Browsing by Subject "forest"

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  • Macias-Hernandez, Nuria; Ramos, Cândida; Domènech, Marc; Febles, Sara; Santos, Irene; Arnedo, Miquel A.; Borges, Paulo A. V.; Emerson, Brent C.; Cardoso, Pedro (2020)
    Background There is an increasing demand for databases including species trait information for biodiversity and community ecology studies. The existence of trait databases is useful for comparative studies within taxa or geographical regions, but there is low availability of databases for certain organisms. Here we present an open access functional trait database for spiders from Macaronesia and the Iberian Peninsula, recording several morphological and ecological traits related to the species life histories, microhabitat and trophic preferences. New information We present a database that includes 12 biological traits for 506 spider species present in natural forests of the Iberian Peninsula (Spain) and three Macaronesian archipelagoes (Azores, Madeira and Canary Islands). The functional trait database consists of two sections: 1. individual-level data for six morphological traits (total body size, prosoma length, prosoma width, prosoma height, tibia I length and fang length), based on direct measurements of 2844 specimens of all spider species; and 2. species-level aggregate data for 12 traits (same 6 morphological traits as in the previous section plus dispersal ability, vertical stratification, circadian activity, foraging strategy, trophic specialization and colonization status), based on either the average of the direct measurements or bibliographic searches. This functional trait database will serve as a data standard for currently ongoing analyses that require trait and functional diversity statistics.
  • Väisänen, Eero; Kellomäki, Seppo; Hari, Pertti (Suomen metsätieteellinen seura, 1977)
  • Myllyviita, Tanja; Sironen, Susanna; Saikku, Laura; Holma, Anne; Leskinen, Pekka; Palme, Ulrika (2019)
    Journal of Cleaner Production 236: 117641
    Impacts of bioeconomy on climate have been much discussed, but less attention has been given to biodiversity deterioration. One approach to assess biodiversity impacts is Life Cycle Assessment (LCA). Finland is a forested country with intensive forest industries, but only coarse biodiversity LCA methods are available. The aim of this study was to further develop and apply approaches to assess the biodiversity impacts of wood use in Finland. With the species richness approach (all taxons included), biodiversity impacts were higher in Southern than in Northern Finland but impacts in Southern and Northern Finland were lower when mammals, birds and molluscs were included. With the ecosystem indicators approach, if the reference situation were forest in its natural state, biodiversity impacts were higher than in the case where the initial state of forest before final felling was used to derive biodiversity loss. In both cases, the biodiversity impacts were higher in Northern Finland. These results were not coherent as the model applying species richness data assesses biodiversity loss based on all species, whereas the ecosystem indicators approach considers vulnerable species. One limitation of the species richness approach was that there were no reliable datasets available. In the ecosystem indicators approach, it was noticed that the biodiversity of managed Finnish forests is substantially lower than in natural forests. Biodiversity LCA approaches are highly sensitive to reference states, applied model and data. It is essential to develop approaches capable of comparing biodiversity impacts of forest management practices, or when looking at multiple environmental impacts simultaneously with the LCA framework.
