Implications of growth uncertainties associated with climate change for stand management

Climate change is expected to have substantial effects on many aspects of forest ecosystems, including timber production. Temperatures in northern Europe are expected to increase considerably, although there is substantial uncertainty about both the seasonal and average changes that will occur. In Scandinavia, production is predicted to increase across most of the area covered by boreal forest, since the growth of trees in the region is currently limited by temperature. Therefore, we have analyzed the importance of adapting management practices to future climate changes and considered possible ways to address associated stand management problems. For this purpose, we simulated climate scenarios with temperature increases ranging from 2.5 to 6.0°C over a 100-year period, and effects on typical Swedish stands with several species, then optimized their management with simulated annealing. The results indicate that the maximum considered temperature trend would raise the economic value of the stands by almost 5% more than the minimum trend. However, the importance of optimizing management plans in accordance with the correct temperature scenario appears to be limited. The plan optimized for the minimum temperature trend was only marginally inferior to the plan optimized for the maximum temperature trend in the maximum trend scenario, and vice versa. It also seemed adequate to use a deterministic formulation of the problem, and in cases where a stochastic climate change model generated more robust plans, the advantage could be attributed to model artifacts rather than climate change per se.     

Bacterial and fungal response to nitrogen fertilization in three coniferous forest soils

Forest soil carbon (C) pools may act as sinks for, or sources of, atmospheric carbon dioxide, while nitrogen (N) fertilization may affect the net exchange of C in forest ecosystems. Since all major C and N processes in soil are driven by soil microorganisms, we evaluated the effects of N fertilization on biomass and bacterial and fungal activity in soils from three Norway spruce forests with different climatic and N availability conditions. N deposition and net N mineralization were higher at the sites in southern Sweden than at the site in northern Sweden. We also studied the extent to which N fertilization altered the nutrient(s) limiting bacterial growth in soil. We found that on average microbial biomass was reduced by ～40% and microbial activity by ～30% in fertilized plots. Bacterial growth rates were more negatively affected by fertilization than fungal growth rates, while fungal biomass (estimated using the phospholipid fatty acid (PLFA) 18:2ω6,9) decreased more than bacterial biomass as a consequence of fertilization. The microbial community structure (indicated by the PLFA pattern) was changed by fertilization, but not in the same way at the three sites. Soil bacteria were limited by a lack of carbon in all forests, with the carbon limitation becoming more evident in fertilized plots, especially in the forests that had previously been the most N-limited ones. This study thus showed that the effects of N fertilization differed depending on the conditions at the site prior to fertilization.     

Linking watershed and microhabitat characteristics: effects on production of Atlantic salmonids (Salmo salar and Salmo trutta)

The spatial scale of environmental factors influencing population dynamics ranges from microhabitat to continental or even global scales. Integration of multiple spatial scales is important in order to understand links between environmental variation and population processes. In the present study, we investigate how multiscale drivers influence the production of stream‐rearing Atlantic salmonids (Atlantic salmon, Salmo salar L. and brown trout, Salmo trutta L.) measured in terms of abundance. Variation in juvenile production was studied using data from single‐pass electrofishing surveys (measured as biomass per m²) from nine rivers. These data were combined with habitat data ranging from an important in‐stream microhabitat variable (shelter availability) to properties of the catchment. Variation in productivity within and among rivers was affected by both properties of in‐stream habitat and catchment properties. Shelter availability and the proportion of the catchment consisting of cultivated land and lakes influenced biomass positively, while catchment area had the opposite effect. For a different set of rivers (N = 20), river gradient and catchment area were shown to positively affect the amount of shelter. Finally, the variables identified in the two preceding analysis were included in the analysis of population productivity using catch statistics from 160 rivers. The proportion of cultivated land and lakes, estimated shelter availability were found to have positive effects. In addition, temperature had a positive effect, while river width had a negative effect. This study shows that combining multiple‐scale environmental factors can explain a substantial proportion of variation in population productivity among and within the populations of Atlantic salmonids.     

