The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jose Leonardo De Moraes Goncalves - One of the best experts on this subject based on the ideXlab platform.
-
nitrogen fixation rate of acacia mangium wild at mid rotation in brazil is higher in mixed plantations with Eucalyptus grandis hill ex maiden than in monocultures
Annals of Forest Science, 2018Co-Authors: Ranieri Ribeiro Paula, Jose Leonardo De Moraes Goncalves, Jean-pierre Bouillet, Yann Nouvellon, Paulo Cesar Ocheuze Trivelin, Fabiano De Carvalho Balieiro, Julianne De Castro Oliveira, Jose C De Deus, Bruno Bordron, Jeanpau LaclauAbstract:Inter-specific interactions with Eucalypts in mixed plantations increased N 2 fixation rate of acacia trees compared to monocultures. N 2 fixation was higher during the wet summer than during the dry winter both in acacia monocultures and in mixed plantations. Introducing N-fixing trees in fast-growing tropical plantations may contribute to reducing the long-term requirements of N fertilizers. Management practices established in forest monocultures should be revisited in mixed-species plantations. This field experiment aimed to compare N2 fixation rates of Acacia mangium Wild in monospecific stands and in mixed-species stands with Eucalyptus grandis W. Hill ex Maiden. A secondary objective was to gain insight into the seasonal variations of N2 fixation. 15N was applied to acacia and Eucalypt monocultures and mixed-species with a 1:1 ratio at mid rotation. Leaves were collected in autumn, winter, spring, and summer to determine the foliar N concentrations and 15N atom fraction. The N content in the above-ground biomass was estimated as well as the percentage of N derived from atmospheric N2 (%Ndfa) using Eucalypts in monoculture as reference plants. %Ndfa values averaged over the year were 14% in monoculture and 44% in mixed-species stands. While the stocking density of acacia trees was twice as high in monoculture as in mixture, the amounts of N fixed in above-ground biomass of acacia trees were close (35–39 kg N ha−1) at 39 months after planting. %Ndfa values were higher during the wet summer than the dry winter both in acacia monocultures and in mixed plantations. The stocking density of acacia trees can be reduced in mixed plantations with Eucalypts in comparison to acacia monocultures with a low influence on the input of N to soil through biological fixation.
-
integrating genetic and silvicultural strategies to minimize abiotic and biotic constraints in brazilian Eucalypt plantations
Forest Ecology and Management, 2013Co-Authors: Jose Leonardo De Moraes Goncalves, Luciana Duque Silva, James Stahl, Antonio Rioyei Higa, Acelino Couto Alfenas, Walter De Paula Lima, Pedro H S Brancalion, Silvio Frosini De Barros Ferraz, Clayton Alcarde Alvares, Ayeska HubnerAbstract:Abstract Organized forestry in Brazil began in the late 1960s, stimulated by a government policy which subsidized afforestation programs from 1967 to 1989 to develop an internationally-competitive wood-based industry, managed by the private sector. Currently, planted forests in Brazil total about 6.9 million ha, from which 4.9 million ha is planted with Eucalypt (around 25% of world plantation), 1.6 million ha with pine, and 0.42 M ha with other species. Roundwood consumption of forest plantations totaled 170.1 million m3 in 2011, Eucalypt plantation accounted for 80.6% of this total. Most Eucalypt plantations are managed in short rotations (6–8 years) and are established in regions with water, nutritional and frost stresses of low to high degrees. The mean annual increment is 40 m3 ha−1 year−1 roundwood, ranging from 25 to 60 m3 ha−1 year−1 depending on the level of environmental stress. Improving natural resources use efficiency by breeding and matching genotypes to sites and using appropriate site management practices is a key challenge to sustain or increase productivity. The wide range of Eucalypt species and hybrids with different climatic and edaphic suitability associated with the easy propagation by seeds and cloning allow the adaptation of plantations to various tropical and subtropical regions in Brazil. The possibility of using Eucalypt wood in a range of purposes has led large and small enterprises to establish Eucalypt forests for multiple uses. The desirable characteristics in association with the accumulated knowledge on Eucalypt silviculture encourage the use of this genus in most plantations. The most important factors in the selective process for a genotype are wood characteristics, productivity level, susceptibility to pests and diseases, drought tolerance, especially in tropical regions (frost free), and frost tolerance in subtropical regions (mostly without water deficit). In regions with pronounced seasonality and moderate to long drought periods, the planting of hybrid genotypes predominates, propagated by cloning. Under subtropical conditions, the planting of single species predominates, propagated by seed. Clonal plantations with interspecific hybrids have been fundamental for Eucalypt adaptation in regions under water and nutritional stresses. Given the rapid advances in Eucalypt breeding, regarding adaptation to water stress and resistance to diseases and pests, and the adoption of clonal propagation techniques, genotypes are rapidly becoming obsolete and are replaced by more productive ones after harvesting. Thus, the replanting of crops has become a common procedure after the second half of the 1990s in Brazil. This paper describes the basic requirements for integrating genetic and silvicultural strategies to minimize abiotic and biotic constraints in Eucalypt plantations.