  • Hemmilä, Marja (2020)
    Finnish Meteorological Institute Contributions 162
    Atmospheric aerosol particles are small, liquid or solid pieces that are floating in the air. They have a significant effect on air quality, human health and cloud formation. Sources of aerosols can be either primary or secondary, meaning that they can directly be emitted from the source to the air (e.g. sea salt, sand or pollen) or they can be formed from the precursor gases in the air. For example, sulphuric acid, ammonia, amines and oxidised organic vapours are gases that affect the nucleation process. Biogenic Volatile Organic Compounds (VOCs) are gases that are emitted by e.g. boreal forest, and they affect secondary organic aerosol (SOA) population by contributing to the production of oxidised organic vapours that participate in the formation and growth of secondary aerosol particles. In this thesis, thermal desorption inlet gas chromatograph coupled with mass spectrometer (TD-GC-MS) was used to determine how monoterpenes, which are one sub-group of the BVOCs, are emitted from Scots pine and Norway spruce trees. It was discovered that individual trees emit different amounts of various monoterpenes, even when the trees belong to the same species. We concluded that the emissions depend on the chemotype of the trees, which is an inherited property of the individual tree. Nitrogen containing gases, such as ammonia, amines and nitric acid can also take part in the aerosol formation and growth processes. Ammonia and amines stabilise sulphuric acid clusters, therefore helping the new aerosol particles to form. Another nitrogen contain gas, HONO, strongly affects atmospheric chemistry because it reacts with solar radiation and forms a OH• radical, which is one of the main radicals in the atmosphere. We measured the seasonal and diurnal variation of ammonia, nitric acid and HONO in the boreal forest with an instrument of Measuring AeRosols and Gases in Ambient air (MARGA), which is an online ion chromatograph with a sampling system. In this thesis, I developed a method for measuring aliphatic amines from the boreal forest air. I also coupled MARGA with a mass spectrometer (MARGA-MS) and used it to measure amine concentrations from the boreal forest air, observing the seasonal and diurnal variation of atmospheric amines. While I was measuring the atmospheric concentrations, the idea that amines could be emitted from the boreal forest floor and also melting snow and thawing ground, was born. To test this hypothesis, I measured with the MARGAMS connected to a dynamic flow through chamber emissions from the boreal forest floor. I found that the boreal forest floor is indeed a source of amines. *** Ilmakehän aerosolihiukkaset ovat pieniä, nestemäisiä tai kiinteitä hippusia, jotka leijuvat ilmassa. Niillä on merkittävä vaikutus ilmanlaatuun, terveyteen ja pilvien muodostumiseen. Aerosolien lähteitä on sekä primäärisiä että sekundäärisiä, mikä tarkoittaa sitä että ne voivat joko suoraan emittoitua lähteestä ilmaan (kuten merisuola, hiekka tai siitepöly), tai ne voivat muodostua suoraan ilmakehän kaasuista. Esimerkiksi rikkihappo, ammoniakki, amiinit ja hapettuneet orgaaniset höyryt ovat kaasuja, jotka voivat vaikuttaa nukleaatioprosessiin. Biogeeniset haihtuvat orgaaniset yhdisteet (BVOC) ovat kaasuja, jotka emittoituvat mm. pohjoisesta metsästä. Ne tuottavat hapettuneita orgaanisia höyryjä, jotka vaikuttavat sekundäärisien orgaanisien aerosolien muodostumiseen ja kasvuun. Tässä väitöskirjassa termodesorptio-kaasukromatografi-massaspektrometri-laitteistoa (TD-GC-MS) käytettiin määrittämään BVOCien alaluokkaan kuuluvien monoterpeenien haihtumista männyistä ja kuusista. Havaittiin, että yksittäiset puut emittoivat erimääriä erilaisia monoterpeeneitä, vaikka ne kuuluisivat samaan lajiin. Johtopäätöksenä oli, että emissiot riippuvat puun kemotyypistä, joka on yksittäisen puun peritty ominaisuus. Typpeä sisältävät kaasut kuten ammoniakki, amiinit ja typpihappo voivat myös ottaa osaa aerosolien muodostukseen ja kasvuun.Ammoniakki ja amiinit tasapainoittavat rikkihapporyppäitä auttaen aerosolihiukkasta syntymään. Eräs typpeä sisältävä kaasu, HONO, vaikuttaa vahvasti ilmakemiaan koska se reagoi auringon säteilyn kanssa tuottaen OH• radikaalin, joka on yksi tärkeimmistä radikaaleista ilmakehässä. Ammoniakin, typpihapon ja HONOn vuosi- ja vuorokausivaihtelua mitattiin pohjoisessa metsässä jatkuvatoimisella ionikromatografilla, joka myös ottaa näytteen itsenäisesti ilmasta (MARGA). Tässä väitöskirjassa kehitettiin menetelmä mittaamaan alifaattisia amiineita pohjoisesta metsäilmasta. MARGA yhdistettiin massaspektrometriin (MARGA-MS), ja sitä käytettiin määrittämään pohjoisen metsäilman amiinipitoisuuksia, havainnoiden amiinipitoisuuksien vuosi- ja vuorokausivaihtelu. Pitoisuuksia mitatessa syntyi ajatus metsämaan sekä sulavan lumen ja maan mahdollisuudesta olla amiinien lähde metsäilmassa. Hypoteesi testattiin liittämällä MARGA-MS dynaamiseen kammioon ja mittaamalla amiini- ja guanidiiniemissioita metsämaasta. Tulokseksi saatiin, että metsämaa tosiaan on amiinien lähde.
