Category :
Research article
article id 10617,
category
Research article
Highlights:
New allometric equations were developed for predicting aboveground and belowground biomass (AGB and BGB) of trees and multi-stemmed shrubs in the Guinean savannas based on field measurements, providing information for West African mesic savannas and filling a critical knowledge gap; AGB and BGB of trees were better predicted from the quantity ρDb2H (with ρ the specific wood density in g cm–3, Db the stem basal diameter in cm, and H the tree height in m); Obtaining accurate estimates of AGB and BGB in multi-stemmed shrubs required additional consideration of the total number of stems; The root/shoot biomass ratio decreased with increasing of the stem size (measured by Db) for trees but remains relatively unchanged for shrubs.
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Currently, tools to predict the aboveground and belowground biomass (AGB and BGB) of woody species in Guinean savannas (and the data to calibrate them) are still lacking. Multispecies allometric equations calibrated from direct measurements can provide accurate estimates of plant biomass in local ecosystems and can be used to extrapolate local estimates of carbon stocks to the biome scale. We developed multispecies models to estimate AGB and BGB of trees and multi-stemmed shrubs in a Guinean savanna of Côte d’Ivoire. The five dominant species of the area were included in the study. We sampled a total of 100 trees and 90 shrubs destructively by harvesting their biometric data (basal stem diameter Db, total stem height H, stump area SS, as well as total number of stems n for shrubs), and then measured their dry AGB and BGB. We fitted log-log linear models to predict AGB and BGB from the biometric measurements. The most relevant model for predicting AGB in trees was fitted as follows: AGB = 0.0471 (ρDb2H)0.915 (with AGB in kg and ρDb2H in g cm–1 m). This model had a bias of 19%, while a reference model for comparison (fitted from tree measurements in a similar savanna ecosystem, Ifo et al. 2018) overestimated the AGB of trees of our test savannas by 132%. The BGB of trees was also better predicted from ρDb2H as follows: BGB = 0.0125 (ρDb2H)0.6899 (BGB in kg and ρDb2H in g cm–1 m), with 6% bias, while the reference model had about 3% bias. In shrubs, AGB and BGB were better predicted from ρDb2H together with the total number of stems (n). The best fitted allometric equation for predicting AGB in shrubs was as follows: AGB = 0.0191 (ρDb2H)0.6227 n0.9271. This model had about 1.5% bias, while the reference model overestimated the AGB of shrubs of Lamto savannas by about 79%. The equation for predicting BGB of shrubs is: BGB = 0.0228 (ρDb2H)0.7205 n0.992 that overestimated the BGB of the shrubs of Lamto savannas with about 3% bias, while the reference model underestimated the BGB by about 14%. The reference model misses an important feature of fire-prone savannas, namely the strong imbalance of the BGB/AGB ratio between trees and multi-stemmed shrubs, which our models predict. The allometric equations we developed here are therefore relevant for C stocks inventories in trees and shrubs communities of Guinean savannas.
