Macro-invertebrates accelerate litter decomposition and nutrient release in a Hawaiian rainforest

Macro-invertebrates (>2 mm in size) can play a key role in litter decomposition by influencing litter chemistry and other components of the decomposer community, thus affecting rates of decomposition, nutrient release, and primary production. However, in many ecosystems the influences of macro-invertebrates on key ecosystem processes have not been adequately addressed. We investigated the influence of the macro-invertebrate community in litter decomposition and the cycling of nutrients in a young rainforest site on the island of Hawaii by using litter bags with and without 2.5 cm holes to allow or prevent access by macro-invertebrates. Presence of macro-invertebrates increased rates of litter decomposition by 16.9% and rates of nutrient release for N and Mn by 33.2% and 30.3%, respectively. Macro-invertebrate activity thus has a major impact on N release accounting for 3.32 kg/ha/yr. This internal ecosystem transfer of N from the litter is greater than estimates of nitrogen inputs from rain water, dry deposition, volcanic sources, atmospheric dust, and nitrogen fixation for this ecosystem. These findings demonstrate that improved knowledge of the ecosystem effects of macro-invertebrates is necessary to understand how ecosystems function.     

Concurrent increase in 15N and radiocarbon age in soil density fractions

Differences in the isotopic signature of organic matter between soil fractions are indicative of transformation and ageing processes. Here we show that with increasing microbial transformation measured by δ¹⁵N, there is a concomitant increase in carbon age as measured by ¹⁴C. The age of the soil's heavy fraction further increases with microbial utilization, indicating that stabilized OM ages yet continues to be reused.     

Testing the durability of timber above ground: A review on methodology

The majority of timber products in outdoor use are exposed above ground, e.g. façades, terrace decking, playground equipment, garden furniture, windows, balconies or carports. In contrast, the durability of wood and wood products is most often determined in laboratory against Basidiomycete monocultures or in-ground field tests, where wood samples are submitted to permanent wetting. Worldwide, only a few above ground field test methods evaluating durability against fungal decay have been standardized. Wood used in above ground situations can be exposed to a wide range of moisture loads reflecting different design details such as varying shelter, distance to ground, ventilation and water trapping, whereas temperature and rainfall variations are overall influences on service life performance. The aim of this review was to gather information about standardized and non-standardized above ground field test methods used to determine the durability of wood and wood-based products. In total, more than 60 methods have been evaluated according to different criteria, such as principle set-up and design, severity of exposure and distance to ground. Their suitability to reflect a certain exposure under real-life conditions is discussed as well as practical aspects regarding acceleration measures, decay assessment and practicability, costs and time efforts.     

Antiviral and antituberculous activity of Helichrysum melanacme constituents

Bioassay guided fractionation of the acetonic extract of Helichrysum melanacme using human Influenza virus type A and a drug-sensitive strain of Mycobacterium tuberculosis in vitro resulted in the isolation of 2 4',6'-trihydroxy-3'-prenylchalcone (1) and 4',6',5'-trihydroxy-6',6'-dimethyldihydropyrano[2',3'-2',3'] chalcone (2) as active constituents. 3-O-methylquercetin and quercetin were also isolated but were inactive against the microorganisms tested in this study.     

When nature takes over from man: Dead wood accumulation in previously managed oak and beech woodlands in North-western and Central Europe

The accumulation of dead wood and its characteristics are analysed in forests that have been withdrawn from regular silvicultural management and left unmanaged between 10 and 150 years ago. These forests are dominated by beech (Fagus sylvatica) and oak (Quercus robur and Quercus petraea) and located in the lowlands of North-western and Central Europe.     

