Browsing by Subject "carbon sequestration"

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  • Freudenthal, Ines (Helsingin yliopisto, 2022)
    The objective of the thesis is to review and characterize (i) typical agroforestry systems in the temperate zone, (ii) levels of soil organic carbon (SOC) in agroforestry and control plots, and (iii) identify the conditions under which agroforestry farming is most likely to enhance SOC. A meta-analysis was conducted to investigate the impact of agroforestry farming systems on SOC stocks at soil depths of 0 – 20, 0 – 40 and 0 – 100 cm. Data was collected from 15 published studies and all sites are located in temperate climates. Studies had to report at least measurements on SOC concentration or stock for an agroforestry plot and a control plot (arable land, grassland, forest). Investigated treatment variables were soil depth, agroforestry system type, soil type, tree species and age. The results have shown significantly higher SOC stocks under agroforestry in comparison to controls in all three soil depth datasets. The largest amount of SOC in agroforestry was found in the first 20 cm of topsoil and at a soil depth of 60 – 100 cm. There were no significant differences found between alley cropping, silvopasture and shelterbelt systems. The most popular tree species in temperate agroforestry were Populus spp., M.domestica, Juglans regia and Picea. But no significant differences in C sequestration could be observed between tree species across all datasets. The assumption that systems with older trees have higher stocks of SOC could not be confirmed. Most common soil types of temperate agroforestry systems were Luvisol, Fluvisol and Chernozem. The meta-analysis did not verify results of other studies, which have shown that clay contents in the soil promote C sequestration. The wide variability and diversity of agroforestry systems has shown to be problematic in conducting a meta-analysis, indicated by a high heterogeneity. Furthermore, different types of study designs, lack of standardized sampling procedures and explanatory variables may have influenced the results. However, the study showed that agroforestry can be a promising carbon dioxide (CO2) mitigation option, also for the temperate climate zone.
  • Nummi, Petri Johannes; Vehkaoja, Mia Christina; Pumpanen, Jukka; Ojala, Anne Kristiina (2018)
    With the recent population increase in beavers (Castor spp.), a considerable amount of new riparian habitat has been created in the Holarctic. We evaluated how beaver‐induced floods affect carbon (C) dynamics in the beaver ponds and in the water‐atmosphere and riparian zone interfaces. Beaver disturbance affects soil organic C storage by decreasing or increasing it, resulting in a redistribution of C. Upon flooding, the concentration of dissolved organic carbon (DOC) increases in the water. This C can be released into the atmosphere, it can settle down to the bottom sediments, it can be sequestered by vegetation, or it can be transported downstream. The carbon dioxide (CO2) emissions vary between 0.14 and 11.2 g CO2 m−2 day−1, averaging 4.9 CO2 g m−2 day−1. The methane (CH4) emissions vary too, from 27 mg m−2 day−1 to 919 mg m−2 day−1, averaging 222 mg CH4 m−2 day−1. Globally, C emission from beaver ponds in the form of CH4 and CO2 may be 3.33–4.62 Tg (teragram, 1012 g) year−1. The yearly short‐term sedimentation rates in beaver ponds vary between 0.4 and 47 cm year−1, and individual ponds contain 9–6355 m3 of sediment. The approximate global estimate for yearly C sedimentation is 3.8 Tg C; beaver ponds globally contain 380 Tg sedimented C. After being formed, beaver pond deposits can remain for millennia. Both C sequestration and CO2 and CH4 emissions in ponds of various ages should be taken into account when considering the net effect of beavers on the C dynamics. With present estimates, beaver ponds globally range from a sink (−0.47 Tg year−1) to a source (0.82 Tg year−1) of C. More research is needed with continuous flux measurements and from ponds of different ages. Likewise, there is a need for more studies in Eurasia to understand the effect of beaver on C biogeochemistry.
