Pl@ntWood: A computer-assisted identification tool for 110 species of Amazon trees based on wood anatomy

World interest in conservation of tropical forests has increased due to elevated rates of deforestation and climate change issues. Tropical forests are threatened by extensive agriculture and timber trade among other factors; thus, sustainable management and conservation of tropical tree species require reliable and user accessible identification tools. Although wood anatomical features provide a considerable amount of information, only a handful of experts are able to use it for plant species identification. Here, we propose an interactive tool, based on vector graphics, illustrating 96 states of 22 wood anatomical characters from 110 Amazonian tree species belonging to 34 families. Pl@ntWood is a graphical identification tool based on the IDAO (Identification des plantes Assistée par Ordinateur) system, a multimedia approach to plant identification. This system allows non-specialists to identify plants in a user-friendly interface while stimulating self-training in wood anatomy of tropical species. (Texte intégral

Consumer Attitude Towards Tropical Hardwoods in the United Kingdom

A survey in United Kingdom on public attitude towards tropical timbers showed negative disposition towards tropical hardwoods and wood products. Those considering buying tropical wood products would do so if it was competitively priced, not treated with chemicals or manufactured from timber species known to them. Tropical wood products may not fare better in the future due to greater awareness of environment quality. The survey results revealed that males and those from higher incomes groups unlike the others were willing to purchase tropical hardwood, especially if it was from substainable forests

Characterization of the fire behaviour of tropical wood species for use in the construction industry

It is widely acknowledged that wood is a combustible and flammable material. However, not all woods have the same fire behaviour; this can change significantly depending on the type and species of wood. Usually, hardwoods have better fire behaviour in comparison with softwoods. This is often due to their physical structure (morphology), their density and hardness and also their moisture content. However, in some cases the main cause is their chemical composition. Some tropical woods with relatively low density present better fire behaviour than other with high density. This indicates that other aspects such as the content of extracts, exudates (oils, waxes, mucilage, tannins etc.) and minerals can greatly influence their fire performance. In this study, seven Mexican tropical wood were characterized in order to determine their fire behaviour. For this purpose, an extensive series of laboratory tests were conducted. The results show a different behaviour in all the species studied, in some cases, with very significant differences. It is observed that although there is some correlation between high density and hardness of the species and their good fire behaviour, these factors are not always determinant. In some species, other factors as anatomy and composition of wood are more relevant to achieve a better fire behaviour.Peer ReviewedPostprint (published version

Fire Behaviour of Tropical and European Wood and Fire Resistance of Fire Doors Made of this Wood

In the building industry, there is currently a significant lack of information on fire resistance properties of room separation elements made of tropical wood species. The objective of the present study is to fill this gap by investigating the fire behaviour of tropical wood species and subsequently assessing the fire resistance of elements made of this material. In particular, the prime target was to find easy to measure parameters which correlate with both the charring rate and the deflection, the latter caused by fire induced rapid dehumidification. Further, the so found parameters have been investigated for suitability as reliable predictors for fire resistance of fire doors when tropical wood is used as substitute for European native wood. A series of measurements were carried out for tropical and European wood species. Beam deflection and charring rate as well as the fire resistance of doors were measured in standard fire (ISO 834-1). In addition, the oxygen permeability index (OPI) of wood, which appears to have a strong correlation with the charring rate, was measured. It is shown that in consideration of fire resistance both the charring rate and the deflection have to be addressed when tropical wood is used as substitute for European native wood. Finally, it is clearly confirmed that a single parameter such as wood density is not reliable to assess the substitution of an alternative wood species for a species on which fire resistance test results are availabl

Use of sonic tomography to detect and quantify wood decay in living trees.

Premise of the studyField methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes.Methods and resultsLiving trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness.ConclusionsSonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees

Decomposition of coarse woody debris in a long-term litter manipulation experiment: A focus on nutrient availability

The majority of above-ground carbon in tropical forests is stored in wood, which is returned to the atmosphere during decomposition of coarse woody debris. However, the factors controlling wood decomposition have not been experimentally manipulated over time scales comparable to the length of this process.We hypothesized that wood decomposition is limited by nutrient availability and tested this hypothesis in a long-term litter addition and removal experiment in a lowland tropical forest in Panama. Specifically, we quantified decomposition using a 15-year chronosequence of decaying boles, and measured respiration rates and nutrient limitation of wood decomposer communities.The long-term probability that a dead tree completely decomposed was decreased in plots where litter was removed, but did not differ between litter addition and control treatments. Similarly, respiration rates of wood decomposer communities were greater in control treatments relative to litter removal plots; litter addition treatments did not differ from either of the other treatments. Respiration rates increased in response to nutrient addition (nitrogen, phosphorus, and potassium) in the litter removal and addition treatments, but not in the controls.Established decreases in concentrations of soil nutrients in litter removal plots and increased respiration rates in response to nutrient addition suggest that reduced rates of wood decomposition after litter removal were caused by decreased nutrient availability. The effects of litter manipulations differed directionally from a previous short-term decomposition study in the same plots, and reduced rates of bole decomposition in litter removal plots did not emerge until after more than 6 years of decomposition. These differences suggest that litter-mediated effects on nutrient dynamics have complex interactions with decomposition over time