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Kouamé,
UFR Sciences de la Nature, UFR-SN/ Station d’Ecologie de Lamto (CRE), Pôle de recherche Environnement et Développement Durable, Université NANGUI ABROGOUA, 02 BP 801 Abidjan 02, Côte d’Ivoire); Institute of Ecology and Environmental Sciences IEES-Paris (Sorbonne Université, CNRS, Université Paris Diderot, IRD, UPEC, INRA), 4 Place Jussieu, 75005, Paris, France
https://orcid.org/0000-0002-0847-2569
E-mail:
kouameyag@gmail.com
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Millan,
Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, South Africa; Global Change Biology Group, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa; Institute of Botany of the Czech Academy of Sciences, v.v.i, Dukelská 135, Třeboň, 379 01, Czech Republic
https://orcid.org/0000-0002-0151-6055
E-mail:
mathieu.millan@gmail.com
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N'Dri,
UFR Sciences de la Nature, UFR-SN/ Station d’Ecologie de Lamto (CRE), Pôle de recherche Environnement et Développement Durable, Université NANGUI ABROGOUA, 02 BP 801 Abidjan 02, Côte d’Ivoire
https://orcid.org/0000-0002-6333-6279
E-mail:
brigitte.aya@gmail.com
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Charles-Dominique,
Institute of Ecology and Environmental Sciences IEES-Paris (Sorbonne Université, CNRS, Université Paris Diderot, IRD, UPEC, INRA), 4 Place Jussieu, 75005, Paris, France
https://orcid.org/0000-0002-5767-0406
E-mail:
tristan.charles-dominique@sorbonne-universite.fr
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Konan,
UFR Sciences de la Nature, UFR-SN/ Station d’Ecologie de Lamto (CRE), Pôle de recherche Environnement et Développement Durable, Université NANGUI ABROGOUA, 02 BP 801 Abidjan 02, Côte d’Ivoire
E-mail:
marcelkonan.lamto@gmail.com
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Bakayoko,
UFR Sciences de la Nature, UFR-SN/ Station d’Ecologie de Lamto (CRE), Pôle de recherche Environnement et Développement Durable, Université NANGUI ABROGOUA, 02 BP 801 Abidjan 02, Côte d’Ivoire
E-mail:
bakadamaci@yahoo.fr
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Gignoux,
Institute of Ecology and Environmental Sciences IEES-Paris (Sorbonne Université, CNRS, Université Paris Diderot, IRD, UPEC, INRA), 4 Place Jussieu, 75005, Paris, France
https://orcid.org/0000-0003-3853-9282
E-mail:
jacques.gignoux@upmc.fr
article id 1553,
category
Research article
Miguel Angel Salinas-Melgoza,
Margaret Skutsch,
Jon C. Lovett,
Armonia Borrego.
(2017).
Carbon emissions from dryland shifting cultivation: a case study of Mexican tropical dry forest.
Silva Fennica
vol.
51
no.
1B
article id 1553.
https://doi.org/10.14214/sf.1553
Highlights:
Under REDD+, shifting cultivation should be considered degradation rather than deforestation; Carbon stocks in old fallows (>20 years) are higher than those in old growth forests which have never been used for shifting cultivation; Extending length of fallows increases rates of carbon emissions; Shortened fallow cycles result in higher carbon stocks and lower emissions at the landscape level; Cycle lengths could be optimized for carbon sequestration in a land sharing approach.
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The article considers the relation of shifting cultivation to deforestation and degradation, and hence its impacts in terms of carbon emissions and sequestration potential. There is a need to understand these relationships better in the context of international policy on Reduced Emissions from Deforestation and Forest Degradation (REDD+). The article reviews the way in which shifting cultivation has been incorporated in global and national estimations of carbon emissions, and assembles the available information on shifting cultivation in Tropical Dry Forests (TDF) in Mexico, where it is widely practiced. It then takes the case of two villages, Tonaya and El Temazcal, which lie within the basin of the River Ayuquila in Jalisco, Mexico. Field data for the typical carbon stocks and fluxes associated with shifting cultivation are compared with stocks and fluxes associated with more intensive agricultural production in the same dry tropical forest area to highlight the carbon sequestration dynamics associated with the shortening and potential lengthening of the fallow cycles. The biomass density in the shifting cultivation system observed can reach levels similar to that of old growth forests, with old fallows (>20 years) having higher carbon stocks than old growth forests. Per Mg of maize produced, the biomass-related emissions from shifting cultivation in the traditional 12 year cycle are about three times those from permanent cultivation. We did not, however, take into account the additional emissions from inputs that result from the use of fertilizers and pesticides in the case of permanent agriculture. Shortening of the fallow cycle, which is occurring in the study area as a result of government subsidies, results in higher remaining stocks of carbon and lower emissions at the landscape level.
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Salinas-Melgoza,
University of Twente, Drienerlolaan 5, 7522 NB Enschede, the Netherlands
http://orcid.org/0000-0003-3209-1659
E-mail:
ma.masm@gmail.com
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Skutsch,
Universidad Nacional Autónoma de México (CIGA-UNAM), Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, Campus Morelia, C.P. 58190, Michoacán, Mexico
http://orcid.org/0000-0001-6120-4945
E-mail:
mskutsch@ciga.unam.mx
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Lovett,
University of Leeds, Leeds, LS2 9JT, UK
E-mail:
j.lovett@leeds.ac.uk
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Borrego,
CONACYT-Centro de Investigaciones en Geografía Ambiental, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, Campus Morelia, C.P. 58190, Michoacán, México
E-mail:
aborrego@ciga.unam.mx
article id 935,
category
Research article
Loice M. A. Omoro,
Mike Starr,
Petri K. E. Pellikka.
