Improved timber harvest techniques maintain biodiversity in tropical forests

Tropical forests are selectively logged at 20 times the rate at which they are cleared, and at least a fifth have already been disturbed in this way. In a recent pan-tropical assessment, Burivalova et al. demonstrate the importance of logging intensity as a driver of biodiversity decline in timber estates. Their analyses reveal that species richness of some taxa could decline by 50% at harvest intensities of 38 m3 ha-1. However, they did not consider the extraction techniques that lead to these intensities. Here, we conduct a complementary meta-analysis of assemblage responses to differing logging practices: conventional logging and reduced-impact logging. We show that biodiversity impacts are markedly less severe in forests that utilise reduced-impact logging, compared to those using conventional methods. While supporting the initial findings of Burivalova et al., we go on to demonstrate that best practice forestry techniques curtail the effects of timber extraction regardless of intensity. Therefore, harvest intensities are not always indicative of actual disturbance levels resulting from logging. Accordingly, forest managers and conservationists should advocate practices that offer reduced collateral damage through best practice extraction methods, such as those used in reduced-impact logging. Large-scale implementation of this approach would lead to improved conservation values in the 4 million km2 of tropical forests that are earmarked for timber extraction

Uprooting and snapping of trees: structural determinants and ecological consequences

Journal ArticleThe influence of mechanical and architectural properties of trees on growth rates, mortality rates, and relative probabilities of snapping and uprooting were examined on Barro Colorado Island, Republic of Panama. Of 310 fallen trees, 70% snapped, 25% uprooted, and 5% broke off at ground level. Stepwise discriminant analysis between snapped and uprooted trees indicated that of the variables measured, wood properties were the most important factors determining the type of death in trees. Uprooted trees tended to be larger, shorter for a given stem diameter, and to have denser, stiffer, and stronger wood than snapped trees. There were no significant differences between trees that snapped and trees that uprooted in the extent of buttress development or in the slope of the ground upon which they grew. Trees with low density wood grew faster in stem diameter than those with high density wood but also suffered higher mortality rates. After damage, many of the snapped trees sprouted; small trees sprouted more frequently than large trees. Sprouting is proposed as a means by which weak-wooded fast-growing trees partially compensate for being prone to snapping

A Sustainable Forest Future?

Concern about the rate at which the world's forests are being depleted is wide-spread. Recent international calls for radical efforts to reduce deforestation include the United Nations Inter-governmental Forum on Forests of the UN Commission on Sustainable Development (1999), and the World Commission on Forests and Sustainable Development (1999). This concern reflects an appreciation of the ecological and economic functions of forests: as providers of timber and many non-timber predicts, as the habitat for much of the world's biological diversity, and as regulators of local, regional and global environments. These functions are at risk. Most of the forest clearance is in areas of high forest cover and high human population pressure in tropical areas for agriculture. In temperate and boreal areas the pressures from logging are more important. But in all areas, forestry itself has an important role to play both as a partial cause of deforestation, and, if practiced wisely, as a potential source of salvation for at least some of the world's forests. In terms of its causal role, forestry tends to open up primary forest areas, enabling colonists to move in, using roads forged by the timber companies. In some parts of the world, forests are converted not to agriculture but to biomass plantations of fast growing trees or to other agro-industries based on tree-crop plantations such as palm oil and rubber. Here the primary agent is not the peasant, but the richer elements of local and international society. How, then, can the world's forests be used more wisely? It is this admittedly grand and complex question that we seek to answer in this paper. Some argue for outright protection, caricatured perhaps in the phrase 'fence and forget'. Others argue for 'sustainable forest management', and still others for systems of forest management that rely on acceptance of an initial period of exploitation of valuable species followed by outright protection. The issue, then, is the optimal use of forested land , which begs the question of what is meant by 'optimal'. This is addressed shortly

Is Sustainable Forestry Economically Possible?