-
partitioning of net primary production in Eucalyptus and acacia stands and in mixed species plantations two case studies in contrasting tropical environments
Forest Ecology and Management, 2013Co-Authors: Daniel Epron, Louis Mareschal, Jean-paul Laclau, Yann Nouvellon, Rildo Moreira E Moreira, Lydiestella Koutika, Blandine Geneste, Juan Sinforiano Delgadorojas, Gael Sola, Jose Leonardo De Moraes GoncalvesAbstract:The introduction of nitrogen fixing species (NFS) in fast-growing tree plantations is an alternative option to reduce fertilizer inputs. However, the success of mixed-species plantations depends on the balance between positive interactions among species (resulting from facilitation and/or complementarity) and the negative effects of interspecific competition. Using a carbon budget approach and coupling measurements of standing biomass, aboveground litterfall and soil CO2 efflux, we assessed the influence of replacing half of Eucalypt trees by Acacia mangium on total belowground carbon flux (TBCF), net primary production (NPP) and its partitioning between above- and belowground growth at two tropical sites in Brazil (Itatinga) and in Congo (Kissoko) exhibiting contrasting climates, edaphic conditions and wood productions. Annual soil CO2 efflux (F-S) was significantly lower in the acacia monocultures than in Eucalypt monocultures and mixed-species stands at both sites. Annual F-S was significantly lower at Itatinga compared to Kissoko for all stands while TBCF was significantly lower in the Eucalypt stands only. In the Eucalypt monocultures we found a significantly lower aboveground NPP (ANPP) and wood production (wood NPP) at Kissoko compared to Itatinga that was almost fully balanced by a significantly higher belowground NPP (BNPP), leading to similar NPP. Similarly, acacia monocultures exhibited significantly higher ANPP and wood NPP at Itatinga than at Kissoko. The mixed-species stands exhibited a significantly lower wood NPP and ANPP than the Eucalypt monocultures at the Brazilian site while NPP of the mixture was not significantly different than the average NPP of the two monocultures. At the Congolese site, NPP of the mixture was significantly higher than the average NPP of the two monocultures. NPP was similar in the mixed-species stand and the Eucalypt monoculture with a significantly lower partitioning of NPP to belowground production, leading to a one third higher wood biomass at harvest in the mixed-species stand. A positive effect of growing Eucalypts with the nitrogen fixing acacia trees on stand wood production occurred at Kissoko but not at Itatinga. Mixed-species plantations with NFS can be advocated at sites where the productive gains resulting from nitrogen fixation are not compromised by other resource limitations. (c) 2012 Elsevier B.V. All rights reserved.
-
Partitioning of net primary production in Eucalyptus and Acacia stands and in mixed-species plantations: Two case-studies in contrasting tropical environments
Forest Ecology and Management, 2013Co-Authors: Daniel Epron, Louis Mareschal, Jean-paul Laclau, Yann Nouvellon, Lydiestella Koutika, Blandine Geneste, Gael Sola, Rildo Moreira E Moreira, Juan Sinforiano Delgado-rojas, Jose Leonardo De Moraes GoncalvesAbstract:The introduction of nitrogen fixing species (NFS) in fast-growing tree plantations is an alternative option to reduce fertilizer inputs. However, the success of mixed-species plantations depends on the balance between positive interactions among species (resulting from facilitation and/or complementarity) and the negative effects of interspecific competition. Using a carbon budget approach and coupling measurements of standing biomass, aboveground litterfall and soil CO2 efflux, we assessed the influence of replacing half of Eucalypt trees by Acacia mangium on total belowground carbon flux (TBCF), net primary production (NPP) and its partitioning between above- and belowground growth at two tropical sites in Brazil (Itatinga) and in Congo (Kissoko) exhibiting contrasting climates, edaphic conditions and wood productions. Annual soil CO2 efflux (F-S) was significantly lower in the acacia monocultures than in Eucalypt monocultures and mixed-species stands at both sites. Annual F-S was significantly lower at Itatinga compared to Kissoko for all stands while TBCF was significantly lower in the Eucalypt stands only. In the Eucalypt monocultures we found a significantly lower aboveground NPP (ANPP) and wood production (wood NPP) at Kissoko compared to Itatinga that was almost fully balanced by a significantly higher belowground NPP (BNPP), leading to similar NPP. Similarly, acacia monocultures exhibited significantly higher ANPP and wood NPP at Itatinga than at Kissoko. The mixed-species stands exhibited a significantly lower wood NPP and ANPP than the Eucalypt monocultures at the Brazilian site while NPP of the mixture was not significantly different than the average NPP of the two monocultures. At the Congolese site, NPP of the mixture was significantly higher than the average NPP of the two monocultures. NPP was similar in the mixed-species stand and the Eucalypt monoculture with a significantly lower partitioning of NPP to belowground production, leading to a one third higher wood biomass at harvest in the mixed-species stand. A positive effect of growing Eucalypts with the nitrogen fixing acacia trees on stand wood production occurred at Kissoko but not at Itatinga. Mixed-species plantations with NFS can be advocated at sites where the productive gains resulting from nitrogen fixation are not compromised by other resource limitations.
-
mixed species plantations of acacia mangium and Eucalyptus grandis in brazil
Forest Ecology and Management, 2008Co-Authors: Jean-paul Laclau, Jose Leonardo De Moraes Goncalves, Jean-pierre Bouillet, Laurent Saintandre, E V Silva, Christophe Jourdan, M C S Cunha, M R Moreira, Valerie Maquere, Yann NouvellonAbstract:Abstract Nitrogen fertilizer inputs increased sharply over the last decade in Brazilian Eucalypt plantations. Due to the economic and potential environmental cost of fertilizers, mixed plantations with N-fixing species might be an attractive option to improve the long-term soil N status. A randomized block design was set up in southern Brazil, including a replacement series and an additive series design, as well as a nitrogen fertilization treatment. The development of mono-specific stands of Eucalyptus grandis (0A:100E) and Acacia mangium (100A:0E) was compared with mixed plantations in proportions of 1:1 (50A:50E), and other stands with different densities of acacia for the same density of Eucalypts. The objective was to assess the effect of inter-specific interactions on the early development of the two species. Aboveground biomass was measured 6, 12, 18 and 30 months after planting, sampling 6–10 trees of each species per treatment at each age, and allometric equations were established in 0A:100E, 100A:0E, 50A:50E and 50A:100E. The height and basal area of E. grandis seedlings were enhanced by 12% and 30%, respectively by N fertilization at age 1 year. Inter-specific competition led to a stratified canopy, with suppression in acacia growth earlier for basal area than for height. The mean number of stems per acacia tree at 36 months after planting was significantly higher in pure stands (3.7), than in 50A:50E (2.7) and in the additive series (between 1.6 and 1.8). H / D ratios were highly sensitive to inter-tree competition for the two species. The suppressed acacia understorey in mixed-species stands did not influence biomass production and partitioning within Eucalypts. This pattern led to biomass accumulation combining the two species in 50A:100E that was about 10% higher than in 0A:100E, from age 12 months onwards. Aboveground net primary production (ANPP) amounted to 25 Mg ha −1 and 37 Mg ha −1 from age 18 to 30 months in 100A:0E and 0A:100E, respectively. Acacia ANPP in 50A:100E amounted to 2 Mg ha −1 over the same period, as a result of substantial inter-specific competition. An increment in biomass production in these very fast-growing Eucalypt plantations was achieved introducing acacia as an understorey and not in the 50A:50E design, as observed in other studies.
