Männyt oikeille viljelypaikoille myös muuttuvassa ilmastossa

Näytä koko lehti201

Clonal variation in basic density, moisture content and heating value of wood, bark and branches in hybrid aspen

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Forest condition monitoring under the UN/ECE and EU programmes in Finland

Part of the online report: Merilä, P. & Jortikka, S. (eds.). Forest Condition Monitoring in Finland – National report. The Finnish Forest Research Institute. http://urn.fi/URN:NBN:fi:metla-201305087568. Original webpages have been converted to a PDF file

Geographical patterns in the radial growth response of Norway spruce provenances to climatic variation

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User guide for PRELES, a simple model for the assessment of gross primary production and water balance of forests

Climforisk EU Life+ (EU/ENV/FI/00571) http://www.metla.fi/life/climforisk. Deliverable of the Action 3 of the Climforisk project: Modelling software and documentation , 30.6.2012.Simple models of ecosystem processes are useful tools for various kind of ecosystem impact studies. We built a simple model of ecosystem gross primary production, evapotranspiration and soil water content, which requires minimal input data, and which is efficient to run. In this report, we briefly describe the model equations, document the model program and provide user guide for the current version of the model. We also use the model to run a few example simulations that describe how the model responds to the environment, and test the model predictions of soil water in reference conditions with ICP level II data on soil water. The model is intended to be used in large scale prediction of GPP, ET, and drought in the Climforisk EU Life+ project

Hybridihaavan kloonien välinen puun, kuoren ja oksien tiheyden, kosteuden ja lämpöarvon vaihtelu

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Site index models with density effect for hybrid aspen (Populus tremula L. × P. tremuloides Michx.) plantations in southern Finland

This study was conducted to examine the characteristics of dominant height growth and develop site index models for clonal hybrid aspen plantations in southern Finland. Data were obtained from repeatedly measured clonal hybrid aspen trials with varying initial spacing: 2.5 m × 2.5 m (1600 trees ha−1), 3.0 m × 3.0 m (1200 trees ha−1), 3.5 m × 3.5 m (800 trees ha−1), and 5.0 m × 5.0 m (400 trees ha−1). The total number of data points in the analysis was 389 for the age of 3–20. Within the range of observed data, the dominant height grew linearly over age and was significantly different due to the initial planting density; growth was higher when the planting was denser. Using the initial density effect, dominant height growth models were developed based on the Chapman-Richards function through nonlinear mixed-effects modelling. The density variable was found to be statistically the best variable when modifying only the shape parameter of the Chapman-Richards function. All fixed-effects were significant for both models, with and without the density effect. The residual plots of the model did not show any bias over the predicted value, stand age or planting density. The predicted dominant height was higher with increasing initial density. The predicted dominant height increment was faster with higher planting densities until the age of 14 years. The anamorphic site index curves were presented with base age of 20 years including the planting density effect. The overall pattern of site index curves was consistent with those observed in previous studies. The models developed in this study can be used to estimate the dominant height and site index of hybrid aspen plantations in southern Finland

Finland’s forest genetic resources, use and conservation

Three fourths of the land area of Finland is covered by forests. The forest area, 22.8 million hectares, has remained almost unchanged over the last 50 years, whereas the volume of growing stock has increased by more than 40% since 1971, being now 2 473 million m3. In the same time, the area of protected forests has tripled. The vision of the updated National Forest Strategy 2025 is: Sustainable forest management is a source of growing welfare. The vision highlights the diverse welfare derived from forests as well as the fact that forests provide solutions to people´s and society´s needs. The forest sector is the cornerstone in the development of a sustainable and circular bioeconomy in Finland. The use of genetically improved material in forest regeneration has already significantly contributed to the increase of the annual increment of the growing stock in Finland for all three major tree species and will continue to do so also in the near future. The strategy acknowledges the importance of both the use and conservation of forest genetic resources to guarantee the genetic diversity, vitality and adaptability of tree species, in changing climatic conditions. Finland’s National Genetic Resources Programme for Agriculture, Forestry and Fishery (2018) brings together for the first time the gene conservation of plants and animals. For forest trees it lays out the need for conservation and defines the primary conservation methods (in situ or ex situ) for a total of 14 tree species, continuing the strategy that was already chosen in the previous national programme on forest genetic resources. Thus, conservation covers almost all financially or ecologically important tree species in Finland. The total number of gene reserve forests in Finland in 2020 is 44, covering an area of 7 218 ha. Ex situ –collections include 9 species for which material was collected from altogether 314 natural populations. Forest genetic resources in Finland are used in a sustainable way. Around one fifth of forest regeneration is natural and four fifth artificial through planting or direct sowing. There is increasing interest in alternative forest management practises, such as continuous-cover forestry and there is a need to study the effect of this on the genetic variability. Finland has a long-term tree improvement programme for the six most important tree species. The breeding programme is managed by the Natural Resources Institute Finland (Luke) as a fully state-financed public service. Breeding goals for all species include volume production, timber quality and adaptedness to various sites and climates. Around 60‒70% of the seed for reforestation is produced in seed orchards. Cold hardiness is an important trait in the harsh climate of Finland and the application of optimal deployment areas for both non-improved and improved origins of forest reproductive material is considered highly important. For the users of forest reproductive material there are new tools to assist in making the right choice of regeneration material but there is still a need to promote the use of these tools and to expand their usability to a wider selection of species. For monitoring the success and for adapting the decision support tools as well as the regulations, it is extremely important to set up a geo-referenced system that keeps records on the origin of the regeneration material that has been used at a given location. Because the distribution areas of forest tree species go beyond political borders, international cooperation on forest genetic resources is crucial. Finland is actively participating in several important networks on the field of conservation and use of forest genetic resources, especially within the FAO and EUFORGEN. Regional cooperation is highly important in the sustainable management of forest genetic resources and cooperation brings sustainable multilateral benefits. The most urgent needs for development of the conservation programme are the characterisation of the conserved material and the subsequent evaluation of the conservation network. Genetic information of all individual conservation units should be generated in a systematic way and this information needs to be made available for all stakeholders. Ideally the methods and descriptors would be harmonized at regional level to enable further development of the existing pan-European network and development of widely applicable genetic monitoring programme. At national, regional and global level there are various processes that require reporting on forest genetic resources for monitoring and development purposes. To make these parallel processes coherent and cost-effective it is essential that all reporting is organised in a transparent way, with open and accessible data records

