1,720,990 research outputs found
Identifying old Norway spruce and Scots pine trees by visual inspection : an analysis of the relationship between age, spatial distribution and morphological traits in trees
Full text linkOld trees are important to biodiversity, yet they are in global decline. In Scandinavia, due to former forest management, old trees were declining, but now possibly on the rise. In Norway, identification of old trees has been incorporated as part of forest planning in the form of Old-tree habitats. The Old-tree habitats are management units, which in turn can be given the status of woodland key habitat. Forest planners delimit Old-tree habitats during fieldwork based on visual characteristics detailed in a field guide. This study aimed to evaluate if the Old-tree habitats on average contained higher densities of old Norway spruce and Scots pine trees compared to surrounding mature forests. Furthermore, the validity of the variables in the field guide was tested. In addition to tree variables, site variables detailing environmental conditions and proxies for anthropogenic influence were assessed.
The research design consisted of 373 trees sampled from 37 localities in four municipalities in southeastern Norway. On each locality, the age of the five oldest trees in an Old-tree habitat was sampled along with a corresponding reference plot situated in neighboring forests. Tree level variables and site variables were collected during fieldwork and through GIS. The age difference between the Old-tree habitats and surrounding mature forests were tested using a pairwise t-test. Three different types of age models were included: models for single trees, stand-level models fitted with tree variables, and stand-level models using site variables. These were mainly developed as mixed models
The Old-tree habitats were, on average 43 years older than neighboring mature forests. Old trees were present at each locality, but the density and age of the oldest trees in the Old tree habitats were higher than the reference plots. The single tree model for Norway spruce was weak, whereas the respective model for Scots pine had moderately explanatory power. The Stand level model tree based models for the species both explained a moderate amount of variance. The most consistent morphological trait for both models was bark structure, size-related variables were, however, generally weakly correlated with the age. The site-based models were weakly correlated with age.Gamle trær er viktig for det biologiske mangfoldet, likevel er de i nedgang globalt. Grunnet tidligere skogforvaltning var gamle trær i Skandinavia tidligere i nedgang, men denne negative trenden har muligens snudd. I Norge har registreringen av gamle trær blitt inkludert som en del av skogbruksplanleggingen igjennom MIS (Miljøregistrering i skog) livsmiljøet «Gamle trær». «Gamle trær» figureres ut ved hjelp av visuelle kjennetegn nedtegnet i feltinstruksen til MIS. Formålet med denne studien var å evaluere hvorvidt «Gamle trær» inneholdt flere gamle trær sammenlignet med hogstmoden skog i nærheten. Videre, ble validiteten til beskrivelsene av gamle trær i feltinstruksen vurdert. I tillegg til dette ble bruken av areal baserte variabler testet for å vurdere effekten av ulike miljøforhold og menneskelig påvirkning.submittedVersionM-S
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Spredningsøkologi hos skoglevende kryptogamer
Full text linkSpredning er en grunnleggende egenskap hos alle levende organismer som gjør det mulig å kolonisere nye levesteder når de gamle forsvinner. Det har vært uttrykt bekymring for at skoglevende kryptogamer er begrenset av dårlig spredningsevne slik at de ikke overlever i dagens skoglandskap med korte omløpstider og store avvirkninger. De siste syv årene har vi gjennomført feltundersøkelser av sopp, lav og moser for å studere deres evne til å kolonisere nye miljøer i kulturskogen. Hovedfokus har vært på skogbruk i Skandinavia, og feltinnsatsen har vært konsentrert til Vestlandet og Østlandet. Komparative studier har vært gjort i Nord-Amerika, med feltturer til Island og Ny-Caledonia. I denne rapporten presenterer vi resultatene fra fi re delprosjekter, initiert og ledet av Biomangfold- gruppen ved Norsk institutt for skog og landskap. Prosjektene har hovedsakelig vært fi nansiert gjennom Norges forskningsråd (Spredningsprosjektet, 158848/I10) med forvaltningsstøtte fra Landbruks- og matdepartementet (MiS-prosjektet). [...]publishedVersio
MiS 15 år. Resymé av fagforedrag på Lysaker 10. november 2015
Full text linkRapporten inneholder resyméer av seks fagforedrag som ble holdt på jubileumsarrangementet MiS 15 år på Lysaker, Oslo, 10. november 2015. Foredragene tar for seg ulike temaer som har stått sentralt i forskningsdelen av prosjektet Miljøregistrering i Skog
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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