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Basalt weathering and plant recycling in permafrost-bearing watersheds of Central Siberia: A multi-isotope approach (Si, Mg, Ca, Zn, and Cu)
Factors promoting larch dominance in central Siberia: fire versus growth performance and implications for carbon dynamics at the boundary of evergreen and deciduous conifers
The relative roles of fire and climate in determining canopy species composition and
aboveground carbon stocks were investigated. Measurements were made along a transect
extending from the dark taiga zone of Central Siberia, where Picea and Abies
dominate the 5 canopy, into the Larix zone of Eastern Siberia. We test the hypotheses
that the change in canopy species composition is based (1) on climate-driven performance
only, (2) on fire only, or (3) on fire-performance interactions. We show that the
evergreen conifers Picea obovata and Abies sibirica are the natural late-successional
species both in Central and Eastern Siberia, provided there has been no fire for an
10 extended period of time. There are no changes in the climate-driven performance of
the observed species. Fire appears to be the main factor explaining the dominance of
Larix. Of lesser influence were longitude, hydrology and active-layer thickness.
Stand-replacing fires decreased from 300 to 50 yr between the Yenisei Ridge and the
upper Tunguska. Repeated non-stand-replacing surface fires eliminated the regenera15
tion of Abies and Picea. With every 100 yr since the last fire, the percentage of Larix
decreased by 20 %.
Biomass of stems of single trees did not show signs of age-related decline. Relative
diameter increment was 0.41±0.20% at breast height and stem volume increased
linearly over time with a rate of about 0.36 tCha−1 yr−1 independent of age class and
20 species. Stand volumes reached about 130 tCha−1 (equivalent to about 520m3 ha−1).
Individual trees of Larix were older than 600 yr. The maximum age and biomass
seemed to be limited by fungal rot of heart wood. 60% of old Larix and Picea and
30% of Pinus sibirica trees were affected by stem rot. Implications for the future role
of fire and of plant diseases are discussed.JRC.H.3-Forest Resources and Climat
Technical note: A view from space on global flux towers by MODIS and Landsat: The FluxnetEO dataset
Funding Information:
Acknowledgements. We thank the team at the ICOS Carbon Portal for their support in publishing the FluxnetEO data sets, with great thanks in particular to Ute Karstens and Zois Zogopoulos. SW acknowledges funding from an ESA Living Planet Fellowship in the project Vad3e mecum. Alexey Vasilevich Panov acknowledges funding from the Max Planck Society (Germany), Russian Foundation for Basic Re- search, Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science, project no. 20-45-242908. Frederik Schrader and Christian Brümmer acknowledge funds from the German Federal Ministry of Food and Agriculture (BMEL) received through Thünen Institute of Climate-Smart Agriculture. Simon Besnard acknowledges funding from the European Union through the BIOMAS-CAT (project code: 4000115192/18/I/NB) (https://eo4society.esa. int/projects/biomascat/, last access: 3 May 2022) and VERIFY (project code: BO-55-101-006) (https://cordis.europa.eu/project/id/ 776810, last access: 3 May 2022) projects.
Funding Information:
Financial support. This research has been supported by the Euro-
Publisher Copyright:
© 2022 Sophia Walther et al.The eddy-covariance technique measures carbon, water, and energy fluxes between the land surface and the atmosphere at hundreds of sites globally. Collections of standardised and homogenised flux estimates such as the LaThuile, Fluxnet2015, National Ecological Observatory Network (NEON), Integrated Carbon Observation System (ICOS), AsiaFlux, AmeriFlux, and Terrestrial Ecosystem Research Network (TERN)/OzFlux data sets are invaluable to study land surface processes and vegetation functioning at the ecosystem scale. Space-borne measurements give complementary information on the state of the land surface in the surroundings of the towers. They aid the interpretation of the fluxes and support the benchmarking of terrestrial biosphere models. However, insufficient quality and frequent and/or long gaps are recurrent problems in applying the remotely sensed data and may considerably affect the scientific conclusions. Here, we describe a standardised procedure to extract, quality filter, and gap-fill Earth observation data from the MODIS instruments and the Landsat satellites. The methods consistently process surface reflectance in individual spectral bands, derived vegetation indices, and land surface temperature. A geometrical correction estimates the magnitude of land surface temperature as if seen from nadir or 40g off-nadir. Finally, we offer the community living data sets of pre-processed Earth observation data, where version 1.0 features the MCD43A4/A2 and MxD11A1 MODIS products and Landsat Collection 1 Tier 1 and Tier 2 products in a radius of 2 km around 338 flux sites. The data sets we provide can widely facilitate the integration of activities in the eddy-covariance, remote sensing, and modelling fields.publishersversionpublishe
Electrified BPS Giants: BPS configurations on Giant Gravitons with Static Electric Field
We consider D3-brane action in the maximally supersymmetric type IIB
plane-wave background. Upon fixing the light-cone gauge, we obtain the
light-cone Hamiltonian which is manifestly supersymmetric. The 1/2 BPS
solutions of this theory (solutions which preserve 16 supercharges) are either
of the form of spherical three branes, the giant gravitons, or zero size point
like branes. We then construct specific classes of 1/4 BPS solutions of this
theory in which static electric field on the brane is turned on. These
solutions are deformations about either of the two 1/2 BPS solutions. In
particular, we study in some detail 1/4 BPS configurations with electric dipole
on the three sphere giant, i.e. BIons on the giant gravitons, which we hence
call BIGGons. We also study BPS configurations corresponding to turning on a
background uniform constant electric field. As a result of this background
electric field the three sphere giant is deformed to squashed sphere, while the
zero size point like branes turn into circular or straight fundamental strings
in the plane-wave background, with their tension equal to the background
electric field.Comment: 32 pages, 1 eps figure; v2: Presentation of derivation of light-cone
Hamiltonian improved, Refs adde
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