  • Simola, Noora (Helsingin yliopisto, 2018)
    Tiivistelmä – Abstrakt – Abstract Over the recent decades Vietnam has implemented extensive reforestation and afforestation programs that have turned the country’s forestry sector’s net carbon balance positive. Smallholder forestry has contributed to this positive trend as individual farmers, households, and cooperatives have regreened degraded lands with fast-growing exotics such as Acacia hybrid. The purpose of the study was to estimate the carbon stocks and sequestration potential of smallholder Acacia hybrid plantations in Thuy Phu, Hue, Vietnam, where the short rotation plantations have been established on the government allocated barren lands. The effect of afforestation on these stocks was studied through quantification of the mean ecosystem carbon and sub-stocks of both acacia holdings and barren lands. Additionally, the impact of stand age and planting density on these stocks was studied. The carbon stocks of Acacia hybrid plantations were quantified using methods of forest inventory and soil sampling. The barren lands results were obtained from sites proxy to the land use prior to afforestation. Allometric equations, modelling, statistical analysis, and root:shoot ratios were used to estimate the mean vegetation stocks. The biomass results were converted to carbon and the soil samples were analyzed in laboratory for the soil organic matter content. The sequestration of short rotation plantation was quantified using estimates of time-averaged carbon stocks and the stock difference-method. The smallholder Acacia hybrid plantations were found to have prominently higher ecosystem carbon stocks than the barren lands due to gains in tree biomass sub-stocks. Afforestation had no statistically significant impact on the soil organic carbon or ground vegetation stocks. The impact of planting density on the carbon stocks was found to be marginal. The mean ecosystem carbon in the plantations of Thuy Phu was 67.27 t C ha-1, including the sub-stocks of aboveground trees 24.38, ground vegetation 0.23 ±0.08, tree roots 5.36, ground vegetation roots 0.18 and soil 37.13±8.17 t C ha-1. The time-averaged ecosystem carbon stock of 5 years rotation was 65.23 t C ha-1. The mean barren land ecosystem carbon was 37.40, including the sub-stocks of aboveground vegetation 0.15 ±0.11 t C ha-1, belowground vegetation 0.12, and soil 37.13±8.17 t C ha-1. The additional stock gain and sequestration was found to be 27.83 t C ha-1, comparable to an uptake of 102.14 t CO2 ha-1.
  • Husa, Miikka Helmer (Helsingin yliopisto, 2021)
    Climate change and the biodiversity loss have created a need to change forest management in commercial forests. Carbon sequestration, climate change adaptation, and biodiversity conservation can be promoted in commercial forests through various measures, and this thesis examines what factors affect non-industrial private forest (NIPF) owners’ willingness to adopt such forest management practices. Additionally, the aim was to examine whether these factors vary among different measures. A systematic literature review was conducted to summarize previous research on the subject and to serve as reference for an empirical analysis. In the empirical part of the study, survey data of 405 Finnish NIPF owners was utilized to establish binary logistic regression models for forest owners’ willingness to adopt 13 distinct forest management practices. In the empirical analysis statistically significant factors varied among assessed forest management practices, although some patterns were recognized. The most striking consistencies were found concerning older forest owners reluctance towards deadwood in general, and positive effect of environmental motivation in willingness to adopt variety of measures, as long as they do not conflict with biodiversity. Overall, the results imply that the diversity of NIPF owners concerns also their stances on various forest management practices, and they are not indifferent in terms of what forest management practices they are willing to adopt. Thus, when designing and implementing policies and advisory services aiming to promote carbon sequestration, climate change adaptation, or biodiversity protection in commercial forests, policy makers should take into account forest owners’ heterogenous preferences regarding different forest management practices.
  • Tammeorg, Priit; Soronen, Päivi Anneli; Riikonen, Anu; Salo, Esko; Tikka, Suvi Maria; Koivunen, Minja; Salonen, Anna-Reetta; Kopakkala, Topi Pietari; Jalas, Mikko (2021)
    In order to achieve the goals of carbon (C) neutrality within next 20 year, municipalities worldwide need to increasingly apply negative emission technologies. We focus on the main principles of urban demonstration areas using biochars for C sequestration and explore the lessons learned from a co-creation process of one such park, Hyvantoivonpuisto in Helsinki, Finland. Demonstration sites of urban C sinks in public parks must be safe, visible and scientifically sound for reliable and cost-effective verification of carbon sequestration. We find that different interests can be arbitrated and that synergy that emerges from co-creation of urban C sink parks between stakeholders (scientists, city officials, companies, and citizens) can result in demo areas with maximized potential for impact, dissemination and consideration of principles of scientific experimentation.
  • Mäki, Ilona (Helsingin yliopisto, 2022)
    Biochar is a porous, carbon-rich material, made from organic material by pyrolysis in low oxygen conditions, and it can be used to sequester carbon into the soil. This review aspires to give an overview of the economic dimensions of using biochar in Finnish (Boreal and sub-boreal) forests. A literature review was conducted to collect and summarize the information about studies and applications elsewhere, and how we could possibly apply them into Finnish forest ecosystems. This thesis is done as part of Helsus Co-Creation Lab -project, where our group was tasked with looking into how biochar could enhance biodiversity in soil and accelerate transformation to low carbon economy. From this larger topic, this paper is looking into the economic side, and whether it is economically viable to use biochar to enhance and uphold biodiversity. This is evaluated by reviewing and categorizing 164 papers and conducting a literature review. My conclusions are that the current biochar applications show lower economic efficiency than other carbon dioxide abatement technologies. The stability of biochar in soil is a key factor, as the half-lives of biochars may not be as long as commonly suggested. Furthermore, competition for biomass resource use can restrict the availability of feedstock, and make it more expensive. Subsidies for biochar application are required if biochar is to be- come a significant part of the national or global climate mitigation policy. The results in different articles are quite variable and there is currently no standard approach to them. There is a need for specific research on what kind of biochar benefits what soil and vegetation, which is expensive. A primary goal is to incorporate a consistent and standardized testing or analysis method for biochar stability into the certification programs run and administered by the International and the European Biochar Initiatives. In the foreseeable future, biochar by itself is unlikely to play a significant role in climate mitigation strategies. Biochar might be just one of several alternatives in a bundle strategy to re- duce carbon emissions. However, its potential use must still be researched more.
  • Assmuth, Aino; Ramo, Janne; Tahvonen, Olli (2018)
    We study the economics of carbon storage using a model that includes forest size structure and determines the choice between rotation forestry and continuous cover forestry. Optimal harvests may rely solely on thinning, implying infinite rotation and continuous cover forestry, or both thinning and clearcuts, implying finite rotation periods. Given several carbon prices and interest rates, we optimize the timing and intensity of thinnings along with the choice of management regime. In addition to the carbon storage in living trees, we include the carbon dynamics of dead trees and timber products. Forest growth is specified by an empirically validated transition matrix model for Norway spruce (Picea abies (L.) Karst.). The optimization problem is solved in its general dynamic form by applying bilevel optimization with gradient-based interior point methods and a genetic algorithm. Carbon pricing postpones thinnings, increases stand density by directing harvests to larger trees, and typically yields a regime shift from rotation forestry to continuous cover forestry. In continuous cover solutions, the steady-state harvesting interval and the diameter distribution of standing and harvested trees are sensitive to carbon price, implying that carbon pricing increases the sawlog ratio of timber yields. Additionally, we obtain relatively inexpensive stand-level marginal costs of carbon storage.
  • Baumann, Moritz; Taucher, Jan; Paul, Allanah J.; Heinemann, Malte; Vanharanta, Mari; Bach, Lennart T.; Spilling, Kristian; Ortiz, Joaquin; Aristegui, Javier; Hernandez-Hernandez, Nauzet; Banos, Isabel; Riebesell, Ulf (2021)
    Reduction of anthropogenic CO2 emissions alone will not sufficiently restrict global warming and enable the 1.5 degrees C goal of the Paris agreement to be met. To effectively counteract climate change, measures to actively remove carbon dioxide from the atmosphere are required. Artificial upwelling has been proposed as one such carbon dioxide removal technique. By fueling primary productivity in the surface ocean with nutrient-rich deep water, it could potentially enhance downward fluxes of particulate organic carbon (POC) and carbon sequestration. In this study we investigated the effect of different intensities of artificial upwelling combined with two upwelling modes (recurring additions vs. one singular addition) on POC export, sinking matter stoichiometry and remineralization depth. We carried out a 39 day-long mesocosm experiment in the subtropical North Atlantic, where we fertilized oligotrophic surface waters with different amounts of deep water. The total nutrient inputs ranged from 1.6 to 11.0 mu mol NO3- L-1. We found that on the one hand POC export under artificial upwelling more than doubled, and the molar C:N ratios of sinking organic matter increased from values around Redfield (6.6) to similar to 8-13, which is beneficial for potential carbon dioxide removal. On the other hand, sinking matter was remineralized at faster rates and showed lower sinking velocities, which led to shallower remineralization depths. Particle properties were more favorable for deep carbon export in the recurring upwelling mode, while in the singular mode the C:N increase of sinking matter was more pronounced. In both upwelling modes roughly half of the produced organic carbon was retained in the water column until the end of the experiment. This suggests that the plankton communities were still in the process of adjustment, possibly due to the different response times of producers and consumers. There is thus a need for studies with longer experimental durations to quantify the responses of fully adjusted communities. Finally, our results revealed that artificial upwelling affects a variety of sinking particle properties, and that the intensity and mode with which it is applied control the strength of the effects.
  • Harjuniemi, Aliisa (Helsingfors universitet, 2014)
    The Atlantic forest on the Eastern coast of Brazil is one of the world’s most endangered biotopes. Less than 12 % of the original forest remains due to agricultural and pasture expansion. In addition, many Atlantic forest restoration projects in the past have failed, largely because of inadequate silvicultural practices. Meanwhile, the growth rates of Eucalyptus and pine plantations have been increased 3 to 4 fold in Brazil over the last four decades by utilizing intensive silvicultural methods such as site preparation, fertilization, and weed control which in turn increases resource supply (nutrient, water and light). This study determines the effects of these same intensive silvicultural methods on Atlantic forest restoration regarding initial growth and carbon sequestering. Two parallel research sites were established in 2004 on latitudes 11°S and 23°S on the Eastern coast of Brazil to determine the effects of intensive silviculture, planting density and species composition on the development of 20 native tree species. This research focused on the Northern site (200 km North of Salvador, Bahia State) which has a typical tropical climate and soil type. The project has a 23 factorial design totalling 8 treatments, with the following factors: i) intensive and traditional treatments; ii) initial planting densities (3333 trees ha-1 and 1667 trees ha-1); and iii) species composition proportion (50:50 and 67:33 ratio of pioneer vs. late successional species). After 8 years from planting, survival and development of each species, aboveground biomass and leaf area index (LAI) were determined for all the treatments to compare the effects of the different factors. In summary, the main findings of this study are: 1) The more intensive management methods improved survival and the initial growth of tree species 2) Lower stand density (1667 trees ha-1) had the best response to the intensive management for LAI, stemwood production, and above ground carbon sequestration 3) Out of 20 species, 19 had significantly higher growth with intensive management, indicating that both pioneer and late successional species are constrained by the original site conditions. 4) Intensive management was essential, especially for non-pioneer species. 5) Under low intensity silviculture, the 67:33 ratio pioneers vs. non-pioneers with higher planting density (3333 trees ha-1) was the best option to obtain the highest stemwood volumes 8 years from planting, while the 50:50 ratio pioneers vs. non-pioneers with lower planting density (1667 tree ha-1) could be recommended under intensive silviculture. Conclusion: Intensive management methods have the potential to increase early restoration success by increasing biodiversity through enchancing survival and growth of non-pioneer species and accelerating the canopy closure. Intensive management methods increased the above ground carbon sequestered in 8 years, remarkably, up to 3-fold compared to traditional management, making it an attractive management option for carbon offsets.
  • Mattila, Kaarle (Helsingin yliopisto, 2018)
    Cost-effective mitigation of climate change is essential for climate policy. Forest rotation age is a silvicultural measure by which forest carbon stocks can be influenced with in accordance with the Kyoto Protocol, Article 3.4. The purpose of this study was to evaluate how lengthening the forest rotation periods would affect the profitability of forestry and carbon sequestration. The discounted net revenues of the forest owner’s economical optimal (Faustmann’s rotation model) were compared with 10 and 20 years longer rotation periods, where the additional carbon dioxide sequestrated was compensated with prices 20 € and 50 € per ton of CO2. All calculations were made with a 2 % and a 4 % interest rate. Ten test sites were selected from a list of forest stands in Eastern-Finland, 5 of which were Norway spruce stands and 5 were Scots pine stands. The forest growth of these stands was simulated with Motti-simulator, a software developed by Metsäntutkimuslaitos (METLA) to estimate tree growth at forest stand levels. The results indicate, that lengthening the rotation period increases the carbon stocks of forests. The additional carbon dioxide sequestrated obeys the rule of decreasing marginal utility, so that the increment is greater for the first 10 years than the following 10 years lengthening of lengthening. The unit costs for carbon sequestration were between 2.3 – 18.1 (€/ton of CO2) for Norway spruce and 0.2 – 15.9 for Scots pine. However, the carbon sequestration was by average higher and more cost-efficient for Norway spruces than for Scots pines. The discounted net revenues of the forest owner increased in almost every case, which implies that the carbon sequestration is profitable in the right circumstances. The incompleteness of carbon trading is an obstacle for the commercialization of forest carbon sequestration. In the future, more research data is required to enable a more efficient execution for the forest carbon sequestration markets.
  • Dukat, Paulina; Ziemblinska, Klaudia; Olejnik, Janusz; Malek, Stanislaw; Vesala, Timo; Urbaniak, Marek (2021)
    The accurate estimation of an increase in forest stand biomass has remained a challenge. Traditionally, in situ measurements are done by inventorying a number of trees and their biometric parameters such as diameter at the breast height (DBH) and height; sometimes these are complemented by carbon (C) content studies. Here we present the estimation of net primary productivity (NPP) over a two years period (2019-2020) at a 25-year-old Scots pine stand. Research was based on allometric equations made by direct biomass analysis (tree extraction) and carbon content estimations in individual components of sampled trees, combined with a series of stem diameter increments recorded by a network of band dendrometers. Site-specific allometric equations were obtained using two different approaches: using the whole tree biomass vs DBH (M1), and total dry biomass-derived as a sum of the results from individual tree components' biomass vs DBH (M2). Moreover, equations for similar forest stands from the literature were used for comparison. Gross primary productivity (GPP) estimated from the eddy-covariance measurements allowed the calculation of carbon use efficiency (CUE = NPP/GPP). The two investigated years differed in terms of the sum and patterns of precipitation distribution, with a moderately dry year of 2019 that followed the extremely dry 2018, and the relatively average year of 2020. As expected, a higher increase in biomass was recorded in 2020 compared to 2019, as determined by both allometric equations based on in situ and literature data. For the former approach, annual NPP estimates reached ca. 2.0-2.1 t C ha(-1) in 2019 and 2.6-2.7 t C ha(-1) in 2020 depending on the "in situ equations" (M1-M2) used, while literature-derived equations for the same site resulted in NPP values ca. 20-30% lower. CUE was higher in 2020, which resulted from a higher NPP total than in 2019, with lower summer and spring GPP in 2020. However, the CUE values were lower than those reported in the literature for comparable temperate forest stands. A thorough analysis of the low CUE value would require a full interpretation of interrelated physiological responses to extreme conditions.
  • Hildén, Mikael; Soimakallio, Sampo; Seppälä, Jyri; Liski, Jari (Suomen ympäristökeskus, 2016)
    SYKE Policy Brief
  • Salo, Inkeri (Helsingin yliopisto, 2021)
    Recognizing and evaluating the benefits of trees is important for creating sustainable, safe and recreational urban spaces. i-Tree Eco software is developed by USDA for evaluation and valuation of ecosystem services of urban trees and forests. The objective of this research was to find out how does the quality of collected data affect i-Tree Eco modelling. Two different types of data and modelling results were compared in this research. All trees of the park Kupittaanpuisto in Turku were measured and evaluated according to the i-Tree guidance in late summer 2018 (later inventory). The contrasting data was selected from the tree register maintained by the city of Turku (later tree register). i-Tree Eco models several ecosystem services, of which carbon storage, carbon sequestration, avoided surface water runoff and pollution removal were analyzed in this research. The software estimates the structural value of the trees considering the land use and tree condition as well. The results show that the quality of data affects modelling results. Based on the total inventory data, the amounts of carbon sequestration, avoided surface water runoff and pollution removal were higher than the amounts modelled according to the tree register data. On the other hand, the structural value and carbon storage were bigger based on the register data than on the total inventory measurements. Lack of canopy dimensions and estimates of canopy condition had an impact on the modelling results. According to the total inventory, there were 1315 trees in the Kupittaanpuisto (ca. 34 ha), the structural value was approx. 2 430 000 €, carbon storage was 563 t, annual carbon sequestration 12 t, annual avoided surface water runoff 811 m3 and annual pollution removal 307 kg. On grounds of this research it can be stated that canopy measurements and canopy condition estimates are needed to make more accurate estimates of ecosystem services when using i-Tree Eco. This research showed that trees in the Kupittaanpuisto produce many ecosystem services and the trees are valuable. In the future, the results can be used as a reference for other research projects on ecosystem services of urban trees in the Nordic countries.
  • Jansson, Päivi Susanna (Helsingfors universitet, 2013)
    This thesis studies market demand and supply in the voluntary forest carbon markets. The first section focuses on demand and provides an overview about the market mechanisms, buyer’s reasons to buy credits, and current demand in the markets. Supply will be studied with supply-chain approach. Supply-chain is a system moving a product or service from supplier to customer. The supply-chain section is divided into three parts. The first part finds out whether or not forests have the ability to sequester carbon and what kind of forest projects there has been. It also introduces the processes in which forest carbon credits are issued. The second part focuses on certification and verification schemes. Third part presents market places and the actors involved in carbon credit trading. Carbon markets will be evaluated on foreign and domestic basis. The aim of this thesis is to find out how well the voluntary carbon markets meet the conditions of perfect competition. The theory is based on the theory of competitive market structure and the price mechanism, where demand equals supply at the equilibrium price and quantity. The equilibrium should be found automatically within a perfectly competitive market when buyers and sellers interact. The empirical part of the study examines carbon credit issuance, project processes, certification and markets. The research questions are: 1. Do markets have infinite buyers and sellers? 2. Are products homogenous? 3. Do consumers and producers have perfect knowledge of price, utility, quality and production methods? 4. Is it easy to enter or exit the markets? The thesis is based on literature. Standards, marketplaces, and projects that were selected to the study were chosen according to the popularity based on market volume or forest-related characters. The research approach is qualitative. The collected data was analysed using content analysis. Economics and market theory form the theoretical basis of the analysis. Classification of the data is based on the theoretical framework. According to the theories a loose framework was formed to allow data reduction. Framework divides demand and supply-chain into separate parts. Research question number one is examined using a demand section. Research questions numbers 2-4 are examined using supply-chain sections. The study resulted in a conclusion that voluntary forest markets do not meet the conditions of perfect competition. Voluntary forest carbon markets are not perfectly competitive. Instead markets are uncompetitive where commodities are heterogeneous. There is only limited amount of forest projects and forestry based credits. Unit price is set to match the cost, in which case it is not determined by the market. Price-setting is possible because it is possible to differentiate projects. Imperfect competition in the market remains for mobility obstacles between markets have been set. Credit certified under certain standard, are not generally acceptable to another standard. The study results support the findings of studies conducted in the past.
  • Yrjölä, Hanna (Helsingin yliopisto, 2019)
    The study examines forest owners’ views on the profitability of forestry and their economic objectives. The aim is to find out how forest owners determine and evaluate profitability, and how the methods differ from those used by business enterprises. In addition to profitability perceptions, the study examines forest owners’ willingness to store carbon in their forests. The data for the study were collected by semi-structured interviews, which were undertaken with nine forest owners in spring 2019. The interviewees had participated in a training program called Metsänomistajan Talouskoulu that provides the forest owners with an opportunity to develop one’s understanding in forest management. Also, as the aim was to examine forest owners’ attitudes towards a hypothetical carbon offset program, the forest owners were asked to state their willingness to accept (WTA) presented in a questionnaire form. The results show that forest owners display diverse attitudes and the views on profitability differ from one owner to another. Even though the forest owners are familiar with different profitability assessment methods, utilizing them in one’s actions is relatively rare. While forest owners are generally interested in biodiversity protection, more information regarding carbon sequestration programs is still needed. According to the results, the actual participation rate would depend on factors such as the protocol requirements and the compensation amount. As a whole, majority of forest owners require financial incentives in order to participate in carbon sequestration programs.
  • Holder, Jonathan (Helsingin yliopisto, 2019)
    Forests have acted as a substantial Carbon sink during the last decades. In Finland, forests currently sequester about half of the total anthropogenic CO2 emissions. In order to mitigate climate change, most recent policies, both on the European and the Finnish level, are focussing on increasing forest utilisation, and use forest biomass to substitute fossil resources for material or energy production purposes. However, as increasing harvests commonly reduce the growth potential of forests, their function as a carbon sink could be reduced. This reduction of the forest carbon sink might offset the reduction in emissions gained by substitution. The aim of this study is to analyse how different levels of forest utilisation, i.e. harvest levels, and climate change affect the carbon sink function of Finnish forests at a national level during the period of 2015–2100. In order to quantify these effects in detail, the semi-empirical, climate- and management-sensitive forest growth simulator FORMIT-M is employed to estimate carbon stocks and fluxes in living biomass. The carbon stocks and balances of soils are calculated by applying the Yasso15 soil model to litter input as modelled by FORMIT-M. The carbon balance of harvested wood products is estimated by applying species- and assortment-specific decay functions to harvested timber assortments derived from dimensions. Four harvest scenarios were applied, covering total annual harvest levels between 40 and 87 million m3 a-1, i.e. both reduced and increased levels compared to current levels. The simulations were run for three climate scenarios: current climate (1981-2010 means), and RCP2.6 and RCP8.5 scenarios, the latter two based on predictions of the general circulation model CanESM2. The general findings of the simulations largely confirm earlier research, indicating that higher harvest levels decrease the total C sink. This was true across all climate scenarios examined; in general, the total C sink function of forests was predicted to increase under climate change conditions, with higher C sinks under RCP8.5 than RCP2.6. Under climate change, the relative effect of increasing harvests is reduced, but management in the form of harvest levels remains a more influential factor than climate change. In addition, the reduction in C sink function per unit of additionally harvested C is larger at higher harvest levels, especially under current climate. In the highest harvest scenario, managed forests acted as C sources in the beginning of the modelling period, and the total Finnish forest areas remain net C sinks only due to net C sequestration in preservation areas during this period. The simulations of this study therefore suggest that, from a climate change mitigation perspective, a reduction of harvests is more beneficial than increasing harvests. This is true even when avoided greenhouse gas emissions by replacing fossil resources with forest biomass are considered in the form of a rough estimation of substitution effects. In general, both the absolute magnitude of the C sink and the differences between harvest scenarios are likely to be overestimated in this study, as neither the reduction in growth potential nor the potential reduction of C stocks due to natural disturbances were considered; in addition, potential limiting factors such as nutrient deficiency did not restrict the fertilisation effect of elevated atmospheric CO2 levels. The results include large uncertainties, both regarding the effect and extend of climate change and the potential accumulation of misrepresentations within the growth modelling; hence, the reliability can be expected to decrease during the modelling period. Future applications of the FORMIT-M simulator in Finland should consider the effects of natural disturbances as well as limitations to the substantially improving growing conditions due to climatic conditions and elevated atmospheric CO2 levels; in addition, an optimisation procedure for the distribution of harvests would be beneficial.
  • Husa, Miikka Helmer; Kosenius, Anna-Kaisa (2021)
    In boreal commercial forests, carbon sequestration, climate change adaptation, and biodiversity conservation can be promoted through various measures. This study examines the factors affecting non-industrial private forest (NIPF) owners' preferences for such forest management practices. A systematic literature review serves as a reference for the empirical analysis of a survey data on the Finnish NIPF owners' stated willingness to adopt thirteen distinct forest management practices. Binary logit models reveal socio-demographic factors, site-specific characteristics, previous forest management, and motivations for forest ownership that are associated with the stated adoption of management practices. Especially, environmental and financial motivations play an important role in decisions concerning forest management practices. Statistically significant factors vary depending on the forest management practice, reflecting the NIPF owner heterogeneity. Younger and highly educated forest owners are more supportive for various management practices that promote biodiversity, while older forest owners are reluctant towards deadwood retention. The results underline the importance of accounting for heterogeneous preferences regarding forest management practices when designing and implementing policies and advisory services aiming at enhancing carbon sequestration, climate change adaptation, or biodiversity in boreal commercial forests.
  • Soimakallio, Sampo; Kalliokoski, Tuomo; Lehtonen, Aleksi; Salminen, Olli (Springer, 2021)
    Mitigation and Adaption Strategies for Global Change 26: 4
    Forest biomass can be used in two different ways to limit the growth of the atmospheric greenhouse gas (GHG) concentrations: (1) to provide negative emissions through sequestration of carbon into forests and harvested wood products or (2) to avoid GHG emissions through substitution of non-renewable raw materials with wood. We study the trade-offs and synergies between these strategies using three different Finnish national-level forest scenarios between 2015 and 2044 as examples. We demonstrate how GHG emissions change when wood harvest rates are increased. We take into account CO2 and other greenhouse gas flows in the forest, the decay rate of harvested wood products and fossil-based CO2 emissions that can be avoided by substituting alternative materials with wood derived from increased harvests. We considered uncertainties of key parameters by using stochastic simulation. According to our results, an increase in harvest rates in Finland increased the total net GHG flow to the atmosphere virtually certainly or very likely, given the uncertainties and time frame considered. This was because the increased biomass-based CO2 and other greenhouse gas emissions to the atmosphere together with decreased carbon sequestration into the forest were very likely higher than the avoided fossil-based CO2 emissions. The reverse of this conclusion would require that compared to what was studied in this paper, the share of long-living wood products in the product mix would be higher, carbon dioxide from bioenergy production would be captured and stored, and reduction in forest carbon equivalent net sink due to wood harvesting would be minimized.
  • Assmuth, Aino (Helsingin yliopisto, 2015)
    This study applies two novel forest economic models to analyze the effect of optimal carbon storage on the choice between clearcuts and continuous cover forestry. Unlike previous studies, we determine the economically optimal management regime endogenously, by optimization. We study a policy where the society pays forest owners a Pigouvian subsidy for the carbon that is sequestered by the stand as it grows. The focus of our analysis is a subsidy system that also takes into account the carbon both stored in and released from wood products. In the first part of the thesis, the question of optimal carbon storage is studied using a continuous time biomass model that does not include any a priori assumptions on clearcuts vs. continuous cover forestry. We show analytically that subsidized carbon sequestration postpones thinning and increases optimal stand volume along the rotation. With high carbon price the shadow value of stand volume becomes negative. Numerical results show that carbon prices within a realistic range may switch the optimal management regime from clearcuts to continuous cover management. A higher interest rate can lead to a higher stand volume and a longer optimal rotation, which contrasts the results of the classic Faustmann model. Next, the question is studied applying a more detailed size-structured transition matrix model based on empirically estimated Scandinavian growth data. This approach produces a more accurate description of the complex dynamics of uneven-aged stands and optimization of harvesting activities. According to numerical results, thinning is invariably carried out from above, and the size of the harvested trees increases with carbon price. Optimal rotation age increases with carbon price, and moderate carbon pricing is sufficient to switch the management regime to continuous cover management. Optimal rotation age also increases with interest rate. Clearcut management is the more competitive, the more productive is the site type. Both models suggest that carbon storage has a significant effect on optimal forest management, and that it typically favors continuous cover forestry. Similar analysis on optimal carbon storage in forestry has not been presented before. We also discuss various carbon subsidy systems in the context of developing climate policy.
  • Santalahti, Tanya (Helsingin yliopisto, 2022)
    Carbon neutral agriculture plays a key role in climate change mitigation. However, Finnish farmers are struggling with the impacts of climate change and the profitability crisis. This study aims at providing market insight on potential sources of income for Finnish farmers in carbon neutral agriculture by 2030. However, this thesis does not focus on the question whether carbon neutral agriculture is achievable. The role of policy instruments is also investigated to determine whether they facilitate or prevent changes. The thesis is commissioned by Envitecpolis Oy. Six experts from the agriculture field were interviewed and the data were analysed with theory-driven content analysis. The analysis is based on the future signals sense-making framework (FSSF) that focuses on the weak signals, drivers and trends found in the data. Each theme includes two categories; the nonlinear and linear paths of change. In addition, policy instruments were divided into promoters and disrupters of change. The relevant weak signals identified are innovations, the formation of premium markets, the adoption of paludiculture, novel and existing market mechanisms for carbon neutral practices, the substitution of materials and energy in production, digitalization, the increasing requirements for producers by food industry and by consumers and lastly, strengthened cooperation between actors in agriculture. The drivers of change, such as climate change, knowledge and advances in technology, significantly influence the adoption of these weak signals. However, various trends function as blockers of change whilst some trends are inevitable large change processes. In light of the results, weak signals of potential sources of income are not likely to become mainstream by 2030. However, existing or emerging issues may play a key role in providing additional income for farmers. National agriculture policy and the EU Common Agriculture Policy (CAP) are complex schemes that are gradually emphasizing climate issues. However, these policies fail to incentivize farmers to adopt practices for carbon neutral agriculture. Recommendations for future research include the cost-effectiveness of climate change mitigation measures and a follow-up on the sources of income for farmers in 2030.