Examination of the failure behavior of wood with a short crack in the radial–longitudinal system by single-edge-notched bending test

The failure behavior of wood with a short crack was examined by conducting the single-edge-notched bending tests of a radial-longitudinal system on Agathis specimens. In the test, the mode I critical stress intensity factor was measured, and its validity was checked by the result from double cantilever beam testing method. The mode I critical stress intensity factor decreased when the crack length approached zero. With crack length correction, a constant critical stress intensity factor was obtained over a wide range of crack length including crack-free specimen.     

Intra-specific patterns of δ13C,growth and wood density variation at sites of contrasting precipitation with implications for modelling carbon sequestration of tropical tree species

Agroforestry Systems - Tropical agroforestry practices play a crucial role in mitigating global climate change by absorbing CO2 from the atmosphere through photosynthesis and storing carbon in...     

Is there a Nordic Model for the treatment of introduced tree species? A comparison of the use,policy, and debate concerning introduced tree species in the Nordic countries

This article compares the use, policy, and debate concerning introduced tree species in the five Nordic countries (Finland, Sweden, Norway, Denmark, and Iceland). These countries have a long common history and are culturally similar. They are often framed under the benchmark of the “Nordic Model” or even the “Nordic Forestry Model”. Therefore, we hypothesize that the Nordic countries’ treatment of introduced tree species share common aspects, and that global environmental agreements and international currents in science and policy have reinforced these similarities. The comparison shows that globalization is strong and it seems, at least at a first glimpse, that the Nordic countries follow a kind of “Nordic Model” in their approach to introduced tree species. However, the history and importance of forestry, ecological conditions, afforestation campaigns, traditions of using introduced trees, understandings, and stakeholder positions have shaped different national and even regional path dependencies and circumstances. This, in turn, has transmuted international policy-making, regulations, and discussions into different specific ways to interpret, control, and implement the use of introduced trees in practice. This article concludes that global environmental agreements and international currents in science and policy adapt to diverse national contexts.     

Coppicing ability of dry miombo woodland species harvested for traditional charcoal production in Zambia:a win–win strategy for sustaining rural livelihoods and recovering a woodland ecosystem

The miombo woodland is one of the most extensive woodlands in Africa, supporting livelihoods based on biomass fuel for millions of rural people. However, there are growing concerns about the sustainability of harvesting for biomass fuel(mainly charcoal). Thus, the aim of this study was to examine whether regeneration by coppice is a viable option for sustainably managing miombo woodlands for biomass fuel production. We tested the hypotheses that(1) species, stump diameter, stump height and time since cutting significantly affect the number of sprouts per cut stump(coppice density) and mean sprout height(shoot vigour) and(2) higher coppice density reduces shoot vigour due to competition among coppice shoots in a given stump. In an inventory in areas that were harvested for charcoal production by the local people, 369 stumps of 11 species were recorded with mean coppice stumps ranged from 6 to 84. The mean coppice density ranged from 5 to 8 shoots per stump while the mean height of coppice shoots ranged from 46 to 118 cm with marked interspecific variations. Stump size was significantly and positively correlated with coppice density for some of the species, but not with shoot vigour for the majority of the species. However, shoot vigour was significantly positively correlated to time since cutting of trees for nearly half of the species. Coppice density had a significant negative correlation with shoot vigour for two species, and a positive correlation for one species. In conclusion, the results provide evidence about the importance of coppice management as a win–win strategy for sustaining charcoal-based rural livelihoods and recovering the miombo woodland ecosystem.     

