Skogsbränslets elementära sammansättning med tanke på förbränningsprocessen och för näringsämnesförluster i ekosystemet

There are several reasons for increasing the usage of forest biomass for energy in Finland. Apart from the fact that forest biomass is a CO2 -neutral energy source, it is also a domestic resource distributed throughout the country. Usage of forest biomass in the form of logging residues decreases Finland’s dependence of energy import and increases both incomes and employment. Wood chips are mainly made from logging residues, which constitute 64 % of the raw material. A large-scale use of forest biomass requires heed also to the potential negative aspects. Forest bioenergy is used extensively, but its impacts on the forests soil nutrition and carbon balance has not been studied much. Nor have there been many studies on the heavy metal or chlorine content of logging residues. The goal of this study was to examine the content of carbon, macronutrients, heavy metals and other for the combustion harmful substances in Scots pine and Norway spruce wood chips, and to estimate the effect of harvesting of logging residues on the forests carbon and nutrient balance. Another goal was to examine the energy content of the clear cut remains. The Wood chips for this study were gathered from pine and spruce dominated clear cut sites in southern Finland, in the costal forests between Hankoo and Siuntio. The number of sample locations were 29, and the average area was 3,15 ha and the average timber volume 212,6 m3 ha -1. The average logged timber volume was for Scots pine timber 70 m3 ha -1 and for Norway spruce timber 124 m3 ha -1 and for deciduous timber (birch and alder) 18,5 m3 ha -1. The proportion of spruce in the logging residues and the stand-volume were relevant for how much nutrients were taken from the forest ecosystem when harvesting logging residues. In this study it was noted that the nutrient content of the logging residues clearly increased when the percentage of spruce in the timber volume increased. The S, K, Na and Cl -contents in the logging residues in this study increased with an increasing percentage of spruce, which is probably due to the fact that the spruce is an effective collector of atmospheric dry-deposition. The amounts of nutrients that were lost when harvesting logging residues were less than those referred to in the literature. Within a circulation period (100 years), the forest soil gets substantially more nutrients from atmospheric deposition, litter fall and weathering than is lost through harvesting of logging residues after a clear cut. Harvesting of the logging residues makes for a relatively modest increase of the quantity of carbon that is removed from the forest compared to traditional forestry. Due to the fact that the clear cut remains in my study showed a high content of chlorine, there is a risk of corrosion in connection to the incineration of the logging residues in power plants especially at coastal areas/forests. The risk of sulphur -related corrosion is probably rather small, because S concentrations are relatively low in woodchips. The clear cut remains showed rather high heavy metal contents. If the heavy metal contents in this study are representative for the clear cut remains in the coastal forests generally, there might be reason to exert some caution when using the ash for forest fertilizing purposes.

Influence of harvesting strategy on nutrient supply and production of dairy cows consuming diets based on grass and red clover silage

