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Browsing by study line "Forest ecology and management"

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  • Papunen, Saija (2022)
    Measuring the effectiveness of protected areas (PAs) is essential as they are key tools in tackling the ongoing biodiversity loss and there is substantial variation in their effectiveness (the estimated ability of protected areas to prevent unnatural disturbances). In forested PAs, the most common variable in effectiveness estimation is forest loss, but fire can also be used as a proxy for conversion. There is, however, a lack of robust comparisons between different data sets and proxies. This thesis aims to provide more insight into the issue by comparing three satellite-based data sets in protected area effectiveness assessment using Madagascar as a case study. The questions to be answered here are whether the data sets and variables derived from them produce similar PA effectiveness estimates and whether they could be used interchangeably in research and for practical management purposes. The hypotheses are as follows: H1: The three proxies produce similar results with the two fire proxies most likely having a stronger relationship. H2: The data sets can be used interchangeably both for science purposes and in practical management of PAs. The effectiveness of Malagasy protected areas established in or before 2005 (N=42) was examined from 2005 to 2017. Three binary response variables were compared: forest loss, fire incidence, and burned area. In addition, a continuous forest loss variable was examined. Forested areas and the full landscape were studied separately i.e. estimates were produced for both forested areas only and full landscape (forested areas + other areas). 1-kilometre parcels in a uniform grid were sampled using nearest neighbour Mahalanobis distance matching, controlling for the factors affecting conversion pressures with appropriate covariates: altitude, slope, distance to cities, distance to roads, distance to waterways, and rainfall for forested areas and full landscape, and in addition, distance to forest edge for forested areas. Relative effect, pooled relative effect, and network relative effect were calculated for the binary variables, mean effect for the continuous variable. The effects were calculated on country level, biome level (tropical and subtropical moist broadleaved forests, tropical and subtropical dry broadleaved forests, and deserts and xeric shrublands), and individual PA level. Protected areas appeared to be at least moderately effective, and all variables produced parallel, consistent results on the country and biome level, especially when using pooled relative effect. On average, PAs in tropical and subtropical moist broadleaf forests were most effective in avoiding land-use pressures, the ones in tropical and subtropical dry broadleaf forests slightly less, and the ones in deserts and xeric shrublands most ineffective. There was substantial variation between and inside individual PAs, and in approximately half of the PAs all variables indicate that the given area is significantly effective (α = 0,05). In a little over half of the PAs the effects were mixed, and in forested areas, no PA was indicated to be ineffective by all variables. In full landscape, this was the case for one PA. There were small differences between forested areas and the full landscape in all levels, but they were statistically significant only in a few cases. This study thus suggests that the data sets could be used interchangeably, at least on country and biome level, when conducting matching to assess PA effectiveness in a tropical setting. They could be utilised on individual PA level, too, with certain precautions and understanding of the nature and behaviour of the data. They are well suited for research; however, in practical management forest loss and fire incidence might be more feasible than burned area, due to its certain characteristics (it for example demands quite a lot of processing depending on the use purpose) and accessibility issues.
  • Blomberg, Laura (2022)
    Since the 1980s, international funding provided by diverse and changing donors has significantly changed Madagascar’s conservation landscape. The various challenges and development needs related to biodiversity conservation and its international funding have long been known to the international community and solutions have been sought. Despite this, deforestation and the destruction of the environment in Madagascar continue. The aim of this study was to identify the perceptions of various stakeholders on the current challenges and development needs for biodiversity conservation and its international funding in Madagascar by using qualitative methods. This study was based on 26 semi-structured interviews. The interviewees represented stakeholders involved in internationally funded biodiversity conservation projects in Madagascar. 14 of these interviews were conducted specifically for this study. The remaining, 12 interviews were from the material collected for the research project “Conservation Legacies: Understanding the Long-term Impacts of Private Foundation Investment in International Biodiversity Conservation”. The qualitative content analysis combining a deductive and inductive approach revealed a number of different challenges and development needs that were strongly interlinked. The identified challenges were related to, for example, weak governance and its different indicators, political instabilities, poverty and internal migration, donor requirements, insufficient amount of funding, funding gaps, dependency of international funding, donor-driven priority setting, lack of coordination, and the challenges posed by the operating environment. The identified development needs included the need for longer funding cycles, flexibility, stronger local participation, more holistic and cross-sectoral approaches, and involvement of private sector. Extensive cooperation across actors and sectors is still needed to tackle the challenges and put development needs into practice. Without this, there is a risk that the objectives for conserving biodiversity and making development aid more effective will not be achieved. Achieving these objectives would be supported by research into how the prioritisation and ownership of biodiversity conservation could be increasingly transferred to the local level, while ensuring that all aspects of sustainable development - social, ecological and economic – are considered.
  • Waldmann, Salla (2023)
    Carbon dioxide (CO2) has an important role in tree functioning, as it is needed for photosynthesis, used in biomass growth, and released in respiration. Stem CO2 efflux depends mainly on the stem respiration, which is why air temperature is the best predictor of the efflux. Most of the respiratory CO2 is released to the atmosphere, while a part is re-fixated in woody tissue photosynthesis and some dissolves in xylem water and is transported up along the stem in the sap flow. Stem CO2 efflux rate is therefore also affected by solar radiation and vapour pressure deficit. CO2 efflux varies vertically within the stem, as respiration rate is higher in the younger parts of the stem, younger parts have thinner bark and thus smaller diffusion barrier, and since some CO2 is transported up along the stem in the sap flow the increased xylem gas-to-water ratio in the higher parts of the stem accelerates the diffusion rate of CO2. Studies of stem CO2 efflux that use long-term data are rare. Long-term measurements enable the study of seasonality, annual variations, and the effect of different environmental factors more deeply than shorter measurement periods or point measurements allow. Chamber measurements give information on the gas exchange of a single component and its reactions to environmental factors. Long-term chamber measurements are therefore important in understanding forest carbon balance. This thesis analyses long-term stem chamber CO2 flux data measured continuously year-round at the SMEAR II station in the years 2010 – 2020. It studies the differences of different stem chamber types used in collecting the data, how the stem CO2 dynamics vary annually, seasonally, diurnally, individually, between two boreal tree species (Pinus sylvestris & Betula pendula) and vertically within the stem, and how different environmental factors affect the efflux. The data consists of two steady-state chamber types (measured in 2010 – 2012 and 2012 – 2016, respectively) and one dynamic chamber type (measured in 2016-2020) attached to one birch tree and four pine trees. The effects of environmental factors were studied through the temperature-dependence of respiration. It was modelled from the night-time efflux, as during night photosynthesis does not occur and sap flow is almost non-existent, and was utilized to predict whole-day respiration. Modelled respiration values were reduced from measured values and the part of stem efflux that was not caused by respiration but with photosynthesis and sap flow was left. The different chamber types were analysed with correlations of chamber and ambient temperature. Monthly and yearly effluxes were estimated and compared, and monthly estimates were normalized to compare the seasonality of the efflux. The results indicate that the stem CO2 efflux varies between years, seasons, species, individuals and vertically within the stem. The seasonal dynamics of birch occur more suddenly while the dynamics of pine increase and decrease more gently in spring and autumn, which might be due to birch being a deciduous and pine a coniferous species. There was clear vertical variation in stem CO2 efflux rates, which was possibly due to differences in growth respiration rates in different heights of the stem. The difference in the efflux sizes between higher and lower measurement point was higher in warmer months, and the efflux followed air temperature more closely in the higher measurement point. Photosynthesis and sap flow both decreased the stem CO2 efflux especially in warmer months, and sap flow had also a slight positive effect on the efflux when transpiration was low. The dynamic chamber type had chamber conditions closest to ambient conditions due to its adequate air mixing and can be said to alter the measurement results less than the two steady-state chamber types. This thesis highlights the importance of long-term continuous measurements of stem CO2 flux in the future. Annual, seasonal, individual, and vertical variation together with species stem CO2 efflux dynamics should all be accounted for when upscaling the efflux to stem- or stand-scale.