Temperature responses,flowering and fruit yield of the June-bearing strawberry cultivars Florence,Frida and Korona

The effect of night temperature on short day (SD) floral induction has been studied in three June-bearing strawberry cultivars of different geographic origin and compared with yield performance in the cool Nordic environment. At the optimum day temperature of 18 °C, the SD flowering response of the cultivars ‘Florence’ and ‘Korona’ increased significantly with increasing night temperature from 9 to 18 °C, while an optimum was reached at 15 °C in the cultivar ‘Frida’ that is selected under cool-environment conditions in Norway. Also, while saturated flowering response was obtained with 3 weeks of SD treatment at all temperatures in ‘Frida’, several plants of ‘Florence’ and ‘Korona’ failed to initiate flowers at 9 °C night temperature even with 5 weeks of SD. The effect of extended SD period was particularly pronounced in ‘Florence’. The slow SD floral induction response of ‘Florence’ was associated with a 2 week delay of anthesis in subsequent long day (LD) conditions at 21 °C. Yield performance of the same cultivars during 2 years under field conditions at Nes Hedmark and in North Norway also demonstrated that the yield potential of ‘Florence’ was not realized under the climatic conditions prevailing at these locations. In both years the yields varied significantly among the cultivars, ‘Frida’ having the highest yields followed by ‘Korona’, with ‘Florence’ far below. It is concluded that, in the Nordic environment, autumn (September) night temperatures are obviously sub-optimal for yield performance of some June-bearing strawberry cultivars, and that this effect is mediated by autumn temperature effects on flower initiation responses.     

Custom total knee replacement in a dog with femoral condylar bone loss

Objective— To report surgical planning, technique, and outcome of custom total knee replacement (TKR) performed to manage a medial femoral condylar nonunion in a dog.
Study Design— Clinical case report.
Animal— A 3-year-old, 20 kg Karelian Bear Hound.
Methods— Computed tomographic scan of the left pelvic limb was used to build a stereolithography model of the distal portion of the femur. The model was used to create a custom augment to replace the missing medial femoral condyle and a custom stem for intramedullary condylar cemented fixation. The augment and stem were adapted to femoral and tibial components already available. The model was used to rehearse the surgery and then the custom prosthesis was implanted.
Results— Weight bearing returned 8 hours after surgery and improved thereafter. Joint alignment was normal and prosthetic joint motion was 60–165° postoperatively. The dog resumed moose hunting 3 months after surgery. Peak vertical force and impulse of the operated limb measured 17 months after surgery were 65% and 47% of the normal, contralateral limb.
Conclusion— Based on short-term follow-up, cemented canine TKR was successfully achieved for management of a severely abnormal stifle joint.
Clinical Relevance— With further refinement and development of commercially available prostheses, TKR should be possible for canine patients.     

Preparation of Polyurethane Silicon Oxide Nanomaterials as a Binder in Leather Finishing

Leather finishing processes using toxic organic solvent based produce volatile organic compounds (VOC), chronic exposure to this chemicals effect on workers' health causing many diseases especially lung cancer. So, polyurethane waterbased was synthesized for application in leather finishing instead of organic solvent based because it’s economic and safety for industry and workers. Preparation of water-based polyurethane (PU) depends on the reaction of polyethylene glycol (PEG, 300) with isophorone diisocyanate (IPDI) and the reaction of IPDI-1,4-butanediol (BDO) together with dimethylolpropionic acid (DMPA), was synthesized by poly-addition polymerization reaction. PU was then modified with different amounts of silicon dioxide nanoparticles (1-5 % SiO₂), used as a binder in leather finishing. Leather coated was characterized physically, chemically and thermally by FTIR, GPC, DLS, TEM, SEM and TGA. The results revel that, water vapor permeability (WVP) of leather coated with PU modified with SiO₂ showed improvement due to the existence of SiO₂ particles which increases the interspaces of the polyurethane coating. SEM showed that when the amount of SiO₂ nanoparticles increases, there is uniform nanoparticles accumulated can be observed. EDX prove the presence of Si and O₂ elements and the formation of SiO₂ nanoparticles. Mechanical properties discussed that tensile strength; tear strength and elongation at break % increase with increase SiO₂ concentration until 3 % SiO₂ nanoparticles. TGA showed an improvement of thermal stability of coated leather modified with SiO₂. Therefore, this study succeeded in preparation of safe, ecofriendly of water-based polyurethane binders which modified with SiO₂ for using in leather finishing.     

