Elevated atmospheric CO2 alters wood production, wood quality and wood strength of Scots pine (Pinus sylvestris L) after three years of enrichment

Scots pine ( Pinus sylvestris L.) trees were grown in open top chambers for three years under ambient and elevated CO₂ concentrations. The trees were aged 3 y at the beginning of the CO₂ exposure, and the effects of the treatment on total stem volume, stem wood biomass, wood quality and wood anatomy were examined at the end of the exposure. The elevated CO₂ treatment lead to a 49% and 38% increase in stem biomass and stem wood volume, respectively. However, no significant effects of the elevated CO₂ treatment on wood density were observed, neither when green wood density was estimated from stem biomass and stem volume, nor when oven-dry wood density was measured on small wood samples. Under elevated CO₂ significantly wider growth rings were observed. The effect of elevated CO₂ on growth ring width was primarily the result of an increase in earlywood width. Wood compression strength decreased under elevated CO₂ conditions, which could be explained by significantly larger tracheids and the increased earlywood band, that has thinner walls and larger cavities. A significant decrease of the number of resin canals in the third growth ring was observed under the elevated treatment; this might indicate that trees produced and contained less resin, which has implications for disease and pest resistance. So, although wood volume yield in Scots pine increased significantly with elevated CO₂ after three years of treatment, wood density remained unchanged, while wood strength decreased. Whilst wood volume and stem biomass production may increase in this major boreal forest tree species, wood quality and resin production might decrease under future elevated CO₂ conditions.     

橡胶木防霉试验

研制了一种新型、安全、广谱的木材防霉剂。经检测,它对木材具有良好的防霉效果,且稳定持久。初步核算,DCMX木材防霉剂处理木材成本低于市场使用的其他木材防霉剂。     

Effect of wood density and water permeability on wood decomposition rates of 32 Bornean rainforest trees

Aims A better understanding of wood litter decomposition is essential for predicting responses of forest ecosystems to global climate change. Recent studies suggest that chemical properties of wood litters, rather than physical ones such as wood density, are more important for interspecific differences in wood decomposition rates. However, empirical data are still limited, especially for tropical trees. In addition, decomposition rate of wood litter often varies with time, which makes interspecific comparison difficult. We studied the wood decomposition of 32 rainforest trees to elucidate (i) the degree of interspecific variation in wood decomposition rate of a given size and configuration and (ii) if initial wood density and water permeability are consistent predictors of the overall decomposition rate and its pattern over time.Methods A common garden decomposition experiment was conducted in a tropical rainforest in Malaysian Borneo for 32 native tree species. Small wood sticks were set on the forest floor and the weight loss was monitored monthly for 2.7 years.Important findings We found large variation in the wood decomposition rate (a 49-fold range), suggesting that we need to consider this variation when calculating community-level carbon dynamics of tropical rain forests. The physical traits of wood, i.e. wood density and water permeability, were related to wood decomposition rate and its pattern over time. Decomposition half-time related positively and negatively to initial wood density and water permeability, respectively. The time-dependent-rate model fitted better for 18 species (56% of the study species) that had higher water permeabilities than the others, suggesting that micelle porosity in wood relates to temporal changes in decomposition rate.     

Late prehistoric wood use in an andean intermontane valley

Late Prehistoric Wood Use in an Andean Intermontane Valley. Economic Botany 59(4): 337-355, 2005. Data from carbonized wood remains from five late prehistoric sites (A.D. 1300–1530) in the Upper Mantaro Valley, Peru, are presented. The wood assemblage recovered is diverse. We illustrate and describe the twelve main morpho-types, one of which is more than likely to have been imported from the eastern slopes of the Andean mountains into the Mantaro Valley. The Inka conquest of the area created a change in socio-political power and also brought about a shift in the way wood species were utilized. From the Wanka II to the Inka occupations we find an increase in theBuddleja, Polylepis, Alnus, andColletia morpho-types: all of these species are reported as being cultivated by the Inka and possibly by pre-Inka inhabitants of the valley. A quantitative analysis shows higher amounts of wood in the elite dwellings of both the Wanka II and Wanka III times, suggesting a social aspect in the way this valuable Andean commodity was distributed and used.

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Résumé   El Uso de Madera Prehistorico Tardio en un Valle Andino. Fueron analizados los restos de madera provenientes de cinco sitios del período prehistorico tardio (1300–1530 d.C.) del Alto Valle Mantaro, Perú. La asamblea de moderns era muy variada Ilutramos y describimos las doce categorías taxonómicas prinicipales, una de las cuales probablamente fue importada desde las cuestas orientales de los Andes. La conquista Inkaica de la región efectuó un cambio de énfasis en los morfotipos de madera usados, con un aumento deBuddleja, Polylepis,Alnus, yColletia. Un análisis cuantitativo muestra una concentracion de maderas en las habitaciones de la clase élite, sugeriendo un aspecto social en el uso de la madera.