The main objective of this thesis was to elucidate the effects of regrowth grass silage and red clover silage on nutrient supply and milk production of dairy cows as compared with primary growth grass silages. In the first experiment (publication I), two primary growth and four regrowth grass silages were harvested at two stages of growth. These six silages were fed to 24 lactating dairy cows with two levels of concentrate allowance. Silage intake and energy corrected milk yield (ECM) responses, and the range in these response variables between the diets, were smaller when regrowth silages rather than primary growth silages were fed. Milk production of dairy cows reflected the intake of metabolizable energy (ME), and no differences in the ME utilization were found between the diets based on silages harvested from primary growth and regrowth. The ECM response to increased concentrate allowance was, on average, greater when regrowth rather than primary growth silages were fed. In the second experiment (publication II), two silages from primary growth and two from regrowth used in I were fed to rumen cannulated lactating dairy cows. Cows consumed less feed dry matter (DM), energy and protein, and produced less milk, when fed diets based on regrowth silages rather than primary growth silages. Lower milk production responses of regrowth grass silage diets were mainly due to the lower silage DM intake, and could not be accounted for by differences in energy or protein utilization. Regrowth grass silage intake was not limited due to neutral detergent fibre (NDF) digestion or rumen fill or passage kinetics. However, lower intake may be at least partly attributable to plant diseases such as leaf spot infections, dead deteriorating material or abundance of weeds, which are all higher in regrowth compared with primary growth, and increase with advancing regrowth. In the third experiment (publications III and IV), red clover silages and grass silages harvested at two stages of growth, and a mixed diet of red clover and grass silages, were fed to five rumen cannulated lactating dairy cows. In spite of the lower average ME intake for red clover diets, the ECM production remained unchanged suggesting more efficient utilisation of ME for red clover diets compared with grass diets. Intake of N, and omasal canal flows of total non-ammonia N (NAN), microbial and non-microbial NAN were higher for red clover than for grass silage diets, but were not affected by forage maturity. Delaying the harvest tended to decrease DM intake of grass silage and increase that of red clover silage. The digestion rate of potentially digestible NDF was faster for red clover diets than for grass silage diets. Delaying the harvest decreased the digestion rate for grass but increased it for red clover silage diets. The low intake of early-cut red clover silage could not be explained by silage digestibility, fermentation quality, or rumen fill but was most likely related to the nutritionally suboptimal diet composition because inclusion of moderate quality grass silage in mixed diet increased silage DM intake. Despite the higher total amino acid supply of cows fed red clover versus grass silage diets, further milk production responses on red clover diets were possibly compromised by an inadequate supply of methionine as evidenced by lower methionine concentration in the amino acid profile of omasal digesta and plasma. Increasing the maturity of ensiled red clover does not seem to affect silage DM intake as consistently as that of grasses. The efficiency of N utilization for milk protein synthesis was lower for red clover diets than for grass diets. It was negatively related to diet crude protein concentration similarly to grass silage diets.

Teaching in Higher Education : From Content-focused to Learning-focused Approaches to Teaching

The aim of this dissertation was to explore teaching in higher education from the teachers’ perspective. Two of the four studies analysed the effect of pedagogical training on approaches to teaching and on self-efficacy beliefs of teachers on teaching. Of these two studies, Study I analysed the effect of pedagogical training by applying a cross-sectional setting. The results showed that short training made teachers less student-centred and decreased their self-efficacy beliefs, as reported by the teachers themselves. However, more constant training enhanced the adoption of a student-centred approach to teaching and increased the self-efficacy beliefs of teachers as well. The teacher-focused approach to teaching was more resistant to change. Study II, on the other hand, applied a longitudinal setting. The results implied that among teachers who had not acquired more pedagogical training after Study II there were no changes in the student-focused approach scale between the measurements. However, teachers who had participated in further pedagogical training scored significantly higher on the scale measuring the student-focused approach to teaching. There were positive changes in the self-efficacy beliefs of teachers among teachers who had not participated in further training as well as among those who had. However, the analysis revealed that those teachers had the least teaching experience. Again, the teacher-focused approach was more resistant to change. Study III analysed approaches to teaching qualitatively by using a large and multidisciplinary sample in order to capture the variation in descriptions of teaching. Two broad categories of description were found: the learning-focused and the content-focused approach to teaching. The results implied that the purpose of teaching separates the two categories. In addition, the study aimed to identify different aspects of teaching in the higher-education context. Ten aspects of teaching were identified. While Study III explored teaching on a general level, Study IV analysed teaching on an individual level. The aim was to explore consonance and dissonance in the kinds of combinations of approaches to teaching university teachers adopt. The results showed that some teachers were clearly and systematically either learning- or content-focused. On the other hand, profiles of some teachers consisted of combinations of learning- and content-focused approaches or conceptions making their profiles dissonant. Three types of dissonance were identified. The four studies indicated that pedagogical training organised for university teachers is needed in order to enhance the development of their teaching. The results implied that the shift from content-focused or dissonant profiles towards consonant learning-focused profiles is a slow process and that teachers’ conceptions of teaching have to be addressed first in order to promote learning-focused teaching.