(2013).
Tree biomass and soil carbon stocks in indigenous forests in comparison to plantations of exotic species in the Taita Hills of Kenya.
Silva Fennica
vol.
47
no.
2
article id 935.
https://doi.org/10.14214/sf.935
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Carbon (C) densities of the tree biomass and soil (0–50 cm) in indigenous forest and plantations of eucalyptus, cypress and pine in the Taita Hills, Kenya were determined and compared. The cypress and pine plantations were about 30-years-old and eucalyptus plantations about 50-years-old. Biomass C densities were estimated from breast height diameter and wood density using allometric functions developed for tropical species and an assumed C content of 50%. Belowground biomass C densities were estimated using root:shoot biomass ratios. Soil organic C (SOC) densities were calculated from measured organic carbon contents (0–20 and 20–50 cm layers) and modelled bulk density values. Mean total biomass C and SOC densities for indigenous forest were greater than those of the plantations, and the difference was significant (p < 0.05) in the cases of cypress and pine biomass and pine SOC. The correlation between biomass C and SOC densities was nearly significant in the case of indigenous forest, but negative. Biomass C densities were not significantly correlated with mean annual precipitation, mean annual temperature or potential evapotranspiration, but pine biomass C densities were significantly correlated to actual evapotranspiration. SOC densities were more strongly correlated to mean annual precipitation than biomass C densities, but only significantly so in the case of pine. Neither biomass C nor SOC densities were correlated to plant available water capacity of the soil. Indigenous forest SOC densities were significantly correlated to soil clay contents, but negatively. Indigenous forests sequester more C in biomass and soil than do 30 to 50-year-old plantations of exotics, but it remains unclear if this is an intrinsic difference between indigenous forest and plantations of exotics or because of insufficient time for SOC levels in plantations to recover after clearance of original indigenous forest.
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Omoro,
Viikki Tropical Resources Institute, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland
E-mail:
loice.omoro@helsinki.fi
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Starr,
Department of Forest Sciences, P. O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland
E-mail:
mike.starr@helsinki.fi
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Pellikka,
Department of Geosciences and Geography, P. O. Box 64 (Gustaf Hällströminkatu 2), FI-00014 University of Helsinki, Finland
E-mail:
petri.pellikka@helsinki.fi
article id 449,
category
Research article
Thomas Wutzler,
Ingolf Profft,
Martina Mund.
(2011).
Quantifying tree biomass carbon stocks, their changes and uncertainties using routine stand taxation inventory data.
Silva Fennica
vol.
45
no.
3
article id 449.
https://doi.org/10.14214/sf.449
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For carbon (C) trading or any other verifiable C reports, it would be reasonable to identify and quantify continuous changes in carbon stocks at regional scales without high investments into additional C-specific, time- and labor-intensive inventories. Our study demonstrates the potential of using routine stand taxation data from large scale forestry inventories for verifiable quantification of tree biomass C stocks, C stock change rates, and associated uncertainties. Empirical models, parameters, and equations of uncertainty propagation have been assembled and applied to data from a forest management unit in Central Germany (550 000 ha), using stand taxation inventories collected between 1993 and 2006. The study showed: 1) The use of stand taxation data resulted in a verifiable and sufficiently precise (cv = 7%) quantification of tree biomass carbon stocks and their changes at the level of growth-regions (1700 to 140 000 ha). 2) The forest of the test region accumulated carbon in tree biomass at a mean annual rate of 1.8 (–0.9 to 4.5) tC/ha/yr over the studied period. 3) The taxation inventory data can reveal spatial patterns of rates of C stock changes, specifically low rates of 0.4 tC/ha/yr in the northwest and high rates of 3.0 tC/ha/yr in the south of the study region.
