Water – drinkable, usable water – is likely to be one of the most limiting resources in the future, given the growing global population, the high water demand of most agricultural production systems, and the confounding effects of climate change. We need to manage water wisely – efficiently, cost-effectively and equitably – if we are to avoid the calamity of a lack of usable water supply. Forested watersheds provide an estimated 75 percent of the world’s accessible freshwater resources, on which more than half the Earth’s people depend for domestic, agricultural, industrial and environmental purposes. Forests therefore, are vital natural infrastructure, and their management can provide “nature-based solutions” for a range of water-related societal challenges. This edition of Unasylva explores that potential.

Cities need forests. The network of woodlands, groups of trees and individual trees in a city and on its fringes performs a huge range of functions – such as regulating climate; storing carbon; removing air pollutants; reducing the risk of flooding; assisting in food, energy and water security; and improving the physical and mental health of citizens. Forests enhance the look of cities and play important roles in social cohesion; they may even reduce crime. This edition of Unasylva takes a close look at urban and peri-urban forestry – its benefits, pitfalls, governance and challenges.

This publication deals with the composition and structure of both natural and artificially established tropical forests. After a general introduction, the role of tropical forests in the production of timber is discussed. Attention is then given to the structure of natural tropical forests, especially in Congo, Gabon, Ghana and Laos. The structure of artificially established forests is dealt with in another chapter. At the end, information is given on the thinning of such forest stands in Tanzania.

In La Frontera, Thomas Miller Klubock offers a pioneering social and environmental history of southern Chile, exploring the origins of today’s forestry "miracle" in Chile. Although Chile's forestry boom is often attributed to the free-market policies of the Pinochet dictatorship, La Frontera shows that forestry development began in the early twentieth century when Chilean governments turned to forestry science and plantations of the North American Monterey pine to establish their governance of the frontier's natural and social worlds. Klubock demonstrates that modern conservationist policies and scientific forestry drove the enclosure of frontier commons occupied by indigenous and non-indigenous peasants who were defined as a threat to both native forests and tree plantations. La Frontera narrates the century-long struggles among peasants, Mapuche indigenous communities, large landowners, and the state over access to forest commons in the frontier territory. It traces the shifting social meanings of environmentalism by showing how, during the 1990s, rural laborers and Mapuches, once vilified by conservationists and foresters, drew on the language of modern environmentalism to critique the social dislocations produced by Chile's much vaunted neoliberal economic model, linking a more just social order to the biodiversity of native forests.