No description available.

This dissertation presents research results of Norway spruce (Picea abies L. Karst) populations in timberline ecotone of the Hrubý Jeseník Mts. The work is presented in the form of five scientific articles, 3 of which are accepted for publication, or already printed. Two articles are in the form of submitted manuscripts. The first article describes the biometric and age structure of spruce populations, including the assessment of the possibility of their vegetative as well as seed-based reproduction and compares these characteristics between two vertically connected sections of timberline ecotone. The second article analyzes the influence of dwarf pine stands of different cover on the ability of vegetative reproduction of spruce and their height growth. The third article deals with the historical dynamic of spruce trees establishment within timberline ecotone. This are correlated with both temperature characteristics and agricultural land abandonment during the last 100 years. The fourth article deals with measurements of the quantity and directions of sap flow in layering branches as well as parent and daughter trees in Norway spruce clonal groups. The article evaluates the importance of sap flow quantity in layering branch to the total amount of water use by parent and daughter trees. The fifth article substantially extends the fourth article of measurements on more interconnected tree pairs within a longer time series. Additionally, this article includes the drought stress experiment in the daughter tree and subsequent monitoring of changes in sap flow in layering branch.

The effect climate change has on forest trees is a large scaled topic. It is to believe that one of the largest threat to the environment today is global warming (IPPC, 2007). The use of fossil fuels seems to be the big threat with its greenhouse gas (GHG) emission and therefore forest is of interest. Forest contributes in several ways. Forest trees work as a renewable source of numerus materials and as it takes up CO 2 from the greenhouse gasses it gives us oxygen (O2). The important process of photosynthesis, to able production of more trees and creation of more forests, tells us the vitality of understanding the tree physiology to the fullest. The response of photosynthesis to temperature is a central facet of trees’ response to climate change. With its photosynthesis plants play a large role in the carbon cycle as they store the hazardous carbon dioxide helping us humans to deal with problems directly linked to climatic change and in the same time they build up biomass that can be used as a renewable source. To understand, and to find the key, how plants can achieve optimum potential of photosynthesis several observations were made using plant material from fertilized and unfertilized Picea abies. Well acknowledged leaf gas exchange measurements were used to see the limitations of photosynthesis, observing the net CO2 uptake rate (Anet), the maximum Rubisco carboxylation (Vcmax), maximum rate of electron transport for regeneration of RuBP (Jmax) and their unique response to temperatures. For three days observations were conducted at the Slu Asa field research station in Lammhult, Sweden. In addition to gas exchange measurements, nitrogen (N), phosphorus (P) and chlorophyll content was measured in needles of the fertilized and unfertilized P. abies to see if the content somehow made an impact on photosynthetic parameters and the influence nutrients might have on the specific leaf area (SLA). Results from the observations showed that optimum temperature for photosynthesis varies to be by fertilized 22°C and unfertilized 19°C. The net photosynthetic rate responded to the influence by added fertilizers to almost a double, 9.10 μmol m−2 sec−1 than of the unfertilized, 5.36 μmol m−2 sec−1. These results indicate that a fertilized P. abies has a greater potency to capture carbon than of an unfertilized P. abies. The result also reveals the future prospect of adding fertilizer to a P. abies as a potential of growth in biomass as well as a carbon sink when atmospheric CO2 levels rise. There were no great differences in the behaviour between Vcmax and Jmax to the added or non-added fertilized P. abies. Perhaps the fact that given fertilizer contained both nitrogen and phosphorous could have in their combinations influenced the sensitivity of the relationship between them two and therefore also the result. The presence of N and P in the fertilized P. abies affected the concentration of chlorophyll positively, paving the way for photosynthesis, accumulated biomass and possibly for trees defence against abiotic stress factors.

