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In recent years, psychedelics have shown promise in the treatment of conditions like depression and addiction. The therapeutic effects of psychedelics have been linked to their ability to increase plasticity in the brain, an effect that has also been seen for antidepressants. Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family, which has an important role in the development of the nervous system, as well as promotion of neuronal survival and differentiation during adulthood. BDNF, through its receptor TrkB, has been implicated in antidepressant action, and BDNF-TrkB signalling is involved in many aspects of plasticity. Recently, antidepressants have been reported to bind directly to TrkB, and through this binding mediate their plasticity-enhancing, as well as behavioural effects. Psychedelics have been shown to increase structural and functional plasticity, but the mechanisms behind these effects are not fully understood. For example, the serotonergic receptor 5-HT2A is known to be behind the acute hallucinogenic effects of psychedelics, but its role in plasticity is still debated. The aim of this study was to investigate the mechanisms of LSD-induced plasticity. The dimerization of TrkB was examined after LSD treatment in the protein-fragment complementation assay (PCA). Phosphorylation of TrkB signalling markers mTOR and ERK, which have known effects on plasticity, was assessed in Western blot, and the total expression of BDNF was examined with the enzyme-linked immunosorbent assay (ELISA). The timeline of the effects was investigated, and the involvement of 5-HT2A in TrkB dimerization and the phosphorylation of ERK was assessed by combining LSD treatment with the 5-HT2A antagonist M100907. Dimerization was also assessed in a TrkB mutant (Y433F) that has previously been shown to disrupt antidepressant effects on plasticity. These experiments showed that LSD treatment increased TrkB dimerization as well as phosphorylation of mTOR and ERK. The Y433F mutation interfered with LSD-induced TrkB dimerization, but the effects of LSD on TrkB dimerization or ERK phosphorylation were not blocked by M100907. Together, these data suggest that 5-HT2A is not involved in LSD-induced promotion of TrkB dimerization or ERK phosphorylation. The increases in phosphorylation and dimerization were found to be most robust after a 1 h LSD treatment, however an increase in BDNF expression was seen in cortical neuron cultures only after a 24 h treatment with LSD. The results reported in this study support the view that 5-HT2A might not be needed for the plasticity-inducing effects of psychedelics. If this is true, the development of treatments that target plasticity without hallucinatory effects could be possible. Overall, this research provides insight into the mechanisms of LSD-induced plasticity and offers new and interesting directions for future research in the field.

4-Methylmethcathinone (Mephedrone) is one of the the most prevalent synthetic cathinones that bears close structural similarity to amphetamines. Like other stimulants, mephedrone is often used with alcohol (ethanol). In animal studies ethanol has been observed to potentiate the neurotoxicity of amphetamine-type stimulants, and same has been observed when mephedrone and alcohol is combined. The long-term effects of mephedrone have still remained largely elusive. The aim of this thesis is to study the effects of mephedrone, methamphetamine, and ethanol on dendritic spine density and morphology in the hippocampus, nucleus accumbens and caudate putamen, and compare the spine densities with changes in brain activation observed in manganese-enhanced magnetic resonance imaging (MEMRI). Dendritic spines are small membranous protrusions on dendrites that act as the post-synaptic sites for most of the excitatory synapses. Amphetamine and methamphetamine have been shown to affect the density and morphology of the spines. The goal of this thesis was to investigate the long-term effect of binge-like (two times a day, four consecutive days) stimulant treatment on dendritic spines using Golgi-stained rat brain sections. The brains of 48 male Wistar rats were imaged using AxioImager Z2 microscope and the number and the size of the spines was analyzed using Reconstruct software. In this thesis no effect on dendritic spines was observed in the hippocampus and nucleus accumbens in animals treated with mephedrone, methamphetamine, ethanol or combination of them. In the caudate putamen significant increase in the total density of dendritic spines and in the density of filopodia-like spines was observed in mephedrone-treated animals. Other treatments showed no observable effect. These results were conflicting with previous studies where amphetamine-type stimulants have been shown to increase the spine density in the nucleus accumbens and the hippocampus and increase the density of branched spines. In the caudate putamen methamphetamine has been observed to decrease the spine density. There was no correlation between spine densities and brain activation observed in MEMRI. To my best knowledge this is the first time when the effect of mephedrone on dendritic spines has been studied. It is possible that the treatment regimen used here was not strong enough to produce marked long-term changes on dendritic spines. It is also possible, that mephedrone is not as neurotoxic as other amphetamine-type stimulants, which may explain why the effects remained limited and conflicting. More research is still required to establish the long-term structural effects of mephedrone.

