Effects of stump extraction on the carbon sequestration in Norway spruce forest ecosystems under varying thinning regimes with implications for fossil fuel substitution

The overall aim of this work was to assess the effects of stump and root extraction on the long‐term carbon sequestration and average carbon storage in the integrated production of energy biomass and stemwood (pulpwood and sawlogs) under different thinning options (unthinned, current thinning and 30% increased thinning thresholds from current thresholds). The growth and development of Norway spruce (Picea abies L. Karst.) stands on a fertile site (Oxalis‐myrtillus) in central Finland (Joensuu region: 62?39?N, 29?37?E) was simulated for two consecutive rotation periods (80 + 80 years/160 years). Stemwood and energy biomass production, carbon sequestration, and average storage and emission dynamics related to the entire production process of biomass were assessed. The assessment was done by employing a life cycle assessment tool, which combines simulation outputs from an ecosystem model and the related technosystem emissions. It was found that stump and root harvesting constituted 21–36% of the total biomass production (energy biomass and stemwood) depending on the thinning regimes and rotation period. No considerable effect was found in stemwood production when stump and root extraction was compared to the regime in which stumps and roots were left at the site. Stump and root extraction did not affect carbon sequestration on the following rotation and, in fact, an increase in forest growth was found for the unthinned and 30% increased thresholds compared to the first rotation. The results also showed that if current thinning threshold is increased, win‐win situations are possible, especially when climate change mitigation is the main concern. The substitution of coal with energy biomass is possible without reducing carbon storage in the forest ecosystem. The utilization of energy biomass, including stumps and roots, instead of coal could reduce up to 33% of emissions over two rotation periods depending on the thinning regimes. Even if stumps and roots were excluded, a maximum of 19% carbon emissions could be reduced by using only logging residues.     

Water level drawdown makes boreal peatland vegetation more responsive to weather conditions

Climate warming and projected increase in summer droughts puts northern peatlands under pressure by subjecting them to a combination of gradual drying and extreme weather events. The combined effect of those on peatland functions is poorly known. Here, we studied the impact of long-term water level drawdown (WLD) and contrasting weather conditions on leaf phenology and biomass production of ground level vegetation in boreal peatlands. Data were collected during two contrasting growing seasons from a WLD experiment including a rich and a poor fen and an ombrotrophic bog. Results showed that WLD had a strong effect on both leaf area development and biomass production, and these responses differed between peatland types. In the poor fen and the bog, WLD increased plant growth, while in the rich fen, WLD reduced the growth of ground level vegetation. Plant groups differed in their response, as WLD reduced the growth of graminoids, while shrubs and tree seedlings benefited from it. In addition, the vegetation adjusted to the lower WTs, was more responsive to short-term climatic variations. The warmer summer resulted in a greater maximum and earlier peaking of leaf area index, and greater biomass production by vascular plants and Sphagnum mosses at WLD sites. In particular, graminoids benefitted from the warmer conditions. The change towards greater production in the WLD sites in general and during the warmer weather in particular, was related to the observed transition in plant functional type composition towards arboreal vegetation.     

Catalytically Significant Macrochelate Formation in Zn2+Promoted Hydrolysis of Oligoribonucleotides: Model Studies with Chimeric Phosphodiester/Methylphosphonate Oligomers

Abstract

The kinetics of Zn²⁺ promoted hydrolysis of chimeric oligonucleotides Up[Tp(Me)]₃T and UptTp(Me)]₃Tp was studied. The results were compared to those obtained with corresponding phosphodiester oligonucleotides, and discussed in terms of an oligonucleotide-metal ion macrochelate formation.     

Ant communities in taiga clearcuts: habitat effects and species interactions

We surveyed the structure of ant communities in young taiga forests by pitfall trapping in southern Finland The sampling sites were clearcut and planted with conifers 14-20 yr before the sampling The results indicated that the structure of the ant communities was largely determined by the top competitors the territorial species of the wood-ant group (Formica aquilonia and F lugubris) in the older, and the aggressive slavemaking ant ( F sanguinea )in the younger clearcuts Species interactions resulted in district spatial distributions of individual species depending on the competitive status of the species concerned Competition and slavemaking were the most important factors on larger spatial scales The spatial scale of competitive structuring was determined by the territory and colony sizes of the top competitors On a finer scale, variability in moisture and tree-canopy shading seemed to have enhanced coexistence of some competing submissive species by alleviating the effects of nest-site comp)edition and slavemaking Competition between the wood ants and the slavemaking ant affected indirectly the distribution and abundance of the species subject to slavemaking. F fusca and F lemam Similarly, the top competitors presumably affected the distributions of other interacting subordinate species indirectly through differential competitive effects on them Overall, species interactions seemed to have induced considerable determinism in ant-community succession in young forests     

