Mackensen, Jens

[["dc.bibliographiccitation.firstpage","111"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Biogeochemistry"],["dc.bibliographiccitation.lastpage","128"],["dc.bibliographiccitation.volume","64"],["dc.contributor.author","Schwendenmann, Luitgard"],["dc.contributor.author","Veldkamp, Edzo"],["dc.contributor.author","Brenes, Tania"],["dc.contributor.author","O'Brien, Joseph J."],["dc.contributor.author","Mackensen, Jens"],["dc.date.accessioned","2017-09-07T11:43:43Z"],["dc.date.available","2017-09-07T11:43:43Z"],["dc.date.issued","2003"],["dc.description.abstract","Our objectives were to quantify and compare soil CO2 efflux of two dominant soil types in an old-growth neotropical rain forest in the Atlantic zone of Costa Rica, and to evaluate the control of environmental factors on CO2 release. We measured soil CO2 efflux from eight permanent soil chambers on six Oxisol sites. Three sites were developed on old river terraces (‘old alluvium’) and the other three were developed on old lava flows (‘residual’). At the same time we measured soil CO2 concentrations, soil water content and soil temperature at various depths in 6 soil shafts (3 m deep). Between ‘old alluvium’ sites, the two-year average CO2 flux rates ranged from 117.3 to 128.9 mg C m−2 h−1. Significantly higher soil CO2 flux occurred on the ‘residual’ sites (141.1 to 184.2 mg C m−2 h−1). Spatial differences in CO2 efflux were related to fine root biomass, soil carbon and phosphorus concentration but also to soil water content. Spatial variability in CO2 storage was high and the amount of CO2 stored in the upper and lower soil profile was different between ‘old alluvial’ and ‘residual’ sites. The major factor identified for explaining temporal variations in soil CO2 efflux was soil water content. During periods of high soil water content CO2 emission decreased, probably due to lower diffusion and CO2 production rates. During the 2-year study period inter-annual variation in soil CO2 efflux was not detected."],["dc.identifier.doi","10.1023/a:1024941614919"],["dc.identifier.gro","3150216"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/6956"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.issn","0168-2563"],["dc.subject","CO 2 efflux; Neotropical rain forest; Seasonality; Soil CO 2 storage; Soil temperature; Soil water content"],["dc.title","Spatial and temporal variation in soil CO2 efflux in an old-growth neotropical rain forest, La Selva, Costa Rica"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","598"],["dc.bibliographiccitation.lastpage","621"],["dc.contributor.author","Hölscher, Dirk"],["dc.contributor.author","Mackensen, J."],["dc.contributor.author","Roberts, J. -M."],["dc.contributor.editor","Bonell, M."],["dc.contributor.editor","Bruijnzeel, L. A."],["dc.date.accessioned","2017-09-07T11:45:40Z"],["dc.date.available","2017-09-07T11:45:40Z"],["dc.date.issued","2005"],["dc.identifier.doi","10.1017/cbo9780511535666.031"],["dc.identifier.gro","3149068"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5713"],["dc.language.iso","en"],["dc.notes.intern","Hoelscher Crossref import"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.publisher","Cambridge University Press"],["dc.publisher.place","Cambridge"],["dc.relation.isbn","978-0-521-82953-3"],["dc.relation.ispartof","Forests, water and people in the humid tropics past, present and future hydrological research for integrated land and water management"],["dc.title","Forest recovery in the humid tropics: changes in vegetation structure, nutrient pools and the hydrological cycle"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","106"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","AMBIO"],["dc.bibliographiccitation.lastpage","112"],["dc.bibliographiccitation.volume","32"],["dc.contributor.author","Mackensen, J."],["dc.contributor.author","Klinge, R."],["dc.contributor.author","Ruhiyat, D."],["dc.contributor.author","Folster, H."],["dc.date.accessioned","2018-11-07T10:40:11Z"],["dc.date.available","2018-11-07T10:40:11Z"],["dc.date.issued","2003"],["dc.description.abstract","Industrial tree plantations in the tropics usually follow short rotations and intensive site management including slash and burn, and the use of heavy machinery. We attempt to quantify the implied nutrient losses (harvest export, erosion, slash and burn, leaching) in order to give plantation managers a chance to understand the significance of their planning and decisions. We used the scarce globally available information and a case study plantation in East Kalimantan, Indonesia (Acacia mangium and Eucalyptus deglupta). Adaptation involves problems and is discussed in some detail. Results are approximate only. Assuming a harvest volume of 200 m(3) ha(-1), we assessed a loss of 427-680 kg ha(-1) N, 12-13 kg ha(-1) P, 178-252 kg ha(-1) Ca, 276-370 kg ha(-1) K, and 45-57 kg ha(-1) Mg per rotation. Of this overall loss, stand harvest accounted for 18-29% (N), 21-30% (P), 56-26% (K), 48-64% (Ca) and 22-37% (Mg). This means that the cumulative loss by erosion, slash and burn, and leaching exceeds that of the harvest. These losses can be influenced by management."],["dc.identifier.doi","10.1639/0044-7447(2003)032[0106:AOMDNL]2.0.CO;2"],["dc.identifier.isi","000182798700006"],["dc.identifier.pmid","12733794"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/46237"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0044-7447"],["dc.title","Assessment of management-dependent nutrient losses in tropical industrial tree plantations"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","121"],["dc.bibliographiccitation.issue","1-3"],["dc.bibliographiccitation.journal","Forest Ecology and Management"],["dc.bibliographiccitation.lastpage","128"],["dc.bibliographiccitation.volume","86"],["dc.contributor.author","Mackensen, J."],["dc.contributor.author","Hölscher, Dirk"],["dc.contributor.author","Klinge, R."],["dc.contributor.author","Fölster, Horst"],["dc.date.accessioned","2017-09-07T11:45:47Z"],["dc.date.available","2017-09-07T11:45:47Z"],["dc.date.issued","1996"],["dc.description.abstract","After replacement of tropical primary