  • Kettunen, Kaisa (2022)
    This Master’s thesis compares different nature and recreation associations in terms of their activity to organize species observation activities and collect species data. The aim is to fill gaps in knowledge concerning on which volunteer groups are actively producing data, and if some of them could be included stronger in biodiversity monitoring and evaluation work. Further, the thesis evaluates how important the Finnish Biodiversity Information Facility (FinBIF) is for different nature and recreation associations as a data sharing channel. The main study material was collected by a qualitative questionnaire that was sent to variety of different nature and recreation associations. As a result, species enthusiast associations, hunting associations and nature conservation associations were shown to be the most active in organizing species observation, that is in accordance with earlier studies such as Santaoja (2013). From other studied groups the Scouts surprisingly showed relatively high interest toward species observation, but they were not active in data sharing. Evaluating associations willingness to use the FinBIF’s services and devises for observation data sharing, revealed, that the FinBIF’s channel was not popular among the studied associations, keeping in mind that the study did not examine FinBIF’s popularity among individual volunteers. In the light of the results, the FinBIF services and the concept of citizen science should be more actively promoted toward nature and recreation associations, especially to the Scouts who would be potential group to co-operate with in biodiversity monitoring and evaluation work.
  • Mäkipää, Tiina (2023)
    Opinnäytetyö on tehty osana Suomen metsäkeskuksen esiselvityshanketta Keski-Suomen ensiharvennuksien laadusta. Työssä tarkastellaan Metsäkeskuksen tekemän korjuujäljen laadun seurannan perusteella ensiharvennusmetsiköiden jäävän puuston tunnuksia, pääasiassa runkolukuja. Aineiston avulla simuloitiin OpeMotti-ohjelmistolla puuston kehitys koko kiertoajalle. Mitattuja ensiharvennuskuvioita oli 85, joista simulaatioissa mukana oli 83. Mäntyvaltaisia metsiköitä oli 42, kuusivaltaisia 32 ja koivuvaltaisia 9 kappaletta. Simulaatioiden tuloksista selvitettiin koko kiertoajan muutoksia ensiharvennettujen metsiköiden puuston runkoluvuissa, tilavuudessa, biomassassa ja hiilen sekä hiilidioksidin sidonnassa. Maastomittausten perusteella ensiharvennusten laatu oli heikko. Kaikki kuviot oli harvennettu liian harvoiksi, ja ajouran osuus pinta-alasta oli keskimäärin 28 %. Hakkuuvaurioita tai ajourapainaumia oli alle 3 %. Suositusten mukaisen maastodatan puuttuessa kiertoaikasimuloinnit tehtiin sekä maastodatan että laskettujen suositusarvojen perusteella. Simulaatioita tehtiin yhteensä 166 eri kuviotiedoilla; mitattu data ja suositusdata jokaisesta 83 kuviosta. Simulointien mukaan tarkastettujen ensiharvennettujen kuvioiden runkotilavuus vähenisi kiertoajan aikana 15 % ja biomassan tuotto 14 % verrattuna suositusten mukaisesti ensiharvennettuihin. Vaikka voimakas harvennus hieman nopeutti puuston kasvua, nopeampi kasvu ei korvannut menetettyä puumäärää normaalin kiertoajan aikana. Tulos ei juurikaan muuttunut valtapuulajeittain tarkasteltuna, vaikka puulajien kasvutavat ja -nopeudet erosivat toisistaan. Liian voimakkaat ensiharvennukset saattavat aiheuttaa metsänomistajille tulonmenetyksiä tulevaisuudessa. Simulaatioiden mukaan suositusten mukaan ensiharvennetuista kuvioista voisi saada päätehakkuussa 800–2000 euroa enemmän tuloa hehtaarilta. Suositusten mukaiset kuviot sitoivat hiilidioksidia 15 % ja hiiltä 14 % enemmän kiertoajan aikana. Vaikka esiselvitys oli alueellinen ja verrokkina olleet suositusarvot olivat mallien mukaisia keskiarvoja, tulokset kertovat ensiharvennuksen laadun heikkenemisestä. Ensiharvennuksen voimakkuudella on pitkäaikaiset vaikutukset metsän puuston tilavuuteen ja metsien hiilensidontaan. Koska ensiharvennuksia tehdään liian vähän tarpeeseen nähden, ensiharvennusten oikea-aikainen ja suositusten mukainen tekeminen on hyvin tärkeää. Ongelman korjaamiseen tarvitaan koko metsäalan toimijoiden yhteistyötä, koska syitä ensiharvennusten laadun heikentymiseen on monia.
  • Ahokas, Aarne (2022)
    The root rot fungus Heterobasidion annosum is one of the worst conifer pathogens in the boreal forests. Root diseases decrease forest growth, and their abundance could increase with climate change. Disease can reduce the carbon stored into forests even more than wildfires or pest outbreaks, further impacting the climate. Widespread Heterobasidion root rot can develop within the stem of susceptible trees without external symptoms. Therefore, research on the pathogen is difficult on a large extent and its dynamics at the landscape level could be researched with models. A model may be used to understand a system better or to predict its behaviour. Random maps are neutral landscape models, and they are not always significantly different from real random landscapes, except that things shaping real landscapes, such as waterways, human activities, or topography, are missing and the focus is on map cells representing habitats, their occupancy and connectivity across the landscape. Neutral landscape models are an application of percolation theory within landscape ecology; therefore, the connectivity and randomness are important. Heterobasidion spread by sporulation at the landscape level is of interest, as the focus of research has been on the spread by root contacts. In this study, simulations made with Motti and iLand software are compared, the effects of Heterobasidion spread on the dimensional variables of trees at the landscape level are evaluated, and the effects of various maximum dispersal distances on the number of new Heterobasidion colonies and the tree volume per hectare are studied. Forest growth and management practices were simulated with the Motti software, forest dynamics were simulated with the iLand software that uses a neutral landscape model, and Heterobasidion dynamics were simulated with the BITE modelling framework that was connected to iLand for the vegetation and environmental data. Betula pendula had a trend of underestimated values of the dimensional variables except for the basal area in iLand when compared to Motti. There was no clear trend for Picea abies or Pinus sylvestris. Overall, the change in basal area was overestimated the most and height was the most underestimated variable by iLand. A single dimensional variable could have different trends during a forest growth cycle in Motti and iLand. The effect of Heterobasidion on the dimensions of trees at the landscape level was minimal. Larger maximum dispersal distances resulted in more Heterobasidion colonies than shorter distances.