     

The dendrochronological potential of decayed yew wood

A significant difficulty in the accurate ageing of many of the largest-diameter yew trees (Taxus baccata L.) found in the United Kingdom is their vulnerability to heartwood decay. This has presented a considerable barrier to extending yew chronologies beyond c.330 years into the past. Decayed wood often survives within the sound cylindrical structure of hollow and hollowing yews. Here we present the analysis of such decayed yew wood using a novel wet-scanning technique. Long series for four out of five large hollow yew trees sampled are successfully cross-matched to produce a 374-year-long mean series spanning 1532–1905. These newly dated series extend the previous mean UK yew chronology by 158 years. Although currently undated, the central decayed material from the largest yew at Selborne produces a 196-year series which is likely to include material from the 14th century. Given the number of large hollow yew trees surviving in the UK, this research highlights the potential for using decayed yew wood to improve the ageing of yew trees and extending a regional yew chronology.     

Fossil wood of the Juglandaceae: Some questions of taxonomy,evolution, and phylogeny in the family based on wood anatomy

Some problems in the taxonomy of the Juglandaceae are discussed based on wood anatomy; the identification of fossil juglandaceous wood is considered. Data on fossil wood of the Juglandaceae are summarized; a key for identification of wood anatomy in modern and fossil Juglandaceae is compiled. Wood anatomical characters in members of the family are discussed in the light of major evolutionary trends in the secondary xylem of dicots, and a comparative characterization of members of the family is developed. A hypothesis is proposed that the subfamily Engelhardioideae is the most primitive member of the Juglandaceae based on wood anatomy, the tribe Juglandeae and subfamily Platycaryoideae are slightly more highly specialized, and the tribe Hicorieae is the most advanced. Evolutionary relationships between the members of the Juglandaceae are reviewed based on wood anatomy.     

中国木质林产品碳贮量

一直以来,在国家温室气体清单的计量中,均假定森林采伐后其贮存的生物量碳在采伐年全部释放进入大气。实际上,森林采伐后形成的木质林产品中的碳并没有立即排放,而是在随后的数年或数十年间逐渐排放,部分以垃圾形式填埋的废旧木质林产品中的碳还可能得到长期保存。但是,由于不同的计量方法导致计量结果的不确定性,木质林产品碳贮量变化是否纳入国家温室气体清单土地利用、土地利用变化和林业(LULUCF)部门的计量和报告,还存在很大争议,这也是缔约方会议争论的焦点议题之一。许多国家在国家温室气体清单中报告了木质林产品碳贮量。采用IPCC好的做法指南提出的碳贮量变化法、大气通量法、生产国法和一阶衰变法计算了我国木质林产品碳贮量及其变化,比较了不同方法和不同数据源(我国统计数据和联合国粮食和农业组织(FAO)统计数据)计算得到的碳贮量的差异,并分析了产生差异的原因。结果表明:(1)我国木质林产品碳贮量一直处于增长趋势,1900~2003年年均增长量为2.25×106MgC.a-1,随着木质林产品消费量的增加,2020年碳贮量将达到6.14×108MgC。(2)3种计量方法计算结果差异显著,用碳贮量变化法计算2003年的碳贮量为2.35×108MgC,大气通量法为0.47×108MgC,生产国法为1.79×108MgC。由于我国是木质林产品生产及进口大国,运用碳贮量变化法,1900~2020年间碳贮量年变化的平均值比生产国法多1.17×106MgC,比大气通量法多5.66×106MgC。(3)用FAO数据计算我国2003年碳贮量,其结果是我国统计数据的2~7倍。     

Effect of wood ash treatment on improving the fermentability of wood hydrolysate

Softwood hydrolysates were overlimed with wood ash to improve the fermentability of hydrolysates. It could be demonstrated in fermentation tests that wood ash treatment increases fermentability compared to the hydrolysates untreated and treated with alkaline compounds such as Ca(OH)(2), NaOH, and KOH, which are commonly used for overliming. The enhanced fermentability of the hydrolysate treated with wood ash is due to the reduction of the inhibitors of the fermentation such as furan and phenolic compounds and to nutrient effects of some inorganic components from the wood ash on the fermentation.     