The research of the dissertation thesis was focused on the ability of forests to activate and immobilize metals in the environment with their huge grants from deep mining of mineral resources. The research was be located in the area of Rožná with ongoing uranium mining, and area of Olší with ended uranium mining in the Czech Republic. During the years 2014 and 2015 was at the alluvial streams of Nedvědička (Rožná) and Hadůvka (Olší) recipients of pollution by radionuclides and metals from mining, taken in spring and autumn aspect of the overall 380 samples of leaves from trees, herb layer and river sediments. The samples were analyzed by the XFR and ICP-OES methods. In the organic matter were found such as elements Al, Cl, Cu, Cr, Fe, Mn, Mo, Ni, Rb, S, Sr, U, Zn and Zr, in many cases at high concentrations corresponding to polluted areas in the mining or industrial areas. A statistically significant difference in the concentrations of chemical elements in the fytomasss and river sediment between the upper, middle and lower stream areas of interest was not found. In the area of Nedvědička were found higher concentrations of a greater range of metals than in the area of Hadůvka. In the area of Hadůvka were by ICP-OES found significantly higher levels of uranium in the leaves than in the area of Nedvědička, reaching up to 34.86 mg.kg-1 in the dried material.The seasonal dynamics of the content of chemical elements in fytomass was confirmed. The species composition of the forest growth in the areas of interest with a predominance of Picea abies and the type of management has been evaluated as unfavorable for immobilization of metals in the environment. In the area of Nedvědička were suggested corrective actions - planting vegetation with a predominance of Fagus silvatica which should have a beneficial effect on soil and water pH by a suitable character of waste and contribute to the spread of inhibition of metals in the environment. In the area of Hadůvka are the suggested measures focused on the redevelopment of existing vegetation with a predominance of Picea abies on vegetation with a predominance of deciduous trees, especially Fagus silvatica, in order to adjust gradually the pH of the soil and thereby reduce the mobility of metals in the environment.

The aim of the study was to determine the dynamics of wood decay using acoustic tomography. Different devices are use to estimate range of internal damage of the tree caused by wood rot as is possible to find in literature. For purpose of these measurements were used devices ArborSonic Decay Detector 3D and Resistograph IML F400-S. Thesis was divided in two main sections. The first section was focused on practical testing of both devices, acquiring knowledge about research procedure and also learning about possible mistakes to be avoid during research. It was necessary to perform two measurements at a time interval of approximately one year. In first year, 70 samples of Norway spruce (Picea abies) were measured and evaluated their health and vitality status. Trees, that had symptoms of fungi wood decay, were measured in the second year once more. Subsequently, the ranges and changes of inner damages by wood fungi were determined and compared results from both devices. The second part was focused on comparison of the graphical results of the range of decay in the Fakopp 3D software with the actual state of the affected tree trunk. An obtained result showed the dynamics of wood decay in years 2018-2019 and therefore was possible to determine the dynamics of wood decay in Norway spruce wood, verify the influence of the basic parameters and also to compare the graphical image of the decay range with the real status in the trunk. The average change of decay range of evaluated Norway spruce trees was 3,32%. It was found out, that Acoustic tomograph overestimated cavity section in 21 cases, which was 84 % in comparison with Resistograph. This overestimation fact was was also proved by graphical result from Fakopp 3D software, which was compared with real status of trunk. The use of device methods for assessment of tree status and preparation for tree care plans were more described in Discussion chapter.

The diploma thesis deals with the effect of artificial mycorrhization on the growth and on the development of the root system of Picea abies (L.) Karst. cultures. The thesis was conducted at 2 sites under the administration of the Vojenské lesy a statky ČR, s.p., division Lipník nad Bečvou, that were afforested in 2012 and 2013. Every site was divided into 2 parts of the same area. One of the parts was afforested with the use of the mycorrhizal preparation Ectovit and the fertiliser Vápnitý dolomit. The effect of preparations on the above-ground part of trees was evaluated on 210 sample trees at every site. The effect of preparations on roots was evaluated on 10 sample trees. Following parameters were assessed for every sample: the height of the tree; the thickness of root collar; height increments; length of needles; the damage caused by biotic or abiotic factors; number, thickness and length of both horizontal and vertical roots; the number of fine roots; the weight of dry mass of both fine and coarse roots; branching index of fine roots and the specific length of fine roots. Unfortunately, one site had to be omitted from further evaluation of effects on the roots due to the high occurrence of root deformations. The measurement was carried out in June and July 2016. As regards the above-ground part, the research has not proved significant positive effect of preparations. The differences in height increments speak in some cases for, however in some cases against the application of preparations. The lengths of needles were in some years shorter at the sites with preparations and thus may indicate even negative effects of preparations. Regarding root system, a difference was found out only in the case of branching index. No difference was identified for other parameters of the trees on the check and on the test site. Some parameters (e.g. height increments), however, might be considerably influenced by the damage caused by wildlife or by other factors (e.g. heavily stony soil in some parts of the sites). Last but not least, the thesis formulates recommendations regarding the future use of preparations within the company VLS Lipník nad Bečvou.