Basal area growth rates of five major species in a Pinus–Cunninghamia forest in eastern China affected by asymmetric competition and spatial autocorrelation

We analyzed basal area (BA) growth using growth data obtained from permanent plots over 4 years for five major tree species in Anhui Province, eastern China. The studied species were dominant conifers (Pinus massoniana and Cunninghamia lanceolata) and co-dominant broad-leaved species (Castanopsis eyrei, Castanopsis sclerophylla, and Loropetalum chinense). A hierarchical Bayesian approach was used to estimate species-specific parameters and to quantify a spatially autocorrelated random effect. We selected a model that included only the following relevant predictor variables: initial size, asymmetric competition, spatially autocorrelated random effect, and random effect associated with plots. For all species analyzed, the model accounted for significant proportions of the variation (R ² = 70–98 %) in BA growth rates. The initial slope of the relationship between BA growth rate and the initial BA tended to be steeper for P. massoniana than for C. lanceolata. The BA growth rate increased from an initial low value and then leveled off, with a lower maximum BA growth rate for C. lanceolata than for P. massoniana. The BA growth rate of P. massoniana was significantly affected by asymmetric competition with neighbors. The results of our analyses were used to predict to what extent thinning neighboring trees at different intensities would reduce competition impacts on BA growth of P. massoniana and C. lanceolata. Our results also helped to clarify the ecological characteristics of the species analyzed, as well as the spatial distribution of unknown factors influencing tree growth.     

Quantitative determination of cyproconazole,as a wood preservative,by gas chromatography–mass spectrometry analysis: matrix effect observed in determining cyproconazole and efficacy of adding analyte protectant

Quantitative determination of cyproconazole by gas chromatography–mass spectrometry (GC/MS) analysis was investigated. The results suggest that cyproconazole determination is significantly affected by wood extracts. In the presence of methanol extracts of Japanese cedar (Cryptomeria japonica) heartwood, cyproconazole showed 50 % larger peak area than that without the extracts. This phenomenon whereby contaminants in the sample solution affect the intensity of the peak signal is known as the matrix effect. An investigation for eliminating the matrix effect revealed that adding sorbitol as an analyte protectant drastically increased the analyte peak intensity and successfully mitigated the matrix effect of the wood extracts. Adding hexaconazole as an internal standard was also useful in reducing the deviation of the data. The efficacy of a novel sample preparation method consisting of adding sorbitol and hexaconazole as analyte protectants and the internal standard, respectively, were applied to the GC/MS analysis of cyproconazole in the presence of wood extracts of the other nine species. It is revealed that cyproconazole can be precisely determined by GC/MS analysis in combination with the analyte protectant and the internal standard.     

Estimating a suitable microsatellite marker set for individual identification and parentage tests of brown bear (Ursus arctos) in the Akan–Shiranuka Region, eastern Hokkaido, Japan

We examined 24 microsatellite markers to select those most suitable for individual identification and parentage tests of brown bears (Ursus arctos) based on statistical parameters and experimental error using liver samples (38 issues) from nuisance bears killed in the Akan–Shiranuka Region, eastern Hokkaido, Japan from 1996 to 2006. We found seven microsatellite markers suitable for identifying individuals (G1A, G10B, G10L, UarMU5, UarMU23, UarMU50, and UarMU51; probability of identity P _id = 3.17  × 10⁻⁷; probability of identity of sibs P _id-sib  = 2.23 × 10⁻³), 12 microsatellite markers suitable for parentage testing when one parent is known [G1A, G1D, G10B, G10L, G10P, UarMU5, UarMU23, UarMU50, UarMU51, UarMU59, UarMU61, and UarMU64; probability of excluding one parent (PE I = 0.9991)], and 15 microsatellite markers for parentage testing when neither parents are known [three markers added to the above: G10M, G10X, and UarMU9; probability of excluding both parents (PE II = 0.9869)].     

Evaluation and comparison of size–density relationships for pure even-aged stands of ash (Fraxinus excelsior L.), beech (Fagus silvatica L.), oak (Quercus petraea Liebl.), and sycamore maple (Acer pseudoplatanus L.)

• Introduction   

Size-density relationships define the maximum number of stems that even-aged stands of a given species can hold in relation to the mean size of trees. They are used to derive stand density measures and are useful tools used to control tree mortality.     

Amelioration of planting stress by soil amendment with a hydrogel–mycorrhiza mixture for early establishment of beech (<Emphasis Type="Italic">Fagus sylvatica</Emphasis> L.) seedlings

Introduction   

The mortality of nursery-grown beech (Fagus sylvatica L.) seedlings after out planting into the field is usually high.