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Hybridaspens utveckling på skogsmark
Full text linkHybridaspen (Populus tremula x Populs tremuloides) har på grund av dess snabba initiala tillväxt en hög produktionspotential vilket har bekräftats i Södra Sverige, där tillväxtnivåer på 20m3sk per hektar och år under en 25-årig omloppstid har uppmätts. Samtidigt har trädslaget fördelaktiga egenskaper lämpliga till dissolvingmassa, ett massasortiment som nyttjas för vidare tillverkning av textilier, och som idag produceras vid Södra skogsägarnas massabruk i Mörrum.
Majoriteten av den forskning som ligger till grund för hybridaspens produktionspotential är dock baserade på odlingar gjorda på tidigare jordbruksmark, vilket innebär att underlaget som bekräftar potentialen på skogsmark är bristfällig. Syftet med detta arbete är således att bidra med en ökad erfarenheten om hybridaspens utveckling på skogsmark.
I studien ingår en inventering av totalt 23 bestånd som efter stormen Gudrun 2005 återbeskogats med hybridasp. Bestånden är planterade åren 2007, 2008 och 2009 och är resultaten av de objekt, som i en tidigare etableringsstudie från 2010, påvisat en överlevnad på >70%. Faktorer som studerats är: fortsatt överlevnad, tillväxt samt kvalitétsnedsättande skador. Arbetet inkluderar även en översiktlig resultatredovisning av den tidigare studien, en diskussion om vad som påverkat utvecklingen samt rekommendationer till de markägare som funderar på att plantera hybridasp på skogsmark.
Resultaten tyder på att den långa hyggesvila som förelåg många av planteringarna, har påverkat både överlevnaden och den fortsatta tillväxten negativt. Försommartorka antas även ha bidragit till en nedsatt vitalitet för bestånd planterade 2008. Tillväxten varierade kaftigt både inom och mellan bestånden och är i genomsnitt långt under de nivåer som bekräftats på tidigare jordbruksmark. Trots detta var resultaten stundvis bra vilket indikerar att bland annat ståndortsanpassning, klonutveckling samt mer forskning tillämpad på skogsmark, sannorlikt kan bidra till både högre och jämnare resultat.
Att samtliga bestånd var uppkomna efter stormen Gudrun kan, på grund av den rådande situationen, ha haft en stor påverkan på resultaten. Det är således av stor vikt att fler studier inom detta ämne genomförs.Hybrid aspen (Populus tremula x Populs tremuloides) is highly productive due to its fast initial growth and has in the south of Sweden reached yields of 20 m3 of stem wood ha-1 during a 20-25 years rotation period. In addition to its exceptional growth, hybrid aspen has advantageous properties suitable for dissolving pulp, which is used for textile production and today produced at Södra skogsägarnas pulp mill in Mörrum.
However, the majority of research covering hybrid aspen establishments is based on cultivations made on former agricultural land, which means there is a lack of knowledge regarding the potential on forest land. The purpose of this thesis is therefor to provide with an improved knowledge of the development of hybrid aspen on forest land.
The study is based on a survey of 23 hybrid aspen stands, all established after the Gudrun storm in 2005. The stands were planted in 2007, 2008 and 2009 and have in a previous study from 2010 demonstrated a survival rate of >70 %. Studied factors included in this thesis are: continued survival rate, growth, and quality-reducing damages. Furthermore, an overview of the results from the previous study is included, as well as a discussion about factors which may have affected the development. In the final end some recommendations to forest owners who might be interested in establishing hybrid aspen on forest land is presented.
The findings in this study suggest that a postponed establishment has a negative influence on both survival and continued growth. An early summer drought in 2008 is also believed to have contributed to a reduced vitality for stands planted this year. Growth varied both within and between the stands and is on average far below levels confirmed on former agricultural land. Despite this, some results stood out, indicating that site-adaption, development of clones as well as research applied on forest land, probably will contribute to both higher and more consistent outcomes.