  • D'Amato, D.; Korhonen-Kurki, Kaisa; Lyytikainen, V.; Matthies, B.D.; Horcea-Milcu, A-I. (Elsevier, 2022)
    Forest Policy and Economics
    The circular bioeconomy is a highly scrutinized concept in Finland and internationally, with a high degree of polarization regarding forest utilization rates and distrust between certain actors. This offers an interesting case for an exploratory analysis of issues associated with knowledge co-production. Knowledge co-production entails the integration of different knowledge types and collaboration across multiple societal actors with potentially conflicting viewpoints and agendas. We interviewed key organizations operating at the nexus of science and policy in the processes of knowledge co-production regarding the circular bioeconomy in Finland, including representatives from ministries, universities, research institutes, innovation promoters, and interest organizations. Using qualitative content analysis, we assessed the actors' tacit knowledge and perceptions regarding 1) their role in knowledge co-production across knowledge types; 2) elements enabling knowledge co-production; and 3) tensions and needs/opportunities of knowledge co-production. To frame our data collection and analysis, we particularly draw from recent sustainability science literature on knowledge types in co-production. The findings reveal that the three main knowledge types – lay, expert, and scientific – are acknowledged by all actors, but are dealt with, to different extents, according to the roles played by different actors in the process of knowledge generation. Collaboration was reported to be largely project-oriented, enabled by funding, similar mindsets, and organizational/individual networks. Tensions included conflicting ideological positions held by various actors in the circular bioeconomy, mainly hampering the co-production of normative/target knowledge; funding-induced gaps and risks in inter-actor cooperation, mainly affecting process/system knowledge of the circular bioeconomy; and gaps and difficulties in cross-sectoral and cross-discipline engagement, mainly affecting predictive/transformative knowledge. Knowledge synthesis, policy-supporting knowledge, and transformative knowledge were perceived by several interviewees to be important avenues towards improving the sustainability potential of the Finnish forest sector. Highlights • We investigated knowledge co-production on the circular bioeconomy in Finland. • We interviewed key organizations operating at the nexus of science and policy. • Co-production enabled by funding, similar mind-sets, and organizational / individual networks. • Tensions were ideological positions, funding, cross-sectoral/cross-discipline engagement.
  • Zamorano, Juan Gallego; Hokkanen, Tatu; Lehikoinen, Aleksi (2018)
    Aims Understanding fluctuations in plant reproductive investment can constitute a key challenge in ecology, conservation and management. Masting events of trees (i.e. the intermittent and synchronous production of abundant seeding material) is an extreme example of such fluctuations. Our objective was to establish the degree of spatial and temporal synchrony in common four masting tree species in boreal Finland and account for potential causal drivers of these patterns. Methods We investigated the spatial intraspecific and temporal interspecific fluctuations in annual seed production of four tree species in Finland, silver birch Betula pendula Roth, downy birch Betula pubescens Ehrh., Norway spruce Picea abies (L.) H.Karst. and rowanberry Sorbus aucuparia L. We also tested to see whether variations in seed production were linked to annual weather conditions. Seeding abundance data were derived from tens of stands per species across large spatial scales within Finland during 1979 to 2014 (for rowanberries only 1986 to 2014). Important Findings All species showed spatial synchrony in seed production at scales up to 1000 km. Annual estimates of seed production were strongly correlated between species. Spring and summer temperatures explained most variation in crop sizes of tree species with 0-to 2-year time lags, whereas rainfall had relatively little influence. Warm weather during flowering (May temperature) in the flowering year (Year t) and 2 years before (t-2) were correlated with seed production. However, high May temperatures during the previous year (t-1) adversely affected seed production. Summer temperatures in Year t-1 was positively correlated with seed production, likely because this parameter enhances the development of flower primordials, but the effect was negative with a time lag of 2 years. The negative feedback in temperature coefficients is also likely due to patterns of resource allocation, as abundant flowering and seed production in these species is thought to reduce the subsequent initiation of potential new flower buds. Since the most important weather variables also showed spatial correlation up to 1000 km, weather parameters likely explain much of the spatial and temporal synchrony in seed production of these four studied tree species.