Les gestionnaires forestiers sont demandeurs d'une aide à la décision pour la conservation du mélange Sapin et Epicéa en forêt de montagne. Pour répondre à leur attente, nous avons modélisé, pour les deux espèces, les fonctions démographiques (croissance, mortalité et recrutement) et les fonctions d'allométries à partir de données de terrain. Ces fonctions ont été implémentées dans un modèle de dynamique forestière afin d'améliorer les connaissances sur la dynamique naturelle des deux espèces et d'envisager des tests de scénarios sylvicoles. L'estimation statistique des paramètres des modèles a été effectuée dans un cadre bayésien hiérarchique. Elle a permis de mettre en évidence et de quantifier les différences entre espèces : le Sapin, espèce tolérante à l'ombre comparativement à l'Epicéa, est moins sensible à l'autoéclaircie, a une croissance plus forte et un taux de recrutement plus important à faibles niveaux de lumière que l'Epicéa. Les modèles développés ont pris en compte l'incertitude sur les observations et la variabilité spatio-temporelle des processus. La variabilité individuelle (ou intraspécifique) et temporelle (interannuelle et intra-individuelle) est forte et tend à égaliser la fitness des deux espèces en inversant la hiérarchie des espèces localement dans l'espace ou sporadiquement dans le temps. Les premières simulations à l'aide du simulateur Samsara2 indiquent un meilleur comportement du modèle lorsque la variabilité spatio-temporelle est inclue dans les processus. La variabilité assure une structuration en hauteur et en diamètre ainsi qu'une évolution de la surface terrière qui correspondent à des patterns plus réalistes que lorsque la variabilité n'est pas prise en compte. A l'issue des premières simulations sur un peuplement test en mélange, on observe une exclusion compétititve systématique de l'Epicéa par le Sapin. Les mécanismes égaliseurs associés à la variabilité ne parviennent pas à contrebalancer l'avantage compétitif du Sapin sur l'Epicéa. Toutefois, la dynamique transitoire du système est lente et la coexistence apparente des deux espèces peut s'étaler sur plusieurs centaines d'années.

Vor dem Hintergrund sich verändernder Umweltbedingungen durch den allgegenwärtigen Klimawandel wächst das Interesse an Vorhersagen zur zukünftigen Waldentwicklung. Der prognostizierten Häufung von Witterungsextremen wird ein wesentlicher Einfluss auf das Wachstum und die Vitalität der Waldbaumarten zugeschrieben. Wichtige Erkenntnisse bringen hier Untersuchungen zu den physiologischen Wachstumsgrenzen der Gehölze, die sich besonders deutlich an deren heutigen Verbreitungsgrenzen nachweisen lassen. An diesen offenbart sich das Potential einer Baumart, die Migration unter zukünftigen Bedingungen fortsetzen zu können. Großes Interesse herrscht an ökonomisch wichtigen Baumarten wie der Gemeinen Fichte (Picea abies [L.] Karst.) und der Rot-Buche (Fagus sylvatica L.). Deren Wuchsverhalten unter natürlichen Bedingungen, in natürlich erwachsenen Mischwäldern wurde in der vorliegenden Arbeit an den derzeitigen Arealsgrenzen beider Arten in Südschweden (Rågetaåsen, Siggaboda, Tolseboda) untersucht. Als Vergleichsstandort diente ein Naturwald im Harz (Rehberg), welcher geografisch zentral im Verbreitungsgebiet der Buche liegt und durch seine montane Höhenlage ideale Wuchsbedingungen für die Fichte liefert. Mittels dendroklimatologischer Analysemethoden wurden die wesentlichen, den radialen Zuwachs beeinflussenden Witterungsvariablen bestimmt und deren Anpassung bzw. Veränderung über verschiedene Zeitintervalle untersucht. Dendroökologische Untersuchungen ermöglichten einen Blick in die vergangene Entwicklung der Mischbestände und das Konkurrenzverhalten beider Baumarten untereinander. Diese Untersuchungen wurden auf zwei Ebenen durchgeführt: auf der Bestandesebene und auf der Ebene kleinerer Untersuchungsgruppen, durch welche direkte Konkurrenzsituationen der intra- und interspezifischen Beeinflussung analysiert werden konnten. Beide Methoden sind retrospektiver Natur