Effects of 100-Hz magnetic fields with various waveforms on the development of chick embryos

Summary Chick embroys were exposed during their 52 first hours of development to 100-Hz magnetic fields. Sinusoidal, square and pulsed waveforms were used at average field strengths from 0.1 A/m to 80 A/m. After exposure, the embryos were examined for abnormalities and classified by the developmental stages. When bipolar oscillations (oscillating at both sides of the zero-level) were used, the percentage of abnormal embryos was significantly increased above 1 A/m. In exposure to unipolar square waves, no significant effect on the percentage of abnormalities could be demonstrated. The developmental stage was possibly affected by unipolar square waves at 0.1 A/m, all other field strengths and wave-forms being apparently ineffective.     

Individual variation in immune function in the ant Formica exsecta; effects of the nest, body size and sex

It has been generally thought that sex differences in the immune system are the result of the differing life history strategies of the sexes, although the available data are not entirely consistent with the hypothesis. In this study, we studied the variation in the immune function in the mound-building wood ant Formica exsecta. F. exsecta has two forms of males, distinguished by size: the small males (micraners) and the large males (macraners), which die after the mating period, whereas females live tens of years laying their eggs. We found that in general males have a lower encapsulation response against nylon monofilament (i.e. lower immune function) than queens. Among males, the micraners had a lower encapsulation rate than the macraners. However, in queens, there was no correlation between size and encapsulation rate. The origin nest had an effect on the encapsulation rate of males: males from the large nests had a stronger encapsulation rate than males from small nests. However, in queens, nest size did not have any effect on encapsulation response. The observed variation between sexes and individuals in the encapsulation rate is discussed in the context of reproductive strategies and parasite-mediated sexual selection.     

Geospatially structured biodiversity information as a component of a regional biodiversity clearing house

To function effectively, the international biodiversity Clearing HouseMechanism (CHM), based on the Convention on Biological Diversity (CBD), needs tobe rooted at the regional and local levels. This article presents an example ofhow stakeholders of regional data and information can be encouraged to formnetworks linked to national biodiversity focal points (NFPs). We pay specialattention to exploiting the geospatial properties of biodiversity data andinformation, and demonstrate how data and information can best be filtered,classified and labelled to facilitate geographically based information retrievalon the Internet. The geocodability of bibliographic reports proved to be poor,indicating an urgent need to reconsider the geographical properties ofbiodiversity information under production. Also, it is useful to utilisenetworking processes with information from fields other than biodiversity wheninitiating the network. Finally, we present and discuss problems of integrityand interoperability of data, and also the process of biodiversity informationproduction from the point of view of general information theory and innovationsoffered by modern information technology.     

S-RNases in apple are expressed in the pistil along the pollen tube growth path

 The molecular bases of self-incompatibility have been intensively studied in a restricted number of model species, but for most families the expression and distribution of S-proteins is unknown. In this work, pistil cryosections from apple were used for in situ detection of S-proteins. Two specific antibodies, one against the S3-protein and another against all apple S-proteins were used. S-proteins were shown to be localised in the intercellular space of the transmitting tissue, both in the stigma and style, which agrees with the proposed mechanism of action for S-RNases in gametophytic self-incompatibility. Some intracellular labelling was also observed in all ovary sections, confined to one layer of the nucellus surrounding the embryo sac, but this labelling was found to be non-S-allele-specific. Nevertheless, the signal in the ovary was tissue-specific, which may indicate that some component not encoded by the S-locus but similar to S-proteins was detected. To the best of our knowledge this is the first report on the precise distribution of S-RNases in a rosaceous species. Received: 15 July 1998 / Revision accepted: 29 December 1998     

Physical training under the influence of beta-blockade in rats. II. Effects on vascular reactivity.

Rats were treated by daily swimming or running exercises for 7 weeks. One group of rats was also trained under the influence of propranolol, while another group received daily propranolol injections only. The rat groups trained without beta blockade maintained a higher tail skin temperature when exposed to 5 degrees C after the 7-week training period. This phenomenon was not observable in the animals having received their training under the influence of beta-blockade. Both rat groups trained without beta-blockade showed increased vasodilatatory response to isoprenaline, as judged from a higher elevation of the tail skin temperature in response to the drug. This response was absent in the animal group having performed its training periods under the influence of propranolol. After the injection of phenylephrine the trained rats had a higher tail skin temperature than did the controls or propranolol-treated rats. The present results suggest an elevated sensitivity of beta 2-adrenoceptors and/or decreased sensitivity of alpha-adrenoceptors in trained rats. It is suggested that for the development of these changes repeated activation of the sympathetic nervous system by exercise periods is needed. That is why they are preventable if the training is performed under the influence of beta-blockade.