  • Malinen, Markus (2023)
    Suomessa puun teollinen hyödyntäminen on painottunut vahvasti pääpuulajeihimme eli mäntyyn, kuuseen ja koivuun. Ns. erikoispuulajien käyttö on, suhteellisen runsaista puuvaroista huolimatta, ollut hyvin vähäistä. Erikoispuulajien kohdalla puutavaran myyjät ja ostajat eivät ole löytäneet toisiaan riittävän helposti. Kysynnän ja tarjonnan kohtaamattomuus pyritään tulevaisuudessa ratkaisemaan Suomen Sahayrittäjät ry:n, Puuteollisuus ry:n ja Suomen Metsäkeskuksen yhteisellä erikoissahatavaran kauppapaikka -hankkeella. Tämän maisterintutkielman tavoite on selvittää erikoissahatavaran kotimaan markkinoita, paikallista kysyntää ja saatavuutta Suomen metsistä. Aineisto tutkielmaan kerättiin verkkokyselyllä, joka suunnattiin puuta jalostaville yrityksille. Kyselyyn valittiin harkitusti otannalla yrityksiä eri toimialoilta sekä eri puolilta Suomea. Näin pyrittiin saamaan mahdollisimman tarkka kokonaiskuva erikoispuutavaran paikallisesta tarpeesta ja saatavuudesta. Aineisto koostuu 17 vastauksesta. Tutkielman tulokset perustuvat näihin vastauksiin. Tutkielman tulosten perusteella erikoispuulajien kohdalla ongelma on edelleen pirstaloituneet markkinat. Erikoispuulajeja kaupataan hajanaisissa pienissä erissä, eikä riittävän suurta raaka-ainevirtaa puusepänteollisuuden käyttöön ole ollut. Lehtikuusi-, haapa- sekä leppäraaka-aineen osalta kärsitään paikallisesta pulasta. Suurin vaje markkinoilla on kuitenkin laadukkaasta koivuraaka-aineesta, jonka puutteesta kärsitään joka toimialalla. Venäjän tuontikielto on kärjistänyt tilannetta entisestään. Kaikesta päätellen erikoissahatavaran kauppapaikalle on suuri tarve. Puun jalostajat käyttäisivät mielellään kotimaista puuta ulkomaisen sijaan, mutta monen puulajin kohdalla se ei ole toistaiseksi ollut markkinaehtoisesti mahdollista. Kuitenkin puun jalostajat suhtautuivat optimistisesti kotimaisten erikoispuulajien tulevaisuuden mahdollisuuksiin. Myös ilmastonmuutoksen vaikutus sekä kuluttajien ostokäyttäytymisen kehitys ovat isossa roolissa. Puun suosio rakennusmateriaaleissa on kasvussa, lisäksi kuluttajat muodostavat kotimaisuudelle yhä suuremman lisäarvon.
  • Malm, Micke (2023)
    The European spruce bark beetle (Ips typographus L.) is one of the most concerning forest pest to Norway spruce (Picea abies Karst) forests in Central and Northern Europe. The species has been fairly well studied, especially after the storm Gudrun in Sweden in 2005 and some widespread damages in spruce forests in Central Europe in the recent years. I. typographus is a highly opportunistic species and a population can expand drastically if favorable conditions, mainly weakened or windthrown trees and suitable temperatures, are met. After reproducing on these favorable conditions, the species may have reached a population size so large that it is capable of infesting and killing even standing, healthy trees in the nearby areas. Damages caused to standing trees are the most problematic as there losses in economic revenue, carbon storage and, in some cases, ecosystem services. In Finland, the problems caused by I. typographus have fortunately been localized, but with climate change increasing extreme weather patterns, the problems are likely to increase in the future, which is why the species, as well as other potentially problematic species should be studied as intensively as possible, so that informed decisions can be made in case of a windthrown or other pest inducing event was to occur. After the Asta-storm in 2010, some 9000 cubic meters of wood had fallen in Ruokolahti municipality. Quickly after the storm, two areas (Viitalampi and Paajasensalo) were conserved under METSO-program and no commercial harvests were done in the sites, and permissions for bark beetle studies were given to increase knowledge especially on I. typographus. The two sites were mostly harvest-ready or mature Norway spruce dominated forests. Field work began in 2011 in Viitalampi, and new study plots were established in Viitalampi and Paajasensalo in subsequent years. To study bark beetle population dynamics, a total of 140 fallen trees were studied. From each tree diameters were measured at base (d0), breast-height (d1.3) and ten meters (d10), as well as full height of the tree. An entomological analysis was done in two-meter intervals (from 0m to 10m) to establish changes of bark beetle activity on a stem. A 25cmx50cm piece of bark was analyzed on each height, from which new and old entry and exit holes and different bark beetle maternal galleries were calculated. This was done on a different tree each year on a plot, although it was done only to trees which had root connections to the soil and were thus deemed alive and potential breeding and feeding ground for bark beetles. In addition, National Land Survey of Finland provided high resolution aerial images from the study sites so that the surrounding areas and conditions could be taken into account in studying bark beetle population dynamics. From the aerial images, a number of fallen and standing trees were calculated on a 25-meter zone around the center of a plot, as well as the size of the closest windthrown gap and the plot’s distance to that gap. The analysis of each measured factors’ significance to I. typographus maternal gallery density (m²) were calculated with Generalized Linear Models. Yearly changes in I. typographus occurrence were expectedly high and complied with observations in previous studies. In addition, there was a significance found in gap size and distance to gap in 2013, which could be explained with population behavior in previous years and with the exhaustion of larger and more nearby resources in the beginning of population build-up. Extensive field work combined with aerial images and other spatial tools are important in understanding the complexity of bark beetle, or any other forest pest, population dynamics. As extreme weather patterns increase, so do the damages caused by biotic agents, such as the European spruce bark beetle. Future studies are needed to educate and prepare forest owners for forest disturbances, be it from the viewpoint of commercial forestry, carbon storage or biodiversity conservation.
