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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Seasonal growth dynamic of norway spruce at the study site of Rájec (Drahanská vrchovina Highland)

Chekuimo Tagne, Georges Herbert January 2016 (has links)
Evaluation of the circumference increment of Norway spruce focused on the effect of inter-tree competition in the mature spruce stand was made at the study site of Rájec (Drahanská vrchovina Highland) over a 5-year period. Data were collected from 49 trees, which were monitored continuously with mechanical band dendrometers from 2010 to 2014. The dependency of the circumference increment on competition index, diameter at breast height, Lang's rain factor, mean temperature of various periods and sum of precipitation of various periods was evaluated. Climatic conditions of the study site are characterised with warm and wet summers and cold-dry winters. In 5 years average around 61 % of the annual precipitation falls during growing season. There was highly significant correlation between relative increment and temperature (p=2.324e-13) and significant correlation between relative increment and precipitation (p=0.0439). The performed results confirmed that inter-tree competition and diameter at breast height are sufficient variables for circumference increment estimation of unmeasured trees in the particular year. Coefficient of determination reached 0.25 - 0.63 for competition and 0.40 - 0.84 for tree diameter at breast height. The present investigation brings important results about tree growth and seasonal growth dynamics and its relation with competition and microclimatic conditions in mature spruce stand. It is obvious that unsuitable climatic conditions for spruce can lead to stem shrinkage during growing season. Here we assume that these responses are caused mostly by water storage deficit in stem and this leads to decreasing of the tree vitality. Such phenomenon will have significantly negative ecological and economic consequences in expected climatic changes in the future.
142

Přeměny smrkových porostů na majetku Dr. Kinského ve Žďáru nad Sázavou

Hromádko, Petr January 2009 (has links)
No description available.
143

Studium růstových a fenologických fází u smrku ztepilého (Picea abiesL./ Karst.) a buku lesního (Fagus sylvatica L.) v závislosti na mikroklimatu stanoviště

Merklová, Lucie January 2008 (has links)
No description available.
144

Biogeography of Norway spruce (Picea abies (L.) Karst.) : Insights from a genome-wide study

Fagernäs, Zandra January 2017 (has links)
Norway spruce (Picea abies (L.) Karst.) together with the sister species Siberian spruce (P. obovata Ledeb.) form a vast continuous distribution over Eurasia. The present distribution of P. abies in Europe was formed recently, after the last glacial maximum. Theories about the colonization routes and history of this species differ depending on the datasets examined to date. This thesis aims to investigate the genetic structure and diversity of P. abies and establish its glacial refugia and postglacial migration. A range-wide sampling was performed of both P. abies and P. obovata, and a genotyping-by-sequencing approach was used to obtain whole-genome single nucleotide polymorphism (SNP) data. Two major genetic lineages of P. abies were found; northern and central Europe. The northern lineage was further divided into a Scandinavian and a north-east European cluster; the Scandinavian cluster being more closely related to P. obovata and the north-east European cluster to the central European lineage. Introgression from P. obovata was detected far into northern Fennoscandia. The central European lineage was divided into an Alpine and a Carpathian cluster, originating from different glacial refugia. Genetic diversity was higher in the northern part of the range, which can be attributed to the relatively large refugium that recolonized this area, as well as introgression from P. obovata. Genetic diversity was also somewhat elevated where the two central European clusters meet, as is expected in areas where two previously isolated lineages admix. This study is the first range-wide investigation of P. abies using whole-genome SNP information, and shows how the genetic structure of the species has been shaped by the last glacial maximum and postglacial recolonization.
145