Detection of pine needle diseases caused by Dothistroma septosporum,Dothistroma pini and Lecanosticta acicola using different methodologies

Dothistroma and Lecanosticta needle blight are among the most damaging foliage diseases in plantations and natural pine stands worldwide, and are therefore listed as quarantine organisms in numerous countries. The aim of this study was to validate different methodologies used for the detection of both diseases. Based on multiplex quantitative PCR (qPCR), simultaneous detection and discrimination of the three pathogens Dothistroma septosporum, Dothistroma pini and Lecanosticta acicola were possible in symptomatic needles. Additionally, the same set of needles was analysed for the presence of all three pathogens using novel end‐point PCR assays followed by enzymatic digestion of PCR products. Results were compared with the qPCR data, and for validation, collected needles were screened morphologically for the presence of typical fruiting bodies and spores. Differences in detection sensitivity were found between the detection tools. The qPCR‐based detection allowed for specific and efficient identification and quantification of all three pathogens simultaneously. At the same time, conventional PCR assays, which target the multicopy ITS region, showed increased detection sensitivity and can be conducted without the use of expensive infrastructure and reagents.     

Impact of artificial pruning on growth and secondary shoot development of wild cherry (Prunus avium L.)

Producing high value veneer wood requires that the tree bole be branch-free. This can be accomplished by natural or artificial pruning. Since wild cherry does not self prune well, pruning artificially is the only practical option. The study analysed the effect of conventional whorl-wise pruning and selective pruning, on height growth, diameter growth and secondary shoot development of wild cherry. Four pruning treatments were applied on cherry trees in summer 2007, one group of cherries was left unpruned to serve as a control: treatment C1 (upper 5 whorls left), C2 (upper 3 whorls left), S1 (removal of branches larger than 3 cm or with an angle to the stem < 40°), S2 (removal of branches larger than 2 cm or with an angle to the stem < 40°), N (unpruned). Data showed that height growth was not affected by pruning. In contrast, diameter growth at breast height of the C2 pruned cherry was reduced by approximately 5% (SE = 2.7%) in the year of pruning (trees were pruned in July). This pruning treatment produced significant (p = 0.028) nine percent less diameter growth than the control in the second year following pruning. The diameter increment of the C1 pruned trees with five whorls left after pruning and the selective pruned cherries were only about 4% (SE = 4.0%) smaller than the control after two years. This loss was statistically not significant. Analyses showed that on selective pruned trees the survival rate of secondary shoots was significantly reduced compared to those on whorl-wise pruned trees. Significant differences in the size of the secondary shoots were only found between the C1 and S1 (p < 0.05) pruned trees. We did not find differences in the total number of secondary shoots per tree among pruning treatments. Solely from a tree growth perspective, the moderate whorl-wise pruning treatment C1 and the selective prunings were equally effective in minimizing the reduction of diameter growth and are recommended in practice. However it was found that the survival of secondary shoots was reduced on selective pruned trees although the amount of pruning work needed in selective pruning was slightly greater than conventional moderate pruning.     

Ethnopharmacy of the ethnic Albanians (Arbëreshë) of northern Basilicata,Italy

Intercultural studies about the methods of use and perceptions of traditional remedies in Europe are strategically important in understanding how pharmaceutical means in our multicultural modern societies are differently accepted by diverse ethnic groups. In this survey, we analysed the biological means traditionally used in the ethnomedicine of three Arb?resh? (ethnic Albanians) communities in the Vulture area (northern Lucania, southern Italy). The majority of remedies are represented by plants belonging to 54 botanical taxa. A few of the recorded species have a traditional therapeutic use that has never previously been reported in southern Italy. Other means-especially used in the past-are comprised of mineral, animal and industrial derived materials. In specific cases, some of these materials and even plants are neither applied externally or internally, but are instead utilised as symbolic ritual objects in spiritual healing ceremonies. Ethnopharmacological and anthropological considerations about these usages are discussed.     

Single-molecule torsional pendulum

We have built a torsional pendulum based on an individual single-walled carbon nanotube, which is used as a torsional spring and mechanical support for the moving part. The moving part can be rotated by an electric field, resulting in large but fully elastic torsional deformations of the nanotube. As a result of the extremely small restoring force associated with the torsional deformation of a single molecule, unusually large oscillations are excited by the thermal energy of the pendulum. By diffraction analysis, we are able to determine the handedness of the molecule in our device. Mechanical devices with molecular-scale components are potential building blocks for nanoelectromechanical systems and may also serve as sensors or actuators.