  • Järveläinen, Mikko (2023)
    Urban development can generate substantial greenhouse gas emissions through deforestation and land-use change. This underscores the urgency for effective climate change mitigation strategies. This thesis scrutinizes the feasibility of local forest conservation, specifically at a municipal level, as a strategy to compensate for losses in carbon storage and reductions in carbon sequestration linked to land-use changes. The study uses a case study approach, focusing on a proposed development of a data centre in Espoo's Hepokorvenkallio area in Finland. The proposed construction site spans 19 hectares and consists mainly of a forest earmarked for clearance. As a possible countermeasure, the city is considering conserving the nearby Hynkänlampi forest, covering an area of 79 hectares. The study leverages empirical modelling via long-term forest simulations to assess carbon storage and sequestration dynamics for these two sites under different scenarios. For Hepokorvenkallio, the analysis compares a construction scenario with continued forest management. The findings suggest that land clearing necessary for construction could result in a carbon storage loss of 15,820 tCO2 over a century, thereby indicating a need for compensatory measures. For Hynkänlampi, the modelled forecasts propose that a conserved forest could theoretically offset these losses. However, the offset capacity is notably influenced by the chosen discount rates applied to the carbon storage values. While simulation results for Hynkänlampi indicate a buffer capacity exceeding 10,000 tCO2 with a 0% discount rate, this buffer decreases to approximately 5,800 tCO2 with a 1% discount rate. Beyond the numerical aspects of carbon accounting, the thesis also addresses existing uncertainties and the prevailing regulatory landscape for carbon accounting procedures. Considering Finland's current legal and regulatory framework, the interpretation of this study posits that Espoo could view forest conservation at Hynkänlampi as a viable carbon offsetting measure to mitigate the impacts of land clearing at Hepokorvenkallio.
  • Laakkonen, Hilla (2022)
    This study was conducted with the participation of HOAS and AYY residents at the two biggest Universities in the Helsinki metropolitan area (HMA), Finland. A total of 187 residents took part in an online survey. The aim of the study is to investigate the association between experiences of nature, environmental identity, and environmental concern. This master’s thesis explores how the experiences of nature (EoN) defined by Clayton and others (2017), as well as the environmental identity, determined by Clayton (2003), were associated with environmental concern. The survey consisted of questions about environmental identity and experiences of nature. The self-estimation about the environmental concern was also taken into consideration. The data were analyzed both via quantitative and qualitative methods, so mixed methods were applied in this study. Factor analysis from multivariate methods was conducted as a part of the quantitative analysis. Content analysis with topic modeling was performed as part of the qualitative analysis. Survey results from the quantitative analysis showed that the residents of HOAS and AYY experience nature mostly as integrated into their daily lives and routines. Yet, the qualitative analysis revealed that more complex nature connections were experienced during vacation times such as leisure time activities (e.g., boating and trekking). Also, experiences of nature are themed under three themes using the results of the factor analysis. Overall, the survey participants were very concerned about the environmental crisis, and they showed a very strong environmental identity. The correlation between EoN and environmental concern was the weakest, and there were stronger correlations between environmental identity and EoN or environmental concern. The result of this study supports Clayton’s (2003) theoretical model that there is a connection between environmental identity and environmental concern.
  • Adhikari, Gopal (2022)
    Northern peatlands store approximately one-third of total global terrestrial carbon (C). These peatlands were partly drained for agriculture and forestry. In drained peatland forest, beside tree stands, ground vegetation is another relevant component concerning C fluxes between the land and the atmosphere. Thus, to explore ground vegetation gross primary production (GPPGV) dynamics, its affecting factors, and impacts of the partial harvest; forest floor net exchange (NEFF) and respiration (RFF) were measured on an hourly interval with an automated closed flux chamber method were analysed. These measurements were conducted in a forestry drained peatland before (pre-harvest, 2013 – 2015) and after (post-harvest, 2016 – 2017) the partial harvest and a control area (2015 – 2017) located in southern Finland. The results showed a similar diurnal pattern of GPPGV in all three scenarios yet, with a considerably varying magnitude between these scenarios. An 83% increase in photosynthetically active radiation (PAR) was observed in 2016 followed by the harvest event. However, a markedly higher GPPGV was obtained in the year 2017 (139.04 mg CO2 m-2 h-1) a year after the partial harvest compared to the year 2016 (42.82 mg CO2 m-2 h-1), thereby indicating a delaying effect of partial harvest induced changes on productivity. A linear mixed effect model with fixed effects of treatment (control and partial harvest) and random effects of chambers further supported this result with a significant effect of partial harvest on GPPGV in 2017 as compared to 2016. Further, a strong positive correlation was found between the daily mean GPPGV and PAR. Additionally, types of vegetation and its share of projection cover (PC) also explained GPPGV variations between flux chambers. An increase in GPPGV after the partial harvest event showed that the ground vegetation can play a considerable role in the C cycle of a managed drained peatland forest beside tree stands. As expected, after the partial harvest more lights reached the ground layer altering productivity. Besides light availability, productivity also depends on the types and phenology of inhabiting vegetation. Thus, exploration and realization of the response of ground vegetation to the partial harvest induced changes may contribute to our understanding of natural regeneration and system recovery processes.
  • Kokkonen, Eemeli (2023)
    Puukaupassa eletään monen syyn seurauksena muutoksen aikaa. Entistä kehittyneempi kaukokartoituspohjainen metsä-varatieto, muuttuva metsänomistajarakenne sekä puun noussut kysyntä antavat mahdollisuuksia kehittää, mutta myös pakottavat muuttamaan puukaupan vakiintuneita menetelmiä. Runkohinnoittelun, eli puutavaralajien katkonnasta riippumaton puun hinnoittelutapa on kasvattanut nopeasti osuuttaan markkinoilla. Samanaikaisesti metsävaratiedon tarkkuus on lisääntynyt uuden laserkeilauskierroksen myötä, ja kilpailu uusiutuvasta puuraaka-aineesta kasvanut sekä energia- että teollisuuskäytössä maailmanlaajuisten megatrendien ja Venäjän aloittaman hyökkäyssodan aiheuttaminen maailmankaupan muutosten seurauksena. Metsäkeskus tuottaa avointa metsävaratietoa, joka on saatavissa metsätalouden operatiivisen suunnittelun tueksi erilai-siin metsäjärjestelmiin. Tieto on nopeaa ottaa käyttöön, objektiivista, ajantasaistettua sekä varttuneissa metsissä luotet-tavaa. Tutkimuksessa käytettiin tätä avointa tietoa kuvioina vuoden 2020 ajantasaistetussa muodossa. Referenssiaineiston muodostivat 114 korjuulohkoa, joiden harvennuspoistuman keskijäreys ja puutavaralajijakauma tiedettiin hakkuukoneen mittaustietojen perusteella. Lohkot olivat työn tilaajan, Skogsvårdsföreningen Österbotten rf:n puunkorjuuyhtiön hakkaamia. Tutkimuksessa etsittiin parhaat selittäjät ja luotiin mallit poistuman keskijäreyden ja tukkiprosentin ennustamiseksi metsänvaratiedosta harvennushakkuulla. Lisäksi selvitettiin yllä mainittujen tunnusten ennustettavuus eri järeyksillä. Ennusteiden tilastolliset tunnusluvut laskettiin ja mallien käytännön sovellettavuutta arvioitiin. Tulokseksi saatiin, että etenkin poistuman keskijäreys kyetään ennustamaan jopa suhteellisen vanhasta metsävaratiedosta sen verran tarkasti, että mallien käyttöä voisi kokeilla puunhankinnan operaatioissa. Ennalta tunnetun mukaisesti ennustaminen oli luotettavaa varttuneemmissa puustoissa. Keskijäreyden osalta paras selittäjä oli metsävaratiedon summapuuston keskiläpimitta, johon pohjautuva malli ennusti hakkuussa toteutuneen keskijäreyden alle 10 % suhteellisella ennustevirheellä. Tukkiprosenttia kyettiin ennustamaan vastaavalla tavalla, mutta aineiston vähäisen tukkikertymän vuoksi mallien ennusteet eivät olleet kovinkaan luotettavia. Molempien vastemuuttujien tapauksessa mallien selitysasteet jäivät noin 50 %:n tasolle. Tulokset olivat osittain kuvioittaisen maastoarvioinnin yleisinä pidettyjä virhemarginaaleja parempia, sekä toteuttajasta riippumattomia. Tulokset olivat siten kuitenkin rohkaisevia ja tukevat kaukokartoitetun metsävaratiedon entistä laajempaa soveltamista tulevaisuudessa.
