Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2010
Abstract
In European forests, standing stocks are currently higher than ever during the last decades, in part due to reduced logging or the abandonment of agricultural land. However, data from intensive monitoring plots reveal an increased growth even without direct human intervention.We used a set of 363 plots from 16 European countries to investigate the influence of environmental factors on forest growth: nitrogen, sulphur and acid deposition, temperature, precipitation and drought, for Norway spruce, Scots pine, common beech and European as well as sessile oak.We used existing information on site productivity, stand age and stand density to estimate expected growth. Relative tree growth, i.e., the ratio between actual growth within a five-year period and expected growth, was then related to environmental factors in a stepwise multiple regression.The results consistently indicate a fertilizing effect from nitrogen deposition, with roughly one percent increase in site productivity per kg of nitrogen deposition per ha and year, or 20 kg C fixation per kg N deposition. This was most pronounced for plots having soil C/N ratios above 25. We also found a positive albeit less clear relationship between relative growth and summer temperatures.From the study, we cannot conclude on any detrimental effects on growth from sulphur and acid deposition or from drought periods. A very recent study from the U.S., comprising 4800 plots and 24 tree species, confirms our results. However, we also show that the magnitude of N deposition effects on global forest C balance is currently a highly controversial matter, and comment on this debate. http://www.cef-cfr.ca/uploads/Colloque/Programme10_5.pdf
Abstract
The Lange Bramke catchment has been investigated as a monitored catchment for 60 years. However, its utilization history even dates back to medieval times, and is well documented in part. The intense interplay between ore mining, forestry, and water resources exploitation left remains such as scoriae piles and modified forest growth, e.g. due to local pollution at smelter locations. It is demonstrated that considering local land use history is important for a proper understanding and interpretation of modern monitoring data. A theoretical framework is proposed for the integration of the two data sources. This requires a joint approach combining two modelling paradigms, the functional one dominating in current ecosystem research, and an interactive one which best characterizes the human–environment relationship in historic times.
Authors
Carl Jonas Jorge Spetz Jihong Liu Clarke Merete Dees Sissel Haugslien Roar Moe Dag-Ragnar BlystadAbstract
No abstract has been registered
2009
Abstract
The molecular composition of plant residues is suspected to largely govern the fate of their constitutive carbon (C) in soils. Labile compounds, such as metabolic carbohydrates, are affected differently from recalcitrant and structural compounds by soil-C stabilisation mechanisms. Producing 13C-enriched plant residues with specifically labeled fractions would help us to investigate the fate in soils of the constitutive C of these compounds. The objective of the present research was to test 13C pulse chase labeling as a method for specifically enriching the metabolic carbohydrate components of plant residues, i.e. soluble sugars and starch. Bean plants were exposed to a 13CO2-enriched atmosphere for 0.5, 1, 2, 3 and 21 h. The major soluble sugars were then determined on watersoluble extracts, and starch on HCl-hydrolysable extracts. The results show a quick differential labeling between water-soluble and water-insoluble compounds. For both groups, 13C-labeling increased linearly with time. The difference in δ13C signature between water-soluble and insoluble fractions was 7% after 0.5 h and 70% after 21 h. However, this clear isotopic contrast masked a substantial labeling variability within each fraction. By contrast, metabolic carbohydrates on the one hand (i.e. soluble sugarsRstarch) and other fractions (essentially cell wall components) on the other hand displayed quite homogeneous signatures within fractions, and a significant difference in labeling between fractions: δ13C=414±3.7% and 56±5.5%, respectively. Thus, the technique generates labeled plant residues displaying contrasting 13C-isotopic signatures between metabolic carbohydrates and other compounds, with homogenous signatures within each group. Metabolic carbohydrates being labile compounds, our findings suggest that the technique is particularly appropriate for investigating the effect of compound lability on the long-term storage of their constitutive C in soils.