Tropical dryland agroforestry on clay soils: : Analysis of systems based on Acacia senegal in the Blue Nile region, Sudan

Acacia senegal, the gum arabic producing tree, is the most important component in traditional dryland agroforestry systems in the Blue Nile region, Sudan. The aim of the present study was to provide new knowledge on the potential use of A. senegal in dryland agroforestry systems on clay soils, as well as information on tree/crop interaction, and on silvicultural and management tools, with consideration on system productivity, nutrient cycling and sustainability. Moreover, the aim was also to clarify the intra-specific variation in the performance of A. senegal and, specifically, the adaptation of trees of different origin to the clay soils of the Blue Nile region. In agroforestry systems established at the beginning of the study, tree and crop growth, water use, gum and crop yields, nutrient cycling and system performance were investigated for a period of four years (1999 to 2002). Trees were grown at 5 x 5 m and 10 x 10 m spacing alone or in mixture with sorghum or sesame; crops were also grown in sole culture. The symbiotic biological N2 fixation by A. senegal was estimated using the 15N natural abundance (δ15N) procedure in eight provenances collected from different environments and soil types of the gum arabic belt and grown in clay soil in the Blue Nile region. Balanites aegyptiaca (a non-legume) was used as a non-N-fixing reference tree species, so as to allow 15N-based estimates of the proportion of the nitrogen in trees derived from the atmosphere. In the planted acacia trees, measurements were made on shoot growth, water-use efficiency (as assessed by the δ13C method) and (starting from the third year) gum production. Carbon isotope ratios were obtained from the leaves and branch wood samples. The agroforestry system design caused no statistically significant variation in water use, but the variation was highly significant between years, and the highest water use occurred in the years with high rainfall. No statistically significant differences were found in sorghum or sesame yields when intercropping and sole crop systems were compared (yield averages were 1.54 and 1.54 ha-1 for sorghum and 0.36 and 0.42 t ha-1 for sesame in the intercropped and mono-crop plots, respectively). Thus, at an early stage of agroforestry system management, A. senegal had no detrimental effect on crop yield, but the pattern of resource capture by trees and crops may change as the system matures. Intercropping resulted in taller trees and larger basal and crown diameters as compared to the development of sole trees. It also resulted in a higher land equivalent ratio. When gum yields were analysed it was found that a significant positive relationship existed between the second gum picking and the total gum yield. The second gum picking seems to be a decisive factor in gum production and could be used as an indicator for the total gum yield in a particular year. In trees, the concentrations of N and P were higher in leaves and roots, whereas the levels of K were higher in stems, branches and roots. Soil organic matter, N, P and K contents were highest in the upper soil stratum. There was some indication that the P content slightly increased in the topsoil as the agroforestry plantations aged. At a stocking of 400 trees ha-1 (5 x 5 m spacing), A. senegal accumulated in the biomass a total of 18, 1.21, 7.8 and 972 kg ha-1of N, P, K and OC, respectively. Trees contributed ca. 217 and 1500 kg ha-1 of K and OC, respectively, to the top 25-cm of soil over the first four years of intercropping. Acacia provenances of clay plain origin showed considerable variation in seed weight. They also had the lowest average seed weight as compared to the sandy soil (western) provenances. At the experimental site in the clay soil region, the clay provenances were distinctly superior to the sand provenances in all traits studied but especially in basal diameter and crown width, thus reflecting their adaptation to the environment. Values of δ13C, indicating water use efficiency, were higher in the sand soil group as compared to the clay one, both in leaves and in branch wood. This suggests that the sand provenances (with an average value of -28.07 ) displayed conservative water use and high drought tolerance. Of the clay provenances, the local one (Bout) displayed a highly negative (-29.31 ) value, which indicates less conservative water use that resulted in high productivity at this particular clay-soil site. Water use thus appeared to correspond to the environmental conditions prevailing at the original locations for these provenances. Results suggest that A. senegal provenances from the clay part of the gum belt are adapted for a faster growth rate and higher biomass and gum productivity as compared to provenances from sand regions. A strong negative relationship was found between the per-tree gum yield and water use efficiency, as indicated by δ13C. The differences in water use and gum production were greater among provenance groups than within them, suggesting that selection among rather than within provenances would result in distinct genetic gain in gum yield. The relative δ15N values ( ) were higher in B. aegyptiaca than in the N2-fixing acacia provenances. The amount of Ndfa increased significantly with age in all provenances, indicating that A. senegal is a potentially efficient nitrogen fixer and has an important role in t agroforestry development. The total above-ground contribution of fixed N to foliage growth in 4-year-old A. senegal trees was highest in the Rahad sand-soil provenance (46.7 kg N ha-1) and lowest in the Mazmoom clay-soil provenance (28.7 kg N ha-1). This study represents the first use of the δ15N method for estimating the N input by A. senegal in the gum belt of Sudan. Key words: Acacia senegal, agroforestry, clay plain, δ13C, δ15N, gum arabic, nutrient cycling, Ndfa, Sorghum bicolor, Sesamum indicum