Finite element study of growth stress formation in wood and related distortion of sawn timber

Lack of straightness in timber is the most frequent complaint regarding solid (and laminated) timber products worldwide. Nowadays, customers demand higher quality in the shape stability of wood products than they did earlier. The final distortion of timber boards is mostly caused by moisture-related stresses in wood (drying distortions) and growth-related stresses (distortions appearing when logs are split up to timber boards by sawing). To get more knowledge on how these distortions can be reduced in wooden products, there is a need for improved understanding of this material behaviour through good numerical tools developed from empirical data. A three-dimensional finite element board distortion model developed by Ormarsson (Doctoral thesis, Publ. 99:7, 1999) has been extended to include the influence of growth stresses by incorporating a one-dimensional finite element growth stress model developed here. The growth stress model is formulated as an axisymmetric general plane strain model where material for all new annual rings is progressively added to the tree during the analysis. The simulation results presented include how stresses are progressively generated during the tree growth, distortions related to the redistribution of growth stresses during log sawing, and distortions and stresses in drying reflecting the effects of growth stresses. The results show that growth stresses clearly vary during tree growth and also form a large stress gradient from pith to bark. This in itself can result in significant bow and crook deformations when logs are sawn into timber boards. The distortion results from the simulations match well with the results observed in reality. The parametric study also showed that the radial growth stress distribution is highly influenced by parameters such as modulus of elasticity, micro fibril angle and maturation strain.     

Unequal deployment of clones to seed orchards by considering genetic gain, relatedness and gene diversity

Related clones in seed orchards lead to inbreeding depressionand reduced genetic value of the seeds. This study aims to developthe methodology for deployment of related clones to seed orchardswhen the breeding value and the pedigree are available for eachcandidate. The following goals were considered: high geneticgain, high genetic gain adjusted for predicted inbreeding depression(net gain), high gene diversity, and high effective clone number.The selection strategies included truncation selection withor without relatedness restrictions, maximizing genetic gain(linear deployment) with or without restrictions on relatednessand maximizing net gain. The selection strategies were appliedto Norway spruce seed orchard candidates evaluated in clonaltests. The material comprised full-sib and half-sib relationships.Comparisons were made both at the same gene diversity and atthe effective clone number. Maximizing net gain by unequal rametnumber deployment resulted in considerable higher net gain anda considerable reduction of related ramets in many comparisons.Linear deployment restricted against related clones comparedat the same status number resulted in almost as high net gain.Reduction in gene diversity may be a more important reason toavoid relatives in seed orchards than the subsequent inbreedingfor achieving a high net gain.     

Formation of harvest units with genetic algorithms

Operational planning is normally based on stands as the primary unit of treatment. In recent years, interest has been directed towards the use of smaller area units such that the formation of treatment units becomes part of the operational planning. Here, the method of genetic algorithms was used in order to delineate harvesting units in a forest described as a grid of 20 m × 20 m pixels. Remote sensing data and inventory plots were employed to derive pixel estimates of forest variables. Appropriate parameter settings for the algorithm were investigated for two cases that consisted of 26 × 25 pixels. Based on the experience from these tests, the algorithm was employed in forming treatment units in an area encompassing 100 × 100 grid cells, or 400 ha. Due to the size of the problem, a two-stage procedure was suggested. The solutions of the genetic algorithm were compared with a heuristic, a cell removal algorithm, that was proposed in earlier studies of treatment unit formation. The genetic algorithm performed better than the heuristic for all the cases that were tested.