Jean-paul Laclau - One of the best experts on this subject based on the ideXlab platform.
-
Introducing N2-fixing trees (Acacia mangium) in Eucalypt plantations rapidly modifies the pools of organic P and low molecular weight organic acids in tropical soils
Science of the Total Environment, 2020Co-Authors: Kittima Waithaisong, Louis Mareschal, Agnès Robin, Jean-pierre Bouillet, Jean-paul Laclau, Philippe Deleporte, José Leonardo Moraes Gonçalves, Jean-michel Harmand, Claude PlassardAbstract:Many studies have shown that introducing N2-fixing trees (e.g. Acacia mangium) in Eucalypt plantations can increase soil N availability as a result of biological N2 fixation and faster N cycling. Some studies have also shown improved Eucalypt P nutrition. However, the effects of N2-fixing trees on P cycling in tropical soils remain poorly understood and site-dependent. Our study aimed to assess the effects of planting A. mangium trees in areas managed over several decades with Eucalypt plantations on soil organic P (Po) forms and low molecular weight organic acids (LMWOAs). Soil samples were collected from two tropical sites, one in Brazil and one in the Congo. Five different treatments were sampled at each site: monospecific acacia, monospecific Eucalypt, below acacias in mixed-species, below Eucalypts in mixed-species as well as native vegetation. Po forms and LMWOAs were identified in sodium hydroxide soil extracts using ion chromatography and relationships between these data and available P were determined. At both sites, the concentrations of most Po forms and LMWOAs were different between native ecosystems and monospecific Eucalypt and acacia plots. Also, patterns of Po and LMWOAs were clearly separated, with glucose-6-P found mainly under acacia and phytate and oxalate mainly under Eucalypt. Despite the strongest changes occurred at site with a higher N2 fixation and root development, acacia introduction was able to change the profile of organic P and LMWOAs in
-
partitioning of net primary production in Eucalyptus and acacia stands and in mixed species plantations two case studies in contrasting tropical environments
Forest Ecology and Management, 2013Co-Authors: Daniel Epron, Louis Mareschal, Jean-paul Laclau, Yann Nouvellon, Rildo Moreira E Moreira, Lydiestella Koutika, Blandine Geneste, Juan Sinforiano Delgadorojas, Gael Sola, Jose Leonardo De Moraes GoncalvesAbstract:The introduction of nitrogen fixing species (NFS) in fast-growing tree plantations is an alternative option to reduce fertilizer inputs. However, the success of mixed-species plantations depends on the balance between positive interactions among species (resulting from facilitation and/or complementarity) and the negative effects of interspecific competition. Using a carbon budget approach and coupling measurements of standing biomass, aboveground litterfall and soil CO2 efflux, we assessed the influence of replacing half of Eucalypt trees by Acacia mangium on total belowground carbon flux (TBCF), net primary production (NPP) and its partitioning between above- and belowground growth at two tropical sites in Brazil (Itatinga) and in Congo (Kissoko) exhibiting contrasting climates, edaphic conditions and wood productions. Annual soil CO2 efflux (F-S) was significantly lower in the acacia monocultures than in Eucalypt monocultures and mixed-species stands at both sites. Annual F-S was significantly lower at Itatinga compared to Kissoko for all stands while TBCF was significantly lower in the Eucalypt stands only. In the Eucalypt monocultures we found a significantly lower aboveground NPP (ANPP) and wood production (wood NPP) at Kissoko compared to Itatinga that was almost fully balanced by a significantly higher belowground NPP (BNPP), leading to similar NPP. Similarly, acacia monocultures exhibited significantly higher ANPP and wood NPP at Itatinga than at Kissoko. The mixed-species stands exhibited a significantly lower wood NPP and ANPP than the Eucalypt monocultures at the Brazilian site while NPP of the mixture was not significantly different than the average NPP of the two monocultures. At the Congolese site, NPP of the mixture was significantly higher than the average NPP of the two monocultures. NPP was similar in the mixed-species stand and the Eucalypt monoculture with a significantly lower partitioning of NPP to belowground production, leading to a one third higher wood biomass at harvest in the mixed-species stand. A positive effect of growing Eucalypts with the nitrogen fixing acacia trees on stand wood production occurred at Kissoko but not at Itatinga. Mixed-species plantations with NFS can be advocated at sites where the productive gains resulting from nitrogen fixation are not compromised by other resource limitations. (c) 2012 Elsevier B.V. All rights reserved.
