Pervasive Growth Reduction in Norway Spruce Forests following Wind Disturbance

Background: In recent decades the frequency and severity of natural disturbances by e.g., strong winds and insect outbreaks has increased considerably in many forest ecosystems around the world. Future climate change is expected to further intensify disturbance regimes, which makes addressing disturbances in ecosystem management a top priority. As a prerequisite a broader understanding of disturbance impacts and ecosystem responses is needed. With regard to the effects of strong winds – the most detrimental disturbance agent in Europe – monitoring and management has focused on structural damage, i.e., tree mortality from uprooting and stem breakage. Effects on the functioning of trees surviving the storm (e.g., their productivity and allocation) have been rarely accounted for to date. Methodology/Principal Findings: Here we show that growth reduction was significant and pervasive in a 6.79?million hectare forest landscape in southern Sweden following the storm Gudrun (January 2005). Wind-related growth reduction in Norway spruce (Picea abies (L.) Karst.) forests surviving the storm exceeded 10 % in the worst hit regions, and was closely related to maximum gust wind speed (R 2 = 0.849) and structural wind damage (R 2 = 0.782). At the landscape scale, windrelated growth reduction amounted to 3.0 million m 3 in the three years following Gudrun. It thus exceeds secondary damage from bark beetles after Gudrun as well as the long-term average storm damage from uprooting and stem breakage in Sweden

Use of near-infrared spectroscopy on predicting wastewater constituents to facilitate the operation of a membrane bioreactor

The use of near-infrared (NIR) spectroscopy in wastewater treatment has continuously expanded. As an alternative to conventional analytical methods for monitoring constituents in wastewater treatment processes, the use of NIR spectroscopy is considered to be cost-effective and less time-consuming. NIR spectroscopy does not distort the measured sample in any way as no prior treatment is required, making it a waste-free technique. On the negative side, one has to be very well versed with chemometric techniques to interpret the results. In this study, filtered and centrifuged wastewater and sludge samples from a lab-scale membrane bioreactor (MBR) were analysed. Two analytical methods (conventional and NIR spectroscopy) were used to determine and compare major wastewater constituents. Particular attention was paid to soluble microbial products (SMPs) and extracellular polymeric substances (EPSs) known to promote membrane fouling. The parameters measured by NIR spectroscopy were analysed and processed with partial least squares regression (PLSR) and artificial neural networks (ANN) models to assess whether the evaluated wastewater constituents can be monitored by NIR spectroscopy. Very good results were obtained with PLSR models, except for the determination of SMP, making the model qualitative rather than quantitative for their monitoring. ANN showed better performance in terms of correlation of NIR spectra with all measured parameters, resulting in correlation coefficients higher than 0.97 for training, testing, and validation in most cases. Based on the results of this research, the combination of NIR spectra and chemometric modelling offers advantages over conventional analytical methods.BN/Cees Dekker LabBT/Environmental Biotechnolog

Why do forest owners fail to heed warning? : conflicting risk evaluations made by the Swedish forestagency and forest owners

In the aftermath of a hurricane in Sweden thatfelled some 250 million trees, the Swedish Forest Agency advised forest ownersto reduce forest vulnerability by planting different tree species. This paperanalyses why forest owners failed to heed the Forest Agency’s recommendation,thereby reproducing a forest vulnerable to storms. This paper focuses on thedeliberations and risk evaluations of forest owners when deciding which treespecies to plant. The analysis identifies three main categories of reasoningthat guided the forest owners’ decision-making process: short-term economicreasoning caused by the pressing situation they faced; an understanding ofwindstorms as natural catastrophes that are impossible to influence; and theuncertainties associated with alternative forest management practices.Furthermore, given their risk-averse strategy, their approach to understandingand coping with uncertainty was crucial in determining their responses. Thispaper concludes that the forest owners primarily employed experience-based,practical and embodied knowledge, implying that abstract risks and theoreticalknowledge regarding future developments were not deemed relevant. An additionalconclusion is that even if a huge storm felling shows the need to change forestmanagement practice, it does not provide the most favourable social conditionsfor achieving change.Funding Agency:Forestry Research Institute of Sweden (Skogforsk)  Swedish University of Agricultural Sciences (SLU)  Umea University Future Fores