Kartläggning över spridning av silvergran, Abies alba

Henriksson Larsson, Henny January 2021 (has links)
Silvergran, Abies alba, är en ursprungligen odlad art som har fått snabb spridning i södra och mellersta Sverige de senaste 100 åren. Risk finns att denna art är invasiv och kan påverka vår inhemska flora och fauna negativt. I ett lövskogsområde norr om Uppsala finns en ungefär 70 år gammal plantering av silvergran som är nära 1200 kvadratmeter stor. I området kring planteringen har ett stort antal plantor av silvergran etablerat sig och syftet med denna studie är att kartlägga spridningen av arten i området. Studien kan bidra till att skapa ett generellt spridningsmönster för silvergran i liknande miljöer i Sverige. Att kartlägga spridningsmönstret kan vara fördelaktigt både för att kunna avgöra om arten måste klassas som invasiv, och om åtgärder behöver vidtas mot den möjligt invasiva ädelgranen. Skogsområdet är omgivet av åkermark och har inventerats genom transekter indelade i rutor. Från inventeringen är en generell spridning av silvergran kartlagd för skogsområdet. Granarna uppmättes i olika storlekskategorier, vilket är representerat i de framställda kartorna. På så sätt får man direkt en visuell överblick över spridningen av silvergran i skogsområdet från ursprungskällan. Tydligt är att silvergranen har stor möjlighet att på egen hand sprida sig i den sydliga, svenska lövskogen och hur spridningen av silvergran i framtiden kommer se ut är ett ämne för diskussion och studier.
146

Stanovení těkavých izoprenoidů jako markerů vlivu vodního stresu na rezistenci smrku vůči kůrovcům / Determination of volatile isoprenoids as water stress markers of spruce resistance against bark beetle

Slušná, Michaela January 2012 (has links)
Isoprenoids are important components of conifer resin and represent an important part of constituted defence system against herbivores and pathogens. Drought is one of the most important factors that influences the tree physiology and resitance. Due to decreased turgor of resin canal cells, the water insufficiency affects the pressure of the resin and thereby the ability of trees to physically prevent pathogen or herbivore invasion by effective outpouring of the resin. In addition, drought can also change the resin composition and thus can influence the quality of volatiles emitted by the tree. The Norway spruce, Picea abies, is the predominant species of production forests in moderate climate zone. Bark beetles, Ips typographus, represent the most important pest species of spruce. In general, pioneer bark beetles use host volatiles to orient themselves toward the tree suitable for colonization and in many species host volatiles synergize bark beetle aggregation pheromones. Thus the host volatile composition could affect significantly host colonization. This diploma thesis studied the influence of drought on the production and composition of isoprenoid volatile organic compounds in 80 - 100 years old spruce trees. Using I. typographus antennae as biological detectors, we also studied which resin...
147

Dendrokronologisk undersökning av granbeståndet i Siggaboda naturreservat / Dendrochronologic study of Norway spruce stand in Siggaboda nature reserve, Sweden

Regnér, Alexander January 2013 (has links)
Med hjälp av såg- och borrprover studerades åldern på 41 granar och en tall i Siggaboda naturreservat i sydligaste Småland, med syfte att undersöka granens etablering och döende på lokalen. Vidare har reservatet delats in i tre områden för att undersöka om några geografiska skillnader i granarnas etablerings- och dödsår förekommer. Analysarbetet utfördes på Nationella laboratoriet för vedanatomi och dendrokronologi vid Lunds universitet. På lokalen har tidigare bland annat en pollenanalys utförts (Björkman & Bradshaw 1996) samt en kombinerad pollenanalytisk och dendrokronologisk studie (Hannon et al. 2010). Enligt dessa har granen etablerats i Siggaboda under sista halvan av 1700-talet. Någon undersökning med sågprover som material har tidigare inte genomförts på lokalen. Resultaten visar att det äldsta trädet grodde runt 1771 och att en kraftig expansion skedde under mitten av 1800-talet. De visar även att merparten av granarna har dött mellan åren 2005 och 2008, vilket indikerar att granbarkborre etablerade sig till följd av januaristormen 2005 och därefter spred sig även till stående träd - något som har fått omfattande konsekvenser för granarna i reservatet.
148

Možnosti využití hnojení při zalesňování nelesních půd v PLO 31 Českomoravské mezihoří

Dujka, Petr January 2017 (has links)
An afforestation of agricultural lands in the Czech Republic has a long tradition. In the future, a few thousands of hectares of agricultural lands is considered to be afforested. The aim of this thesis is to research possibilities of fertilisation usage in process of agricultural lands afforestation within Natural forest area (NFA) 31 Českomoravské mezihoří. The research part of the thesis contains results of soil and nutrition analyses applied in Letovice-Kochov research area. The main goal of analyses was to find the impact of fertilisation on chemical soil characteristics, on nutrition of Norway spruce's needles (Picea abies (L.) Karsten), on the development of morphological quantity, and on the health of specimen. All of the characteristics are assessed in the context of climate in 2016. The positive effects of fertilisers were researched despite a low-humid year. The best effects were spotted at fertiliser SilvamixR30. To the results, SilvamixR30 fertilizer could be used in praxis, especially for agricultural lands afforested in named NFA.
149