-
Partitioning of net primary production in Eucalyptus and Acacia stands and in mixed-species plantations: Two case-studies in contrasting tropical environments
Forest Ecology and Management, 2013Co-Authors: Daniel Epron, Louis Mareschal, Jean-paul Laclau, Yann Nouvellon, Lydiestella Koutika, Blandine Geneste, Gael Sola, Rildo Moreira E Moreira, Juan Sinforiano Delgado-rojas, Jose Leonardo De Moraes GoncalvesAbstract:The introduction of nitrogen fixing species (NFS) in fast-growing tree plantations is an alternative option to reduce fertilizer inputs. However, the success of mixed-species plantations depends on the balance between positive interactions among species (resulting from facilitation and/or complementarity) and the negative effects of interspecific competition. Using a carbon budget approach and coupling measurements of standing biomass, aboveground litterfall and soil CO2 efflux, we assessed the influence of replacing half of Eucalypt trees by Acacia mangium on total belowground carbon flux (TBCF), net primary production (NPP) and its partitioning between above- and belowground growth at two tropical sites in Brazil (Itatinga) and in Congo (Kissoko) exhibiting contrasting climates, edaphic conditions and wood productions. Annual soil CO2 efflux (F-S) was significantly lower in the acacia monocultures than in Eucalypt monocultures and mixed-species stands at both sites. Annual F-S was significantly lower at Itatinga compared to Kissoko for all stands while TBCF was significantly lower in the Eucalypt stands only. In the Eucalypt monocultures we found a significantly lower aboveground NPP (ANPP) and wood production (wood NPP) at Kissoko compared to Itatinga that was almost fully balanced by a significantly higher belowground NPP (BNPP), leading to similar NPP. Similarly, acacia monocultures exhibited significantly higher ANPP and wood NPP at Itatinga than at Kissoko. The mixed-species stands exhibited a significantly lower wood NPP and ANPP than the Eucalypt monocultures at the Brazilian site while NPP of the mixture was not significantly different than the average NPP of the two monocultures. At the Congolese site, NPP of the mixture was significantly higher than the average NPP of the two monocultures. NPP was similar in the mixed-species stand and the Eucalypt monoculture with a significantly lower partitioning of NPP to belowground production, leading to a one third higher wood biomass at harvest in the mixed-species stand. A positive effect of growing Eucalypts with the nitrogen fixing acacia trees on stand wood production occurred at Kissoko but not at Itatinga. Mixed-species plantations with NFS can be advocated at sites where the productive gains resulting from nitrogen fixation are not compromised by other resource limitations.
-
age related changes in litter inputs explain annual trends in soil co2 effluxes over a full Eucalyptus rotation after afforestation of a tropical savannah
Biogeochemistry, 2012Co-Authors: Yann Nouvellon, Jean-pierre Bouillet, Philippe Deleporte, Daniel Epron, Claire Marsden, Antoine Kinana, Guerric Le Maire, Laurent Saintandre, Jean-paul LaclauAbstract:Land use changes such as savannah afforestation with Eucalypts impact the soil carbon (C) balance, therefore affecting soil CO2 efflux (Fs), a major flux in the global C cycle. We tested the hypothesis that Fs increases with stand age after afforestation, due to an increasing input of fresh organic matter to the forest floor. In a Eucalyptus plantation established on coastal savannahs in Congo, bimonthly measurements of Fs were carried out for 1 year on three adjacent stands aged 0.9, 4.4 and 13.7 years and presenting similar growth patterns. Litterfall and litter accumulation on the forest floor were quantified over a chronosequence. Equations were derived to estimate the contribution of litter decomposition to Fs throughout the rotation. Litterfall increased with stand age after savannah afforestation. Fs, that was strongly correlated on a seasonal basis with soil water content (SWC) in all stands, decreased between ages 0.9 year and 4.4 years due to savannah residue depletion, and increased between ages 4.4 years and 13.7 years, mainly because of an increasing amount of decomposing Eucalypt litter. The aboveground litter layer therefore appeared as a major source of CO2, whose contribution to Fs in old stands was estimated to be about four times higher than that of the Eucalypt-derived soil organic C pool. The high litter contribution to Fs in older stands might explain why 13.7 years-old stand Fs was limited by moisture all year round whereas SWC did not limit Fs for large parts of the year in the youngest stands.
-
mixed species plantations of acacia mangium and Eucalyptus grandis in brazil
Forest Ecology and Management, 2008Co-Authors: Jean-paul Laclau, Jose Leonardo De Moraes Goncalves, Jean-pierre Bouillet, Laurent Saintandre, E V Silva, Christophe Jourdan, M C S Cunha, M R Moreira, Valerie Maquere, Yann NouvellonAbstract:Abstract Nitrogen fertilizer inputs increased sharply over the last decade in Brazilian Eucalypt plantations. Due to the economic and potential environmental cost of fertilizers, mixed plantations with N-fixing species might be an attractive option to improve the long-term soil N status. A randomized block design was set up in southern Brazil, including a replacement series and an additive series design, as well as a nitrogen fertilization treatment. The development of mono-specific stands of Eucalyptus grandis (0A:100E) and Acacia mangium (100A:0E) was compared with mixed plantations in proportions of 1:1 (50A:50E), and other stands with different densities of acacia for the same density of Eucalypts. The objective was to assess the effect of inter-specific interactions on the early development of the two species. Aboveground biomass was measured 6, 12, 18 and 30 months after planting, sampling 6–10 trees of each species per treatment at each age, and allometric equations were established in 0A:100E, 100A:0E, 50A:50E and 50A:100E. The height and basal area of E. grandis seedlings were enhanced by 12% and 30%, respectively by N fertilization at age 1 year. Inter-specific competition led to a stratified canopy, with suppression in acacia growth earlier for basal area than for height. The mean number of stems per acacia tree at 36 months after planting was significantly higher in pure stands (3.7), than in 50A:50E (2.7) and in the additive series (between 1.6 and 1.8). H / D ratios were highly sensitive to inter-tree competition for the two species. The suppressed acacia understorey in mixed-species stands did not influence biomass production and partitioning within Eucalypts. This pattern led to biomass accumulation combining the two species in 50A:100E that was about 10% higher than in 0A:100E, from age 12 months onwards. Aboveground net primary production (ANPP) amounted to 25 Mg ha −1 and 37 Mg ha −1 from age 18 to 30 months in 100A:0E and 0A:100E, respectively. Acacia ANPP in 50A:100E amounted to 2 Mg ha −1 over the same period, as a result of substantial inter-specific competition. An increment in biomass production in these very fast-growing Eucalypt plantations was achieved introducing acacia as an understorey and not in the 50A:50E design, as observed in other studies.