  • Rauhala, Mikko (2022)
    The populations of several birds have declined in Finland and overall, in the boreal zone during the last centuries. There is not only one reason behind this decline in the populations of the birds, because it is a result of many different factors and combinations of these factors. Especially, the nesting success of birds affects the size of the bird population. Artificial nest experiments are commonly used for measuring the nesting success of ground-nesting birds worldwide. Artificial nests are done with eggs of some bird species, and the meaning of this is to mimic the real nests of the chosen ground-nesting birds. Usually, the aim with artificial nests is to figure out the number of predations and the distribution of predator species in the research area. Nowadays artificial nests are often monitored with trail cameras. The credibility and truthfulness compared to the situation of real nests have awakened a lot of discussion among researchers (ex. Skagen et al. 1999, Weldon 2022). Especially, the human scents and subjectivity in the setting stage is believed to decline the credibility and the comparability of artificial nest experiments. This master's thesis, figured out with artificial nests and signposts, does the human scent work as a source of bias in artificial nest experiments. The subjects of this research were decided to be mammal predators because these animals search for food mostly with olfaction. From a scientific perspective, the experienced mammal predator group included both small and medium-sized predators. In this master's thesis, the directions from where the mammal predators came to the experimental setups in relation to where the research came from were analysed. The data of this study was collected from a large area where there is human impact in Finland, during the spring and early summer of 2021. Three kinds of experimental setups were used: experiment nests, control nests and signposts. All experimental setups were monitored with trail cameras during a seven-day period, during this time researchers do not visit the area. The experiment and control nests were made in natural nesting places. Depending on the habitat the nests would have been nests of waterfowl, ring-necked pheasant (Phasianus cochicus) or capercaillie (Tetrao urogallus). The experiment nests were done in the ground by digging as natural nest holes as possible with wood stick, and after this, four pheasant eggs were placed in the nest holes. Control nests were done same way as experiment nests but without any eggs. The signposts were done by setting commercial predator lure made from the scent gland of grey fox (Urocyon cinereoargenteus) with 20cm wood stick to the underside of small flat stone (rain cannot wash the lure away). After this the stick was placed upright next to the stone to spread the smell. The purpose of signposts was to mimic natural territory signs of predators, and to attract predators to the experimental setups. The signposts were made in the same areas as the experiment and control nests. The data consist of 178 experiment nests, 75 control nests and 79 signposts, so in total the data were collected from 332 experimental setups. The modelling of the data was done with R -program and Microsoft Excel. The situation of the first visits (sector analyses) and the survival of experiment nests was analysed by using Generalized linear model (GLM). The situation of all visits was analysed by using G-test (Goodness of Fit). For the analyses, the directions where the mammals came from, were divided into four sector categories. The directions were imagined as a circle around the setup and the circle was divide into four equal-sized sectors (90 degrees each). The sector that the researcher used was always the number one and trail camera was set up in the middle of the sector. There were four most common mammal predators included in the analyses of the directions: raccoon dog (Nyctereutes procyonoides), red fox (Vulpes vulpes), European pine marten (Martes martes) and European badger (Meles meles). This research showed that despite the common beliefs, scent of a researcher does not lead the mammal predators to the experimental setups. According to the results the cues of human scent did not increase the risk of setups found by predators. Neither the passage of time did not change the relation of used sectors in the situation of the first visits. In the situation of first visits mammal predators preferred side sectors (sector two and four) in the experiment nests and signposts, but in the control nests mammal predator did not prefer any sector. There is obvious need of further research because the reason why mammal predators preferred side sectors stayed unclear. The species-specific analyses showed that raccoon dogs, pine martens and badgers arrived in the experimental setups from random directions. However, as expected red foxes were sceptical and avoided the human used sector and the opposite sector three. This research showed that the predatory behaviour of mammal predators is not completely known and there is still need for further research.
  • Jyrinki, Vilja Johanna (2022)
    Climate change and the degradation of soils are global and increasingly prevalent issue. Pyrolyzed organic materials, biochars, are progressively studied as a promising tool to sequester carbon in soils, whilst also improving soil properties. It is important to understand how different biochars affect other integral features of the soil ecosystem, such as soil biota, before they are utilized. Biochars are currently mostly utilized in agricultural settings; in order to extend their use for carbon sequestration in forest soils, more research regarding different biochars in forest settings is necessary. This Master’s thesis was conducted as literature review and meta-analysis of existing forest field studies in which the effect of biochars on soil biota was measured. Two sources (the University of Helsinki digital library collection (Helka), and internet search engine Google Scholar were used. From the studies gathered, soil respiration and microbial biomass carbon (MBC) were used as variables to estimate the effect of biochars on soil biota. Due to the scarcity of existing research, experimental conditions included in this thesis are diverse, including plantations, three climatic regions (boreal, temperate and subtropic) and different biochar types. Subgroups were formed from received data according to different treatments and standard mean differences (SMD) were compared. Contrary to the hypothesis, within this meta-analysis, soils amended with biochars demonstrated either no change or decreased soil respiration and MBC. On average, soil respiration did not show any significant change to biochar amendment, whilst MBC decreased significantly in some subgroups: short-term studies (<= 12 months), small difference in pH between soil and biochar (< 4), low pyrolysis temperature of biochar (<= 450 ˚C) and small quantity of biochar applied (< 10 t/ha). The decreasing in MBC was not consistent and diminished with increasing quantity of biochar and in study periods over 12 months. Given that biochars do not seem to have clear effects on microbial forest soil biota or microbial respiration, the application of biochars to forest soils has its potentials. However, larger scale use should be considered with caution, and further research is necessary.