  • Becker-Scarpitta, Antoine; Auberson-Lavoie, Diane; Aussenac, Raphael; Vellend, Mark (2022)
    Despite many studies showing biodiversity responses to warming, the generality of such responses across taxonomic groups remains unclear. Very few studies have tested for evidence of bryophyte community responses to warming, even though bryophytes are major contributors to diversity and functioning in many ecosystems. Here, we report an empirical study comparing long-term change in bryophyte and vascular plant communities in two sites with contrasting long-term warming trends, using "legacy" botanical records as a baseline for comparison with contemporary resurveys. We hypothesized that ecological changes would be greater in sites with a stronger warming trend and that vascular plant communities, with narrower climatic niches, would be more sensitive than bryophyte communities to climate warming. For each taxonomic group in each site, we quantified the magnitude of changes in species' distributions along the elevation gradient, species richness, and community composition. We found contrasted temporal changes in bryophyte vs. vascular plant communities, which only partially supported the warming hypothesis. In the area with a stronger warming trend, we found a significant increase in local diversity and dissimilarity (beta-diversity) for vascular plants, but not for bryophytes. Presence-absence data did not provide sufficient power to detect elevational shifts in species distributions. The patterns observed for bryophytes are in accordance with recent literature showing that local diversity can remain unchanged despite strong changes in composition. Regardless of whether one taxon is systematically more or less sensitive to environmental change than another, our results suggest that vascular plants cannot be used as a surrogate for bryophytes in terms of predicting the nature and magnitude of responses to warming. Thus, to assess overall biodiversity responses to global change, abundance data from different taxonomic groups and different community properties need to be synthesized.
  • Cailleret, Maxime; Dakos, Vasilis; Jansen, Steven; Robert, Elisabeth M.R.; Aakala, Tuomas; Amoroso, Mariano M.; Antos, Joe A.; Bigler, Christof; Bugmann, Harald; Caccianaga, Marco; Camarero, Jesus-Julio; Cherubini, Paolo; Goeya, Marie R.; Cufar, Katarina; Das, Adrian J.; Davi, Hendrik; Gea-Izquierdo, Guillermo; Gillner, Sten; Haavik, Laurel J.; Hartmann, Henrik; Heres, Ana-Maria; Hultine, Kevin R.; Janda, Pavel; Kane, Jeffrey M.; Kharuk, Vlachelsav I.; Kitzberger, Thomas; Klein, Tamir; Levanic, Tom; Linares, Juan-Carlos; Lombardi, Fabio; Mäkinen, Harri; Meszaros, Ilona; Metsaranta, Juha M.; Oberhuber, Walter; Papadopoulos, Andreas; Petritan, Any Mary; Rohner, Brigitte; Sanguesa-Barreda, Gabriel; Smith, Jeremy M.; Stan, Amanda B.; Stojanovic, Dejan B.; Laura Suarez, Maria; Svoboda, Miroslav; Trotsiuk, Volodymyr; Villalba, Ricardo; Westwood, Alana R.; Wyckoff, Peter H.; Martinez-Vilalta, Jordi (2019)
    Tree mortality is a key driver of forest dynamics and its occurrence is projected to increase in the future due to climate change. Despite recent advances in our understanding of the physiological mechanisms leading to death, we still lack robust indicators of mortality risk that could be applied at the individual tree scale. Here, we build on a previous contribution exploring the differences in growth level between trees that died and survived a given mortality event to assess whether changes in temporal autocorrelation, variance, and synchrony in time-series of annual radial growth data can be used as early warning signals of mortality risk. Taking advantage of a unique global ring-width database of 3065 dead trees and 4389 living trees growing together at 198 sites (belonging to 36 gymnosperm and angiosperm species), we analyzed temporal changes in autocorrelation, variance, and synchrony before tree death (diachronic analysis), and also compared these metrics between trees that died and trees that survived a given mortality event (synchronic analysis). Changes in autocorrelation were a poor indicator of mortality risk. However, we found a gradual increase in inter- annual growth variability and a decrease in growth synchrony in the last similar to 20 years before mortality of gymnosperms, irrespective of the cause of mortality. These changes could be associated with drought-induced alterations in carbon economy and allocation patterns. In angiosperms, we did not find any consistent changes in any metric. Such lack of any signal might be explained by the relatively high capacity of angiosperms to recover after a stress-induced growth decline. Our analysis provides a robust method for estimating early-warning signals of tree mortality based on annual growth data. In addition to the frequently reported decrease in growth rates, an increase in inter-annual growth variability and a decrease in growth synchrony may be powerful predictors of gymnosperm mortality risk, but not necessarily so for angiosperms.