Concern about the rate at which the world's forests are being depleted is wide-spread. Recent international calls for radical efforts to reduce deforestation include the United Nations Inter-governmental Forum on Forests of the UN Commission on Sustainable Development, and the World Commission on Forests and Sustainable Development. This concern reflects an appreciation of the ecological and economic functions of forests: as providers of timber and many non-timber predicts, as the habitat for much of the world's biological diversity, and as regulators of local, regional and global environments. These functions are at risk. Most of the forest clearance is in areas of high forest cover and high human population pressure in tropical areas for agriculture. In temperate and boreal areas the pressures from logging are more important. But in all areas, forestry itself has an important role to play both as a partial cause of deforestation, and, if practiced wisely, as a potential source of salvation for at least some of the worldââ‰��������s forests. In terms of its causal role, forestry tends to open up primary forest areas, enabling colonists to move in, using roads forged by the timber companies. In some parts of the world, forests are converted not to agriculture but to biomass plantations of fast growing trees or to other agro-industries based on tree-crop plantations such as palm oil and rubber. Here the primary agent is not the peasant, but the richer elements of local and international society. How, then, can the world's forests be used more wisely? It is this admittedly grand and complex question that we seek to answer in this chapter

Sustainable Forestry in the Tropics: Panacea or Folly?

The profitability of uncontrolled logging can be a significant obstacle to sustainable forest management, especially in the tropics. Rice et al. (1997) have argued that not only does traditional selective logging provide higher returns but also incurs less damage to forests than sustainable forest management systems that involve harvesting of many species and the creation of large gaps in the forest canopy to foster regeneration of light-demanding species. They claimed that protected areas were the only viable way to conserve forest ecosystems and proposed that loggers be allowed to log forests selectively once, after which the forests should become parks. Here we respond to the challenge posed by Rice et al. by exhaustively reviewing the evidence regarding the viability and desirability of sustainable forest management in the tropics. Following Rice et al., we use the term conventional timber harvesting to refer to existing practice, which typically pays little attention to maintaining long-term timber supply. Sustainable timber management implies taking steps to ensure forests continue to produce timber in the longer term, while maintaining the full complement of environmental services and non-timber products of the forest. Empirical studies tend to confirm the conclusion of Rice et al. (1997) that although sustainable timber management sometimes provides reasonable rates of return, conventional timber harvesting is generally more profitable. This implies that without additional incentives, one cannot expect companies to adopt sustainable management. The shortsightedness of many loggers, the slow rise in international timber prices, political uncertainty, and tenure insecurity simply reinforce this tendency. However, we reject the claim that sustainable timber management generally damages forests more than conventional logging. Rice et al. base their conclusion largely on the particular case of mahogany extraction in Bolivia, and even there it may not hold. In many cases, sustainable timber management performs better in terms of carbon storage and biodiversity conservation than conventional logging approaches, as well as producing more timber. If new carbon markets emerge, sustainable forest management might compete effectively with conventional timber harvesting. Timber certification systems may also provide a sufficient incentive for sustainable forest management in certain circumstances

Deep Neuromuscular Blockade Improves Surgical Conditions During Gynecological Laparoscopy

Obtaining an appropriate laparoscopic workspace depends on several factors related to the patient (i.e., weight and abdominal compliance) and the procedure (i.e., body’s position, depth of anesthesia and intra-abdominal (IA) pressure). Among them, a deep neuromuscular blockade (NMB) contributes to provide the surgeon with better operating conditions. This chapter discusses the interests and challenges of muscle relaxation during gynecological laparoscopy. The introduction of sugammadex into clinical practice provides the opportunity to modify the management of neuromuscular blockade to improve the surgical conditions during laparoscopy as well as the safety of the patients. The maintenance of a rocuronium-induced deep neuromuscular block from the trocar insertion until the end of laparoscopy is no longer incompatible with rapid recovery and awakening in optimal conditions. Neuromuscular transmission (NMT) monitoring is the key to adequate management and should be used in all cases. Objective measurements allow for excellent intubation and surgical conditions, the definition of thresholds and doses for the administration of reversal agents, and the exclusion of residual blockade prior to the patient extubation