  • Verkkosaari, Heidi (2022)
    This research will study commercial field students' relationship with nature and how it affects their sense of responsibility. The aim is to find out what the students' relationship with nature is like, whether it has a connection to a sense of responsibility and whether the background factors have an effect on the relationship with nature. The issue is topical, as life on Earth is threatened by many environmental problems, such as climate change, the loss of biodiversity and the over-consumption of natural resources. As a result of urbanization, people can somehow become estranged from nature. We need more information about the background factors of our relationship with nature and the connection with a sense of responsibility. Maybe that will help us to maintain our relationship with nature and take responsibility for our environment. Based on previous research, it seems that the more distant a person experiences nature, the less he appreciates it and wants to take care of its well-being. The relationship with nature is always a subjective experience; an individual experiences his relationship with nature differently depending on the experiences, feelings and attitudes towards being in nature and towards it.In the study, I used the Nature Relatedness (NR) Scale to measure the nature relationship. Responsibility refers to a person's responsibility for the effects of his or her actions on, for example, the environment and society. This study focuses on a sense of responsibility; how a person feels responsible. The sense of responsibility was measured with the Responsibility scale (RS). The study was carried out in collaboration with the Ruralia Institute of the University of Helsinki. The data was collected in the autumn 2020. Students were told that the purpose of the survey was to research their relationship with nature and their views on the use of state hiking areas and national parks. Data was collected from 246 Finnish business schools students with the electronic survey. In the analysis of the data, the average sum variables were created from the responses of the survey in order to obtain figures describing the nature relatedness and responsibility for each respondent. The correlation between the nature relatedness and the sense of responsibility was then examined using linear regression. Background variable analyzes were performed using the Mann-Whitney U test and cross-tabulation. The study found a positive correlation between the nature relatedness and the sense of responsibility, making students with a stronger nature relatedness also feel more responsible. Background variable studies revealed that women have a slightly better level of nature relatedness than men. In addition, respondents born before the 1990s were found to have a higher level of nature relatedness. However due to the small number of respondents in older age groups, no more precise conclusions could be drawn. The results are similar to those obtained in previous environmental studies. Although a correlation was found between the nature relatedness and the sense of responsibility, the sense of responsibility does not necessarily tell anything about responsible behavior. New ways should be found to explore the connection bet-ween the sense of responsibility and behavior towards nature. More information would also be needed on how various background factors, such as childhood residence, will affect on the relationship with nature. As people's relationships with nature develops throughout life, information on the cause-and-effect relationship between nature relatedness and responsibility could be used even more in the environmental education of not only children but also adults, too.
  • Honkala, Mikaela (2022)
    Tiivistelmä/Referat – Abstract Kausikosteikot ovat huonosti tunnettu kosteikkoekosysteemi, joita on kadonnut Suomesta paljon metsäojitusten myötä. Nyt kausikosteikkoja uhkaa ilmastonmuutos, etenkin lumisateiden väheneminen ja alkukesän korkeat lämpötilat. Kausikosteikot saavat kaiken vetensä lumien sulamisvetenä tai sateena. Niillä ei ole pysyvää vedenlähdettä, joten niiden hydroperiodin pituus vaihtelee. Kausikosteikon vuotuinen elinkierto koostuu täyttymisestä, vetisestä jaksosta, vähittäisestä kuivumisesta ja lopulta äärimmäisestä kuivuudesta. On tärkeää tietää, miten eri lajit hyödyntävät kausikosteikkoja, jotta suojelutoimet voidaan kohdentaa oikein.Tässä tutkimuksessa vertaillaan keskenään kausikosteikkojen ja pienten boreaalisten järvien lintu- ja lepakkopopulaatioita. Majavakosteikoiden on havaittu olevan etenkin pohjanlepakoille järviä mieluisampia elinympäristöjä ja saman oletetaan pätevän myös kausikosteikoihin. Linnuille kausikosteikot tarjoavat suojaisan pesintä- ja poikasympäristön. Sorsalinnuista etenkin telkkä (Bucephala clangula) ja tavi (Anas crecca) poikueet voivat hyötyä kausikosteikkojen kalattomuudesta, koska se tarkoittaa vähemmän kilpailua ravinnosta sekä vähemmän petoja. Tarjolla olevan hyönteisravinnon määrän ja laadun arvioimiseksi kerättiin hyönteisaineistoa. Aineistoa kerättiin Evolla kesä-heinäkuussa 2020. Mukana tutkimuksessa oli 10 kausikosteikkoa sekä 10 järveä. Aineistonkeruumenetelminä olivat passiiviset lepakkodetektorit, lintujen havainnointi maastossa sekä kahdenlaiset hyönteispyydykset: ikkunapyydys ja kuoriutuvaispyydys. Kuoriutuvaispyydykset olivat käytössä niillä kausikosteikoilla, joilla oli seurannan alkaessa vettä ja ikkunapyydykset muilla. Itse keräämäni aineiston lisäksi hyödynsin huhti-toukokuun aikana samoilta koealoilta kerättyä lepakkoaineistoa. Lintuhavaintoja tehtiin järvillä 111 ja kausikosteikoilla 100. Lajeja havaittiin kausikosteikoilla 17 ja järvillä 21. Lajiston koostumuksessa ja havaintomäärissä oli pieniä mutta ei merkittäviä eroja. Pesiviä tai poikasten kanssa liikkuvia hyönteissyöjiä havaittiin vain kausikosteikoilla. Lepakoita havaittiin enemmän järvillä kuin kausikosteikoilla. Elinympäristöllä oli enemmän vaikutusta havaintojen määrään keväällä kuin kesällä. Hyönteisravinnon saatavuuden ja lepakoiden elinympäristövalinnan välillä ei havaittu selkeää yhteyttä. Voidaan olettaa, että elinympäristön muilla tekijöillä, kuten sijainnilla, on enemmän vaikutusta siihen, missä lepakot kulloinkin saalistavat. Kausikosteikoita tulisi tutkia lisää nyt kun niitä vielä on jäljellä. Lepakoiden osalta tarvitaan monipuolisempaa tutkimusmenetelmien käyttöä, jotta mikkien huonosti havaitsemien hiljaisten lajien edustus saataisiin paremmaksi. Tarvitaan pidempiä seurantajaksoja yli kaikkien vuodenaikojen. Nyt lintuseurannan ulkopuolelle jäi toukokuu ja kesäkuun alku sekä syksy, mikä saattoi vaikuttaa tuloksiin.