Yann Nouvellon - One of the best experts on this subject based on the ideXlab platform.
-
nitrogen fixation rate of acacia mangium wild at mid rotation in brazil is higher in mixed plantations with Eucalyptus grandis hill ex maiden than in monocultures
Annals of Forest Science, 2018Co-Authors: Ranieri Ribeiro Paula, Jose Leonardo De Moraes Goncalves, Jean-pierre Bouillet, Yann Nouvellon, Paulo Cesar Ocheuze Trivelin, Fabiano De Carvalho Balieiro, Julianne De Castro Oliveira, Jose C De Deus, Bruno Bordron, Jeanpau LaclauAbstract:Inter-specific interactions with Eucalypts in mixed plantations increased N 2 fixation rate of acacia trees compared to monocultures. N 2 fixation was higher during the wet summer than during the dry winter both in acacia monocultures and in mixed plantations. Introducing N-fixing trees in fast-growing tropical plantations may contribute to reducing the long-term requirements of N fertilizers. Management practices established in forest monocultures should be revisited in mixed-species plantations. This field experiment aimed to compare N2 fixation rates of Acacia mangium Wild in monospecific stands and in mixed-species stands with Eucalyptus grandis W. Hill ex Maiden. A secondary objective was to gain insight into the seasonal variations of N2 fixation. 15N was applied to acacia and Eucalypt monocultures and mixed-species with a 1:1 ratio at mid rotation. Leaves were collected in autumn, winter, spring, and summer to determine the foliar N concentrations and 15N atom fraction. The N content in the above-ground biomass was estimated as well as the percentage of N derived from atmospheric N2 (%Ndfa) using Eucalypts in monoculture as reference plants. %Ndfa values averaged over the year were 14% in monoculture and 44% in mixed-species stands. While the stocking density of acacia trees was twice as high in monoculture as in mixture, the amounts of N fixed in above-ground biomass of acacia trees were close (35–39 kg N ha−1) at 39 months after planting. %Ndfa values were higher during the wet summer than the dry winter both in acacia monocultures and in mixed plantations. The stocking density of acacia trees can be reduced in mixed plantations with Eucalypts in comparison to acacia monocultures with a low influence on the input of N to soil through biological fixation.
-
partitioning of net primary production in Eucalyptus and acacia stands and in mixed species plantations two case studies in contrasting tropical environments
Forest Ecology and Management, 2013Co-Authors: Daniel Epron, Louis Mareschal, Jean-paul Laclau, Yann Nouvellon, Rildo Moreira E Moreira, Lydiestella Koutika, Blandine Geneste, Juan Sinforiano Delgadorojas, Gael Sola, Jose Leonardo De Moraes GoncalvesAbstract:The introduction of nitrogen fixing species (NFS) in fast-growing tree plantations is an alternative option to reduce fertilizer inputs. However, the success of mixed-species plantations depends on the balance between positive interactions among species (resulting from facilitation and/or complementarity) and the negative effects of interspecific competition. Using a carbon budget approach and coupling measurements of standing biomass, aboveground litterfall and soil CO2 efflux, we assessed the influence of replacing half of Eucalypt trees by Acacia mangium on total belowground carbon flux (TBCF), net primary production (NPP) and its partitioning between above- and belowground growth at two tropical sites in Brazil (Itatinga) and in Congo (Kissoko) exhibiting contrasting climates, edaphic conditions and wood productions. Annual soil CO2 efflux (F-S) was significantly lower in the acacia monocultures than in Eucalypt monocultures and mixed-species stands at both sites. Annual F-S was significantly lower at Itatinga compared to Kissoko for all stands while TBCF was significantly lower in the Eucalypt stands only. In the Eucalypt monocultures we found a significantly lower aboveground NPP (ANPP) and wood production (wood NPP) at Kissoko compared to Itatinga that was almost fully balanced by a significantly higher belowground NPP (BNPP), leading to similar NPP. Similarly, acacia monocultures exhibited significantly higher ANPP and wood NPP at Itatinga than at Kissoko. The mixed-species stands exhibited a significantly lower wood NPP and ANPP than the Eucalypt monocultures at the Brazilian site while NPP of the mixture was not significantly different than the average NPP of the two monocultures. At the Congolese site, NPP of the mixture was significantly higher than the average NPP of the two monocultures. NPP was similar in the mixed-species stand and the Eucalypt monoculture with a significantly lower partitioning of NPP to belowground production, leading to a one third higher wood biomass at harvest in the mixed-species stand. A positive effect of growing Eucalypts with the nitrogen fixing acacia trees on stand wood production occurred at Kissoko but not at Itatinga. Mixed-species plantations with NFS can be advocated at sites where the productive gains resulting from nitrogen fixation are not compromised by other resource limitations. (c) 2012 Elsevier B.V. All rights reserved.