Authors
Troy J. Seiler Daniel Rasse Jiahong Li Paul Dijkstra Hans P. Anderson David P. Johnson Thomas L. Powell Bruce A. Hungate C. Ross Hinkle Bert G. DrakeAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Aldo Marchetto Rosario Mosello Gabriele A. Tartari John Derome Kirsti Derome Nils König Nicholas Clarke Anna KowalskaAbstract
A Working Ring Test (WRT) was organised within the framework of the EU/Life+ FutMon Project (`Further Development and Implementation of an EU-level Forest Monitoring System`, LIFE07 ENV/D/000218), to evaluate the overall performance of the laboratories responsible for analysing atmospheric deposition and soil solution samples in European forests, and to verify improvements in the analytical quality resulting from the QA/QC work carried out in the laboratories which participated in previous WRTs organized in the framework of the UN/ECE ICP Forests Monitoring Programme. The WRT was carried out in accordance with International ISO and ILAG guide proficiency test both for sample preparation and numerical elaboration of the results. Four natural atmospheric deposition and soil solution samples and 4 synthetic solutions were distributed to 44 laboratories for analysis using their routine methods for the following variables: pH, conductivity, calcium, magnesium, sodium, potassium, ammonium, sulphate, nitrate, chloride, total alkalinity, total dissolved nitrogen (TDN), dissolved organic carbon (DOC). Two tolerable limits were defined for each variable on the basis of the measured value, the results of previous WRTs, a comparison with the Data Quality Objectives of other international networks, and the importance of the variable in deposition and soil solution monitoring. In the ring test 16% of the results from all the laboratories did not fall within the tolerable limits. This enabled us to identify those variables and laboratories for which improvements in analytical performance are required. The results of the exercise clearly show that the use of data check procedures, as described in the ICP Forests manual for sampling and analysis of atmospheric deposition, makes it possible to detect the presence of inaccurate or outlying results, and would therefore greatly improve the overall performance of the laboratories. Some of the analytical methods used by individual laboratories were found to be unsuitable for the samples included in this WRT, and therefore also for the routine analysis of atmospheric deposition and soil solution samples in European forests. These methods included outdated methods, such as turbidimetry or nephelometry for the determination of sulphate, silver nitrate titration and ion selective electrode for chloride, Kjeldahl digestion for the determination of ammonium and organic nitrogen, and colorimetric titrations for alkalinity. A detailed discussion of the determination of total alkalinity is also given in the report because this variable was associated with the most analytical problems.
Authors
Martin Lorenz Richard Fischer Georg Becher Volker Mues Oliver Granke Tatyana Braslavskaya Alexey Bobrinsky Natalia Lukina Nicholas Clarke Zora Lachmanová Claus SchimmingAbstract
Of the 41 countries participating in ICP Forests, 27 countries reported national results of crown condition surveys in the year 2008 for 210 964 trees on 14 786 plots. The transnational result on the European-wide scale relied on 111 560 trees on 5 002 plots of the 16 x 16 km grid in 25 out of 35 participating countries. Mean defoliation of all sample trees of the transnational survey was 20.2%. Of the main species, Quercus robur and Q. petraea had by far the highest mean defoliation (24.9%), followed by Fagus sylvatica (19.4%), Picea abies (19.3%) and Pinus sylvestris (18.2%). These figures are not comparable to those of previous reports because of fluctuations in the plot sample, mainly due to changes in the participation of countries. Therefore, the long-term development of defoliation was calculated from the monitoring results of those countries which have been submitting data since 1990 every year without interruption. In the period of observation the species group Quercus ilex and Quercus rotundifolia shows the severest increase in defoliation, with 10.3% in 1990 and 21.2% in 2008. A similar increase in defoliation, namely from 11.1% to 20.4%, was experienced by Pinus pinaster. Defoliation of these Mediterranean species is largely attributed to several summer drought events. Defoliation of Fagus sylvatica increased from 17.9% to 19.7%. In contrast, Picea abies, Quercus robur and Quercus petraea and in particular Pinus sylvestris recuperated from peaks in defoliation in the mid 1990s. The spatial and temporal variation of bulk deposition and throughfall of sulphate, nitrate, ammonium, calcium, sodium and chlorine was analysed as a basis of ongoing and future studies. Between 174 and 302 intensive monitoring plots were involved in the study. Mean deposition of the years 2004 - 2006 shows spatial patterns reflecting partly regional emission situations. The temporal variation was calculated for the period 2001 - 2006. Sulphur throughfall decreased from 6.0 kg ha-1 yr-1 in 2001 to 4.5 kg ha-1 yr-1 in 2006. Bulk deposition of sulphur shows a similar decrease at a lower level, namely from 4.9 kg ha-1 yr-1 in 2001 to 3.6 kg ha-1 yr-1 in 2006 (corrected for sea salt input). Nitrogen deposition shows a less pronounced rate of decrease.
Authors
Aldo Marchetto Rosario Mosello Gabriele Tartari O Tornimbeni J Derome Kisti Derome Pia Sorsa Nils Konig Nicholas Clarke Erwin Ulrich Anna KowalskaAbstract
No abstract has been registered
Authors
Nicholas Clarke Květoslava Fuksová Milan Gryndler Zora Lachmanová Hans-Holger Liste Jana Rohlenova Reiner Schroll Peter Schröder Miroslav MatuchaAbstract
No abstract has been registered