Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2010
Sammendrag
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
Forfattere
Harald Kvaalen Gunnhild Søgaard Aksel Granhus Inger Fløistad Kjersti Holt Hanssen Arne Steffenrem Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Forfattere
Toril Drabløs Eldhuset Isabella Børja Nicholas Clarke Kjersti Holt Hanssen O. Janne Kjønaas Holger Lange Ingvald Røsberg Tonje ØklandSammendrag
Hogstavfall er nøkkelen til økt satsing på bioenergi i Norge. Men vil dette påvirke bærekraften i skogøkosystemet og skogproduksjonen? Blir skogsjorda mer næringsfattig? Endres sammensetningen av arter i vegetasjonen? Vil artsmangfoldet bli redusert? Blir det mindre av de soppene som bryter ned planterester? Dette er noen av spørsmålene vi prøver å besvare gjennom prosjektet «Økologiske virkninger av økt biomasseuttak fra skog i Norge» (ECOBREM), som varer fra 2009 til 2013.
Forfattere
Gunnhild Søgaard Harald Kvaalen Aksel Granhus Inger Sundheim Fløistad Kjersti Holt Hanssen Arne Steffenrem Tore SkrøppaSammendrag
Grana avslutter normalt strekningsveksten midtsommers, og begynner forberedelsene til høsten og vinteren. Av og til kan en imidlertid se at knoppene som dannes etter vekstavslutningen bryter på nytt senere samme sommer, og treet utvikler høstskudd. Dette pågår utover sensommeren og tidlig høst, og resulterer i en forsinket vekstavslutning og innvintring. Det nye skuddet tåler lite frost så lenge det er i aktiv vekst, og risikoen for frostskader på høsten øker derfor. Forsinket innvintring kan også resultere i dårligere vinterherdighet, og øke risikoen for frostskader gjennom vinteren.
Forfattere
Kjersti Holt HanssenSammendrag
De siste årene har det blitt rapportert om stedvis kraftige angrep av gransnutebiller i foryngelsesfelt på Vestlandet og i Trøndelagsfylkene. Vi ønsket derfor å gjennomføre en undersøkelse av snutebilleskader i felt på Vestlandet og i Trøndelag. Til sammen 50 flater i kystfylkene Rogaland, Hordaland, Sogn og Fjordane, Møre og Romsdal, Sør-Trøndelag og Nord-Trøndelag ble undersøkt høsten 2009. Disse var plantet til i 2008 eller 2009, og det hadde ikke gått mer enn to sesonger siden hogst ved tilplantingen. På hvert felt ble alle kulturplantene på 20 sirkelflater á 20 m2 undersøkt for snutebillegnag og andre skader, og vitaliteten ble bedømt i fire klasser. For hvert felt ble variabler som høyde over havet, flatestørrelse, helling, eksposisjon og plantetype registrert.....
Sammendrag
Understanding the feedback between terrestrial biosphere processes and meteorological drivers is crucial to ecosystem research as well as management. For example, remote sensing of the activity of vegetation in relation to environmental conditions provides an invaluable basis for investigating the spatiotemporal dynamics and patterns of variability. We investigate the Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) using SeaWiFS satellite observations from 1998 to 2005 and ancillary meteorological variables from the CRU-PIK dataset. To what extent do precipitation and temperature dominate the terrestrial photosynthetic activity on monthly to interannual time scales? A spectral decomposition using Singular System Analysis leads to a global ‘classification’ of the terrestrial biosphere according to prevalent time-scale dependent dynamics of fAPAR and its relation to the meteorology. A complexity analysis and a combined subsignal extraction and dimensionality reduction reveals a series of dominant geographical gradients, separately for different time scales. Here, we differentiate between three time scales: on short time scales (compared to the annual cycle), variations in fAPAR coincide with corresponding precipitation dynamics. At the annual scale, which explains around 50% of the fAPAR variability as a global average, patterns largely resemble the biomes of the world as mapped by biogeographic methods.At longer time scales, spatially coherent patterns emerge which are induced by precipitation and temperature fluctuations combined. However, we can also identify regions where the variability of fAPAR on specific time scales cannot be traced back to climate and is apparently shaped by other geoecological or anthropogenic drivers. http://uregina.ca/prairies/assets/Prairie_Summit_Final_Program.pdf
Sammendrag
Determining the feedbacks between terrestrial biosphere processes and the meteorological drivers (here precipitation and temperature) is crucial to ecosystem research. In this context, the continuous monitoring of the earth surface provides an invaluable basis for investigating the spatiotemporal dynamics in the activity of vegetation in relation to environmental conditions. Here, we seek to identify which patterns of variability in the meteorological drivers dominate the terrestrial photosynthetic activity from monthly to interannual time scales (resp. fluctuation frequencies). We investigate the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) using SeaWiFS observations from 1998 to 2005 and ancillary meteorological variables. A spectralanalysis leads to a global `classification` of the terrestrial biosphere according to prevalent scale dependent dynamics of fAPAR and its relation to the meteorology. A combined subsignal extraction and dimensionality reduction reveals a series of dominant geographical gradients on specific time scales. E.g. we uncover spatially coherent patterns at low frequencies and show where these are induced by precipitation or temperature fluctuations. We also show where high frequency variations (relative to the annual cycle) in fAPAR coincide with corresponding precipitation dynamics. However, we can also identify regions where the variability of fAPAR on specific time scales cannot be traced back to climate and is apparently shaped by other geoecological or anthropogenic drivers. http://www.terrabites.net/fileadmin/user_upload/terrabites/PDFs/Programme_Book_TERRABITES.pdf
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
The utilization history of the Lange Bramke catchment and the northern Harz mountains is dominated by ore mining. Historical documents were used to provide ample evidence that forestry and water utilization were managed according to administrative goals in a largely centralized manner. However, the perception of the landscape and its function and purpose have changed significantly over the centuries. In particular, the distinction between renewable (such as forests) and non-renewable resources (such as ore deposits) is a rather modern one, as is the principle of sustainability. This change in perception is apparent from the type of maps used, the different conflicts on property and exploitation rights, and the request for quantitative inventories of resources, appearing only quite late in the mining history. The remnants of smelters and charcoal production still demonstrate the importance of historical land use for proper interpretation of monitoring data.
Sammendrag
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.