-
Partitioning of net primary production in Eucalyptus and Acacia stands and in mixed-species plantations: Two case-studies in contrasting tropical environments
Forest Ecology and Management, 2013Co-Authors: Daniel Epron, Louis Mareschal, Jean-paul Laclau, Yann Nouvellon, Lydiestella Koutika, Blandine Geneste, Gael Sola, Rildo Moreira E Moreira, Juan Sinforiano Delgado-rojas, Jose Leonardo De Moraes GoncalvesAbstract:The introduction of nitrogen fixing species (NFS) in fast-growing tree plantations is an alternative option to reduce fertilizer inputs. However, the success of mixed-species plantations depends on the balance between positive interactions among species (resulting from facilitation and/or complementarity) and the negative effects of interspecific competition. Using a carbon budget approach and coupling measurements of standing biomass, aboveground litterfall and soil CO2 efflux, we assessed the influence of replacing half of Eucalypt trees by Acacia mangium on total belowground carbon flux (TBCF), net primary production (NPP) and its partitioning between above- and belowground growth at two tropical sites in Brazil (Itatinga) and in Congo (Kissoko) exhibiting contrasting climates, edaphic conditions and wood productions. Annual soil CO2 efflux (F-S) was significantly lower in the acacia monocultures than in Eucalypt monocultures and mixed-species stands at both sites. Annual F-S was significantly lower at Itatinga compared to Kissoko for all stands while TBCF was significantly lower in the Eucalypt stands only. In the Eucalypt monocultures we found a significantly lower aboveground NPP (ANPP) and wood production (wood NPP) at Kissoko compared to Itatinga that was almost fully balanced by a significantly higher belowground NPP (BNPP), leading to similar NPP. Similarly, acacia monocultures exhibited significantly higher ANPP and wood NPP at Itatinga than at Kissoko. The mixed-species stands exhibited a significantly lower wood NPP and ANPP than the Eucalypt monocultures at the Brazilian site while NPP of the mixture was not significantly different than the average NPP of the two monocultures. At the Congolese site, NPP of the mixture was significantly higher than the average NPP of the two monocultures. NPP was similar in the mixed-species stand and the Eucalypt monoculture with a significantly lower partitioning of NPP to belowground production, leading to a one third higher wood biomass at harvest in the mixed-species stand. A positive effect of growing Eucalypts with the nitrogen fixing acacia trees on stand wood production occurred at Kissoko but not at Itatinga. Mixed-species plantations with NFS can be advocated at sites where the productive gains resulting from nitrogen fixation are not compromised by other resource limitations.
-
age related changes in litter inputs explain annual trends in soil co2 effluxes over a full Eucalyptus rotation after afforestation of a tropical savannah
Biogeochemistry, 2012Co-Authors: Yann Nouvellon, Jean-pierre Bouillet, Philippe Deleporte, Daniel Epron, Claire Marsden, Antoine Kinana, Guerric Le Maire, Laurent Saintandre, Jean-paul LaclauAbstract:Land use changes such as savannah afforestation with Eucalypts impact the soil carbon (C) balance, therefore affecting soil CO2 efflux (Fs), a major flux in the global C cycle. We tested the hypothesis that Fs increases with stand age after afforestation, due to an increasing input of fresh organic matter to the forest floor. In a Eucalyptus plantation established on coastal savannahs in Congo, bimonthly measurements of Fs were carried out for 1 year on three adjacent stands aged 0.9, 4.4 and 13.7 years and presenting similar growth patterns. Litterfall and litter accumulation on the forest floor were quantified over a chronosequence. Equations were derived to estimate the contribution of litter decomposition to Fs throughout the rotation. Litterfall increased with stand age after savannah afforestation. Fs, that was strongly correlated on a seasonal basis with soil water content (SWC) in all stands, decreased between ages 0.9 year and 4.4 years due to savannah residue depletion, and increased between ages 4.4 years and 13.7 years, mainly because of an increasing amount of decomposing Eucalypt litter. The aboveground litter layer therefore appeared as a major source of CO2, whose contribution to Fs in old stands was estimated to be about four times higher than that of the Eucalypt-derived soil organic C pool. The high litter contribution to Fs in older stands might explain why 13.7 years-old stand Fs was limited by moisture all year round whereas SWC did not limit Fs for large parts of the year in the youngest stands.
-
mixed species plantations of acacia mangium and Eucalyptus grandis in brazil
Forest Ecology and Management, 2008Co-Authors: Jean-paul Laclau, Jose Leonardo De Moraes Goncalves, Jean-pierre Bouillet, Laurent Saintandre, E V Silva, Christophe Jourdan, M C S Cunha, M R Moreira, Valerie Maquere, Yann NouvellonAbstract:Abstract Nitrogen fertilizer inputs increased sharply over the last decade in Brazilian Eucalypt plantations. Due to the economic and potential environmental cost of fertilizers, mixed plantations with N-fixing species might be an attractive option to improve the long-term soil N status. A randomized block design was set up in southern Brazil, including a replacement series and an additive series design, as well as a nitrogen fertilization treatment. The development of mono-specific stands of Eucalyptus grandis (0A:100E) and Acacia mangium (100A:0E) was compared with mixed plantations in proportions of 1:1 (50A:50E), and other stands with different densities of acacia for the same density of Eucalypts. The objective was to assess the effect of inter-specific interactions on the early development of the two species. Aboveground biomass was measured 6, 12, 18 and 30 months after planting, sampling 6–10 trees of each species per treatment at each age, and allometric equations were established in 0A:100E, 100A:0E, 50A:50E and 50A:100E. The height and basal area of E. grandis seedlings were enhanced by 12% and 30%, respectively by N fertilization at age 1 year. Inter-specific competition led to a stratified canopy, with suppression in acacia growth earlier for basal area than for height. The mean number of stems per acacia tree at 36 months after planting was significantly higher in pure stands (3.7), than in 50A:50E (2.7) and in the additive series (between 1.6 and 1.8). H / D ratios were highly sensitive to inter-tree competition for the two species. The suppressed acacia understorey in mixed-species stands did not influence biomass production and partitioning within Eucalypts. This pattern led to biomass accumulation combining the two species in 50A:100E that was about 10% higher than in 0A:100E, from age 12 months onwards. Aboveground net primary production (ANPP) amounted to 25 Mg ha −1 and 37 Mg ha −1 from age 18 to 30 months in 100A:0E and 0A:100E, respectively. Acacia ANPP in 50A:100E amounted to 2 Mg ha −1 over the same period, as a result of substantial inter-specific competition. An increment in biomass production in these very fast-growing Eucalypt plantations was achieved introducing acacia as an understorey and not in the 50A:50E design, as observed in other studies.
Daniel Epron - One of the best experts on this subject based on the ideXlab platform.