Large wood and fluvial processes

1. Large wood forms an important component of woodland river ecosystems. The relationship between large wood and the physical characteristics of river systems varies greatly with changes in the tree species of the marginal woodland, the climatic and hydrological regime, the fluvial geomorphological setting and the river and woodland management context. 2. Research on large wood and fluvial processes over the last 25 years has focussed on three main themes: the effects of wood on flow hydraulics; on the transfer of mineral and organic sediment; and on the geomorphology of river channels. 3. Analogies between wood and mineral sediment transfer processes (supply, mobility and river characteristics that affect retention) are found useful as a framework for synthesising current knowledge on large wood in rivers. 4. An important property of wood is its size when scaled to the size of the river channel. ′Small′ channels are defined as those whose width is less than the majority of wood pieces (e.g. width < median wood piece length). `Medium' channels have widths greater than the size of most wood pieces (e.g. width < upper quartile wood piece length), and `Large' channels are wider than the length of all of the wood pieces delivered to them. 5. A conceptual framework defined here for evaluating the storage and dynamics of wood in rivers ranks the relative importance of hydrological characteristics (flow regime, sediment transport regime), wood characteristics (piece size, buoyancy, morphological complexity) and geomorphological characteristics (channel width, geomorphological style) in `Small', `Medium' and `Large' rivers. 6. Wood pieces are large in comparison with river size in `small' rivers, therefore they tend to remain close to where they are delivered to the river and provide important structures in the stream, controlling rather than responding to the hydrological and sediment transfer characteristics of the river. 7. For `Medium' rivers, the combination of wood length and form becomes critical to the stability of wood within the channel. Wood accumulations form as a result of smaller or more mobile wood pieces accumulating behind key pieces. Wood transport is governed mainly by the flow regime and the buoyancy of the wood. Even quite large wood pieces may require partial burial to give them stability, so enhancing the importance of the sediment transport regime. 8. Wood dynamics in `Large' rivers vary with the geometry of the channel (slope and channel pattern), which controls the delivery, mobility and breakage of wood, and also the characteristics of the riparian zone, from where the greatest volume of wood is introduced. Wood retention depends on the channel pattern and the distribution of flow velocity. A large amount is stored at the channel margins. The greater the contact between the active channel and the forested floodplain and islands, the greater the quantity of wood that is stored.     

Modelling of the hygroelastic behaviour of normal and compression wood tracheids

Compression wood conifer tracheids show different swelling and stiffness properties than those of usual normal wood, which has a practical function in the living plant: when a conifer shoot is moved from its vertical position, compression wood is formed in the under part of the shoot. The growth rate of the compression wood is faster than in the upper part resulting in a renewed horizontal growth. The actuating and load-carrying function of the compression wood is addressed, on the basis of its special ultrastructure and shape of the tracheids. As a first step, a quantitative model is developed to predict the difference of moisture-induced expansion and axial stiffness between normal wood and compression wood. The model is based on a state space approach using concentric cylinders with anisotropic helical structure for each cell-wall layer, whose hygroelastic properties are in turn determined by a self-consistent concentric cylinder assemblage of the constituent wood polymers. The predicted properties compare well with experimental results found in the literature. Significant differences in both stiffness and hygroexpansion are found for normal and compression wood, primarily due to the large difference in microfibril angle and lignin content. On the basis of these numerical results, some functional arguments for the reason of high microfibril angle, high lignin content and cylindrical structure of compression wood tracheids are supported.     

Fossil coniferous wood from the Middle Jurassic of Liaoning Province, China

Silicified coniferous wood was collected from the Lanqi Formation (late Middle Jurassic in age) at Shebudaigou Village, Liaoning Province, China. Three taxa are identified, namely Pinoxylon dacotense Knowlton, Xenoxylon phyllocladoides Gothan, and Araucariopitys sp. Based on these new data, and those of other fossil plants reported previously from the same formation, we consider the climate during the deposition of the Lanqi Formation was subtropical, humid and seasonal. In this respect the Lanqi flora differs from the coeval Shimengou and Longmen floras from North China. The Longmen flora was deposited during more humid, subtropical conditions, while the Shimengou Formation indicates that the climate was warm temperate and dry. Our data would suggest that the Late Jurassic climatic pattern was initiated as early as the late Middle Jurassic.     

Radiosensitivity of fungi isolated from waterlogged archaeological wood

Waterlogged archaeological timbers of theMary Rose were shown to support a range of fungi, including marine soft rot fungi. These isolates, and other wood degrading fungi, were inactivated by gamma irradiation at doses of 3.1–15.0 kGy. No clear pattern of variation in radioresistance appeared between the Ascomycota, Basidiomycota and Deuteromycota. Terrestrial fungi were generally more resistant than marine fungi. Little variation in radioresistance was observed between vegetative hyphae and sporulating cultures/fruiting bodies. Sublethal doses resulted in reduced viability in some species. Gamma irradiation is suggested as a possible means of controlling fungal colonisation of waterlogged archaeological wood.     