Interactions between transgenic trees and mycorrhizal and pathogenic fungi

The development of biotechnology techniques in plant breeding and the new commercial applications have raised public and scientific concerns about the safety of genetically modified (GM) crops and trees. To find out the feasibility of these new technologies in the breeding of commercially important Finnish hardwood species and to estimate the ecological risks of the produced transgenic plants, the experiments of this study have been conducted as a part of a larger project focusing on the risk assessment of GM-trees. Transgenic Betula pendula and Populus trees were produced via Agrobacterium mediated transformation. Stilbene synthase (STS) gene from pine (Pinus sylvestris) and chitinase gene from sugar beet (Beta vulgaris) were transferred to (hybrid) aspen and birch, respectively, to improve disease resistance against fungal pathogens. To modify lignin biosynthesis, a 4-coumarate:coenzyme A ligase (4CL) gene fragment in antisense orientation was introduced into two birch clones. In in vitro test, one transgenic aspen line expressing pine STS gene showed increased resistance to decay fungus Phellinus tremulae. In the field, chitinase transgenic birch lines were more susceptible to leaf spot (Pyrenopeziza betulicola) than the non-transgenic control clone while the resistance against birch rust (Melampsoridium betulinum) was improved. No changes in the content or composition of lignin were detected in the 4CL antisense birch lines. In order to evaluate the ecological effects of the produced GM trees on non-target organisms, an in vitro mycorrhiza experiment with Paxillus involutus and a decomposition experiment in the field were performed. The expression of a transgenic chitinase did not disturb the establishment of mycorrhizal symbiosis between birch and P. involutus in vitro. 4CL antisense transformed birch lines showed retarded root growth but were able to form normal ectomycorrhizal associations with the mycorrhizal fungus in vitro. 4CL lines also showed normal litter decomposition. Unexpected growth reductions resulting from the gene transformation were observed in chitinase transgenic and 4CL antisense birch lines. These results indicate that genetic engineering can provide a tool in increasing disease resistance in Finnish tree species. More extensive data with several ectomycorrhizal species is needed to evaluate the consequences of transgene expression on beneficial plant-fungus symbioses. The potential pleiotropic effects of the transgene should also be taken into account when considering the safety of transgenic trees.