Peatlands play an important role in the carbon cycle. Natural peatlands are in general sinks of carbon dioxide (CO2) and sources of methane (CH4), whereas drained peatland forests are CH4 sinks but their CO2 emissions increase compared to natural peatlands. Rotational even-aged forestry followed by ditch network maintenance (DNM) affect the water dynamics of the soil by increasing the water table level (WTL) first during clear-cut after which the WTL is lowered by DNM. Rising of WTL causes more anaerobic conditions and risk that CH4 sink turns into CH4 emissions. Lowering the WTL causes more aerobic conditions and strengthens the CH4 sink function but also increases CO2 emissions. In continuous cover forestry (CCF) where only part of the trees are removed, WTL would be naturally maintained. This could maintain CH4 sinks while lowering CO2 emissions by keeping the WTL at an adequate depth. Net emissions of CO2 and CH4 could be expected to follow the changes in CO2 and CH4 concentrations in soil. To understand the processes isotopic values can be used to interpret the production pathways of CO2 and CH4 since different pathways produce different isotope values. In this master’s thesis the aim was to study how the concentration of CO2 and CH4 as well as CO2 isotope values change in a peat soil and how partial harvest affects them. Gas samples were collected from the peat profile (5 – 65cm) at two different drained peatland forests, Lettosuo and Paroninkorpi, from control plots and partial harvested plots during 2019 and 2020. Samples were also collected from the moss layer. In addition, WTL, temperature of peat and O2 concentrations were measured. Concentrations and isotope values were analysed the laboratory with gas chromatography and isotope analyser (Picarro G2201-i). Water table level and temperature were generally higher in partial harvested areas than in control. Highest concentrations of both CO2 and CH4 were found in the deeper layers of the soil. Partial harvest had higher CO2 and CH4 concentrations in the deep layers (50 – 65cm) than control. The differences between partial harvest and control areas could be explained with the higher WTL in partial harvest. The measured isotopic values of CO2 indicated that most of the CO2 in the soil was derived from atmosphere or heterotrophic respiration and only <<20 % of CO2 was derived from CH4 oxidation. Even though both in control and in partial harvest the CH4 concentrations in the deep soil layers were high, the oxidation processes decrease the concentrations under the atmospheric CH4 concentration maintaining the CH4 sinks in both treatments. In partial harvest the CH4 sink is not in risk due to oxidation even though the WTL is higher. This should be verified with gas flux measurements.

Salt-induced flocculation is a process in which dissolved salts in seawater modify dissolved organic matter (DOM) surface charges and enable its transformation into larger fractions. These larger particles can settle to the benthos removing organic matter from the water column. Flocs formed in the flocculation process are often referred to as suspended particulate material (SPM). SPM is an important part of the biogeochemical cycles. SPM is a vector for pollutants, a food source for organisms and a habitat for microbes. Flocculation is part of the estuarine “coastal filter” -system controlling the material fluxes from land to sea. Climate change is causing water temperatures to increase in both inland and coastal waters affecting the biogeochemistry of aquatic ecosystems. Flocculation is a physicochemical process potentially impacted by temperature but the effects of temperature on flocculation are not well known. In my master’s thesis, I studied the effects of water temperature on the salt-induced flocculation of humic-rich river water. The flocculation experiments were conducted in spring 2023 using humic-rich water sampled from Vantaanjoki, Helsinki, Finland. The effects of temperature were studied in two separate experiments at temperatures ranging from 3 ºC to 20 ºC. The studied variables included quantitative suspended particulate matter as well as the optical properties of DOM including colored DOM and fluorescent DOM. Results of the experiments show that temperature did not have a significant effect on the salt-induced flocculation of DOM in humic-rich river water. However, the optical properties of DOM shifted with increasing temperatures and changing flocculation dynamics. Results show that molecular size increased as temperature increased but also when temperature was lower than 3 ºC. Explanation for the observed trends is discussed but more research is needed for more firm conclusions. DOM concentrations are expected to increase in the Arctic and sub-Arctic rivers transporting more organic matter to estuaries. Results of this thesis suggest that rising temperatures will not increase the amount of particulate matter through salt-induced flocculation meaning that a larger portion of the transported material remains in dissolved fraction. Increases in DOM concentrations may shift marine food webs by changing the food and light availability as well as biogeochemistry in estuaries.