Bříza bělokorá jako přípravná dřevina při zalesňování kalamitních holin jedlí bělokorou: vliv na podmínky prostředí a vybrané ekofyziologické parametry jedle

Štefková, Veronika January 2017 (has links)
This thesis compare various uses of silver birch (Betula pendula Roth.) as a preparatory species during afforestation by silver fir (Abies alba Mill.). In this experiment, silver fir was planted at fall of 2015 and measurements were conducted in the vegetation season 2016. There were four variants of experiment with respect to the silver birch: clearcut, birch stand with 50 % stocking density, narrow embankment cut and birch stand with a full stocking density. Air temperature, precipitation, vapor pressure deficit, soil moisture and transmittance of photosynthetically active radiation were measured from the environmental variables. On plants, the growth increment, chlorophyll fluorescence, shoot water potential and needle mas per area were studied. Preparatory forest stand eliminated extreme temperatures, both positive and negative. Maximum temperatures were by 7 °C lower under the forest canopy than on clearcut. Spring frost was eliminated by 2.2 °C which was enough to protect fresh shoots from freezing. On the other hand soil moisture under the birch was by 23 till 47 % lower than at the clearcut. Tallest growth increment of 12 cm was at the clearcut, shortest of 7 cm under the birch without thinning. Needle mass per area corresponded to light availability and it was highest at clearcut and lowest under the birch. Chlorophyll fluorescence in dark did not suggest any differences between treatments (Fv/Fm was higher than 0.80) and therefore differences in growth can be accounted to the light availability. Data suggest that for the silver fir saplings is best to grow under severely thinned silver birch canopy with low stocking density which allows for enough light and soil moisture but still protects saplings against inclement weatherFormula clause:I declare that I am working, "Birch as a preparatory tree species in reforestation calamity clearings silver fir: the impact of environmental conditions and selected ecophysiological parameters fir" worked independently and all used sources and information mention in the list of references. I agree that my work has been published in accordance with § 47 b of the Act no. 111/1998 Coll., On universities, as amended and in accordance with directives on the publication of university theses. I am aware that my work covered by Act no. 121/2000 Coll., The Copyright Act, and the Mendel University in Brno has the right to conclude a license agreement and use this work as school work pursuant to Section 60 paragraph. 1 of the Copyright Act. I also agree that, before drawing up licensing agreements on the use of a work by another person (the subject), I request a written opinion by the university that the subject license agreement is not contrary to the legitimate interests of the university and undertake to pay any contribution to the costs associated with the creation of the work, and up to the full amount
150

Förekomst och spridning av hänglavar från äldre skogar till unga tidigare avverkade områden i Västerbottens inland

Maksimova, Emma January 2023 (has links)
The Swedish forestry and the use of clearcutting models has resulted in great losses of older forests in Sweden, resulting in several species being affected negatively. Hair lichens are important organisms that are providing several ecological functions in forest ecosystems and are declining due to being associated with older forests with high continuity. This study investigates the occurrence and dispersal ability of the genus Alectoria, Bryoria and Usnea between older forests and young secondary forests in three different areas in Storuman municipality, Västerbotten county. Bryoria were found on all trees in all forest patches, both in the old and young forest patches, while Alectoria had much lower occurrence in the young secondary forest. Usnea had no observed pattern in occurrence between the different areas. The average length of the lichens, here used as a proxy for lichen biomass, showed a statistical difference in biomass between areas for genera Bryoria and Usnea. The genera Alectoria showed a difference in biomass between areas, distance to closest older forest and the interaction between these two. Therefore, this study suggests that Alectoria is limited in dispersal in these areas. Some of the results could be explained by distribution and dispersal ability of the studied genera. To further evaluate the differences seen in occurrence and biomass between the genera and the different areas more studies are needed. This could provide important information for sustainable forestry that favors lichens and benefits reindeer husbandry.

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