Egg production in furnished cages

In the European Union, conventional cages for laying hens will be faded out at the beginning of 2012. The rationale behind this is a public concern over animal welfare in egg production. As alternatives to conventional cages, the European Union Council Directive 1999/74/EC allows non-cage systems and enriched (furnished) cages. Layer performance, behavior, and welfare in differently sized furnished cages have been investigated quite widely during recent decades, but nutrition of hens in this production system has received less attention. This thesis aims to compare production and feed intake of laying hens in furnished and conventional cages and to study the effects of different dietary treatments in these production systems, thus contributing to the general knowledge of furnished cages as an egg production system. A furnished cage model for 8 hens was compared with a 3-hen conventional cage. Three consecutive experiments each studied one aspect of layer diet: The first experiment investigated the effects of dietary protein/energy ratio, the second dietary energy levels, and the third the effects of extra limestone supplementation. In addition, a fourth experiment evaluated the effects of perches on feed consumption and behavior of hens in furnished cages. The dietary treatments in experiments 1 3 generally had similar effects in the two cage types. Thus, there was no evidence supporting a change in nutrient requirements for laying hens when conventional cages are replaced with small-group furnished cages. Moreover, the results from nutritional experiments conducted in conventional cages can be applied to small-group furnished cage systems. These results support the view that production performance comparable with conventional cages can be achieved in furnished cages. All of the advantages of cages for bird welfare are sustained in the small-group furnished cages used here. In addition, frequent use of perches and nests implies a wider behavioral repertoire in furnished cages than in conventional cages. The increase observed in bone ash content may improve bird welfare in furnished cages. The presence of perches diminished feed consumption during the prelaying period and enhanced the feed conversion ratio during the early laying period in furnished cages. However, as the presence or absence of perches in furnished cages had no significant effect on feed consumption after the prelaying period, the lower feed consumption observed in furnished cages than in conventional cages could be attributed to other factors, such as the presence of wood shavings or a nest box. The wider feed trough space per hen in conventional than in furnished cages may partly explain the higher feed consumption observed in conventional cages.

Digestion capasity, nutrient digestibilities and physico-chemical conditions in the intestine influenced by the age of growing turkeys

Six experiments have been conducted to examine digestibility and feeding value of domestic Finnish fibre-rich cereals (barley and oats as compared to maize and wheat) and protein sources (rapeseed meal and cake, peas, faba beans, lupin seeds) for growing turkeys and to investigate effects of age of the birds (from 3 to 12 weeks of age) on digestion process and estimated nutrient digestibility and energy values. Besides, an objective of the study was to test applications of digestibility research methodology for turkeys. Total tract digestibility and apparent metabolizable energy (AME) was assayed in experimental cages using excreta collection, and a slaughter method was applied to sample small intestinal digesta for determination of apparent ileal crude protein digestibility (AICPD), jejuno-duodenal digesta viscosity and caecal volatile fatty acid (VFA) concentration. Digesta viscosity decreased and caecal VFA production increased with age of growing turkeys. Digesta retention times in the small intestine were generally longer in the older birds than in the younger ones. Crude fat digestibility and AME increased with age of growing turkeys, especially with viscous diets. AICPD seemed to decrease with age in most cases. Supplementation with β-gucanase-xylanase decreased viscosity, improved crude fat digestibility and metabolizable energy value and increased VFA production especially in barley-fed turkeys and especially in the young birds. Poor protein digestibility and low energy value of rapeseed meal and rapeseed cake decreased their feeding value for turkeys. In addition, a typical goitrogenic effect of rapeseed feeding was detected. Use of legume seeds as feed for growing turkeys is limited mostly by the low energy value in lupin seeds and the low ileal protein and amino acid digestibility in faba beans. Digestibility of fibre-rich protein sources was not improved with age of the turkeys. Euthanizing the turkeys for AICPD determination by carbon dioxide and bleeding led to lower digestibility values than mechanical stunning and cervical dislocation, suggesting inferiority of carbon dioxide stunning in experimental use. Comparison of AICPD and AME results obtained using different markers showed that considerable differences may occur, especially on total tract level, when acid-insoluble ash gave considerably lower AME values than titanium dioxide and chromic oxide.

