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
Forfattere
Holger LangeSammendrag
Skogøkosystemer binder karbon fra atmosfæren via fotosyntesen, men frigjør også karbon gjennom respirasjon. Nye beregninger viser hvor mye temperaturen påvirker denne balansen. Vi finner en nesten universell sammenheng mellom temperatur og utslipp fra økosystemer, og denne økningen i utslipp er mindre enn tidligere antatt. Det gjør klimamodellene mer pålitelige – og det kan være gode nyheter for klimaet vårt.
Forfattere
Tuula Kantola Mikko Vastaranta Xiaowei Yu Paivi Lyytikainen-Saarenmaa Markus Holopainen Mervi Talvitie Sanna Kaasalainen Svein Solberg Juha HyyppäSammendrag
Climate change and rising temperatures have been observed to be related to the increase of forest insect damage in the boreal zone. The common pine sawfly (Diprion pini L.) (Hymenoptera, Diprionidae) is regarded as a significant threat to boreal pine forests. Defoliation by D. pini can cause severe growth loss and tree mortality in Scots pine (Pinus sylvestris L.) (Pinaceae). In this study, logistic LASSO regression, Random Forest (RF) and Most Similar Neighbor method (MSN) were investigated for predicting the defoliation level of individual Scots pines using the features derived from airborne laser scanning (ALS) data and aerial images. Classification accuracies from 83.7% (kappa 0.67) to 88.1% (kappa 0.76) were obtained depending on the method. The most accurate result was produced using RF with a combination of data from the two sensors, while the accuracies when using ALS and image features separately were 80.7% and 87.4%, respectively. Evidently, the combination of ALS and aerial images in detecting needle losses is capable of providing satisfactory estimates for individual trees.
Forfattere
Svein SolbergSammendrag
Four alternative airborne laser scanning (ALS) canopy penetration variables were compared for their suitability for mapping of gap fraction, leaf area index and disturbances in a Scots pine forest. The variables were based on either echo counting or intensity, and on either first or first and last echoes. ALS data and field-measured gap fraction and effective leaf area index (LAIe) were gathered before and after a severe insect defoliation by pine sawflies. LAIe is a commonly used form of leaf area index that is mathematically derived from gap fraction, and includes the areas of foliage, branches and trunks, and which is not corrected for the clumping of foliage. The ALS penetration variables were almost equally strongly related to field-measured gap fraction and LAIe. The estimated slopes in the LAIe models varied from 0.94 to 2.71, and had coefficient of determination R 2 values of 0.92–0.94. They were strongly correlated to each other (R 2 values of 0.95–0.98) and agreed fairly well for temporal changes of LAIe during the summer and the insect defoliation (R 2 values of 0.82–0.95). Counting of first and last echoes produced penetration rates close to the gap fraction, and this penetration variable was able to penetrate tree crowns. Ground-only echoes represented mostly between-tree gaps, and canopy-first-ground-last pulses represented mostly within-canopy gaps. However, the penetration variables based on first and last echoes suffered from the problem that a second echo might be impaired both in low and in tall canopies. In low canopies, two adjacent echoes from the same pulse would be too close in time to be separated by the sensor, while in tall canopies the pulse might apparently be fragmented down through the canopy. The intensity-based penetration variables needed to be supplemented with reflectance values, or at least the ratio between reflectance of the canopy and the ground, and this ratio was estimated from the data. The study demonstrated that one might be able to distinguish between disturbance types, e.g. between defoliation and cutting, by comparing alternative ALS penetration variables. Insect defoliation was dominated by an increase in within-canopy gaps and, correspondingly, the fraction of partly penetrating canopy-first-ground-last pulses. Tree removals from cutting were dominated by increases in between-tree gaps and the corresponding fraction of ground-only pulses.
Forfattere
Tuula Kantola Mikko Vastaranta Xiaowei Yu Paivi Lyytikainen-Saarenmaa Markus Holopainen Mervi Talvitie Sanna Kaasalainen Svein Solberg Juha HyyppäSammendrag
Climate change has been observed to be related to the increase of forest insect damages in the boreal zone. The prediction of the changes in the distribution of insect-caused forest damages has become a topical issue in the field of forest research. The common pine sawfly (Diprion pini L.) (Hymenoptera, Diprionidae) is regarded as a significant threat to boreal pine forests. Defoliation by D. pini caused severe growth losses and tree mortality of Scots pine (Pinus sylvestris L.) (Pinaceae). Logistic regression is commonly used in modelling the probability of occurrence of an event. In this study the logistic regression was investigated for predicting the needle loss of individual Scots pines (pine) using the features derived from airborne laser scanning (ALS) data. The defoliation level of 164 trees was determined subjectively in the field. Statistical ALS features were extracted for single trees and used as independent variables in logistic regression models. Classification accuracy of defoliation was 87.8% as respective kappa-value was 0.82. For comparison, only penetration features were selected and classification accuracy of 78.0% was achieved (kappa=0.56). Based on the results, it is concluded that ALS based prediction of needle losses is capable to provide accurate estimates for individual trees.