  • Toivonen, Marjaana; Karimaa, Anna-Elina; Herzon, Irina; Kuussaari, Mikko (Elsevier, 2022)
    Agriculture, Ecosystems & Environment
    Non-bee insects have been identified as important crop pollinators globally. However, strategies to protect pollinators and enhance crop pollination usually focus on supporting bees. This study examined the effects of landscape structure, location within field, and floral resources on pollinators’ visits on mass-flowering caraway (Carum carvi L.) in boreal farmland, and the effects of the visits on caraway yield. Pollinator visits on caraway flowers were monitored and caraway yield measured in 30 fields at landscapes ranging from field-dominated to forest-dominated landscapes. Hoverflies were the most abundant flower-visitors of caraway, followed by honeybees. Hoverflies and other flies made more flower visits on caraway than all bee species combined. Pollinator groups differed in their responses to landscape and local factors. Flies were most abundant near field edges and in landscapes with high forest cover. Non-syrphid flies and solitary bees responded positively to the cover of flowering herbs in the adjacent field margins. Flower visits by honeybees, instead, were positively related to the flowering crop cover in the study fields. Caraway seed yield increased with increasing number of flower visits by honeybees, hoverflies and all pollinators together. Pollinator exclusion reduced caraway fruit set (i.e. the number of fruits per flower) by 13% and seed yield by 40%. Our study is the first to report the high importance of flies to crop pollination in boreal farmland, where caraway is an important export crop. The results highlight the need of taking flies and their habitat requirements into account when developing strategies to enhance crop pollination. Highlights • Hoverflies were the most frequent flower-visitors on caraway, followed by honeybees. • Flies made more flower visits than all bee species combined. • Flies were abundant near field edges and in landscapes with high forest cover • Honeybees responded positively to the flowering crop cover. • Flower visits by both honeybees and hoverflies increased caraway yield.
  • Salo, Ulla-Maija (2021)
    This paper explores what a forest as a specific place means and does for girls, while it scrutinises how to understand place and how to consider place methodologically. The girls, called 'forest daughters' here, write letters to the female President of Finland. The letters portray a forest as a lived 'place-world' that ties place and self together. The multiplicity of these relations is methodologically displayed as an assemblage of 'girl-place-letter' and conjoined a perspective of the 'where of research'. The paper argues that place and self help construct and activate each other. A forest is a site of pleasures and possibilities and in the letters, it turns out that a forest becomes a stage and practice of power that develops environmental activism and gives rise to utterances of green criticism. To develop and exemplify this discussion, I examine a letter to the president written by one of these young forest daughters.