forests, fire becomes an important management tool. During establishment of plantations with fast-growing tree species and within slash-and-burn agriculture, the export of macronutrients and other elements to the atmosphere by burning was estimated. Two plots of clearcut 40-year-old and one plot of 7-year-old secondary forest with dry fuel weight 33.5 t ha−1 (plot A1), 95.2 t ha−1 (plot A2) and 31.2 t ha−1 (plot B1) were burnt. Total element losses including volatilisation, particle and leaching exports ranged from 94 to 98% C, 93–98% N, 30–47% P, 30–48% Na, 42–50% K, 13–35% Ca, 21–43% Mg and 66–76% S related to the initial nutrient. For the small-holder site (plot B1) where the drying period lasted 4 weeks with a total precipitation of 9 mm, this loss was to the atmosphere. Significant preburn losses due to leaching were observed on the moister plots (A1, A2) where the drying period lasted 80 days and 101 days with 250 mm and 296 mm precipitation, respectively. Here, element transfer to the atmosphere due to particle transport and volatilisation were 94–98% C, 95–98% N, 27–33% P, 17–23% Na, 16–31% K, 9–24% Ca, 17–43% Mg, 67–68% S of the initial element stock in the burnt debris."],["dc.identifier.doi","10.1016/s0378-1127(96)03790-5"],["dc.identifier.gro","3149087"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5734"],["dc.language.iso","en"],["dc.notes.intern","Hoelscher Crossref import"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0378-1127"],["dc.title","Nutrient transfer to the atmosphere by burning of debris in eastern Amazonia"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","63"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Biogeochemistry"],["dc.bibliographiccitation.lastpage","82"],["dc.bibliographiccitation.volume","69"],["dc.contributor.author","Klinge, R."],["dc.contributor.author","Martins, ARA"],["dc.contributor.author","Mackensen, J."],["dc.contributor.author","Folster, H."],["dc.date.accessioned","2018-11-07T10:49:09Z"],["dc.date.available","2018-11-07T10:49:09Z"],["dc.date.issued","2004"],["dc.description.abstract","Nutrient loss from forest ecosystems by burning and leaching can be estimated by comparing nutrient stores before and after the disturbance, and by measuring the nutrient fluxes during disturbance. We applied both methods to a clear cutting experiment near Belem, Eastern Amazon, in a correct time series of 15 months duration. Nutrient flux measurements include wood export, loss to the atmosphere by burning, and leaching. The latter was based on water flux simulation with a soil water model, and on element analysis of soil water extracts (ceramic cup lysimeter). Two plots with 33 and 92 t ha(-1) of residual biomass (left after export of wood >7 cm diameter) were compared with a forest control plot. Store and flux balances agreed well in case of Na, K, Mg, and S, and partially also for Ca and total P. Deviations seem to be caused by erratic but statistically not significant variations of the soil stores (mainly C and total N). Spacial variability of soil parameters demand very high sample replication, especially after disturbance. Flux measurements are better but more costly."],["dc.identifier.doi","10.1023/B:BIOG.0000031040.38388.9b"],["dc.identifier.isi","000221929800004"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48363"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0168-2563"],["dc.title","Element loss on rain forest conversion in East Amazonia: comparison of balances of stores and fluxes"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","101"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Plant Ecology"],["dc.bibliographiccitation.lastpage","119"],["dc.bibliographiccitation.volume","151"],["dc.contributor.author","Mackensen, J."],["dc.contributor.author","Tillery-Stevens, M."],["dc.contributor.author","Klinge, R."],["dc.contributor.author","Folster, H."],["dc.date.accessioned","2018-11-07T10:56:02Z"],["dc.date.available","2018-11-07T10:56:02Z"],["dc.date.issued","2000"],["dc.description.abstract","Our objective was to asses site parameters, species diversity, phytomass structure and element stores of a Terra-firme forest prior to subsequent studies on nutrient fluxes during forest conversion. The soil was classified as a Xanthic Ferralsol, with a low effective cation exchange capacity (ECEC), low nutrient status and a deeply weathered solum. On 0.75 ha, including all trees with a DBH >7 cm, we identified 222 tree species belonging to 58 families. The above-ground phytomass was estimated using logarithmic regression analysis on two plots of 0.25 ha each. Despite differences in forest structure and species composition, no major differences were found in terms of total phytomass or overall element stores. The mean living above-ground phytomass (LAGP) was 257 Mg ha(-1), and mean quantity of litter 14 Mg ha(-1). while dead wood contributed between 10 to 17% of total above-ground phytomass (32-56 Mg ha(-1)). Element store in LAGP was medium to high compared to other studies on tropical forest systems, while LAGP itself was comparatively low. Comparing 26 humid tropical forest stands recorded in literature, no correlation was found between LAGP and the amount of N and base cations stored in LAGP. However, a correlation between LAGP and P storage in LAGP (R-2 = 0.76) indicates the important role P may play in phytomass accumulation on zonal tropical soils. More then 60% of C, 20% of total N, 10% of total P and 66-88% of total K. Ca and Mg of the system (including the first meter of soil) were concentrated in the above-ground phytomass, including deadwood and litter. Consequently, phytomass destruction in form of forest conversion will lead to major element losses from the system."],["dc.identifier.doi","10.1023/A:1026515116944"],["dc.identifier.isi","000166537600001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/49921"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1385-0237"],["dc.title","Site parameters, species composition, phytomass structure and element stores of a terra-firme forest in East-Amazonia, Brazil"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]