Traits mediate drought effects on wood carbon fluxes

CO₂ fluxes from wood decomposition represent an important source of carbon from forest ecosystems to the atmosphere, which are determined by both wood traits and climate influencing the metabolic rates of decomposers. Previous studies have quantified the effects of moisture and temperature on wood decomposition, but these effects were not separated from the potential influence of wood traits. Indeed, it is not well understood how traits and climate interact to influence wood CO₂ fluxes. Here, we examined the responses of CO₂ fluxes from dead wood with different traits (angiosperm and gymnosperm) to 0%, 35%, and 70% rainfall reduction across seasonal temperature gradients. Our results showed that drought significantly decreased wood CO₂ fluxes, but its effects varied with both taxonomical group and drought intensity. Drought‐induced reduction in wood CO₂ fluxes was larger in angiosperms than gymnosperms for the 35% rainfall reduction treatment, but there was no significant difference between these groups for the 70% reduction treatment. This is because wood nitrogen density and carbon quality were significantly higher in angiosperms than gymnosperms, yielding a higher moisture sensitivity of wood decomposition. These findings were demonstrated by a significant positive interaction effect between wood nitrogen and moisture on CO₂ fluxes in a structural equation model. Additionally, we ascertained that a constant temperature sensitivity of CO₂ fluxes was independent of wood traits and consistent with previous estimates for extracellular enzyme kinetics. Our results highlight the key role of wood traits in regulating drought responses of wood carbon fluxes. Given that both climate and forest management might extensively modify taxonomic compositions in the future, it is critical for carbon cycle models to account for such interactions between wood traits and climate in driving dynamics of wood decomposition.     

Towards a worldwide wood economics spectrum

Wood performs several essential functions in plants, including mechanically supporting aboveground tissue, storing water and other resources, and transporting sap. Woody tissues are likely to face physiological, structural and defensive trade-offs. How a plant optimizes among these competing functions can have major ecological implications, which have been under-appreciated by ecologists compared to the focus they have given to leaf function. To draw together our current understanding of wood function, we identify and collate data on the major wood functional traits, including the largest wood density database to date (8412 taxa), mechanical strength measures and anatomical features, as well as clade-specific features such as secondary chemistry. We then show how wood traits are related to one another, highlighting functional trade-offs, and to ecological and demographic plant features (growth form, growth rate, latitude, ecological setting). We suggest that, similar to the manifold that tree species leaf traits cluster around the 'leaf economics spectrum', a similar 'wood economics spectrum' may be defined. We then discuss the biogeography, evolution and biogeochemistry of the spectrum, and conclude by pointing out the major gaps in our current knowledge of wood functional traits.     

变孔异担子菌随进境针叶木传入中国的风险分析

变孔异担子菌Heterobasidion irregulare原产于北美,能引起针叶树根部和根基干部的白色腐朽病,严重时导致树木死亡。目前已扩散至欧洲部分国家,在我国尚未有分布。本研究按照植物检疫的国际标准措施之有害生物风险分析原则(ISPMNo.11),从地理分布、定殖可能性、扩散可能性、经济重要性和管理难度等方面对该病菌进行了定性分析,同时按照有害生物危险性评价指标体系及赋值标准,获得该病菌风险R值。结果显示：变孔异担子菌风险评估R值为2.35,属于高度危险林业有害生物,传入风险较高、危害大,目前尚未列入我国禁止进境检疫性有害生物名录中。因此,建议将该种真菌尽快列入名录中,加强口岸检疫。     

Biodegradation of wood in crude oil-polluted soil

A field investigation (April–November) in Nigeria showed that biodegradation of obeche (Triplochiton scleroxylon) wood blocks was initially retarded in crude oil-contaminated soil but later became enhanced as indicated by loss of compression resistance. Further indication of this pattern was the detection of soft-rot cavities and basidiomycete fungi after 2–3 months exposure when compared to control blocks in uncontaminated soil. Laboratory tests with Pleurotus sp., Trametes sp., Gloeophyllum sp. (basidiomycetes) and Chaetomium sp. (soft-rot fungus) confirmed that degradation of crude oil-coated obeche blocks was markedly retarded without the presence of hydrocarbon-degrading bacteria. The filtrate of hydrocarbon-degrading Pseudomonas sp. grown in mineral salt/crude oil medium for 3–4 weeks supported growth of the test fungi better than in carboxymethyl cellulose medium but less than in potato dextrose broth. Similarly, wood blocks immersed in the filtrate became significantly more susceptible to fungal degradation. Pseudomonas sp. from stationary phase growth in crude oil medium depleted residual sugar in basidiomycete-degraded sawdust with a concomitant marked increase in its population. It may be concluded that readily metabolizable products of crude oil degradation by soil organisms and the removal of residual sugar which may have prevented catabolite repression of cellulases, culminated in increased attack on the wood by soil-borne wood-decomposing organisms.