The fact that all stands were established in the aftermath of the Gudrun storm may, because of the prevailing situation, have had a major impact on the results. It is therefore of great importance that further studies in this topic are carried out
Farmers' willingness to introduce short-rotation tree plantations on agricultural land: a case study in southern Sweden
Full text linkTo meet climate targets, expanding Populus spp. tree cultivation is proposed as a potential biomass feedstock, especially on agricultural land that does not come into conflict with food production. However, biomass potential assessments typically overlook landowners' perspectives, risking a gap between theoretical potentials and realisation. Here, we test empirical consequences of two hypotheses based on a survey targeting southern Swedish farmers: 1) Relying exclusively on agricultural land cover data to identify abandoned agricultural land leads to an overestimation of the total agricultural land that can be utilised for future biomass production from Populus spp. feedstocks. 2) The absence of data on farmers' intentions to cultivate fast-growing tree species on agricultural land leads to overestimation of the potential biomass supply from Populus spp. in biomass assessments. Findings suggest that less than 50 % of farmers with unsubsidised arable land, which is often assumed to be abandoned, would consider cultivating these tree species on this type of land (26 % [7–48]). Furthermore, only 11 % [6–17] would consider cultivating Populus spp. on agricultural land overall during 2021–2030, indicating a generally low level of interest among farmers. However, higher rates were observed in forested areas. The projected near-future cultivation potential of 2.0 kha [1.1–3.0] suggests an at least threefold overestimation in previous theoretical assessments. This study highlights a disparity between biophysical land data and producer perspectives, showing that neglecting farmers’ perspectives risks overestimating the biomass supply, potentially leading to misguided expectations and inefficient policies. Our findings support targeted policy recommendations
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
Gallringsplanering baserat på två olika skattningar av skogstillståndet
Full text linkSCA Skog är en av Sveriges stora privata markägare och har en företagsstruktur som inkluderar flertalet egna bruk och sågverk. För att upprätthålla ett gott flöde, skog och industri mellan, tillämpas en planeringshierarki byggd i tre steg; strategisk, taktisk och operativ.
Tillsammans ska de fungera som en länk mellan verksamhetens olika stadier. Indikationer har uppkommit om att planeringsunderlaget i den strategiska nivån inte är tillräckligt kompatibel med underlaget i den taktiska. Detta gäller främst de gallringsvisa volymerna där fältpersonal på distriktet upplever svårigheter med att återfinna dessa i fält.
Syftet med detta arbete var att med hjälp av Heureka PlanVis analysera och jämföra underlagen för de två första planeringsstegen; den strategiska och den taktiska. Jämförelsen avsåg både initialtillstånd liksom en prognos för de två närmast förestående femårsperioderna.
Analyserna är främst inriktade på skogar föreslagna till gallring och utfallet därav. Underlaget som behandlas är den strategiska planeringsfasens objektiva stickprovdata och den taktiska planeringens heltäckande beståndsdata. Studien gjordes på SCA Skog, Västerbotten, Umeå, distrikt. Analysmaterialet begränsades till en tredjedel av distriktets totala storlek, vilket omfattar nästan 16000 ha. Detta motsvarar 26 stickprovsavdelningar respektive 2677
bestånd. Analysen baserad på det heltäckande beståndsregistret uppvisade en högre volym gallring än
den baserad på stickprovsdatat. Andra markanta skillnader orsakade av de olika indataseten kunde ses i trädslagsfördelningen och sortimentsutfallen vid gallring. Att distriktspersonalen upplever svårigheter med att översätta förvaltningens krav kan delvis bero på att det strategiska planeringsunderlaget inte har någon rumslig förankring där alltså liten hänsyn tas till praktiska aspekter såsom åtkomst till skogarna etc.SCA Skog is a major private landowner in Sweden with a corporate structure that includes pulp-, paper- and sawmills. In order to maintain a good flow from forest to industry they apply a planning approach divided in three levels; strategic, tactical and operational. Together they
support decisions in the ongoing forestry.
A planning problem is indicated when proposed harvest activities at the strategic level appears incompatible with the proposals at the tactical level. Mostly this concern thinnings and thinned volumes, consequently leading to difficulties for foresters at the local level to allocate
the correct harvest activity to the correct forest, in accordance with management plans derived at a more central level of the company.
The aim of this study was to analyze and compare results from the first two planning levels; strategic and tactical, using Heureka PlanWise. The comparison concerned the initial as well as prognoses for the two first five-yearperiods. The analyses focused on the forests relatively close to thinning and its harvest results.
The information at the strategic level is represented by an objective sample compartment dataset and the tactical level is represented by a subjective “wall-to-wall” stand register. The study area is SCA Skogs Umeå district (in the coastal parts of the county of Västerbotten), representing about 16000 hectare of productive forest land. This correspond to 26 sample compartments and 2677 stands.
Analyses based on stand register data proposed more volumes to be thinned than in the case with sample compartment data. Other significant differences were shown in tree species compositions and assortment output. Eventually practical aspects, as the spatial distribution of the forests in relation to roads and soil bearing capacity etc., must be considered
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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