-
partitioning of net primary production in Eucalyptus and acacia stands and in mixed species plantations two case studies in contrasting tropical environments
Forest Ecology and Management, 2013Co-Authors: Daniel Epron, Louis Mareschal, Jean-paul Laclau, Yann Nouvellon, Rildo Moreira E Moreira, Lydiestella Koutika, Blandine Geneste, Juan Sinforiano Delgadorojas, Gael Sola, Jose Leonardo De Moraes GoncalvesAbstract:The introduction of nitrogen fixing species (NFS) in fast-growing tree plantations is an alternative option to reduce fertilizer inputs. However, the success of mixed-species plantations depends on the balance between positive interactions among species (resulting from facilitation and/or complementarity) and the negative effects of interspecific competition. Using a carbon budget approach and coupling measurements of standing biomass, aboveground litterfall and soil CO2 efflux, we assessed the influence of replacing half of Eucalypt trees by Acacia mangium on total belowground carbon flux (TBCF), net primary production (NPP) and its partitioning between above- and belowground growth at two tropical sites in Brazil (Itatinga) and in Congo (Kissoko) exhibiting contrasting climates, edaphic conditions and wood productions. Annual soil CO2 efflux (F-S) was significantly lower in the acacia monocultures than in Eucalypt monocultures and mixed-species stands at both sites. Annual F-S was significantly lower at Itatinga compared to Kissoko for all stands while TBCF was significantly lower in the Eucalypt stands only. In the Eucalypt monocultures we found a significantly lower aboveground NPP (ANPP) and wood production (wood NPP) at Kissoko compared to Itatinga that was almost fully balanced by a significantly higher belowground NPP (BNPP), leading to similar NPP. Similarly, acacia monocultures exhibited significantly higher ANPP and wood NPP at Itatinga than at Kissoko. The mixed-species stands exhibited a significantly lower wood NPP and ANPP than the Eucalypt monocultures at the Brazilian site while NPP of the mixture was not significantly different than the average NPP of the two monocultures. At the Congolese site, NPP of the mixture was significantly higher than the average NPP of the two monocultures. NPP was similar in the mixed-species stand and the Eucalypt monoculture with a significantly lower partitioning of NPP to belowground production, leading to a one third higher wood biomass at harvest in the mixed-species stand. A positive effect of growing Eucalypts with the nitrogen fixing acacia trees on stand wood production occurred at Kissoko but not at Itatinga. Mixed-species plantations with NFS can be advocated at sites where the productive gains resulting from nitrogen fixation are not compromised by other resource limitations. (c) 2012 Elsevier B.V. All rights reserved.
-
Partitioning of net primary production in Eucalyptus and Acacia stands and in mixed-species plantations: Two case-studies in contrasting tropical environments
Forest Ecology and Management, 2013Co-Authors: Daniel Epron, Louis Mareschal, Jean-paul Laclau, Yann Nouvellon, Lydiestella Koutika, Blandine Geneste, Gael Sola, Rildo Moreira E Moreira, Juan Sinforiano Delgado-rojas, Jose Leonardo De Moraes GoncalvesAbstract:The introduction of nitrogen fixing species (NFS) in fast-growing tree plantations is an alternative option to reduce fertilizer inputs. However, the success of mixed-species plantations depends on the balance between positive interactions among species (resulting from facilitation and/or complementarity) and the negative effects of interspecific competition. Using a carbon budget approach and coupling measurements of standing biomass, aboveground litterfall and soil CO2 efflux, we assessed the influence of replacing half of Eucalypt trees by Acacia mangium on total belowground carbon flux (TBCF), net primary production (NPP) and its partitioning between above- and belowground growth at two tropical sites in Brazil (Itatinga) and in Congo (Kissoko) exhibiting contrasting climates, edaphic conditions and wood productions. Annual soil CO2 efflux (F-S) was significantly lower in the acacia monocultures than in Eucalypt monocultures and mixed-species stands at both sites. Annual F-S was significantly lower at Itatinga compared to Kissoko for all stands while TBCF was significantly lower in the Eucalypt stands only. In the Eucalypt monocultures we found a significantly lower aboveground NPP (ANPP) and wood production (wood NPP) at Kissoko compared to Itatinga that was almost fully balanced by a significantly higher belowground NPP (BNPP), leading to similar NPP. Similarly, acacia monocultures exhibited significantly higher ANPP and wood NPP at Itatinga than at Kissoko. The mixed-species stands exhibited a significantly lower wood NPP and ANPP than the Eucalypt monocultures at the Brazilian site while NPP of the mixture was not significantly different than the average NPP of the two monocultures. At the Congolese site, NPP of the mixture was significantly higher than the average NPP of the two monocultures. NPP was similar in the mixed-species stand and the Eucalypt monoculture with a significantly lower partitioning of NPP to belowground production, leading to a one third higher wood biomass at harvest in the mixed-species stand. A positive effect of growing Eucalypts with the nitrogen fixing acacia trees on stand wood production occurred at Kissoko but not at Itatinga. Mixed-species plantations with NFS can be advocated at sites where the productive gains resulting from nitrogen fixation are not compromised by other resource limitations.
