Tuesday, February 4, 2014

Sustainable forest harvesting: shades of gray

Life doesn’t operate in black and white.

If we’re honest, we admit that the things we like have negative impacts, and the things we hate may include positives. Shades of gray.

Take forest management. We can all agree that clearcutting a forest has devastating, even catastrophic impacts. The forest, after all, is entirely removed, even if it or some semblance of it may be regrown later.

You might assume that human collection of non-timber resources in the forest is, by contrast, pretty benign. Like collection of fruits or flowers or roots for medicine, tapping of trees for their latex to make rubber, wandering the Hawaiian forest for maile.

(Image: Prized Hawaiian forest vine, maile. Credit: Forest & Kim Starr.) 

But as benign as they might seem when compared to logging, these activities also have impacts, ranging from minor to very significant.

University of Hawai`i botany professor Tamara Ticktin, a conservation biologist and ethnoecologist, has studied these issues, and her insights have some weight. The British Ecological Society recently named one of her papers one of the 100 most influential among the 17,000 papers it has published.

That 2004 paper was titled, “The ecological implications of harvesting non-timber forest products.” It is available here.

Ticktin herself said the strength of the paper may be that it had pulled together a great deal of information that previously had not been collected in one place.

“Prior to the Ticktin article, our knowledge of the ecological consequences of non-timber forest product extraction was disparate, and spread out across many different case studies. Ticktin made an important advance by systematically reviewing the conclusions of 70 different studies from across the world,” wrote Jos Barlow in a review for the British Ecological Society.

In an interview, Ticktin said there have been widely different views of non-timber harvest—anywhere from the view that any activity by humans is harmful, to the view that traditional collecting in forests is largely benign.

In the paper, she makes the point that “extraction of non-timber plant parts may alter biological processes at many levels.” And dramatically increasing the harvest can turn a relatively non-impactful activity into one with significant negative consequences for the forest.

“One of the take-homes is that it depends on local knowledge. It’s how you do it,” she said.

Reviewer Barlow, an ecologist himself, wrote: “the good news is that some management techniques can be effective at reducing the negative impacts of harvesting. These include enrichment planting, shade management, and focussing on non-lethal harvesting activities that do not affect the population of adult stems (such as the harvesting of bark, fruits, latex and resins).”

As a local example, Ticktin said she has a student looking into methods of harvesting the scented lei vine, maile, in Hawaiian forests. "Improper harvest techniques could damage the plants, while careful, informed harvesting could have no effect or could even stimulate growth" she said.

It can also depend on what plant is being harvested, and what part of the plant is being harvested. Examples of collection goals: There are different impacts from stripping new growth from maile, collecting fruits from mokihana or pulling entire hapu`u plants out of the forest.

None is as destructive as clearcutting, but neither is any entirely without impact.

Shades of gray.

© Jan TenBruggencate 2014

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