Microfibril angle of Norway spruce [Picea abies (L.) Karst.] compression wood: comparison of measuring techniques

The structure of cellulose, especially the microfibril angles (MFAs), in compression wood of Norway spruce [Picea abies (L.) Karst.] was studied by wide- and small-angle X-ray scattering and polarizing microscopy. On the basis of the X-ray scattering experiments the average MF As of the cell wall layers S₂ and S₁ of the studied sample are 39 and 89, respectively; and the average diameter and length of the cellulose crystallites are 2.9 and 20.0nm, respectively. The average of the whole MFA distribution is shown to agree with the one obtained by polarizing microscopy of macerated fibers.     

The effects of fragmentation on the susceptibility of a boreal forest ecosystem to wind damage

The clear cuts and seedling stands can speed up winds and may trigger blowdown at the edges of neighbour stands. Therefore, the height contrast of the neighbour stands and fragmentation at landscape level could be used to indicate the susceptibility of windthrow. In this study, we studied how forest fragmentation affects the susceptibility of a boreal forest ecosystem to wind damage, both at patch and landscape level based on theoretical computations. For this purpose we generated, based on real stand inventory data of a Finnish forest ecosystem, different landscape configurations of Scots pine and Norway spruce forests using Monte Carlo simulation. Thereafter, we applied a mechanistic wind damage model to predict the wind speeds needed for wind damage at forest edges. The fragmentation metrics of Contrast-Weighted Edge Density with three different height dissimilarity calculation methods were used to analyze the fragmentation at the landscape level.     

Characterization and fate of black currant and bilberry flavonols in enzyme-aided processing

The fate of black currant ( Ribes nigrum L.) and bilberry ( Vaccinium myrtillus L.) flavonols in enzyme-aided processing was studied. The flavonols were quantified and characterized by high-performance liquid chromatography equipped with a diode array detector and an electrospray ionization mass spectrometer. A tentative identification for 14 black currant and 19 bilberry flavonols is presented representing 11 previously unpublished conjugates. For the first time in any berry, the presence of laricitrin conjugates is reported. The enzyme-aided processing affected the flavonol extractability, elevating the yield in juices and decreasing that in press residues. Importantly, no significant loss of the berry flavonols was observed during the experiments, although some hydrolysis of flavonol conjugates was recorded. To maximize the effect on flavonol extractability, higher enzyme dosages were needed for black currants than for bilberries. The data show that the flavonol extractability and hydrolysis are dependent on the texture of raw material, the glycosylation pattern of the conjugates, and the activity profile of the enzyme preparation.     

Nitrogen and Phosphorus Flows in the Finnish Agricultural and Forest Sectors, 1910–2000

An assessment of the environmental quality of sediments at several locations of the Ría de Pontevedra (NW of Spain) was performed by integrating toxicity data obtained from multiespecies bioassays, chemical data from analysis of mussels and sediment, and physical–chemical parameters of the sampled sites. Subsequently, a toxicity identification evaluation (TIE) method intended for characterization and identification of the toxic agents was applied to the most polluted location by using the Paracentrotus lividus sea urchin bioassay. Both metals and organic compounds seem to be the causative agents of toxicity in elutriates of the studied sediment. Finally, multivariate statistics were applied for a better interpretation of results. A factor analysis was developed to establish the relationship among variables and to derive local sediment quality guidelines (SQG) by linking chemical contamination to biological effects. When multidimensional scaling and cluster analysis were performed to group the locations according to either the chemistry or toxicity data, P3-site was always clearly broken up the others. The different approaches all supported the same conclusion: site P3 can be considered highly contaminated by both trace metals and PAHs resulting in high toxicity for all the tested species.     

Reconstructing forest canopy from the 3D triangulations of airborne laser scanning point data for the visualization and planning of forested landscapes

Key message

We present a data-driven technique to visualize forest landscapes and simulate their future development according to alternative management scenarios. Gentle harvesting intensities were preferred for maintaining scenic values in a test of eliciting public’s preferences based on the simulated landscapes.

Context

Visualizations of future forest landscapes according to alternative management scenarios are useful for eliciting stakeholders’ preferences on the alternatives. However, conventional computer visualizations require laborious tree-wise measurements or simulators to generate these observations.

Aims

We describe and evaluate an alternative approach, in which the visualization is based on reconstructing forest canopy from sparse density, leaf-off airborne laser scanning data.

Methods

Computational geometry was employed to generate filtrations, i.e., ordered sets of simplices belonging to the three-dimensional triangulations of the point data. An appropriate degree of filtering was determined by analyzing the topological persistence of the filtrations. The topology was further utilized to simulate changes to canopy biomass, resembling harvests with varying retention levels. Relative priorities of recreational and scenic values of the harvests were estimated based on pairwise comparisons and analytic hierarchy process (AHP).

Results

The canopy elements were co-located with the tree stems measured in the field, and the visualizations derived from the entire landscape showed reasonably realistic, despite a low numerical correspondence with plot-level forest attributes. The potential and limitations to improve the proposed parameterization are discussed.

Conclusion

Although the criteria to evaluate the landscape visualization and simulation models were not conclusive, the results suggest that forest scenes may be feasibly reconstructed based on data already covering broad areas and readily available for practical applications.