  • De Frenne, Pieter; Lenoir, Jonathan; Luoto, Miska; Scheffers, Brett R.; Zellweger, Florian; Aalto, Juha; Ashcroft, Michael B.; Christiansen, Ditte M.; Decocq, Guillaume; De Pauw, Karen; Govaert, Sanne; Greiser, Caroline; Gril, Eva; Hampe, Arndt; Jucker, Tommaso; Klinges, David H.; Koelemeijer, Irena A.; Lembrechts, Jonas J.; Marrec, Ronan; Meeussen, Camille; Ogee, Jerome; Tyystjarvi, Vilna; Vangansbeke, Pieter; Hylander, Kristoffer (2021)
    Forest microclimates contrast strongly with the climate outside forests. To fully understand and better predict how forests' biodiversity and functions relate to climate and climate change, microclimates need to be integrated into ecological research. Despite the potentially broad impact of microclimates on the response of forest ecosystems to global change, our understanding of how microclimates within and below tree canopies modulate biotic responses to global change at the species, community and ecosystem level is still limited. Here, we review how spatial and temporal variation in forest microclimates result from an interplay of forest features, local water balance, topography and landscape composition. We first stress and exemplify the importance of considering forest microclimates to understand variation in biodiversity and ecosystem functions across forest landscapes. Next, we explain how macroclimate warming (of the free atmosphere) can affect microclimates, and vice versa, via interactions with land-use changes across different biomes. Finally, we perform a priority ranking of future research avenues at the interface of microclimate ecology and global change biology, with a specific focus on three key themes: (1) disentangling the abiotic and biotic drivers and feedbacks of forest microclimates; (2) global and regional mapping and predictions of forest microclimates; and (3) the impacts of microclimate on forest biodiversity and ecosystem functioning in the face of climate change. The availability of microclimatic data will significantly increase in the coming decades, characterizing climate variability at unprecedented spatial and temporal scales relevant to biological processes in forests. This will revolutionize our understanding of the dynamics, drivers and implications of forest microclimates on biodiversity and ecological functions, and the impacts of global changes. In order to support the sustainable use of forests and to secure their biodiversity and ecosystem services for future generations, microclimates cannot be ignored.
  • Päivänen, Juhani (Suomen metsätieteellinen seura, 1973)
  • Deng, Yange; Kagami, Sara; Ogawa, Shuhei; Kawana, Kaori; Nakayama, Tomoki; Kubodera, Ryo; Adachi, Kouji; Hussein, Tareq; Miyazaki, Yuzo; Mochida, Michihiro (2018)
    The formation of biogenic secondary organic aerosols (BSOAs) in forest environments is potentially important to cloud formation via changes of the cloud condensation nuclei (CCN) activity of aerosols. In this study, the CCN activation of submicrometer aerosols and their chemical compositions and size distributions were measured at a midlatitude forest site in Japan during the summer of 2014 to assess the hygroscopicity of the organic aerosols and their contributions to the local CCN concentrations. The mean number concentrations of the condensation nuclei and CCN at supersaturation (SS) conditions of 0.11-0.80% were 1,238 and 166-740cm(-3), respectively. Organic aerosols and sulfate dominated the submicrometer aerosol mass concentrations. The particle hygroscopicity increased with increases in particle diameters. The hygroscopicity parameter for the organics, (org), was positively correlated with the atomic O to C ratio. The product of (org) and the volume fraction of OA was 0.12, accounting for 38% of the water uptake by aerosol particles. The hygroscopicity parameter of the locally formed fresh BSOA was estimated to be 0.09. The contribution of OA to the CCN number concentration, which was assessed by subtracting the CCN concentration of the hypothetical inorganic aerosols from that of the ambient aerosols, was 50-182cm(-3) for the SS range of 0.11-0.80%. The increase of the CCN number concentrations per 1-g/m(3) increase of the BSOA was 23-299cm(-3) at 0.11-0.80% SS. The contribution of the BSOA to the CCN number concentration can be enhanced by new particle formation. Plain Language Summary Some of the particles suspended in the atmosphere can absorb water vapors around them and act as nuclei to form cloud droplets. These particles are called cloud condensation nuclei (CCN), the quantification of which is important for climate forcing prediction. The ability of a particle to absorb water is referred to as hygroscopicity, which is governed by the chemical composition. Volatile organic vapors emitted by vegetation (i.e., biogenic volatile organic compound) after chemical reactions in the atmosphere can either condense onto existing particles or participate in the formation of new particles and thus change the aerosol chemical composition. The aerosol component originated from biogenic volatile organic compounds, named biogenic secondary organic aerosol (BSOA), is an important constituent of CCN on a global scale. However, the hygroscopicity of BSOA and its contribution to CCN are not understood well. We performed measurements of the hygroscopicity and chemical composition of aerosol particles in a forest in Japan. Based on the observation, we calculated the hygroscopicity of the BSOA formed in the forest and quantified the contribution of the BSOA to the CCN number concentrations. An enhancement of the contribution of BSOA to the CCN number concentrations by new particle formation is suggested, which is an important subject of future studies.
