Post-windthrow management in protection forests of the Swiss Alps

The two storms Vivian (1990) and Lothar (1999) left an area of roughly 9000 ha of fully damaged protection forests in Swiss mountain regions. Given this huge dimension, questions arose on how to manage these areas to keep the protection gap, i.e. the time period with reduced overall protection against natural hazards, short. Quantifications are presented for the stability of lying logs left in place, the frequency of post-disturbance mass movements, and the tree regeneration in windthrow areas. The average height above ground of unsalvaged lying logs decreased from 2.1 m shortly after disturbance to 0.8 m 20 years later. In the period 1990–2014, the number of avalanches in windthrow areas was markedly small, and annual rates of shallow landslides and debris flows in windthrow areas did not differ from rates in comparable undamaged forested areas. Regeneration density rarely exceeded 4000 stems ha^?1 20 years post-windthrow at elevations above 1200–1500 m a.s.l. Mean height of tallest trees reached 5.6 m in areas that were cleared and 6.5 m in those left unsalvaged. Trees planted post-windthrow were 1.0–2.4 m taller than naturally regenerated ones. Practitioners rated the protective effect to be acceptable 24 years post-disturbance in only 5 out from 16 observed windthrow areas (31%), with planting trees as the main cause of success. We conclude that in protection forests the regeneration speed after disturbance rarely meets practitioner’s expectations in terms of both stem density and stand structure. However, leaving woody debris from wind disturbance in place proved to replace protective effects for an astonishingly long time. An intensive management with salvage logging, planting and even technical constructions seems therefore only inevitable on windthrown areas where risks seem too high based on hazard, damage potential and possible spread of bark beetles to nearby protection forests. A management alternative applicable to many other cases of windthrown protection forests is to plant trees between lying stems.     

Improved solution for vitrification of Prochilodus lineatus embryos based on the reduction in risk factors: Toxicity,osmotic responses and ice‐nucleation

The objective of our work was to describe a low toxicity cryoprotectant solution that allowed vitreous solid formation. Embryos of Prochilodus lineatus were submitted to sensitivity evaluations of six internal cryoprotectants (dimethyl sulphoxide – Me₂SO, dimethyl acetamide – DMA, dimethyl formamide – DMF, methanol – MET, glycerol – GLY and 1,2‐propanediol – PROP) at concentrations of 1–6 M; and two external cryoprotectants (sucrose – SUC and glucose – GLU) at concentrations of 0.1–1 M for 20 min. The capacity of the cryoprotectant solutions to exchange heat with the medium and to form glassy solids was evaluated by immersing 10 μl of cryoprotectant in liquid nitrogen. The PROP had a high survival rate at all concentrations evaluated, and was the only substance that allowed a vitreous solid formation. Thus, it is concluded that the PROP‐6 M was the most adequate solution for embryonic vitrification processes, because heat exchange between the system (PROP 6 M/embryos/liquid nitrogen) was faster than for other cryoprotectants and combinations thereof; has low toxicity, promote high rates of dehydration in short periods, and reach the vitreous state, being a good candidate to be used in the tests of embryonic vitrification.     

不同豆科牧草对低缓冲土壤的酸化能力

在盆栽试验中,使用差的缓冲沙土比较Ｓｕｂｃｌｏｖｅｒ,Ｍｅｄｉｃｓ,Ｓｅｒｒａｄｅｌａ,Ｂｉｓｅｒｒｕｌａ和Ｗｏｏｌｙｃｌｏｖｅｒ固氮的酸化潜力,植物生长７、９、１１周后,这些豆科牧草的酸化率,地上部分４４～１４５ｃｍｏｌ／ｋｇ种间变化非常大．Ｓｕｂｃｌｏｖｅｒ和Ｓｅｒｒａｄｅｌａ比Ｗｏｏｌｙｃｌｏｖｅｒ和Ｍｅｄｉｃｓ表现较大的酸化能力,而Ｂｉｓｅｒｕｌａ酸化能力最低,酸化率在地上部不仅与过量阳离子和钙浓度有关,而且与灰碱有关．因此,地上部分总钙,过量阳离子和灰碱含量为土壤产生总的Ｈ＋提供了好的指示．     