und ermöglichen daher in der Hauptsache eine Analyse und Interpretation des vergangenen Zuwachsverhaltens. Doch erlauben beobachtete Trends in der Vergangenheit eine vorsichtige Prognose der Entwicklung von Waldbeständen auf vergleichbaren Standorten. Die dendroklimatologischen Analysen zeigten, dass beide Baumarten eine interessante Variabilität in den jeweiligen zuwachsbeeinflussenden Witterungsvariablen aufweisen. Die Haupteinflussgröße für den Buchenzuwachs ist ein trocken-heißer Vorjahres-Sommer mit Schwerpunkt auf den Monaten Juli und August. Dieser Einfluss zeigt sich seit Beginn des Beobachtungszeitraums, aber seit etwa 1950 verstärkt er sich bedeutend und erfährt seit Mitte der 1990er Jahre eine weitere Steigerung. Die wesentliche Witterungsvariable für den Fichtenzuwachs war bis etwa in die 1950er Jahre ein positiver Einfluss der Niederschläge im Sommer der Ringbildung mit Schwerpunkt auf dem Juni. Seither verschwindet dieser Einfluss jedoch auf fast allen Standorten und weicht einer, der Buchen ähnlichen Dürreempfindlichkeit gegenüber den vorjährigen Spätsommern. Die retrospektive Analyse der Bestandesgeschichte mittels langjähriger Zuwachszeitreihen ermöglicht eine Interpretation der vergangenen Entwicklung der Waldbestände und liefert eine Erklärung für das aktuelle Erscheinungsbild. Auf den schwedischen Standorten zeigt sich im radialen wie im Höhenzuwachs ein deutlicher Vorteil der Fichten. Auf den Standorten Siggaboda und Tolseboda bildet die Buche unter der Fichte sogar die zweite Baumschicht. Im Gegensatz zum Standort Rågetaåsen liegen diese beiden Standorte bereits außerhalb des natürlichen Verbreitungsgebiets von Buchenwäldern, aber im Gebiet der Buchen-Fichten-Wälder. Hier erkennt man deutlich einen Konkurrenzvorteil der Fichte. Am Vergleichsstandort Rehberg erkennt man dagegen das grundsätzlich große Potential der Buche, ähnliche Zuwächse zu leisten wie die Fichte. Das Konkurrenzverhältnis wirkt hier relativ ausgeglichen. Direkte Konkurrenzsituationen zwischen den Baumarten ergeben sich an Randzonen der natürlich gewachsenen reinartigen Gruppen. Es zeigte sich, dass die Buche in unmittelbarer Konkurrenz zur Fichte benachteiligt wird. Im umgekehrten Falle kann die Fichte in Abhängigkeit von ihrer sozialen Stellung sogar von einer Mischung mit Buche profitieren. Diese Ergebnisse gelten für die schwedischen Standorte wie auch für den Harz, wobei die Buchen am Rehberg ein größeres Potential erkennen lassen, dem Druck der Fichten entgegenzustehen. Der Einfluss singulärer Witterungsextreme auf das Wachstum beider Baumarten konnte an starken Zuwachseinbrüchen nachgewiesen werden. Doch in den meisten Fällen zeigte sich bereits im Folgejahr wieder ein ausgeglichenes Wachstum. Eine Herausforderung wird die zukünftige Häufung von Extremen mit fehlenden Erholungsphasen sein. Im letzten Jahrzehnt konnten bereits Sekundärfolgen großer Trockenheiten und deren Einfluss auf den Zuwachs beobachtet werden. Ergeben sich aus derartigen Situationen Schwierigkeiten für eine Baumart, ist dies ein sicheres Zeichen dafür, dass sie an ihre physiologischen Grenzen gerät. Am Standort Siggaboda konnte dies bereits für die Fichten beobachtet werden. Auch am Rehberg stellten sich in den letzten Jahren Bedingungen ein, die der Buche Schwierigkeiten bereiten. Aus den gewonnenen Erkenntnissen lässt sich entnehmen, dass das Konkurrenzverhältnis zwischen Buche und Fichte seit den letzten zwei Jahrzehnten begonnen hat, sich zu verändern. Am südexponierten Hangstandort im Harz scheint die bisher sehr konkurrenzstarke Buche an ihre physiologische Grenze zu geraten. Auf den schwedischen Standorten wird die Buche möglicherweise von wärmeren Sommern und verlängerten Vegetationsperioden profitieren, während die Fichte an die südliche, klimatische Verbreitungsgrenze der borealen Wälder gelangt zu sein scheint. / Against the background of a changing environment due to climate change the interest in prognoses of the development of forest ecosystems increases. The growth and the vitality of forest