Sammendrag
The aim of this study is to use airborne laser scanning (ALS) data to simulate synthetic aperture radar interferometry (InSAR) elevation data [digital elevation model (DEM)] from the spatial distribution of scatterers. A Shuttle Radar Topography Mission X-band DEM data set and an ALS data set from a spruce-dominated forest area are used. A 3-D grid of voxels is made from the spatial distribution of ALS first echoes. The slant angle penetration rate of the SAR microwaves (P-SAR) is simulated to be a function of the vertical ALS penetration rate (P-ALS), i.e., P-SAR = P-ALS(4). The InSAR DEM and heights above the ground are fairly well reproduced by the simulator. A total least squares regression model between the simulated and measured InSAR DEMs has an R-2 value of 0.99 and a slope of 1 : 1. By subtracting the ALS-based terrain heights (digital terrain model), we obtained InSAR heights, which were reproduced with an R-2 value of 0.78, a slope of 0.96, and a root-mean-square error of 2.3 m. With the simulator, it was demonstrated how a disturbance event would affect the InSAR height. Unfortunately, the relationship was curvilinear and concave, which means that the method is not very sensitive to weak disturbances. This might be partly overcome by using a more vertical incidence angle of the SAR microwaves. The simulator might be used for validation or ground truthing of the InSAR data, as well as gaining understanding of how vegetation changes affect the InSAR data.
Forfattere
Inger HansenSammendrag
Historikk, rasevalg og erfaringer med bruk av vokterhunder i inn- og utland ble presentert, med hovedvekt på vokterhundarbeidet i Norge.
Sammendrag
Styrt beitedrift ved bruk av inngjerding kan være en løsning for å unngå store tap til rovvilt. Det er imidlertid en oppfatning at denne driftsformen kan være en utfordring med hensyn til dyrevelferd, helse og kjøttproduksjon. Bioforsk Nord Tjøtta startet opp et treårig prosjekt sommeren 2008 for å kartlegge beitekapasitet og velferds- og produksjonsparametre i utvalgte sauebesetninger i Nord-Trøndelag som benytter denne driftsformen. I løpet av tre-års perioden er det kartlagt åtte sauebesetninger med tilhørende fem beiteområder i Indre Namdal. To av besetningene ble kartlagt både i 2008 og 2010 for å se på evt. endringer i beitekapasitet og smittebelastning i beiteområdene. Målet med prosjektet er å finne en god balanse mellom arealgrunnlag og dyretall ved hjelp av estimering av beitekapasitet og velferdsvurdering av sauene for å sikre god dyrevelferd og tilfredsstillende kjøttproduksjon på inngjerdete beitearealer. Prosjektet viser at det er mulig å oppnå tilfredsstillende dyrevelferd og produksjonsresultater på inngjerdet beite, men at det kreves en del oppfølging av dyrene i beitesesongen, spesielt med hensyn til parasittproblematikk og beitetilgang.
Forfattere
Inger HansenSammendrag
Standarden for "rovviltsikre gjerder", samt foreløpige resultater fra et Bioforsk-prosjekt på tilvekst og dyrevelferd hos sau på inngjerda beiter i Indre Namdal ble gått gjennom.
Sammendrag
Denne rapporten gir en gjennomgang av ulike forebyggende og konfliktdempende tiltak som har blitt finansiert av Fylkesmannen i Nordland i perioden 2000-2009. Det er tatt utgangspunkt i saksdokumenter hos Fylkesmannen, samt data fra erstatningsoppgjøret (Rovbase.no) og Organisert beitebruk. Prosedyrene for finansieringsordningen er også vurdert.
Forfattere
Mette Vaarst Christine Leeb Pip Nicolas Stephen Roderick Gidi Smolders Michael Walkenhorst Jan Brinkman Solveig March Elisabeth Stöger Elisabeth Gratz Vonne Lund Britt I.F. Henriksen Inger Hansen Madeleine NealeSammendrag
Good animal health and welfare is an explicit goal of organic livestock farming, and will need continuous development and adjustment on the farms. Furthermore, the very different conditions in different regions of Europe calls for models that can be integrated into local practice and be relevant for each type of farming context. A European project with participants from seven countries have been established with the aim of developing principles for animal health and welfare planning in organic dairy farming, based on a process where knowledge about the status within a given herd will be included as background for taking decisions and planning future improvements. An important part of the planning process is communication with other farmers as well as animal health and welfare professionals (veterinarians and advisors). Other principles such as systematic evaluation of how the improvements work in the farm ensure the continuity of the planning process. This presentation gives an overview over the current animal health and welfare planning initiatives in the participating countries and lines up the principles which are being gradually implemented in partner countries in collaboration with groups of organic farmers and organisations.