     

Carbon sequestration in the growing stock of trees in Finland under different cutting and climate scenarios

In this work the aim was to determine how carbon sequestration in the growing stock of trees in Finland is dependent on the forest management and increased production potential due to climate change. This was analysed for the period 2003–2053 using forest inventory data and the forestry model MELA. Four combinations of two climate change and two management scenarios were studied: current (CU) and gradually warming (CC) climate and forest management strategies corresponding to different rates of utilisation of the cutting potential, namely maximum sustainable removal (Sust) or maximum net present value (NPV) of wood production (Max). In this analysis of Finland, the initial amount of carbon in the growing stock was 765 Mt (2,802 Tg CO₂). At the end of the simulation, the carbon in the growing stock of trees in Finland had increased to 894 Mt (3,275 Tg CO₂) under CUSust, 906 Mt (3,321 Tg CO₂) under CUMax, 1,060 Mt (3,885 Tg CO₂) under CCSust and 1,026 Mt (3,758 Tg CO₂) under CCMax. The results show that future development of carbon in the growing stock is not only dependent on climate change scenarios but also on forest management. For example, maximising the NPV of wood production without sustainability constraints results, over the short term, in a large amount of wood obtained in regeneration cuttings and a consequent decrease in the amount of carbon in growing stock. Over the longer term, this decrease in the carbon of growing stock in regenerated forests is compensated by the subsequent increase in fast-growing young forests. By comparison, no drastic short-term decrease in carbon stock was found in the Sust scenarios; only minor decreases were observed.     

Impact of needle age on the response of respiration in Scots pine to long-term elevation of carbon dioxide concentration and temperature

Sixteen 20-year-old Scots pine (Pinus sylvestris L.) trees growing in the field were enclosed in environment-controlled chambers that for 4 years maintained: (1) ambient conditions (CON); (2) elevated atmospheric carbon dioxide concentration [CO2] (ambient + 350 micromol mol-1; EC); (3) elevated temperature (ambient + 2-3 degrees C; ET); or (4) elevated [CO2] and temperature (EC+ET). Dark respiration rate, specific leaf area (SLA) and the concentrations of starch and soluble sugars in needles were measured in the fourth year. Respiration rates, on both an area and a mass basis, and SLA decreased in EC relative to CON, but increased in ET and EC+ET, regardless of needle age class. Starch and soluble sugar concentrations for a given needle age class increased in EC, but decreased slightly in ET and EC+ET. Respiration rates and SLA were highest in current-year needles in all treatments, whereas starch and soluble sugar concentrations were highest in 1-year-old needles. Relative to that of older needles, respiration of current-year needles was inhibited less by EC, but increased in response to ET and EC+ET. All treatments enhanced the difference in respiration between current-year and older needles relative to that in CON. Age had a greater effect on needle respiration than any of the treatments. There were no differences in carbohydrate concentration or SLA between needle age classes in response to any treatment. Relative to CON, the temperature coefficient (Q10) of respiration increased slightly in EC, regardless of age, but declined significantly in ET and EC+ET, indicating acclimation of respiration to temperature.     

Effect of shading on leaf structure and photosynthesis in young birches, Betula pendula Roth. and B. pubescens Ehrh.

The canopy structure and within-stand light conditions of several young birch (Betula pendula Roth. and B. pubescens Ehrh.) stands were studied. In addition, 2-year-old silver birch seedlings were subjected to varying degrees of artificial shading for one growing season in order to interpret the results of the former experiments. The shading increased the specific leaf area and the thickness of leaf mesophyll was reduced by increased shading. Similarly, the maximum photosynthetic rate and the light intensity for photosynthetic saturation were decreased in shading. Both phenomena seemed to be associated with the increase in specific leaf area and the decrease in the amount of chlorophyll per unit of leaf area.     

Increased forest production through forest tree breeding

Forest tree breeding started in the middle of the twentieth century and since then the use of improved forest regeneration material has become an essential part of forestry in many countries. This review describes methods and achievements of tree breeding programmes, which aim at increasing the quantities and improving qualities of wood-based raw materials through selection, field testing and controlled crossings. Most improved materials currently deployed are seed crops from first-generation phenotypic or tested seed orchards, which offer 10–25% gains in yield depending on the selection intensity of parent trees. Methods of vegetative propagation are developed intensively so that it could be applied to a larger range of species, because it offers high genetic gain and uniformity of the material. Genomic tools are also developed to enhance the efficacy of selection. Applications of genetic engineering are currently limited to research purposes. Forest tree breeding will be an integral part of bioeconomy in securing the production of good quality raw materials in large quantities and will have a significant economic impact on the profitability of forestry in the long term.     

Modeling the effects of climate change and management on the dead wood dynamics in boreal forest plantations

The present research examines the joint effects of climate change and management on the dead wood dynamics of the main tree species of the Finnish boreal forests via a forest ecosystem simulator. Tree processes are analyzed in stands subject to multiple biotic and abiotic environmental factors. A special focus is on the implications for biodiversity conservation thereof. Our results predict that in boreal forests, climate change will speed up tree growth and accumulation ending up in a higher stock of dead wood available as habitat for forest-dwelling species, but the accumulation processes will be much smaller in the working landscape than in set-asides. Increased decomposition rates driven by climate change for silver birch and Norway spruce will likely reduce the time the dead wood stock is available for dead wood-associated species. While for silver birch, the decomposition rate will be further increased in set-aside in relation to stands under ordinary management, for Norway spruce, set-asides can counterbalance the enhanced decomposition rate due to climate change thereby permitting a longer persistence of different decay stages of dead wood.