Interdisciplinary studies are currently an important topic in education. One reason behind this is the idea that students should learn 21st century skills, such as critical thinking, communication and problem-solving skills for their future careers. Interdisciplinary education has also been shown to increase students’ interest towards natural sciences. Furthermore, organizing cross-curricular learning units has become compulsory at a curricular level in Finland and other countries. Project-based learning is a widely supported teaching method in which learning is organized around projects. It is also a natural method to carry out interdisciplinary learning units. Project-based learning is usually defined by its characteristic features, and its successful implementation requires the teacher to have a good knowledge of them. However, these characteristics tend to be unknown for teachers. Research has also shown that teachers’ conceptions of what interdisciplinary education and project-based learning are, tend to vary. As such, it has been noted in the literature that there is a need to offer training and materials for the implementation of interdisciplinary and project-based learning for in-service teachers. Although MOOCs (Massive Open Online Courses) have a lot of potential as a means of professional development, they are rarely planned to serve primarily as in-service teacher training. Empirical research into their design is also scarce. The main aims in this study were to 1) provide more information about interdisciplinary education within biology education 2) develop a MOOC for the professional development of biology teachers on the topic of interdisciplinary education and project-based learning. In addition to that the study aimed to develop the StarT programme of LUMA Centre Finland. The study was carried out as design-based research. The main research question that directed the design process was: what should a MOOC that supports teachers to carry out interdisciplinary project-based learning within the theme “nature and environment” in biology be like? Nature and environment was chosen as the context of the study as from the perspective of biology education it offers an important and current topic for interdisciplinary project units. The main research question was approached through a theoretical and empirical problem analysis. Theoretical problem analysis focused on researching the question in earlier literature, and the empirical problem analysis was carried out as a case study in which qualitative data was studied through deductive content analysis. The materials studied in the empirical problem analysis were project-based learning units of comprehensive schools and high schools. Their project units were studied through the following research questions: 1. How did teachers and students carry out the characteristics of project-based learning in the context of the theme nature and environment in biology? 2. How is biology taught in an interdisciplinary way in the theme nature and environment? The first question was studied through the characteristics that were identified for project-based learning in the theoretical problem analysis, and the second by looking at which subjects collaborated with biology, how the collaboration was carried out and how the learning communities experienced it. The goal was to find a) challenging characteristics of project-based learning and interdisciplinary education that should be considered the design of the MOOC b) good examples from the studied learning communities to be shared on the MOOC. The study subjects consisted of 12 learning communities who had participated in the international StarT programme of LUMA Centre Finland. In accordance with earlier studies, also the subjects of this study struggled especially with driving questions, the unity of the project activities and in using the projects as a means to learn central contents. Scientific practices were visible well apart from students’ questions, but it could not be defined how strongly student-led the inquiry was. The connection between instructions of StarT and the characteristics of project-based learning that were well represented in the materials seemed evident: collaboration, sharing results, end products and using technology were all visible throughout the analyzed learning communities. However, the materials offered little information about how the collaboration between different subjects was carried out in practice. The study indicated also that students and teachers paid attention to different aspects of the learning taking place in project-based learning, and that teachers might include topics of certain subjects into the project units without realizing it. This should be further researched, however. The issues identified in the problem analyses were used to design an international MOOC that is suitable especially for biology teachers. The course ”Project-based learning and the theory behind it – create your own project!” was created on the Moodle-platform of the University of Helsinki. In addition to this, a phased model for creating professional development in a situation where the studied materials can be used both to direct the design process and as materials on the course was created. The framework that was created for the analyses in this study can also be further used and developed to study how characteristics of project-based learning are represented in other cases where teachers’ and students’ project units are being studied. The study provided also new information about what is possible and feasible to study from the materials of StarT. New information was provided also of the project-based learning that takes place at the schools of the StarT participants, as they have not been researched from the perspective of the characteristics of project-based learning earlier.

