Integrated global assessment of the natural forest carbon potential

Forests are a substantial terrestrial carbon sink, but anthropogenic changes in land use and climate have considerably reduced the scale of this system1. Remote-sensing estimates to quantify carbon losses from global forests2,3,4,5 are characterized by considerable uncertainty and we lack a comprehensive ground-sourced evaluation to benchmark these estimates. Here we combine several ground-sourced6 and satellite-derived approaches2,7,8 to evaluate the scale of the global forest carbon potential outside agricultural and urban lands. Despite regional variation, the predictions demonstrated remarkable consistency at a global scale, with only a 12% difference between the ground-sourced and satellite-derived estimates. At present, global forest carbon storage is markedly under the natural potential, with a total deficit of 226 Gt (model range = 151–363 Gt) in areas with low human footprint. Most (61%, 139 Gt C) of this potential is in areas with existing forests, in which ecosystem protection can allow forests to recover to maturity. The remaining 39% (87 Gt C) of potential lies in regions in which forests have been removed or fragmented. Although forests cannot be a substitute for emissions reductions, our results support the idea2,3,9 that the conservation, restoration and sustainable management of diverse forests offer valuable contributions to meeting global climate and biodiversity targets

Diffractive production of #rho#"0(770) mesons in muon-proton interactions at 470 GeV

The diffractive production of #rho#"0(770) mesons in muon-proton interactions is studied in the kinematic region 0.15 GeV"2 < Q"3 < 20 GeV"2 and 20 GeV < #nu# < 420 GeV. The data were obtained in the Fermilab fixed-target experiment E665 with primary muons of 470 GeV energy. Results are presented on the Q"2, x and #nu# dependence of the cross section, on the shape of the #pi#"+#pi#"- mass spectrum, on the slope of the diffraction peak and on the production and decay angular distributions of the #rho#"0(770). The cross section for diffractive production of #rho#"0 by virtual photons on protons depends mainly on Q"2. At fixed Q"2, no significant dependence on x or #nu# is observed. The extrapolation to Q"2 = 0 yields a photoproduction cross section of (10.30 #+-# 0.33) #mu#b. The slope of the t' distribution has a value of (7.0#+-#0.2) GeV"-"2, with a tendency to decrease as Q"2 increases. The production and decay angular distributions of the #rho#"0 depend strongly on Q"2 and are consistent with s-channel helicity conservation. The ratio R #sigma#_L/#sigma#_T deduced from the decay angular distributions rises strongly with Q"2, passing the value of 1 at Q"2 #approx# 2 GeV"2. (orig.)SIGLEAvailable from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman