Browsing by discipline "Skoglig ekologi och resurshushållning"

In Norway spruce (Picea abies) dominated mineral soil sites, the polypore Heterobasidion parviporum often causes severe decay problems (butt rot, root rot). Not much is however known on the ability of H. parviporum to cause decay losses in peatland. The purpose of this study was to answer some fundamental question: 1) Is H. parviporum able to cause decay losses in drained mires? 2) Is there an effect of other soil microbes during saprotrophic growth of Heterobasidion on peat soil? 3) What are the potential inhibitory effects of microbes inhabiting peat soil on growth of Heterobasidion? For the decay study, wood discs (P. abies) in mesh bags were buried at the different forest sites; mineral soil and peatlands (including drained mire and undrained mire). The amount of weight loss was documented after four months. The study was repeated in vitro by autoclaving soil samples from these sites together with wood discs followed by inoculation with H. parviporum. On mineral soil, H. parviporum decayed spruce (P. abies) wood disc much more than on non-drained pristine mire. On drained (ditched) mire, no significant difference in the weight loss was observed. H. parviporum grew significantly more on the sterilized soil and decayed more wood, compared to non-sterilized soil. The results suggested that secreted metabolites in the unsterilized soil may be able to significantly suppress saprotrophic growth of H. parviporum. In the fungal growth inhibition experiment, water- and acetone-soluble substances were extracted from the soil with acetone and water. No fungal growth inhibiting substances were detected from the various peat soils or mineral soils.

Limited pre-information of wood raw material properties complicates customer-oriented production planning in sawmilling. The problem is especially concerning Scots pine (Pinus sylvestris L.) because its quality varies significantly within single trees but also within different forests. In the modern cut-to-length method decision of crosscutting points has to be made with help of stem profile prediction, optimization calculations and external quality properties of wood material. In the tree length method that is minimally used in Finland bucking can be done in a terminal that makes it possible to study whole external profile of the stem before the bucking. However, in crosscutting that aims to producing of value added products it would be important to know the internal quality of stem. One method that provides information on internal quality of wood raw material is x-ray log scanning that is used for the quality sorting at sawmills. The purpose of this study was to find out whether it is possible to predict the internal quality of Scots pine stems with the help of some stem characteristics. Moreover, it was also examined whether it is possible to develop the quality bucking of Scots pine butt logs if bucking is supported by x-ray log scanning. The study material was collected from eight final felling stands. From each stand 30 Scots pine stems were chosen and marked and of these was measured diameter at breast height, dead branch height, live branch height and total height. All marked Scots pine stems were felled and bucked as stems whose length varied between 12 and 20 meters starting from the butt of stem. After that the marked study stems were scanned with x-ray system in order to study their internal properties. Individual quality border points were calculated for each of the stems based on the x-ray data. Dead branch height was the most correlated stem characteristic with quality border point. The relationship of the dead branch height and the quality border point was examined with logistic mixed model. A binary dependent variable was determined for each of the stems. Limit value between binary categories (0/1) was 37 decimetres height of quality border. The dead branch height that was classified into four classes was used as an explanatory variable. By using this method it was possible to predict the correct class for 71,6 % of the stems. A stand number that was used as a random effect variable in the model was not statistically significant. The butt logs bucking that was made at the terminal and the butt logs bucking that was proposed by the harvester drivers was compared to the simulated butt logs bucking that considered also the quality border point of a stem. The total volume of A-class logs increased in a bucking option that considered the quality border compared to two other examined bucking options. Average volume of the butt logs decreased as a main way for increasing the logs quality was shortening of their average length. The results indicate that it is possible to rather well predict the internal quality of Scots pine stems with dead branch height and when crosscutting of stems is supported with x-ray scanning system, it is possible to increase the quality of butt logs. In order to reduce uncertain elements it would be necessary to use larger study material in the future studies. In addition, it would be beneficial to pay more attention to the interpretation of x-ray scanning data.

Community-based forest management (CBFM) is believed to have potentials to reduce deforestation and forest degradation, achieve sustainable forest management and improve local livelihood especially in developing countries. In the 1980s, Burkina Faso acknowledged and integrated this model in managing some of its forest resources. A fifteen-year rotation period within a forest management unit (FMU), considered one of the few success stories of community forest management in Africa, was established. Until now, most empirical studies conducted on the subject in the country have focused on governance, local participation and benefit sharing. But, with over 80% of the country’s population dependent on fuelwood, as the main source of household energy, observations and other field information of these forests revealed irregularities which questioned the actual management processes. This study therefore aimed to assess the sustainability of community forest management in Burkina Faso by evaluating whether the management practices complied with those in the management plan. A “Chantier d’Aménagement Forestier” (CAF) of Cassou, comprising of twelve forest management units (FMUs), created for fuelwood production destined to the capital city, Ouagadougou was selected, and three managements units: FMU I, FMU VIII and FMU IX were randomly selected for this study. The management plan was analyzed using their prescribed logging information. Management practices were then analyzed by comparing the prescribed logging and actually logged information. Forest inventories and field observations were conducted in the selected FMUs to collected field data and to identify other factors affecting management activities. Findings show that the management plan was appropriately elaborated, but management practices did not adhere to the prescribed norms, which resulted in overexploitation of forests. Field observations revealed that the forest was subjected to many interrelated human activities and processes, which made the logging unsustainable. This study includes proposals, which if correctly applied, can reduce pressure on the forest and improve the sustainability of forest management.

The atmospheric nitrogen (N) deposition has increased in industrialized and densely populated areas, which according to previous studies may cause changes in the vegetation, microtopography, and carbon (C) cycling of peatlands. Knowing the effects of nutrient deposition is important, because a significant amount of C is stored in boreal nutrient-limited ombrotrophic bogs, which are also a significant natural source of methane (CH4). The aim of this study was to investigate how elevated N deposition affects the CH4 fluxes and vegetation in an ombrotrophic bog. This study was conducted at a long-term fertilization experiment at Mer Bleue, a Sphagnum moss and evergreen shrub dominated ombrotrophic bog in Ottawa, Southern Ontario. The experiment consisted of nine nutrient treatments, each with three replicate 3 x 3 m plots. In the summer of 2015, the plots had been fertilized for 11–16 years with 1.6, 3.2, and 6.4 g N m-2 with or without phosphorus (P) and potassium (K) and control plots received distilled water. Methane fluxes were measured weekly from the beginning of May to the end of August using closed chamber method. Peat temperature, water table level, and volumetric soil water content were also measured. The changes in vegetation abundance and species composition were monitored monthly using point-intercept method. The results show that instantaneous CH4 fluxes at the bog are typically small (0–0.2 mmol m-2 h-1). The seasonal average CH4 emissions from N only treatments are equal to controls. However, the average CH4 emissions have increased after 15–16 years of fertilization from the highest NPK treatments compared to unfertilized control due to nutrient induced changes in vegetation, microtopography, and peat characteristics. The changes in vegetation include the loss of Sphagnum mosses and new deciduous species in the area. Due to the loss of moss cover, the peat has subsided and it has become wetter, which may explain the increased CH4 emissions. Direct effects of fertilization on the microbial communities may also be a factor. The results of this study indicate that elevated atmospheric deposition of nutrients may increase loss of C as CH4 in peatlands through a complex suite of feedbacks and interactions among vegetation, microclimate, and microbial communities.

Nursery grown seedlings are an essential part of the forestry industry. These seedlings are grown under high nutrient conditions caused by fertilization. Though grown in a controlled environment, symbionts such as ectomycorrhizal fungi (EcMF) are often found in these conditions. To examine the effects of EcMF in these conditions, colonized Picea glauca seedlings were collected from Toumey Nursery in Watersmeet, MI. After collection, the EcMF present were morphotyped, and seedlings with different morphotypes were divided equally into two treatment types- fertilized and unfertilized. Seedlings received treatment for one growing season. After that time, seedlings were collected, ectomycorrhizas identified using 1morphotyping and DNA sequencing, and seedlings were analyzed for differences in leaf nutrient concentration, content, root to shoot ratio, total biomass, and EcMF community structure. DNA sequencing identified 5 unique species groups- Amphinema sp. 1, Amphinema sp. 5, Thelephora terrestris, Sphaerosporella brunnea, and Boletus variipes. In the unfertilized treatment it was found that Amphinema sp. 1 strongly negatively impacted foliar N concentration. In fertilized seedlings, Thelephora terrestris had a strong negative impact on foliar phosphorus concentration, while Amphinema sp. 1 positively impacted foliar boron, magnesium, manganese, and phosphorus concentration. In terms of content, Amphinema sp. 1 led to significantly higher content of manganese and boron in fertilized treatments, as well as elevated phosphorus in unfertilized seedlings. Amphinema sp. 5 had a significant negative effect on phosphorus content. When examining root to shoot ratio and biomass, those seedlings with more non-mycorrhizal tips had a higher root to shoot ratio. Findings from the study shed light on the interactions of the species. Amphinema sp. 5 shows very different functionality than Amphinema sp. 1. Amphinema sp. 1 appears to have the highest positive effect on seedling nutrition when in both fertilized and unfertilized environments. Amphinema sp. 5 and T. terrestris appear to behave parasitically in both fertilized and unfertilized conditions.

Tutkielmassa tarkasteltiin joulukuusiviljelmän ominaisuuksia ja viljelytoimenpiteitä sekä niiden vaikutusta kasvatettavien puiden tuhoalttiuteen. Tutkielmassa keskityttiin tarkastelemaan metsäkuusta (Picea abies) ja tavoitteena oli selvittää, esiintyykö tutkittavalla joulukuusiviljelmällä jokin tuhonaiheuttaja muita runsaammin aiheuttaen selkeän haitan joulukuusenkasvatukselle. Lisäksi tutkittiin, vaikuttaako joulukuusilla viljeltävää peltoa ympäröivän metsän ja avoimen maaston vaihtelu tuhojen esiintymiseen pellolla. Tarkastelussa pyrittiin myös selvittämään monokulttuurin ja sekapuuston mahdollisia vaikutuksia tuhoriskiin. Aikaisemmin ei ole tehty kattavaa selvitystä joulukuusiviljelmiä vaivaavista tuhonaiheuttajista. Tutkielmaa varten inventoitiin kesän 2016 aikana joulukuusiviljelmään kuuluva pelto Hyvinkäällä. Pelto inventoitiin viidesti kesän aikana, jolloin pystyttiin seuraamaan tuhonaiheuttajien dynamiikkaa kasvukauden aikana. Jokaisella mittauskerralla tarkasteltiin 820 puun otosta. Näin intensiivistä tuhoseurantaa ei metsikkötasolla ole tehty. Jokaisesta puusta määritettiin tuhonaiheuttajat ja arvioitiin latvuksen kunto. Inventointien perusteella luotiin malleja, joilla tarkasteltiin ympäröivän metsän ja avoimen maan vaihtelun sekä maalajin ja taimimateriaalin vaikutusta tuhojen esiintymiseen. Tuhojen aiheuttamien haittojen vakavuutta arvoitiin ristiintaulukoimalla tuhonaiheuttajien frekvenssit latvuksen kunnon suhteen. Kesän aikana esiintyi runsaasti versosurmaa (Gremmeniella abietina). Versosurmaa pidetään hankalana tuhonaiheuttajana joulukuusiviljelmillä. Lisäksi puiden laatuun vaikutti latvuksessa oleva aukko, joka oli syntynyt neljä vuotta aikaisemmin. Tätä tuhonaiheuttajaa ei ollut mahdollista jälkikäteen selvittää. Kolmas mittauskerta sijoittui kuusensuopursuruosteen (Chrysomyxa ledi) itiöintiaikaan, jolloin sienen itiöemät olivat selvästi näkyvissä. Kuusensuopursuruosteen merkit kuitenkin olivat seuraavaan mittauskertaan mennessä pudonneet pois, eikä se aiheuttanut näkyvää haittaa myöhemmin. Hyönteismyrkyn levitys yhdistettynä joulukuusille vuosittain tehtäviin typistyksiin poisti hyönteisten aiheuttamat tuhot tutkimuskohteelta. Typistettäessä leikataan kuusen tuoreimpia vuosikasvaimia, joissa myös iso osa tuhoista on. Joulukuusien kannalta haitallisimmat hyönteiset iskevät juuri uusiin kasvaimiin. Monokulttuurilla ei myöskään näytä olevan joulukuusenkasvatuksen kannalta merkitystä tuhoalttiudelle runsaista hoitotoimenpiteistä johtuen.

The conversion of vegetated land cover to impervious surfaces has made stormwater runoff into a major hydrological concern due to its capacity to deteriorate water quality and stream health in cities. Urban forests are capable of reducing the amount of potential stormwater runoff by regulating throughfall via canopy rainfall interception. The lack of stand-scale studies of urban throughfall hinders realistic estimates of the benefits of urban trees for stormwater regulation. Urban forests are extremely variable with regard to canopy cover and species composition and are to a large extent managed by private residents with varying landscape preferences. To quantify the amount of rainfall interception by vegetation in an urban forest we measured throughfall in Raleigh, North Carolina, USA between July and November 2010. We further analyzed 16 residential yards with varying levels of canopy cover to evaluate the relative importance of different descriptive measures of vegetation in influencing throughfall in an urban watershed. Throughfall comprised 89.7 % (StdErr=0.005) of gross precipitation in the study area. Canopy cover (p<0.0001) and the percentage of coniferous trees (p=0.0305) were the most influential vegetation variables explaining throughfall whereas leaf area index (LAI) was not found to be significant. Throughfall varied significantly among yards (p<0.0001) ranging from 84.0 % (80.2 % canopy cover) to 98.2 % (60.3 % canopy cover). Differences in vegetation between front and backyards resulted in 3.1 % less throughfall in backyards. Thus, residents‘ management choices at yard-level affect the amount of throughfall reduced at the landscape scale.

Taimikonhoito on uudistamisen jälkeen merkittävin kustannus koko kiertoajalla tasaikäisen metsikön kasvatuksessa. Nykyisen ohjeistuksen mukaisesti kaksivaiheinen taimikonhoito-ohjelma jaetaan varhaisperkaukseen ja varsinaiseen taimikonhoitoon. Hoitotoimenpiteillä varmistetaan taimikon häiriötön kehitys tuottavaksi ensiharvennusleimikoksi. Osalla taimikoista yksi hoitokerta voi olla kuitenkin riittävä. Yhden taimikonhoitokerran jäädessä pois on mahdollista saavuttaa merkittäviä kustannussäästöjä erityisesti suurta metsäomaisuutta hallinnoitaessa. Työssä tutkittiin varhaisperkauksen tarpeellisuutta UPM Metsän Väli-Suomen metsätiloilta mitatun koeaineiston perusteella. Työssä selvitettiin, oliko kesällä 2015 varhaisperkaukseen määritellyt tuoreen (MT) ja kuivahkon (VT) kankaan taimikkokuviot todellisuudessa perkauksen tarpeessa nykyisen taimikonhoito-ohjeistuksen mukaisesti. Työssä tarkasteltiin tuoreen (MT) kankaan istutuskuusikoita sekä tuoreen (MT) ja kuivahkon (VT) kankaan kylvömänniköitä. Tavoitteena oli mahdollisuuksien mukaan tunnistaa ne kohteet, joilla varhaisperkaus ei ole vielä tarpeen tai varhaisperkausta ei tarvita lainkaan. Nämä kohteet tunnistamalla olisi mahdollista saada kustannussäästöjä taimikonhoito-ohjeistusta päivittämällä. Työssä tarkasteltiin lisäksi kuviotietojen käyttökelpoisuutta varhaisperkaustarpeen määrittelyssä. Varhaisperkaus oli tarpeellinen nykyisen ohjeistuksen mukaisesti tuoreen kankaan istutetuissa kuusen taimikoissa. Perkaus on ajankohtainen noin viiden vuoden iässä. Istutuskuusikoista ei ole mahdollista hakea kustannussäästöjä taimikonhoitokertoja vähentämällä. Kaksivaiheinen taimikonhoito-ohjelma on lähtökohtaisesti tarkoituksenmukainen. Tuoreen kankaan männiköissä varhaisperkaus oli myös tarpeellinen ja tästä joukosta ei ole syytä hakea kustannussäästöjä. Tutkimuksessa tuoreen kankaan männiköiden osuus oli kuitenkin hyvin pieni. Kuivahkon kankaan kylvömänniköissä varhaisperkaus tehtiin tulosten mukaan liian aikaisin. Tutkimuksen mukaan varhaisperkaus ei ole vielä ajankohtaista noin seitsemän vuoden ikäisissä kylvötaimikoissa. Tästä joukosta olisi mahdollista saada kustannussäästöjä arvioimalla varhaisperkaustarvetta tarkemmin. Männiköissä olisi erityisesti huomioitava kasvatettavan puuston välinen kilpailu, kuvion kokonaisrunkoluku sekä mahdollinen spatiaalinen vaihtelu kuvion sisällä. Kuviotiedoista ei ole mahdollista nykyisen tiedon perusteella määritellä kohteita, joilla varhaisperkausta olisi mahdollista siirtää nykyisestä ohjeistuksesta. Nuorilla taimikoilla tiedot ovat laskennallisia. Tiedon täysimääräinen hyödyntäminen vaatisi taimikoiden tietojen päivittämistä, mikä ei käytännössä ole kustannustehokasta hyötyynsä nähden. Tutkimuksen perusteella kuviotietokannan laskentamalleja olisi syytä tarkistaa. Istutuskuusikoilla puuston kuviotietokannan pituustiedot ovat selvästi aliarvioita, kun taas kylvömänniköillä jossain määrin yliarvioita. Kuviotiedon laatuun ja lisämääreiden käyttöön olisi syytä kiinnittää huomiota, jotta tietoja olisi mahdollista käyttää tarkemmin varhaisperkaustarpeen määrittelemisessä.