How clonal differences and within-tree heterogeneity affect pore properties of hybrid aspen wood and biochar?

Production of applicable and homogeneous biochar for soil amendment purposes would benefit from knowledge on how feedstock heterogeneity impacts key biochar pore properties and how the properties are transformed due to pyrolysis. This study aimed (1) to quantify how clonal differences and within-tree heterogeneity of a hybrid aspen feedstock (wood) impact biochar pore properties and (2) to estimate how pore properties of non-pyrolysed wood materials are transformed when pyrolysed into biochar. The study was conducted by collecting samples from a hybrid aspen (Populus tremula L. x Populus tremuloides Michx.) clonal field trial. Key pore properties of non-pyrolysed and pyrolysed wood samples were quantified with 3D X-ray imaging and quantitative image analyses. The results demonstrated how pyrolysis shifted distinctively bi-modal pore size distributions of the wood samples towards smaller pore size regions. The bi-modal wood tissue structure controlled the pore structure also in the biochars. Due to decreasing cell wall thicknesses, the pyrolysis increased the porosity of the materials. While the thermal process homogenized differences in the wall thicknesses, the thicknesses of the feedstock were also shown to control the resulting thicknesses in the biochars. Mechanisms of biochar pore property formation can be considered important when designing applicable biochars for a chosen purpose. Clonal differences and within-tree heterogeneity had a direct impact only on the wall thicknesses and the pore diameters of vessels. These impacts can be of interest when planning feedstock utilization in biochar production. However, the results suggest that relatively homogeneous biochar can be produced from hybrid aspen feedstocks.Peer reviewe

Multivariate mixed-effects models for stand characteristics of hybrid aspen plantations in southern Finland and southern Sweden

Hybrid aspen, a hybrid between the European aspen and North American trembling aspen (Populus tremula L. × P. tremuloides Michx.), is a promising species because of its fast-growth and its suitability for multi-purpose use. However, models for predicting the age-dependent development of stand characteristics are still missing. The main objectives of this study were therefore to develop the models for predicting stand characteristics of hybrid aspen plantations and to validate the model applicability. The target response variables were stand basal area (BA), basal area-weighted mean diameter (DG) and basal area-weighted mean height (HG). Data were obtained from clonal hybrid aspen trials in southern Finland and southern Sweden. Multivariate mixed-effects modelling was used to estimate the parameters of seemingly unrelated regression for BA, DG, and HG. Model fit provided the following predictor variables: stand age (AGE), the number of trees per hectare (TPH), site index (SI), growing degree-days (GDD5), soil and site type, and thinning treatment. The chosen predictors differed slightly by response variable, but all parameters were highly significant (P < 0.0001), and model goodness-of-fit statistics presented high accuracy: RMSE of 2.59 m2 ha−1 for BA, 1.21 cm for DG, 1.05 m for HG in arithmetic scale. The applied simulations illustrated clear differences in the predicted development of stand characteristics when input variables SI, TPH or GDD5 changed. The developed models were assessed to be easily applicable and useful for predicting the stand and tree characteristics of clonal hybrid aspen plantations, especially for the stands with AGE ≤ 30 years and TPH ≤ 2000 trees ha−1