Popescu C.-M.,Petru Poni Institute of Macromolecular Chemistry |
Hill C.A.S.,Norsk Institutt for Skog Og Landskap |
Hill C.A.S.,JCH Industrial Ecology Ltd |
Curling S.,Bangor University |
And 2 more authors.
Journal of Materials Science | Year: 2014
The water vapour sorption isotherms and sorption kinetics of birch (Betula pendula L) acetylated to different levels have been determined using a dynamic vapour sorption (DVS) apparatus. A DVS instrument was also used to determine the accessible hydroxyl content in the wood samples using deuterium exchange. The results are reported in terms of the reduced equilibrium moisture content (EMCR), in which the moisture content per unit mass of wood substance is used for the calculation. As the level of acetylation of the wood samples increased there was a corresponding reduction in EMCR of the wood samples, which was accompanied by a decrease in hysteresis in the same order. The sorption kinetics were also determined using the DVS and analysed using the parallel exponential kinetics model, in which the sorption kinetics curve is composed of two processes (labelled fast and slow). Using this analysis, it is possible to calculate two pseudo-isotherms associated with the two processes. The sorption isotherm is a composite of the sorption isotherms associated with the fast process water and the slow process water and there are significant differences in behaviour between the two. It is suggested in this paper that the fast process is related to diffusion limited kinetics, whereas the slow process is a relaxation-limited phenomenon. The reduction in accessible OH content due to acetylation was well correlated with the weight gain due to acetylation, although the relationship did not exactly correspond with that theoretically determined. © Springer Science+Business Media New York 2013.
Hagvar S.,Universitetet for Miljo og Biovitenskap |
Tveite B.,Norsk Institutt for Skog Og Landskap
Blyttia | Year: 2011
In Østmarka nature reserve near Oslo, ten small, suppressed spruce trees were studied with respect to age, height and vitality. Being only 56-380 cm high, their age varied between 39 and 99 years. Seven of them were between 77 and 99 years. Ring width means varied between 0.13 and 0.45 mm. The main growth-limiting factor is assumed to be light. The main part of the trees had only a small amount of needles. If sufficiently healthy, such suppressed trees may react with increased growth if released from competition from overstory trees, either naturally (windfall, insects etc.) or by cutting. Our ten trees were, however, probably not healthy enough to react in this way.
Rolstad J.,Norsk Institutt for Skog Og Landskap |
Rolstad E.,Skogfaglig Radgivning
Blyttia | Year: 2011
The red-listed epiphytic lichen Evernia divaricata has only rarely been found with fruiting or sorediate thalli and, until recently, not in Norway. In August 2009, we revisited a previously known locality within the TrillemarkaRollagsfjell nature reserve and found, for the first time in Norway, abundant fertile thalli along a 1.2 km stretch of a small brook. Closer examination of samples taken from the same locality in 2003 revealed that immature fruiting-bodies (apothecia) were present on a few thalli at that time. Today the site is characterized by old mixed conifer forest and small bogs. Two additional Norwegian localities have been found to harbour fertile E. divaricata. At yet another locality we found one thallus with abundant large soralia, also recorded for the first time in Norway. Lack of small sprouting thalli with basal holdfasts suggests that dispersal, until now, has mainly occurred by means of thallus fragmentation, thereby hampering efficient long-distance dispersal.
Mahecha M.D.,Max Planck Institute For Biogeochemie |
Mahecha M.D.,ETH Zurich |
Reichstein M.,Max Planck Institute For Biogeochemie |
Jung M.,Max Planck Institute For Biogeochemie |
And 10 more authors.
Journal of Geophysical Research: Biogeosciences | Year: 2010
Terrestrial biosphere models are indispensable tools for analyzing the biosphere-atmosphere exchange of carbon and water. Evaluation of these models using site level observations scrutinizes our current understanding of biospheric responses to meteorological variables. Here we propose a novel model-data comparison strategy considering that CO2 and H 2O exchanges fluctuate on a wide range of timescales. Decomposing simulated and observed time series into subsignals allows to quantify model performance as a function of frequency, and to localize model-data disagreement in time. This approach is illustrated using site level predictions from two models of different complexity, Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) and Lund-Potsdam-Jena (LPJ), at four eddy covariance towers in different climates. Frequency-dependent errors reveal substantial model-data disagreement in seasonal-annual and high-frequency net CO2 fluxes. By localizing these errors in time we can trace these back, for example, to overestimations of seasonal-annual periodicities of ecosystem respiration during spring greenup and autumn in both models. In the same frequencies, systematic misrepresentations of CO2 uptake severely affect the performance of LPJ, which is a consequence of the parsimonious representation of phenology. ORCHIDEE shows pronounced model-data disagreements in the high-frequency fluctuations of evapotranspiration across the four sites. We highlight the advantages that our novel methodology offers for a rigorous model evaluation compared to classical model evaluation approaches. We propose that ongoing model development will benefit from considering model-data (dis)agreements in the time-frequency domain. Copyright 2010 by the American Geophysical Union.
Agency: Cordis | Branch: H2020 | Program: RIA | Phase: ISIB-04a-2014 | Award Amount: 5.00M | Year: 2015
Europes bioeconomy is expected to foster economic growth and to tackle significant societal challenges with less harmful environmental effects through innovative, sustainable and inclusive use of European forest resources. Increasing demand for biomass and other ecosystem goods and services calls for changes in forest-related policies at different levels and across different sectors. Accordingly, the recent Forest Strategy provides clear signals towards the need for harmonised information for mapping and assessing the dynamic state of forest ecosystems and their services. Building upon scientific advances in COST E4, 39, 43, USEWOOD, FORSYS, ORCHESTRA; the networks ENFIN, EFFIS, SOSIN; the FP7 EUFODOS, S2BIOM, INTEGRAL, SIMWOOD, FIRE PARADOX the project DIABOLO aims to: i) strengthen the methodological framework towards more accurate, harmonised and timely forest information, e.g. on growing stock and stock changes, biomass, carbon, NWFP; enable the analysis of sustainable biomass supply derived from multipurpose and multisource national forest inventories; and facilitate near real-time forest disturbance monitoring, e.g. on forest fires, storm, drought, insect outbreaks; ii) support EU policy processes, international reporting obligations, forest administration and forest planning entities with new methodologies and EU-wide consistent forest information; iii) make innovative use of existing field-collected data and EC space-based applications of EO and satellite positioning systems with reference to INSPIRE and GEOSS, and global monitoring systems such as REDD\, FLEGT and UNFF. To deliver high impact, beyond state-of-the-art work within the ecological and socio-economic diversity in Europe, the trans-disciplinary DIABOLO involves experts in quantitative modelling, policy science and NFIs, from 26 European countries, committed to provide new methodologies and information for various end-uses, including EFDAC (FISE) at JRC, GLOBIOM at IIASA and work at FAO/UNECE.