tree species will mainly be influenced by increased frequency of extreme weather conditions. The analysis of the physiological limits of tree growth has to be conducted at the borders of the natural distribution range of species. Main focus lies on economical important tree species as Common beech (Fagus sylvatica L.) and Norway spruce (Picea abies [L.] Karst.).Growth and competition performance of these two species was investigated under natural conditions in naturally grown mixed forests at both species distribution limits in Southern Sweden (Rågetaåsen, Siggaboda, Tolseboda). As a reference a natural forest in the Harz Mountains (Rehberg) was chosen. By means of dendroclimatological methods the main influencing climate variables and their modifications over time were analysed. Dendroecological methods allow the retrospective analysis of forest history and the development of the competition behaviour of both species in the past. These analyses were conducted on two levels: stand level and plot level. The latter permits the analysis of direct competition situations, intra- and interspecific. By means of these retrospective methods potential trends might be detected and thus allow forecasts for the development of forest stands on comparable sites. Dendroclimatological analyses showed, that both tree species exhibit interesting variability in its main influencing climate variables. The radial growth of beech is mainly determined by warm-dry summers of the previous year with focus on July and August. This influence increases since the 1950s and even stronger since the mid 1990s. Main factor for spruce growth was summer precipitation with focus an June. This influence nearly vanished on all sites since the 1950s. Since then the main climate signal of spruce growth is a sensitivity to drought of previous summers, equally to beech. The retrospective analysis of forest history by means of long-term tree-ring series allows an interpretation of past development of the forest stands and provides explanations for the current appearance. On the Swedish sites the advance of spruce in radial as in height growth is obvious. In Siggaboda and Tolseboda beech even forms the secondary species. These sites lie beyond northern limits of Fagus forests but within Fagus-Picea forests. The advantage of spruce is considerable. Though, on the reference site Rehberg the high potential of beech, to achieve comparable tree-ring widths, is distinct. Here, the competition performance is nearly balanced. At borders of naturally grown pure groups direct competition situations between the species can be found. It could be shown, that beech is disadvantaged under immediate competition with spruce. But in inverse situations, spruce, depending on its social state, even benefits of growing in mixture with beech. These results can be found on the Swedish sites as well as in the Harz Mountains, though, beech at the Rehberg shows a much higher potential to stand against the competition of spruce. Singular impacts of extreme weather conditions on tree growth can be clearly, but in most cases growth is regulated one year later. However, future challenge for tree species will be the increased frequency of extreme conditions without phases of recovery. In the past decade secondary complications of drought and its influence on growth could already be detected. This affects both species similarly. Does a species get disadvantaged due to such situations, would mean that it reaches its physiological limits. In Siggaboda this could be already shown for spruce and at the Rehberg for beech. As a result this study shows, that the competition situation between beech and spruce has begun to change since the last two decades. On exposed sites as the Rehberg, beech trees might reach its physiological limits. On the Swedish sites, however, beech trees could benefit from warm summers and prolonged vegetation periods. In contrast, spruce probably has reached its southern, climatically determined distribution limit of boreal forests.