This interdisciplinary study seeks to raise awareness of and generate interest in projects that combine science and art. A number of such projects are discussed and analyzed with the help of the concept 'Ecovention'. The concept is operationalized to include works of art that ecologically restore, reclaim, and remediate damaged ecosystems by physical actions and inventions. They transform the ecosystem and often slowly disappear into the environment, contributing to the overall wellbeing of the ecosystem. These works of art are long-lasting and site-specific. They are built outdoors by using material that is already available in the ecosystem or by bringing in environmental-friendly material into the ecosystem. The central research question for the study is as follows: How significantly does environmental art affect the local ecosystem when the starting point is ecological restoration? This is a qualitative study. The data for the study consist of interviews with experts together with analyses of the historical, cultural, and ecological background material for two Finnish environmental artworks. The two artworks are Agnes Denes's Puuvuori (Tree Mountain - A Living Time Capsule, 1996) and Jackie Brookner's Veden taika (The Magic of Water, 2007- 2010). These works of art were chosen because of the availability of historical and natural scientific research data about how they were planned and how they were constructed. The availability of this kind of data related to environmental art is rare in Finland. The Magic of Water consists of three floating islands in Salo. They are situated in a lagoon that was formerly used as a clarification pool at the Salo Municipal Sewage Treatment Facility. The artwork has succeeded in supplying a peaceful nesting habitat for the birdlife in the area. It has been shown that a colony of black-headed gulls (Larus ridibundus) is a new species nesting in the islands. The Magic of Water did not provide a significant improvement of the water quality by phytoremediation since the islands are relatively small in relation to the area of the lagoon. Tree Mountain - A Living Time Capsule is to be found in Pinsiönkangas, at the most important groundwater area in Ylöjärvi. The artwork reclaims a former gravel pit. Tree Mountain is a 28 meter tall hill in an area of elliptical shape that spans nine hectares. 10,600 pine tree saplings (Pinus sylvestris) and about 40,000 cubic meters of soil from the area was used to build the artwork. Tree Mountain is nowadays owned by the town of Ylöjärvi and Pinsiönkangas is principally a conservation area. The Tree Mountain - A Living Time Capsule is argued to fit well in the regionally precious ridgescenary since the work of art has enough of biological values. Most likely the building of the artwork has had a preventive effect on possible ecological harm and it has made the community take responsibility for taking care of the reclaimed environment in the long term. In the face of high-quality ecological restoration plans it is important to approach the restoration of ecosystems from a holistic perspective. The artist s vision of how an ecosystem can be restored adds a surplus value to ecological restoration work since also the aesthetic and ideological dimensions are reconstructed. The probable positive view of the community towards the restored ecosystem can promote not only the attendance by the community to that particular area in the future, but it can also promote the attendance of a community to other areas as well.

Permafrost peatlands have a significant role in the global carbon cycle, as they store ca. 185 Pg of carbon. Because of the slow decomposition of organic matter, they have sequestered carbon dioxide from the atmosphere and cooled the climate for thousands of years. However, in anaerobic decomposition also methane – a strong greenhouse gas – is produced. Climate change results in changes in permafrost peatland habitats; distribution and proportional share and these changes also affect the CO2 and CH4 fluxes. In this master’s thesis I compare the net ecosystem exchange and pore water methane concentrations in different microhabitats in the Stordalen palsa mire in Abisko, Sweden. In addition, I review the reported climate change-driven habitat changes in the area and its effects on the CO2 and CH4 fluxes. My results suggest that Sphagnum sp. and Sphagnum fuscum -microhabitats were net sinks of CO2 whereas lichen-, shrub- and Eriophorum-microhabitats were net sources. These results were best explained by the proportional coverage of green vegetation, which was highest in both Sphagnum-microhabitats. No discernible differences were found between pore water methane concentrations in different habitats. Permafrost thawing has increased the occurrence of wet habitats in Stordalen. These habitat changes have increased carbon sequestration in the area but at the same time methane emissions have also increased. Because of this, the radiative forcing of the peatland has changed from negative to positive and the on-going habitat changes will likely continue in future. On a longer timespan though, the radiative forcing will likely switch back to negative as carbon sequestration increases and the effects of the methane emissions decrease.