  • Jyrinki, Vilja Johanna (Helsingin yliopisto, 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.
  • Manninen, Terhikki; Stenberg, Pauline (Ilmatieteen laitos - Finnish Meteorological Institute, 2021)
    Raportteja - Rapporter - Reports 2021:5
    Recently a simple analytic canopy bidirectional reflectance factor (BRF) model based on the spectral invariants theory was presented. The model takes into account that the recollision probability in the forest canopy is different for the first scattering than the later ones. Here this model is extended to include the forest floor contribution to the total forest BRF. The effect of the understory vegetation on the total forest BRF as well as on the simple ratio (SR) and the normalized difference (NDVI) vegetation indices is demonstrated for typical cases of boreal forest. The relative contribution of the forest floor to the total BRF was up to 69 % in the red wavelength range and up to 54 % in the NIR wavelength range. Values of SR and NDVI for the forest and the canopy differed within 10 % and 30 % in red and within 1 % and 10 % in the NIR wavelength range. The relative variation of the BRF with the azimuth and view zenith angles was not very sensitive to the forest floor vegetation. Hence, linear correlation of the modelled total BRF and the Ross-thick kernel was strong for dense forests (R2 > 0.9). The agreement between modelled BRF and satellite-based reflectance values was good when measured LAI, clumping index and leaf single scattering albedo values for a boreal forest were used as input to the model.
  • Virtanen, Pekka (Suomen metsätieteellinen seura, 1987)
  • de Wit, Heleen A.; Lepistö, Ahti; Marttila, Hannu; Wenng, Hannah; Bechmann, Marianne; Blicher-Mathiesen, Gitte; Eklöf, Karin; Futter, Martyn N.; Kortelainen, Pirkko; Kronvang, Brian; Kyllmar, Katarina; Rakovic, Jelena (Wiley, 2020)
    Hydrological Processes 34, 25 (2020)
    Agricultural, forestry-impacted and natural catchments are all vectors of nutrient loading in the Nordic countries. Here, we present concentrations and fluxes of total nitrogen (totN) and phosphorus (totP) from 69 Nordic headwater catchments (Denmark: 12, Finland:18, Norway:17, Sweden:22) between 2000 and 2018. Catchments span the range of Nordic climatic and environmental conditions and include natural sites and sites impacted by agricultural and forest management. Concentrations and fluxes of totN and totP were highest in agricultural catchments, intermediate in forestry-impacted and lowest in natural catchments, and were positively related %agricultural land cover and summer temperature. Summer temperature may be a proxy for terrestrial productivity, while %agricultural land cover might be a proxy for catchment nutrient inputs. A regional trend analysis showed significant declines in N concentrations and export across agricultural (−15 μg totN L−1 year−1) and natural (−0.4 μg NO3-N L−1 year−1) catchments, but individual sites displayed few long-term trends in concentrations (totN: 22%, totP: 25%) or export (totN: 6%, totP: 9%). Forestry-impacted sites had a significant decline in totP (−0.1 μg P L−1 year−1). A small but significant increase in totP fluxes (+0.4 kg P km−2 year−1) from agricultural catchments was found, and countries showed contrasting patterns. Trends in annual concentrations and fluxes of totP and totN could not be explained in a straightforward way by changes in runoff or climate. Explanations for the totN decline include national mitigation measures in agriculture international policy to reduced air pollution and, possibly, large-scale increases in forest growth. Mitigation to reduce phosphorus appears to be more challenging than for nitrogen. If the green shift entails intensification of agricultural and forest production, new challenges for protection of water quality will emerge possible exacerbated by climate change. Further analysis of headwater totN and totP export should include seasonal trends, aquatic nutrient species and a focus on catchment nutrient inputs.
  • Kubin, Eero (Suomen metsätieteellinen seura, 1990)
  • Reunala, Aarne (Suomen metsätieteellinen seura, 1987)
  • Ahponen, Pirkkoliisa (Suomen metsätieteellinen seura, 1987)