Tack vare vissa önskade egenskaper gjordes en storsatsning på contortatall (Pinus contorta) i Sverige på 70-talet. Idag finns cirka 600 000 ha i Sverige som det gjorts provsågningar på och är nu dags att hitta användningsområden till. Syftet med denna studie var att undersöka skillnaden i utbyte mellan contortatall och gran (Picea abies) efter hyvling. Målet var att undersöka om sidobrädor av contortatall kan vara ett substitut till sidobrädor av gran vid hyvling ämnat för den amerikanska marknaden.Efter skanning av brädor samt manuell visuell sortering visade det sig att 92 % av granbrädorna var utan defekt medan 24 % av contortatallen var det. 34 % av contortatallen nedklassades för hål och 3 % av granen. Slutsatsen av studien visar att mängden och storleken på kvistarna är ett problem för contortatallvirket. För att få ett högkvalitativt virke behövs en djupare översyn av tillvägagångssättet för torkning och trädens tillväxtförhållanden.

Skogen är en förnyelsebar energikälla som möjliggör för ett minskat beroende av fossila bränslen. Ur ett politiskt perspektiv minskar såväl klimatpåverkan som beroendet av importerad energi från oroliga delar av världen genom att ta tillvara skogsbränsle lokalt. I Sverige är sågverkens biprodukter fullt utnyttjade och därför har skogsbränsle i from av grot (GRenar Och Toppar) en av de största potentialerna till ökat uttag. Barrträdens barr är en omstridd fråga i samband med tillvaratagandet av grot. Barren står för en liten del av biomassan, men för en stor del av näringen i ett bestånd. Därför är det önskvärt att så mycket som möjligt av barren lämnas på föryngringsytan. Om barrandel i färsk grot är känd kan den även användas för att beräkna hur mycket barr som egentligen lämnas kvar på hygget. Den energiomvandlande industrin vill inte heller ha för mycket barr i bränslet, då de anses skapa problem i förbränningen. Studien är ett fältexperiment genomförd på tio olika hyggen i södra Sverige under mars och april 2015. En grothög lastades på ett personbilssläp och transporterades till företaget Skogsbränsle Smålands flishugg för sönderdelning. Provmaterialet bearbetades sedan på Linnéuniversitetet där bl.a. fukthalt och barrandel bestämdes. Resultatet i denna studie genomförd i södra Sverige pekar på att medelvärdet för barrandelen i färsk grot från gran är 22,2 %, men där variationen mellan olika hygge kan variera stort (17,5–32,4 %). Medelvärdet ligger dock i nedre delen av det vedertagna intervallet motsvarande 20–30 %. Studien visade på ett medelvärde för fukthalt på 38,7 %, vilket är lägre än vad tidigare studier fastställt. Barrträd har lägst fukthalt under vårvintern, dvs. under genomförandet av denna studie vilket kan förklara en relativt låg fukthalt som annars generellt brukar vara 50–55 %. Denna studie har konstaterat att barrandelen för färsk grot från gran i södra Sverige är lägre än vedertaget intervall för hela Sverige. Det har även kunnat konstateras att det förekommer stora lokala avvikelser i barrandel, varför slutsatsen dras att det inte är rätt att anta ett generellt värde för barrandelen. Ett generellt antagande innebär t.ex. att bedömningen av hur mycket barr som lämnats kvar på föryngringsytan blir missvisade. Den ursprungliga barrandelen har en stor inverkan på hur mycket barr som lämnas kvar. Vidare har denna studie fastställt att fukthalten för grot från gran är lägre under vårvintern. / The forest is a renewable source of energy, enabling a reduction in dependence on fossil fuels. From a political point of view both climate impact as the dependence on imported energy from troubled parts of the world can be reduced by making use of forest fuel locally. In Sweden sawmill byproducts are fully exploited and therefore there is a potential to increase the proportion of forest fuels, particularly the removal of logging residues in form of branches and tops. Needles is a contentious issue in connection with the utilization of logging residues. The needles accounts for a small proportion of the biomass, but for a large part of the nutrients in a forest stand. Therefore, it is desirable that as much needles as possible is left in the harvesting area. If the needle