SOC under both land-use types were in mineral-associated fractions. 3) A short-term decomposition study indicated decreased decomposition of lower-quality litter and SOC in the forest, based on reduced decay rates of up to 90% for forest compared to shrubland litter. 4) Forest soil included a significant component of live and dead roots. Our results showed the considerable potential for C sequestration, particularly in soils, following afforestation in semi-arid regions, which is particularly relevant in light of persistent predictions of drying trends in the Mediterranean and other regions.

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Carbon stock in the solum of some coarse-textured soils under secondary forest, grassland fallow, and bare footpath in the derived savanna of south-eastern Nigeria

Soil Research ◽

10.1071/sr11096 ◽

2012 ◽

Vol 50 (2) ◽

pp. 157 ◽

Cited By ~ 4

Author(s):

S. E. Obalum ◽

Y. Watanabe ◽

C. A. Igwe ◽

M. E. Obi ◽

T. Wakatsuki

Keyword(s):

Carbon Stock ◽

Secondary Forest ◽

Terrestrial Ecosystems ◽

C Sequestration ◽

Management Options ◽

Organic C ◽

South Eastern ◽

Derived Savanna ◽

C Stock ◽

Relative Potential

Quantitative data on carbon stock (C stock) in and beyond the topsoil (0–30 cm) under natural terrestrial ecosystems in West African savanna could provide information about their relative potential, and management options, for C sequestration, but these data are still scanty in the region. In selected locations (Nsukka, Obimo, and Ibagwa-aka) in the derived savanna zone of south-eastern Nigeria, secondary forest (SFT), grassland fallow (GLF), and bare footpath (BFP) were sampled from the topsoils (0–30 cm) and subsoils (30–60 cm) in triplicate. The soils are generally sandy, with low (1.4–13.8%) mean silt content. Mean bulk density ranged from 1.30 to 1.83 Mg/m3. The soils were acidic (pHwater 4.0–4.8) and low in organic C (0.10–1.14%). There was a consistent trend in C stock (SFT > GLF > BFP) in the topsoil, whereas only higher values in SFT than BFP were consistent in the subsoil. In both soil layers, the scale of the differences among the land-cover types was location-specific. Values of C stock were higher in the topsoil than subsoil, except for GLF and BFP at Obimo due to recent bush burning. Irrespective of location, the mean topsoil–subsoil values under SFT, GLF, and BFP were 45.7–30.6, 27.7–25.8, and 19.0–18.8 Mg/ha, respectively. Soil structural stability, indexed as the ratio of organic matter to silt + clay, explained roughly 61 and 89% of the variability in C stock of topsoils and subsoils, respectively. These results should benefit the planning of C sequestration projects in savanna agroecosystems of West Africa.

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Estimating stand level stem diameter distribution utilizing harvester data and airborne laser scanning

Silva Fennica ◽

10.14214/sf.10075 ◽

2019 ◽

Vol 53 (3) ◽

Cited By ~ 3

Author(s):

Matti Maltamo ◽

Marius Hauglin ◽

Erik Naesset ◽

Terje Gobakken

Keyword(s):

Norway Spruce ◽

Laser Scanning ◽

Nearest Neighbor ◽

Airborne Laser Scanning ◽

Stem Diameter ◽

Training Data ◽

Diameter Distribution ◽

K Nearest Neighbor ◽

Airborne Laser ◽

Error Index

Accurately positioned single-tree data obtained from a cut-to-length harvester were used as training harvester plot data for k-nearest neighbor (k-nn) stem diameter distribution modelling applying airborne laser scanning (ALS) information as predictor variables. Part of the same harvester data were also used for stand-level validation where the validation units were stands including all the harvester plots on a systematic grid located within each individual stand. In the validation all harvester plots within a stand and also the neighboring stands located closer than 200 m were excluded from the training data when predicting for plots of a particular stand. We further compared different training harvester plot sizes, namely 200 m, 400 m, 900 m and 1600 m. Due to this setup the number of considered stands and the areas within the stands varied between the different harvester plot sizes. Our data were from final fellings in Akershus County in Norway and consisted of altogether 47 stands dominated by Norway spruce. We also had ALS data from the area. We concentrated on estimating characteristics of Norway spruce but due to the k-nn approach, species-wise estimates and stand totals as a sum over species were considered as well. The results showed that in the most accurate cases stand-level merchantable total volume could be estimated with RMSE values smaller than 9% of the mean. This value can be considered as highly accurate. Also the fit of the stem diameter distribution assessed by a variant of Reynoldâs error index showed values smaller than 0.2 which are superior to those found in the previous studies. The differences between harvester plot sizes were generally small, showing most accurate results for the training harvester plot sizes 200 m and 400 m.222222

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Restoring organic matter in a cultivated, semiarid soil using crested wheatgrass

Canadian Journal of Soil Science ◽

10.4141/s00-001 ◽

2000 ◽

Vol 80 (3) ◽

pp. 429-435 ◽

Cited By ~ 9

Author(s):

D. Curtin ◽

F. Selles ◽

H. Wang ◽

R. P. Zentner ◽

C. A. Campbell

Keyword(s):

Organic Matter ◽

Carbon Dioxide Emissions ◽

C Sequestration ◽

Mitigation Strategies ◽

Organic C ◽

Crested Wheatgrass ◽

Soil C ◽

Sequestration Potential ◽

C Stocks

Planting of cultivated land with perennial forages may increase C sequestration in soil organic matter and contribute to atmospheric CO2 mitigation strategies. However, little is known of the effectiveness of introduced grasses in restoring organic C in cultivated soils of the Canadian prairies. Our objective was to evaluate the C sequestration potential of crested wheatgrass (CWG) (Agropyron cristatum L. Gaertn.), a widely introduced, early-season grass. In 1995 and 1996, we measured soil CO2 fluxes, C inputs in plant material and total soil C under CWG and a fallow-wheat (Triticum aestivum L.)-wheat rotation (F-W-W). These were two of the treatments in a replicated crop rotation experiment initiated in 1987 in southwestern Saskatchewan on a medium-textured soil that had previously been under long-term wheat production. Average to above-average growing season (1 May to 31 July) precipitation in 1995–1996 resulted in annual inputs of C in wheat residues of 3000–4500 kg ha−1. Growth of CWG, which was hayed and removed, was relatively poor in both years, but especially in 1995 when dry matter yield was only 1300 kg ha−1. For the 1988–1996 period, there was a strong correlation (R2 = 0.81; P < 0.001) between CWG yield and precipitation received in May, showing the importance of early spring rains determining CWG yield and C inputs to the soil. Carbon inputs under CWG (1200 kg ha−1 in 1995 and 2400 kg ha−1 in 1996) were less than under wheat but CO2-C emissions were similar under CWG and wheat. Soil C measurements in fall 1996 confirmed that CWG did not gain C relative to the F-W-W rotation. Although failure of CWG soil to store more C than cultivated soil may be partly because weather conditions during the experiment were more favourable for wheat than CWG, our results cast doubt on the ability of CWG to restore C stocks in prairie soils degraded by long-term cropping. Key words: Carbon sequestation, carbon dioxide emissions, wheat, crested wheatgrass, fallow

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