Sustained timber yield claims, considerations, and tradeoffs for selectively logged forests

Abstract

What is meant by sustainability depends on what is sustained and at what level. Sustainable forest management, for example, requires maintenance of a variety of values not the least of which is sustained timber yields (STYs). For the 1 Bha of the world's forests subjected to selective or partial logging, failures to maintain yields can be hidden by regulatory requirements and questionable auditing practices such as increasing the number of commercial species with each harvest, reducing the minimum size at which trees can be harvested, and accepting logs of lower quality. For assertions of STY to be credible, clarity is needed about all these issues, as well as about the associated ecological and economic tradeoffs. Lack of clarity about sustainability heightens risks of unsubstantiated claims and unseen losses. STY is possible but often requires cutting cycles that are longer and logging intensities that are lower than prescribed by law, as well as effective use of low-impact logging practices and application of silvicultural treatments to promote timber stock recovery. These departures from business-as-usual practices will lower profit margins but generally benefit biodiversity and ecosystem services. Significance Statement Commitments to sustainable forest management (SFM) deserve praise but also scrutiny. Here we examine the sustained timber yield (STY) component of SFM for the 25% of Earth's forest subjected to selective logging. Legitimacy of STY claims depend on whether, over time, the number of species included in yield calculations increases, minimum cutting diameters decrease, or lower quality logs are accepted. STY is possible without such dubious accounting practices if harvest intensities and collateral damage decrease, harvest intervals increase, and treatments are applied to promote recovery. These changes will reduce profits relative to those of timber mining, but climate-change mitigation funds should be available to cover some of the costs given the carbon and other benefits of responsible forest management.

The principles of natural climate solutions

“…Wood-based materials are particularly important to the success of sustainable climate mitigation because, when well-sourced through selective logging and existing forest plantations, they have much smaller carbon footprints than building alternatives such as steel and concrete. However, unsustainable timber exploitation that involves deforestation or that harvests forests above a scientifically defined level of sustained yield 47 would undermine this principle and would therefore not be considered an NCS.…”

Gestión forestal para la producción de madera y restauración del paisaje forestal en la Amazonía

“…La sostenibilidad del aprovechamiento maderero es una cuestión fundamental para la conservación de los bosques amazónicos y de los bosques tropicales de todo el mundo. Sin embargo, incluso hoy en día, las aplicaciones de este concepto son a menudo confusas o engañosas debido a la falta de definiciones claras y a las diferentes formas en que se puede concebir la sostenibilidad 14,15 . Este concepto fue aplicado por primera vez a la producción maderera por técnicos forestales, pero más recientemente se ha ampliado para incluir una variedad de productos forestales y otros servicios ecosistémicos.…”

“…El regreso a las condiciones forestales anteriores al aprovechamiento no es esencial y no debe considerarse el objetivo principal de la gestión forestal sostenible. En lugar de ello, garantizar el RmS durante siglos puede requerir que los bosques naturales bajo manejo forestal difieran un poco de los bosques naturales intactos pero que mantengan conjuntos similares de rasgos funcionales, niveles de biodiversidad y servicios ecosistémicos 14,27 .…”

Forest management for timber production and forest landscape restoration in the Amazon: The way towards sustainability

“…The sustainability of timber yield is a major issue for the conservation of Amazonian forests and for tropical forests worldwide. Yet even today, applications of this concept are often confused or misleading due to lack of clear definitions and the different ways that sustainability can be conceived 14,15 . This concept was first applied to timber production by foresters, but it has been more recently expanded to include a variety of forest products and other ecosystem services.…”

“…The return to pre-harvest forest conditions after logging is not essential and must not be considered as the main goal of sustainable forest management. Instead, ensuring STY for centuries often may require managed natural forests to differ somewhat from natural forests but with similar suites of functional traits, levels of biodiversity, and environmental services 14,27 . FIGURE 2: Three versions of sustained timber yields (STYs).…”