proportion in fresh logging residues is known, it can also be used to calculate how much needles actually is left in the harvesting area. The energy converting industry does not want too much needles in the fuel, as it seems to create problems with combustion. The study is a field experiment conducted on 10 different harvesting areas in southern Sweden during March and April 2015. A pile of logging residues were loaded on a car trailer and then transported to Skogsbränsle Småland's chipper for decomposition. The test material was then processed at Linnaeus University, where needle and moisture content was determined. The results of this study conducted in the south of Sweden indicate that the average value of the needle content in fresh logging residues from spruce in southern Sweden is 22.2 %. The variation between different harvesting areas can vary greatly (17,5–32,4 %). This study showed a mean moisture content of fresh logging residues from spruce in southern Sweden of 38.7 %, which is lower than previous studies found. Softwood has the lowest moisture during early spring, during the implementation of this study, which may explain a relatively low moisture content which otherwise generally tend to be 50–55 %. This study found that the needle content in fresh logging residues from spruce in the south of Sweden is lower than the established range of 20–30 %. It has also been noted that there are large local variations in the needle content, therefore concluded that it is not right to adopt an overall value of the needle content. A general adoption of the needle content means e.g. that the assessment of how much needles left on the harvesting area becomes misleading. The needle content in fresh logging residues has a great impact on how much needles is left. Furthermore, this study found that the moisture content of logging residues from spruce is lower during early spring. / Metsä on uusiutuva energianlähde, jolla on mahdollista vähentää riippuvuutta fossiili polttoaineista. Poliittisesta näkökulmasta metsäpolttoaine vähentää sekä ilmastovaikutusta kuin tuontienergian riippuvaisuutta peräisin levottomista osista maailmaa. Ruotsissa sahan sivutuotteita hyödynnetään täysimääräisesti, siksi on iso mahdollisuus nostaa metsäpolttoaineiden osuutta, erityisesti hakkuutähteiden oksia ja latvoja. Havupuiden neulaset on kiistanalainen kysymys. Neulasten osuus on pieni osa metsän biomassasta, mutta suuri osa ravinteesta. On toivottavaa että niin paljon neulasia kuin mahdollista jätetään hakkuupaikalle. Energiateollisuus ei halua neulasia polttoaineeseen, koska se näyttää luovan ongelmia poltossa. Osuus neulasia tuoreissa hakkuutähteissä käytetään arvioimaan kuinka paljon neulasia todellisuudessa jää hakkuupaikalle. Tutkimus on kenttäkoe suoritettu kymmenellä eri hakkuupaikalla Etelä-Ruotsissa maalis-huhtikuun aikana 2015. Yksi kasa hakkuutähteitä lastattiin auton perävaunuun ja kuljetettiin Skogsbränsle Småland:in hakkurille hajottamista varten. Testimateriaali käsiteltiin sitten Linnaeus yliopistossa, jossa muun muassa osuus neulasia ja kosteuspitoisuus määritettiin. Tämän tutkimuksen tulokset osoittavat, että osuus neulasia tuoreissa hakkuutähteissä kuusesta Etelä-Ruotsissa on 22,2 %, mutta osuus eri hakkuupaikoilla vaihtelee suuresti (17,5–32,4 %). Yleinen arvo Ruotsissa on 20–30 %. Tämä tutkimus osoittaa myös, että kosteuspitoisuus tuoreissa hakkuutähteissä kuusesta Etelä-Ruotsissa on 38,7 %, joka on vähemmän kuin aiemmissa tutkimuksissa todettu. Havupuilla on alhaisin kosteus kevättalvella, samaan aikaan kun tämän tutkimuksen kenttätyö. Tämä voi selittää suhteellisen alhaisen kosteuspitoisuuden, joka muutoin yleensä pyrkii olemaan 50–55 %. Tutkimuksessa todettiin, että osuus neulasia tuoreissa hakkuutähteissä kuusesta Etelä-Ruotsissa on alempi kuin koko Ruotsin yleinen arvo. On myös todettu, että on olemassa suuria paikallisia vaihteluja hakkutähteiden neulasten osuudessa. Siksi päätellään, ettei ole oikein käyttää yleistä arvoa. Alkuperäisellä neulasosuudella on suuri vaikutus siihen, miten paljon neulasia on jätetty. Lisäksi tässä tutkimuksessa todettiin, että kuusen hakkutähteiden kosteuspitoisuus on alhaisempi kevättalvella.