Are we pushing global forests over the edge?

Global forests over the edgeFalmouth, Mass. – Expanding agriculture, climate change, air pollution and invasive pests are pushing the forests of the world beyond their ability to recover, but identification of the tipping points continues to be elusive.In the introduction to a special issue on Forest Health in the journal Science, Woods Hole Research Center scientist, Paulo Brando and colleagues distill current scientific knowledge about forest health limits and recommend a global strategy for monitoring changes as they occur.

“We know there is a cliff, we know we are pushing forests towards it, but we don’t know exactly where it is,” said Dr. Brando. “If forests fall over that cliff, the consequences for our society are enormous–we depend on their services more than we think.”

As an introduction to the series, the paper frames the analysis of forest health by answering five questions: How is forest health is measured? How long will it take for declining forests to recover? Where is the point at which forests cannot rebound? Can we effectively monitor forest health on a global scale? Is it inevitable that the forests of the world (and the benefits they provide) will disappear?

Dr. Brando and colleagues conclude that forests worldwide appear to be declining in health, but too little is known about the impacts of different stressors in different forests to answer the ultimate question of global forest survivability. According to Dr. Brando, “Sometimes, a seemingly minor change will be the catalyst for, or an indicator of, large-scale forest decline and these small changes are very difficult to detect using our current forest monitoring techniques.” The paper describes the need for a more robust global monitoring system of forest health, which would combine multiple sources of satellite data and fieldwork with intensive species and ecosystem stressor experiments to better monitor and understand the processes of forest change. “We can already monitor major perturbations to global forests such as forest loss and gain, but other forms of forest degradation remains difficult to identify at fine scales globally or scales with good temporal coverage,” said fellow WHRC scientist Scott Goetz.

Dr. Brando and colleagues ultimately conclude that the forests of the world have historically survived very dramatic environmental changes and are most likely to persist in spite of human efforts for good or ill. According to Dr. Brando, “The important question to answer is how the transformations we are imposing on global forests will respond by influencing basic livelihoods of forest dependent peoples, agriculture practices, and the regional climate.”

Link to abstract »

WHRC is an independent research institute where scientists investigate the causes and effects of climate change to identify and implement opportunities for conservation, restoration and economic development around the globe.