-
age related changes in litter inputs explain annual trends in soil co2 effluxes over a full Eucalyptus rotation after afforestation of a tropical savannah
Biogeochemistry, 2012Co-Authors: Yann Nouvellon, Jean-pierre Bouillet, Philippe Deleporte, Daniel Epron, Claire Marsden, Antoine Kinana, Guerric Le Maire, Laurent Saintandre, Jean-paul LaclauAbstract:Land use changes such as savannah afforestation with Eucalypts impact the soil carbon (C) balance, therefore affecting soil CO2 efflux (Fs), a major flux in the global C cycle. We tested the hypothesis that Fs increases with stand age after afforestation, due to an increasing input of fresh organic matter to the forest floor. In a Eucalyptus plantation established on coastal savannahs in Congo, bimonthly measurements of Fs were carried out for 1 year on three adjacent stands aged 0.9, 4.4 and 13.7 years and presenting similar growth patterns. Litterfall and litter accumulation on the forest floor were quantified over a chronosequence. Equations were derived to estimate the contribution of litter decomposition to Fs throughout the rotation. Litterfall increased with stand age after savannah afforestation. Fs, that was strongly correlated on a seasonal basis with soil water content (SWC) in all stands, decreased between ages 0.9 year and 4.4 years due to savannah residue depletion, and increased between ages 4.4 years and 13.7 years, mainly because of an increasing amount of decomposing Eucalypt litter. The aboveground litter layer therefore appeared as a major source of CO2, whose contribution to Fs in old stands was estimated to be about four times higher than that of the Eucalypt-derived soil organic C pool. The high litter contribution to Fs in older stands might explain why 13.7 years-old stand Fs was limited by moisture all year round whereas SWC did not limit Fs for large parts of the year in the youngest stands.
Ronald S C Firth - One of the best experts on this subject based on the ideXlab platform.
-
ecology and conservation status of the brush tailed rabbit rat conilurus penicillatus
2007Co-Authors: Ronald S C FirthAbstract:In this thesis I investigate the ecology of the threatened brush-tailed rabbit-rat Conilurus penicillatus, specifically including diet, movements and shelter sites, population dynamics, and habitat preference and use. I then use this information as a base from which to consider possible causes of decline and to provide advice for remedial management. This study was conducted primarily at two main sites, Cobourg Peninsula (with two sub-sites) and Kakadu National Park, with additional information gathered from the Tiwi Islands. The diet of C. penicillatus consists primarily of seed, particularly from perennial grasses. The mean home range size is 0.79 ha; whilst males had larger home ranges than females, there were no significant differences in home-range size among the sites or between seasons. Conilurus penicillatus denned primarily in fallen logs and in hollows of Eucalypts and bloodwoods. Apparent survival probability for C. penicillatus varied noticeably over the study and was best described by a model that included main and interaction effects of sex, site and sampling occasion. Population densities at the three sites ranged from 0.35 to 7.1 individuals ha-1. Conilurus penicillatus reproduced during the dry season (May-October) and most juveniles also entered the population during this period. On the Tiwi Islands C. penicillatus was most likely to occur in tall Eucalypt forest away from watercourses, where there was more bare ground and where fires had been less severe and/or less recent. The species remains common and widespread on Cobourg Peninsula and Tiwi Islands, but is very restricted within Kakadu National Park. In common with the habitat relationships on the Tiwi Islands, in the mainland study sites Conilurus penicillatus was most likely to occur in tall Eucalypt forests, where there was less bare ground and less cover of annual grasses and where fires had been less severe. The most likely cause of decline is changes in fire regimes as a result of the loss of traditional Aboriginal fire management.
-
environmental relationships of the brush tailed rabbit rat conilurus penicillatus and other small mammals on the tiwi islands northern australia
Journal of Biogeography, 2006Co-Authors: Ronald S C Firth, John C Z Woinarski, Kym Brennan, Craig HempelAbstract:Aim To describe the habitat characteristics and status of the brush-tailed rabbit-rat, Conilurus penicillatus Gould, 1842, on the Tiwi Islands, northern Australia, as part of a broader programme aimed at the conservation management of this species. In addition, comparable environmental modelling is undertaken for other co-occurring small native mammals, including the black-footed tree-rat, Mesembriomys gouldii Gray, 1843, a taxonomically and ecologically related species. These objectives relate to the significance for mammal conservation of islands generally in Australia, and the recent intensification of plantation forestry on these previously little-disturbed islands. Location Melville and Bathurst islands (Tiwi Islands), respectively, Australia's second and fifth largest islands. Methods A systematic survey was conducted for mammals across Bathurst (115 sampled quadrats) and Melville Island (236 quadrats). A broad range of environmental variables was recorded for every quadrat. All quadrats were classified by their woody plant species composition. The relative occurrence of individual mammal species across the resulting vegetation groups was examined using Kruskal-Wallis ANOVA. The habitat relationships of C. penicillatus and the most commonly recorded mammal species were described by generalized linear modelling, with separate models for each island, for both islands combined, for all habitats and for only those sites dominated by Eucalypts. Results Twelve small mammal species (excluding bats, macropods and feral animals) were recorded in this study. The most notable feature of this survey was the lack of records of M. gouldii from Bathurst Island. In contrast, the proportion of quadrats with C. penicillatus was not significantly different between the two islands. There was no significant tendency for these two species to co-occur in quadrats on Melville Island more or less commonly than by chance. Conilurus penicillatus was most abundant in Eucalypt forest while M. gouldii showed a weak association with Eucalypt forests and woodlands and shrub land. The five most commonly recorded species showed highly idiosyncratic relationships with environmental variables, with this relationship showing some variation between the two islands. None showed any significant association with floristic variation within the extensive Eucalypt forests, but most showed significant associations with tree height, basal area (especially of large trees), landscape position (distance to watercourse) and fire history. Main conclusions Conilurus penicillatus was most likely to occur in tall Eucalypt forest away from watercourses. This habitat is now being targeted for clearance for the development of plantations of the exotic Acacia mangium. Seven of the 12 mammal species examined in this study (C. penicillatus, M. gouldii, Rattus tunneyi Thomas, 1904, Melomys burtoni Ramsay, 1887, Sminthopsis butleri Archer, 1979, Phascogale tapoatafa Meyer, 1793 and Petaurus breviceps Gould, 1842) were not recorded at all in plantations, and these (and other) species are likely to be severely disadvantaged by plantation development. The study also demonstrated that the two medium to large arboreal rodent species (C. penicillatus and M. gouldii) vary in environmental associations and found no evidence that C. penicillatus increased in areas unoccupied by M. gouldii.