Eläinten tunnemaailma on meille melko vieras. Sen takia on tärkeää tutkia, millaiset asiat vaikuttavat siihen, miten tulkitsemme niiden tunteita. Tunteiden tulkintaan voivat vaikuttaa tulkitsijan omat kokemukset. Tämän tutkielman tarkoituksena on tutkia sitä, mitkä asiat vaikuttavat siihen, kuinka hyvin eläintarhakävijät tunnistavat villieläinten tunteita. Erityisesti keskityn siihen, miten vastaajan sukupuoli, ikä, kasvuympäristö ja lapsuuden ja aikuisuuden aikaiset eläinkokemukset vaikuttavat eläintarhakävijöiden kykyyn tunnistaa eläinten tunteita. Tutkimus tehtiin kyselytutkimuksena Korkeasaaren eläintarhassa kesällä 2021. Osallistujille näytettiin videolta eläin ja heidän tuli kertoa, onko eläimen tunnetila neutraali, myönteinen vai kielteinen ja onko se rauhallinen vai kiihtynyt. Tutkimuksessa tutkittiin tiikereiden, berberiapinoiden ja markhorvuohien tunnetilan tunnistamista. Osallistujista kerättiin taustatietoja, kuten ikä ja sukupuoli. Tulosteni perusteella eläinlajilla on vaikutusta tunnetilan tunnistamiseen. Tiikerin myönteisyys tai kielteisyys osattiin arvioida huonommin kuin berberiapinan. Myös vastaajan ikä vaikuttaa tunteiden tunnistukseen. Vanhemmat tunnistivat myönteisyyden tai kielteisyyden nuorempia ihmisiä heikommin. Sukupuoli vaikuttaa yhdessä iän kanssa kiihtyneisyyden tunnistamiseen. Kiihtyneisyyden tunnistivat paremmin 18–30-vuotiaat naiset kuin 61–75-vuotiaat naiset, mutta muiden ryhmien välillä ei havaittu merkitseviä eroja. Kiihtyneisyys tunnistettiin myös paremmin, jos eläimet ovat olleet osana vastaajan elämää vain lapsuudessa sen sijaan, että ne olisivat olleet aina osana elämää. Tulosten perusteella voidaan päätellä, että ihmiset tunnistavat eri eläinten tunteet eri tavalla ja ihmismäisempien eläinten tunteet ovat muita helpommin tunnistettavissa. Iällä ja sukupuolella voi olla vaikutusta ihmisten kykyyn tunnistaa eläinten tunteita. Myös eläinkokemus vaikuttaa ihmisten kykyyn tunnistaa tunteita ja kokemus ei ole sama kuin tiedon omaksuminen. Tuloksiani voidaan hyödyntää esimerkiksi ympäristökasvatuksessa.

Supplementary bird feeding is a popular pastime, as well as one of the most important types of human–wildlife interaction, in Western countries. Bird-feeder sites are visited by birds, mammals, as well as other animals; some of these species are wanted visitors, some unwanted. Supplementary food at feeding sites offers visitors benefits, at least during winter. However, effects at the species, population and community level can be complex, and none of these levels necessarily benefit automatically from supplementary feeding. On the other hand, bird feeding generally increases human wellbeing. Animal attitudes affect the way we think about non-human animals. It has been discovered that how we view animals visiting feeding sites affects the ways in which people feasibly change the supplementary feeding they provide. Research on the subject has mostly been Anglo-American in context to date. Animal attitudes also affect official rules and regulations that govern the supplementary feeding or control measures of wildlife, for example. In this thesis, I have investigated the responses from a 2021 survey by the Finnish Museum of Natural History (Luomus) and BirdLife Finland. The survey was concerned with supplementary bird feeding and recent changes thereof. The survey got over 14,000 responses, over 9,000 of which included answers to open-ended questions. I sifted through the open-ended responses to find out which animal species and other organisms affect supplementary bird feeding provided by the respondents, and why. I utilised both quantitative and qualitative research methods to uncover such organisms and their effects. I used qualitative content analysis as my main method. I discovered that there are many types of primarily animal-/organism-related reasons behind changes in bird-feeding behaviour. I categorised these 28 reasons under seven subcategories within three main categories. Many of the reasons can have both negative (stop/decrease/shorten) and positive (start/increase/extend) effects on supplementary feeding. A discernible portion of the reasons are propped by one animal attitude or another. The category-based assortment of reasons acts as the main finding of this study, and it reflects the complexity of animal attitudes. I have additionally listed all taxons (species/groups of organisms) found in the survey responses along with their effects on supplementary feeding. I have produced novel information on which animal-related factors affect supplementary bird feeding in Finland, and why. Were we to better understand the inherent complexity of animal attitudes, authorities’ facts-based decision-making and a favourable general attitude towards endangered-species conservation could be enhanced. Zoonosis control could also gain new perspectives from novel information.