Monitoring of Fungal Growth and Degradation of Wood

Valko- ja ruskolahosienet tunnetaan luonnossa tehokkaimpina puun ja karikkeen lignoselluloosan lahottajina. Valkolahosienet pystyvät hajottamaan kaikkia puun osia: ligniiniä, selluloosaa ja hemiselluloosaa. Selektiivisesti ligniiniä hajottavat sienet lahottavat puusta suhteessa enemmän vaikeasti hajoavaa ligniiniä kuin selluloosaa tai hemiselluloosaa, jolloin jäljelle jää valkoista ja miltei puhdasta selluloosaa. Bioteknisissä sovelluksissa juuri selektiviiviset valkolahottajat ovat kiinnostavia. Niiden avulla voidaan puuhaketta esikäsitellä esimerkiksi paperinvalmistuksessa haitallisen ligniinin poistamiseksi. Ruskolahosienet ovat huomattavia puun, puutavaran ja puisten rakenteiden lahottajia, kuten tässä työssä käytetty Gloeophyllum trabeum (saunasieni ) ja Poria (Postia) placenta (istukkakääpä). Ruskolahosienet hajottavat puusta hemiselluloosan lisäksi selluloosaa, jolloin jää jäljelle ruskea ja jauhomaiseksi mureneva ligniini. Ruskolahosienet muovaavat ligniiniä jonkin verran. Kahden ruskolahosienen G. trabeumin ja P. placentan lisäksi tutkittiin valkolahosieniä, joista Ceriporiopsis subvermispora (karstakääpä) ja harvinainen Physisporinus rivulosus -sieni (talikääpä) hajottavat ligniiniä erittäin selektiivisesti. Phanerochaete chrysosporium on kaikkialla paljon tutkittu sieni, ja Phlebia radiata valkolahosientä (rusorypykkä) on tutkittu paljon mikrobiologian osastolla. Lisäksi tutkittiin Phlebia tremellosa -sienten (hytyrypykkä) ligninolyyttisten entsyymien tuottoa ja 14C-leimatun synteettisen ligniinin (DHP) hajotusta. P. radiata ja P. tremellosa -sienten on todettu aiemmin hajottavan ligniiniä selektiivisesti. Työssä selvitettiin miten sienten kasvua voi mitata, miten vertailukelpoisia eri mittaamismenetelmillä saadut tulokset ovat ja ilmenevätkö sienten aktiivisimmat kasvuvaiheet samaan aikaan eri menetelmillä mitattuna. Tärkeimmät tulokset olivat seuraavat havainnot: (i) P. radiata ja P. tremellosa -sienikannat tuottivat ligniini- ja mangaaniperoksidaasientsyymejä (LiP ja MnP) sekä lakkaasia, ja sienistä puhdistettiin 2-3 LiP- ja P. radiatasta yksi MnP-entsyymi; (ii) P. tremellosa -sienet hajottivat leimattua synteettistä ligniiniä (DHP) yhtä hyvin kuin paljon tutkitut P. chrysosporium ja P. radiata -sienet; (iii) puu, sienen luonnollinen kasvualusta, lisäsi valkolaho- ja ruskolahosienten demetoksylaatiota [O14CH3]-leimatusta ligniinin malliyhdisteestä 14CO2:ksi ilman puuta olleeseen alustaan verrattuna; (iv) demetoksylaatio (14CO2:n tuotto) oli normaalissa ilma-atmosfäärissä useimmiten parempi happeen verrattuna; (v) hapessa paras 14CO2:n tuotto saatiin puupalakasvatuksissa, joihin oli lisätty ravinnetyppeä tai typen lisäksi glukoosia sekä valkolaho- että ruskolahosienillä; (vi) ilmassa 14CO2:n tuotto oli puulla voimakkainta valkolahosienillä ilman lisäravinteita, kun taas G. trabeum -sienellä se oli yhtä hyvä eri alustoissa; (vii) biomassan muodostuminen rihmastojen ergosterolipitoisuuksista mitattuna oli ruskolahosienillä parempi kuin valkolahosienillä; (viii) ja biomassojen huippupitoisuudet olivat 6:lla sienellä eri suuruisia ja niiden maksimimäärien ajankohdat vaihtelivat viiden viikon kasvatusten kuluessa. Mikrobiologian osastolla Viikissä eristetty ja paljon tutkittu P. radiata -valkolahosieni oli mukana kaikissa tehdyissä kokeissa. Sienen LiP-aktiivisuus ja 14CO2:n tuotto 14C-rengas-leimatusta synteettisestä ligniinistä (DHP) korreloivat erittäin hyvin. Biomassan muodostuminen ergosterolilla määritettynä tuki hyvin entsyymiaktiivisuusmittauksilla ja isotooppikasvatuksilla saatuja tuloksia.