  • Tuviala, Johanna (2023)
    Kirjanpainaja (Ips typographus L.) on kaarnakuoriaisten (Coleoptera: Curculionidae, Scolytinae) alaheimoon kuuluva kovakuoriainen, joka voi runsaana esiintyessään aiheuttaa taloudellisesti merkittäviä puustotuhoja varttuneisiin kuusimetsiin (Picea abies [L.] H. Karst.). Kirjanpainaja on merkittävin kuusen puustotuholainen Euroopassa ja tuhojen odotetaan lisääntyvän tulevaisuudessa ilmaston lämpenemisen takia. Puustotuhojen todennäköisyyttä ennustavat riskimallit ovat tarpeellisia päätöksenteon tukena tuhojen syntymisen ennaltaehkäisyssä. Tämän työn tavoitteena oli tutkia, voiko avoimesti saatavien paikkatietoaineistojen avulla kehittää kirjanpainajatuhoriskiä ennustava malli metsämaiseman tasolla. Tutkimusalue (144 km2) sijaitsi Kymenlaaksossa Iitissä, jossa vuonna 2010 havaittiin talousmetsissä kirjanpainajatuhoja. Tuhojen syntyyn mahdollisesti myötävaikutti luonnonsuojelualueella vuonna 2008 tehdyt ennallistamistoimenpiteet, joissa kaulattiin ja kaadettiin kuusia. Suojelualueella ja ympäröivissä talousmetsissä havaittiin kaksi vuotta ennallistamisen jälkeen kirjanpainajan runsastumisen aiheuttamana pystyyn kuolleita kuusia. Tutkimusalueen kuolleiden kuusten keskittymät eli kirjanpainajan tuholaikut kartoitettiin maastotyönä vuonna 2013. Maastossa kartoitettiin myös terveiden kuusikoiden alueita kontrolliaineistoksi. Työssä käytetty aineisto koostui maastosta kerätystä aineistosta, monilähteisen valtakunnan metsien inventoinnin (MVMI) kartta-aineistosta, maaston korkeusmallista ja maalajikartasta. Paikkatietoaineistoista koottiin 29 muuttujaa, jotka mahdollisesti selittävät kirjanpainajatuhoa alan kirjallisuuden perusteella. Muuttujista 25 saatiin suoraan tai johdettiin MVMI:stä, kolme korkeusmallista ja yksi maalajikartasta. Selitettävänä muuttujana oli maastossa todennettu tieto kirjanpainajatuhon esiintymisestä (kyllä/ei). Aineisto jaettiin harjoitus- ja testiaineistoon, joista harjoitusaineistoa käytettiin logistisen regressiomallin luomiseen. Avoimien paikkatietoaineistojen avulla oli mahdollista ennustaa kirjanpainajatuhoriski tutkimusalueelle. Kehitetyn logistisen regressiomallin oikeinluokitusprosentti oli 82 %. Kirjanpainajatuhon riskiä selittävät muuttujat olivat korkeus merenpinnan yläpuolella, etäisyys avoimeen alueeseen, lehtipuiden latvuspeitto, kuusitukin tilavuus ja rinteen ilmansuunta. Mallin mukaan runsas lehtipuiden latvuspeitto ja metsän sijainti etelärinteessä vähensivät tuhoriskiä. Lyhyt etäisyys avoimeen alueeseen ja suuri kuusitukin tilavuus lisäsivät tuhoriskiä. Nämä tulokset vahvistivat aiempaa tutkimustietoa siitä, että sekapuustoisuus vähentää tuhoriskiä ja rinteen ilmansuunnalla on tuhoriskin kannalta merkitystä. Mallin avulla luotiin paikkatieto-ohjelmassa riskikartta, jossa jokaiselle tutkimusaluetta peittävälle 20 × 20 m -hilalle on laskettu kirjanpainajatuhon todennäköisyyttä kuvaava prosentti.
  • Karvonen, Juha K (2022)
    Invasive non-native species create an increasing threat to diversity in nature and economics. Invasive species are expected to spread even wider due to climate chance. The Japanese rose (Rosa rugosa L.) is a species widely spread by humans for its decorative value. The japanese rose replaces native plant species and creates problems on seashores, where it thrives. It creates a threat to many endangered biotopes and their plantation. Chondrostereum purpureum (Pers. ex Fr.) has been studied for a biological method for brushwood maintenance. The method has yielded good results on several species of the Rosaceae family , for instance on Black cherry (Prunus serotina Ehrh.) and Pin cherry (Prunus pensylvaica L.f.) This study aims to declare, whether C. purpureum can be viewed as a potential method for controlling the Japanese rose. The effect of C. purpureum on the Japanese rose was studied for one growing season in Lauttasaari, Helsinki. In the study, the roses were cut and the freshly cut surfaces were treated with a C. purpureum solution in June 2021. The data were collected in June-September 2021. Despite the shortness of the study period, the results were promising. The fungal treatment decreased the number of live sprouts and increased the number of dead sprouts. Living sprouts were shorter and the amount of rosehip berries was lower in roses treated using C. purpureum than in roses that were cut only. It seems that the C. purpureum treatment provides a potential method for controlling the Japanese rose.
  • Puputti, Tuomas (2023)
    Suomessa metsäteollisuus on merkittävä osa vientiä, ja metsät ovat Suomen tärkein luonnonvara. Jotta metsiä voidaan hyödyntää mahdollisimman kestävästi ja tehokkaasti, kannattaa tutkia menetelmiä, joilla voidaan parantaa metsäteollisuuden jalostusketjun arvoa. Metsäteollisuuden puunhankintaa suunnitellaan tällä hetkellä etukäteen puuraaka-aineen tarpeen, ja puuston järeyden mukaan. Metsäteollisuuden jalostusketjun arvoa voitaisiin parantaa tiedolla saatavilla olevan puuraaka-aineen laadusta, sillä sen avulla on mahdollista ohjata raaka-aineen kuljetusta eri tehtaille tarkemmin. Tässä tutkielmassa oli tarkoitus tutkia kuusen (Picea abies (L.) H. Karst.) laadun mittaamista maastolaserkeilauksella (terrestrial laser scanning, TLS), sekä kuusen laatua kuvaavien piirteiden yleistettävyyttä laajemmille alueille kirjallisuudessa esitettyjen tunnusten perusteella. Tutkielmassa selvitettiin kuusen laatua kuvaavien TLS-piirteiden korrelaatio TLS-menetelmillä mitttuun puun pituuteen, tilavuuteen, tukkitilavuuteen, latvussuhteeseen, ja latvuspinta-alaan. Tavoitteena oli myös lisätä ymmärrystä tekijöistä, jotka vaikuttavat laatua kuvaaviin piirteisiin ja niiden mittaamiseen. Tutkielman aineistossa oli 343 puuta, joista 257 kappaletta oli kuusia. Leimikot, joita oli 20 kappaletta, sijaitsivat Örebron läänissä Keski-Ruotsissa. TLS-keilaukset tehtiin 7.5 m säteisiltä ympyräkoealoilta neljällä keilauksella. Kaikille kuusen laatua kuvaaville TLS-piirteille löytyi tilastollisesti merkitseviä selittäjiä (P<0,05). Erot leimikoiden puiden laatua kuvaavien TLS-piirteiden välillä olivat pääasiassa vähäisiä, mutta kapenemisluvun kohdalla merkittäviä. Tuloksista voidaan päätellä, että joitain laatua kuvaavia TLS-piirteitä voi olla yleistettävissä laajemmalle alueelle estimoimalla selittävät tunnukset ilmalaserkeilaus (aerial laser scanning, ALS) -menetelmillä. Monella laatua kuvaavalla TLS-piirteellä korrelaation vahvuus puutunnuksiin vaihteli eri korkeuksilla rungossa, mikä kertoo sekä eri kokoisten puiden välisistä eroista, että oksien ja latvuksen rakenteen vaihtelusta eri korkeuksilla rungossa. Kuusen pitkä elävä latvus aiheuttaa peitteisyyttä ja sen myötä epävarmuutta mittauksiin. Yhdistämällä tutkielmassa mitatut ulkoiset piirteet tukkiröntgenin sisäistä laatua mittaavaan dataan, voitaisiin mallintaa puun sisäistä oksaisuutta ja tiheyttä suhteessa TLS-piirteisiin. Suuremmalla mallinnusdatalla, oikeiden ALS-piirteiden ja kasvupaikkatiedon avulla puuston laadun yleistämisessä laajemmille alueille on tämän tutkielman perusteella potentiaalia, mikä tukee aiempien tutkimusten tuloksia.