In Finland, soil classification in forestry has played only a minor role. However several international classification systems exist, one being the World Reference Base for Soil Resources (WRB) used in this study. The criteria used in WRB to identify diagnostic properties, horizons and soil materials which are to classify a soil may not work everywhere. This is one reason why there is a continuous revision of international soil classification systems and a need to test them nationally. In Finland problems have been encountered with the criteria of international soil classification systems for defining a spodic B horizon. Empirical testing of soils classified as Podzols according to international soil classification systems has not been carried out in Finland. It is not known how many soil profiles considered to be Podzols actually have spodic B horizons, the official requirement for a soil to be classified as a Podzol. Soil classification systems provide detailed information of our soils and its properties in soil horizons. These soil properties are indicators of the degree of development in the soil. Podzols, considered to be the most common upland forest soil type in Finland, are formed through a combination of the five soil formation factors: climate, parent material, topography, biotic and time. These factors determine which soil formation processes operate, which properties develop and then which soil type classes are formed. There have been few studies in Finland that have examined the degree of podzolization of podzolized soil profiles in relation to soil formation factors. The aims of this study were therefore to determine the number of profiles (sampled from all over Finland) that were classified in the field as being Podzol that actually have diagnostic spodic horizons according to World Reference Base for Soil Resources (WRB). The diagnostic spodic criteria of WRB have six criteria and these are based on morphological properties (horizon thickness and Munsell dry/moist colours) and chemical properties (pH, organic carbon content and acid oxalate extractable Al and Fe contents) of the E and B horizon samples. In addition, the degree of podzolization of the profiles using a number of podzolization indices (Thickness index, Rubification index, Al+Fe index and Podzolization Development Index) was determinate and importance of various soil formation factors (climate, topography, parent material, biotic, time) on the degree of development of the profiles evaluated. The study was carried out using soil profiles covering the whole Finland. The soil profile data is from the BioSoil project, Natural Resources Institute Finland, Luke. Study showed that field classification of Podzols based on morphological features (colour and thickness of the albic and spodic horizons) works well in Finnish soils. Except of albic colours criteria of morphological soil properties in spodic horizon are fairly equal with criteria of chemical soil properties. Podzolization intensity is poorly explained by individual soil formation factors (variables). Soil processes occur simultaneously and there is much interaction between/among soil formation factors. In certain situations, indexes based on morphological or chemical properties acts in an opposite way to each other. Nevertheless, time and soil texture (parent material) were the most important factors. Topography was noticed to have only a minor effect on podzolization.

The current study examined the particular land use land cover change process that occurred in one segment of the Tambopata Natural Reserve Buffer Zone, in the Southeastern Peruvian Amazon region of Madre de Dios, during the period 2004-2011. During such period of time, the study area experimented significant land use transitions, mostly from tropical forest and farming areas towards illegal gold mining activities. Theory explained that such processes occur due to a particular combination of direct and underlying drivers. Therefore, the research objectives of the study, focused to undercover both drivers and their intricate interaction and dynamics that shaped the particular transitions in the study site. Theory also indicated that an integral land use cover change analysis is required to properly formulate sound and adequate measures and policies in order to effectively tackle further land use change leading to deforestation. The long term impact of such measures are transcendental in terms of climate change by avoiding considerable carbon emissions to the atmosphere. The chosen methodology was an integration of qualitative and quantitative approaches, which required primary and secondary data correspondingly. The collection of secondary data included land use change maps for each year of analysis and its corresponding land use change matrix, whereas the collection of primary data required extensive semi-structure interviews in the field. Additionally, the qualitative approach required in the inclusion of grey literature. The analysis of each set of data was initially conducted separately, which resulted in two different but complementary interpretations of the particular land use change in the study site. Both results were later integrated and examined altogether, which resulted into a complete and detailed analysis of the particular event in the study area. The final integration exposed the direct and underlying drivers of change. The integral results exposed a dynamic area that experimented rapid forest loss towards mostly illegal gold mining activities, together with a non-compensatory natural regeneration. In addition, important economic activities identified as forestry and farming concessions, experimented similar transitions. Integral results exposed the direct drivers of change, such as the development of illegal gold mining, the pavement of the Inter Oceanic Highway and new informal agricultural expansion. Similarly, the underlying causes of change were also identified as an intricate and complex combination of pre-established variables such as cultural, economic, demographic, social, political and institutional ones. It was acknowledged that a complex interaction of direct and hidden drivers created the particular deforestation process in the site. However, it was identified that new extraordinary variables remarkably accelerated the transition process towards illegal mining. Such variables were the astonishing international gold price, together with the Inter Oceanic Highway pavement and the relatively new but inefficient decentralization of the national forestry system. Such combination resulted into the remarkable land use conversion towards illegal mining, which caused rapid and pervasive deforestation. Finally, the government proved incompetent to deal with such event and its corresponding development by implementing actions that lacked a complete analysis of the direct and underlying causes, including the social and economic particularities of the area. This resulted into insufficient achievements and inefficient solutions.