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Wutzler,
Max Planck Institute for Biogeochemistry, Hans-Knöll-Strasse 10, 07745 Jena, Germany
E-mail:
twutz@bgc-jena.mpg.de
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Profft,
Max Planck Institute for Biogeochemistry, Hans-Knöll-Stra§e 10, 07745 Jena, Germany
E-mail:
ip@nn.de
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Mund,
Max Planck Institute for Biogeochemistry, Hans-Knöll-Stra§e 10, 07745 Jena, Germany
E-mail:
mm@nn.de
article id 128,
category
Research article
Shelley L. Hunt,
Andrew M. Gordon,
Dave M. Morris.
(2010).
Carbon stocks in managed conifer forests in northern Ontario, Canada.
Silva Fennica
vol.
44
no.
4
article id 128.
https://doi.org/10.14214/sf.128
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Carbon pools and net primary productivity (aboveground) were measured in managed stands of jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] B.S.P.), ranging in age from 10 to 53 years, in the Lake Nipigon area of northern Ontario. Organic carbon in the forest floor and surface mineral soil (top 15 cm) ranged from 13 to 46 Mg C ha-1 and 10 to 29 Mg C ha-1, respectively. Carbon in aboveground tree biomass ranged from 11 to 74 Mg C ha-1 in crop trees, and 0 to 11 Mg C ha-1 in non-crop trees. Coarse woody debris (downed woody debris and snags) contained between 1 and 17 Mg C ha-1. Understory vegetation rarely represented more than 1% of total ecosystem carbon accumulation, but was responsible for a larger proportion of aboveground net primary productivity (ANPP). Rates of ANPP (expressed as carbon) ranged from 0.8 to 3.5 Mg C ha-1 y-1. Carbon stocks in managed stands were compared with published values from similarly aged fire-origin stands in the North American boreal region. Carbon stocks in our study stands generally exceeded those in unmanaged fire-origin stands of the same age, due to larger tree and forest floor carbon pools.
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Hunt,
University of Guelph, School of Environmental Sciences, 50 Stone Road East, Guelph, Ontario, Canada N1G 2W1
E-mail:
shunt@uoguelph.ca
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Gordon,
University of Guelph, School of Environmental Sciences, 50 Stone Road East, Guelph, Ontario, Canada N1G 2W1
E-mail:
amg@nn.ca
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Morris,
Ontario Ministry of Natural Resources, Centre for Northern Forest Ecosystem Research, 955 Oliver Rd., Thunder Bay, Ontario, Canada P7B 5E1
E-mail:
dmm@nn.ca
article id 166,
category
Research article
Kim Pingoud,
Johanna Pohjola,
Lauri Valsta.
(2010).
Assessing the integrated climatic impacts of forestry and wood products.
Silva Fennica
vol.
44
no.
1
article id 166.
https://doi.org/10.14214/sf.166
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Managed forests serve as a store of carbon (C) and a renewable source of energy and materials. By using forest products as substitutes for fossil fuels or non-renewable materials, emissions from fossil C sources can be displaced. The efficiency of emissions displacement depends on the product, its lifecycle and the fossil-fuel based reference system that is substituted. Forest management practices have an impact on C stocks in biomass and on the annual supply of products and their mix. There are trade-offs between sequestering C stocks in forests and the climatic benefits obtained by sustainable forest harvesting and using wood products to displace fossil C emissions. This article presents an integrated, steady-state analysis comparing various equilibrium states of managed forests and wood product pools that represent sustainable long-term forestry and wood-use strategies. Two climatic indicators are used: the combined C stock in forests and wood products and the fossil C emissions displaced annually by harvested wood products. The study indicates that long-term strategies could be available that are better according to both indicators than forestry practices based on the existing silvicultural guidelines in Finland. These strategies would involve increasing the basal area and prolonging rotations to produce more sawlogs. Further, the climate benefits appear to be highest in case the sawlog supply is directed to production of long-lived materials substituting for fossil-emission and energy intensive materials and recycled after their useful life to bioenergy.
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Pingoud,
VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
E-mail:
kim.pingoud@vtt.fi
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Pohjola,
University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland
E-mail:
jp@nn.fi
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Valsta,
University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland
E-mail:
lv@nn.fi