Lämpenevä ilmasto muuttaa boreaalisten metsien lajikoostumusta. Uudet lajit levittäytyvät yhä pohjoisemmaksi lämpenemisen siirtäessä kullekin lajille luontaisia elinympäristöjä. Lisäksi perustuotannon, karikkeen hajoamisen ja ravinteiden saatavuuden on ennustettu muuttuvan, mikä asettaa uusia sopeutumistarpeita kasvien typpitaloudelle. Erityisesti pitkäikäiset puut kohtaavat merkittävän haasteen suotuisten elinympäristöjen siirtyessä nopeammin kuin puut kykenevät itse leviämään uusiin kasvuympäristöihin. Tässä pro gradu- työssä tarkastelen elinympäristön muutoksen vaikutuksia neljän rauduskoivupopulaation (Betula pendula) puiden elinvoimaisuutta ilmentäviin ominaisuuksiin sekä niiden tuottaman karikkeen laatuun ja hajoamiseen. Hyödynsin tutkimuksessani olemassa olevaa koeasetelmaa, jossa pohjois-eteläsuuntaista gradienttia edustavista populaatioista (alkuperistä) kloonattuja rauduskoivun taimia on istutettu yhteisille "common garden" -kasvupaikoille Tuusulaan, Joensuuhun ja Kolariin. Erityisesti etelään päin siirron on tarkoitus simuloida ilmaston lämpenemistä. Tutkimusaineistoni koostuu 233 taimesta, joista määritin pituuskasvun, lehtien hiili- (C), typpi- (N) ja vesipitoisuuden sekä typen takaisinottotehokkuuden, lehtialaindeksin ja herbivorivioituksen. Lisäksi määritin maatuvan lehtikarikkeen massahäviön ja lehtikarikkeesta vapautuvan typen määrän 3 kk kestäneessä maatumiskokeessa. Aineiston keräsin puiden neljäntenä kasvukautena aikavälillä 27.6.2014 – 6.3.2015. Tulosten tilastolliseen analysoimiseen käytin varianssi- ja korrelaatioanalyysejä. Vihreiden lehtien N-pitoisuus (%) pieneni lineaarisesti pohjois-eteläsuuntaisesti, kun taas typen takaisinottotehokkuus heikkeni ja muodostuvan lehtikarikkeen N % kasvoi, kun populaatioita siirrettiin pohjoiseen tai etelään alkuperäiseltä kasvupaikaltaan. Siirto vähensi myös pituuskasvua ja lehtien vesipitoisuutta. Herbivorivioitus ja lehtialaindeksi eivät reagoineet siirtoon. Vihreiden lehtien N % korreloi positiivisesti typen takaisinottotehokkuuden kanssa. Mitä suurempi takaisinottotehokkuus, sitä pienempi oli typpipitoisuus lehtikarikkeessa. Maatuvan karikkeen massahäviö kasvoi, mitä suurempi oli maatuvan karikkeen N-pitoisuus. Erityisesti Joensuun ja Tuusulan kasvupaikoilta kerätyn karikkeen massahäviö oli sitä suurempaa, mitä pohjoisemmasta alkuperästä oli kyse. Typpeä ei vapautunut maatumiskokeen aikana, eikä typen vapautuminen korreloinut lehdistä mitattujen ominaisuuksien kanssa. Tulokseni osoittavat, että rauduskoivun pituuskasvu, lehtien vesipitoisuus ja sisäinen typpitalous ovat parhaimmillaan alkuperäisellä kasvupaikalla, ts. populaatiot ovat paikallisesti sopeutuneita. Muutokset typen takaisinottotehokkuudessa näyttävät liittyvän rauduskoivun kasvuun, joka heikkeni elinympäristön muuttuessa. Populaatioiden pohjois-etelä-siirto heikensi typen takaisinottotehokkuutta ja lisäsi maatuvan karikkeen massahäviötä. Tulokseni osoittavat, että tulevaisuuden muuttuvat ilmasto- ja ympäristöolosuhteet voivat heikentää puiden elinvoimaisuutta pohjoisissa ekosysteemeissä, mutta toisaalta samanaikaisesti kiihdyttää karikkeen maatumista parantamalla muodostuvan kasvikarikkeen laatua.