  • Männistö, Lauri (2022)
    Tämä tutkielma käsittelee valittujen kuusi-koivu-sekametsätaimikoiden rakennetta, tilajärjestystä sekä niiden tulevaisuuden kehityksiä eri tavoin toteutettavilla taimikonharvennuksilla. Työ on osa Luonnonvarakeskuksen monivuotista SEKAVA-hanketta. Sekametsät ovat Suomessa harvinaisia puhtaiden havumetsien ollessa vallitsevia. Sekametsien suosimisella olisi kuitenkin lukuisia etuja yhden puulajin metsiin verrattuna. Sekametsällä voidaan pienentää tuhoriskiä, lisätä monimuotoisuutta ja metsien virkistysarvoa sekä hajauttaa taloudellista riskiä. Sekametsillä voidaan valmistautua myös ilmastonmuutoksen aiheuttamiin muutoksiin. Taimikkovaihe on kriittinen sekametsän kasvatuksessa, sillä mikäli sekapuusto menetetään, ei sitä saada takaisin saman kiertoajan aikana. Taimikonharvennus on merkittävä vaihe metsikön tulevaisuuden kannalta, sillä siinä määritetään metsän tilajärjestys ja puulajirakenne. Tutkimuksen aineisto kerättiin kesällä 2021 mittaamalla Etelä- ja Keski-Suomen alueilta sekametsätaimikoita, joihin on tehty varhaisperkaus, muttei taimikonharvennusta. Metsiköissä mitattiin kaksi 500 m2:n ympyräkoealaa, joilta mitattiin jokainen kehityskelpoinen taimi. Kuhunkin mitattuun metsikköön simuloitiin neljä vaihtoehtoista taimikonharvennusta tarkoituksena selvittää eri taimikonharvennusten vaikutusta metsikön kehitykseen. Ensimmäisessä vaihtoehdossa taimikko harvennettiin puhtaaksi kuusikoksi, jossa runkoluku on 1800 r/ha. Toisessa vaihtoehdossa runkoluku pysyi samana, mutta puhtaan kuusikon sijaan metsikköön jätettiin 15 % koivua. Kolmannessa vaihtoehdossa koivun osuus oli 25 % ja neljännessä vaihtoehdossa 25 %, mutta metsikön tiheydeksi jätettiin 1600 r/ha. Taimikkovaiheen metsikkörakenteen tulee olla soveltuva, jotta sekapuustoisuus saadaan aikaan. Taimikossa tulee olla tarpeeksi laadukasta ja oikeassa kehitysvaiheessa olevaa lehtipuustoa, ja puuston täytyy olla jakautunut sopivasti. Mikäli jokin kasvatettavista puulajeista on huomattavasti kehityksessä edellä, kehityksessä perässä olevien lajien kehitys hidastuu tai pahimmillaan ne kuolevat. Sekapuusto ei myöskään saa olla omina ryppäinään, vaan sen tulee tasaisesti alueella. Tämän vuoksi tutkielmassa tarkasteltiin myös kehityskelpoisen puuston tilajärjestystä Ripleyn L- ja L12-funktioilla sekä lähinaapurianalyysilla ja mingling-indeksillä. Metsiköissä oli keskimäärin 3012 kehityskelpoista taimea hehtaarilla. Taimikoiden keskipituus oli 3,8 m. Koivut olivat keskimäärin kuusta edellä kehityksessä, mutta eivät kaikilla koealoilla. Osassa metsiköistä kuusen tiheys ei riittänyt puhtaan kuusikon kasvattamiseen. Kaikki metsiköt soveltuivat sekametsiksi taimiaineksen perusteella. Puuston tilajakauma oli niin ikään sekapuustolle sopiva, sillä viljelytaimet olivat istutuksesta johtuen tasaisesti järjestäytyneet, mutta koko metsikön mittakaavassa kuuset olivat sijoittuneet keskimäärin satunnaisesti. Luontaisesti syntyneet koivut puolestaan kasvoivat metsiköissä satunnaisesti järjestäytyneinä. Puulajit olivat sekoittuneet metsikköön keskenään satunnaisesti, eli ne eivät olleet omina ryhminään. Simulaatioiden perusteella eri taimikonharvennukset eivät juurikaan vaikuttaneet myöhempiin toimenpiteisiin tai kiertoaikoihin. Simulaatioiden lehtipuun osuus pysyi keskimäärin melko muuttumattomana kiertoajan kuluessa, mutta yksittäisissä metsiköissä muutokset olivat suuria. Lievä lehtipuusekoitus johti keskimäärin puhdasta kuusikkoa suurempaan hakkuupoistumaan, mutta erot eri simulaatioiden välillä olivat pieniä. Lehtipuusekoitus kuitenkin pienensi tukkiosuutta ja täten suurin tukkitilavuus saatiin keskimäärin puhtaan kuusikon vaihtoehdolla. Suurin tukkiosuus yhdistettynä kuusen parempaan kantohintaan johti siihen, että suurimmat tulot saavutettiin puhtaalla kuusikolla. Sekametsän kasvatus voi olla houkutteleva vaihtoehto metsänomistajalle, joka ei tavoittele suurinta mahdollista tuottoa vaan taloudellista turvaa, arvostaa myös ei-materiaalisia arvoja tai metsien monikäyttöä, taikka haluaa valmistautua ilmastonmuutoksen aiheuttamiin riskeihin.