Effects of the extreme drought in 2003 on soil respiration in a mixed forest

We present a field study on the drought effects on total soil respiration (SR_t) and its components, i.e., “autotrophic” (SR_a: by roots/mycorrhizosphere) and “heterotrophic” respiration (SR_h: by microorganisms and soil fauna in bulk soil), in a mature European beech/Norway spruce forest. SR_a and SR_h were distinguished underneath groups of beech and spruce trees using the root exclusion method. Seasonal courses of SR_a and SR_h were studied from 2002 to 2004, with the summer of 2003 being extraordinarily warm and dry in Central Europe. We (1) analyzed the soil temperature (T _s) and moisture sensitivity of SR_a and SR_h underneath both tree species, and (2) examined whether drought caused differential decline of SR_a between spruce and beech. Throughout the study period, SR_a of beech accounted for 45–55% of SR_t, independent of the soil water regime; in contrast, SR_a was significantly reduced during drought in spruce, and amounted then to only 25% of SR_t. In parallel, fine-root production was decreased during 2003 by a factor of six in spruce (from 750 to 130 mg l⁻¹ a⁻¹), but remained at levels similar to those in 2002 in beech (about 470 mg l⁻¹ a⁻¹). This species-specific root response to drought was related to a stronger decline of SR_a in spruce (by about 70%) compared to beech (by about 50%). The sensitivity of SR_a and SR_h to changing T _s and available soil water was stronger in SR_a than SR_h in spruce, but not so in beech. It is concluded that SR_a determines the effect of prolonged drought on the C efflux from soil to a larger extent in spruce than beech, having potential implications for respective forest types. This article belongs to the special issue "Growth and defence of Norway spruce and European beech in pure and mixed stands."     

Temporal patterns in the post-larval supply of two crustacean taxa in Rangiroa Atoll,French Polynesia

The post-larval supply of two crustacean taxa (Brachyura and Stomatopoda) was monitored using one crest net over three lunar months at Rangiroa Atoll, French Polynesia. We captured a total of 37,068 brachyuran and 12,697 stomatopod post-larvae during the study. Post-larval supply was higher during the warm season (February–April) than during the cold season (June–July) for both Brachyura (warm season: 85% of total post-larval supply) and Stomatopoda (warm season: 92%). Moreover, the pulse of the brachyuran post-larval supply occurred predominantly around the last quarter, while the pulse of stomatopods occurred predominantly around the new moon. However, for both taxa, the post-larval supply was lowest around the full moon and the first quarter. Overall, our monitoring highlighted that the post-larval supply of Brachyura and Stomatopoda was modulated by seasons and lunar phases at Rangiroa.     

Acetohydroxyacid synthase (AHAS) amino acid substitution Asp376Glu in Lolium perenne: effect on herbicide efficacy and plant growth

Journal of Plant Diseases and Protection - Recently, the acetohydroxyacid synthase (AHAS) amino acid substitution Asp376Glu was detected in a Lolium perenne population originating in France. This...     

Forest structure and soil fertility determine internal stem morphology of Pedunculate oak: a modelling approach using boosted regression trees

This study aims at the explanation of internal stem morphology of vital (co)dominant Pedunculate oak (Quercus robur L.) trees in homogeneous even-aged high-forests by the factors tree age, forest structure and site quality, using boosted regression trees as a powerful modelling technique. The study area covers the region of Flanders (Northern Belgium), which is characterised by the absence of strong topographic and climatic gradients. For 76 adult sample trees covering the entire productivity range of Pedunculate oak, morphological characteristics were derived from measurements of ring width or heartwood area on wood cores. Forest structure, soil physicochemical properties, humus quality, vegetation indices and litter nutrient contents were quantified at each sample location. Model predictive performance and generality are good. Tree age effects correspond to expected trends in age-related radial growth and heartwood portion. Even if management of oak trees in even-aged high-forests is rather similar over Flanders, forest structure is the most important factor determining ring width, followed by soil fertility. Heartwood portion is determined by soil fertility and crown structure. Effects of topsoil and humus physicochemical characteristics, litter nutrient contents and water supply mainly confirm autecological knowledge on oak. However, variables related to soil water availability are only occasionally relevant, and always of lower importance than soil fertility. The low importance of water availability in the models contradicts results from other studies, and the potential effect of confounding is discussed. The observed growth reduction at low litter N/P ratios might be indirectly linked to early litterfall.     

Preliminary study on testicular germ cell isolation and transplantation in an endangered endemic species Brycon orbignyanus (Characiformes: Characidae)

Fish Physiology and Biochemistry - We aimed to develop a simplified protocol for transplantation of Brycon orbignyanus spermatogonial stem cells (SSCs) into Astyanax altiparanae testes. Brycon...     

Authentication of the botanical and geographical origin of honey by mid-infrared spectroscopy

The potential of Fourier transform mid-infrared spectroscopy (FT-MIR) using an attenuated total reflectance (ATR) cell was evaluated for the authentication of 11 unifloral (acacia, alpine rose, chestnut, dandelion, heather, lime, rape, fir honeydew, metcalfa honeydew, oak honeydew) and polyfloral honey types (n = 411 samples) previously classified with traditional methods such as chemical, pollen, and sensory analysis. Chemometric evaluation of the spectra was carried out by applying principal component analysis and linear discriminant analysis, the error rates of the discriminant models being calculated by using Bayes' theorem. The error rates ranged from <0.1% (polyfloral and heather honeys as well as honeydew honeys from metcalfa, oak, and fir) to 8.3% (alpine rose honey) in both jackknife classification and validation, depending on the honey type considered. This study indicates that ATR-MIR spectroscopy is a valuable tool for the authentication of the botanical origin and quality control and may also be useful for the determination of the geographical origin of honey.