Rethinking Forest Plantations

September 10, 2012 | 9:14 am
Doug Boucher
Former contributor

Last winter, after two weeks at the climate negotiations in Durban, I took a few days of vacation and visited the unique “Afrotemperate forests” of the Southern Cape of South Africa, in the Knysna-Tsitsikamma region. Natural forests cover less that 0.5 percent of South Africa, which is much more famous for wildlife-rich savannas and for the incredibly biodiverse fynbos vegetation around the Cape of Good Hope.

Sign describing the Afrotemperate Forest in Tsitsikamma, South Africa. Photo by Doug Boucher.

And it turns out that this rarity is not mostly due to past human clearing, as in the United States and Europe, but much more to climate — it has been like that for many thousands of years.

Visiting the Knysna-Tsitsikamma forests was a marvelous experience, but also one that made me rethink some of my ideas about forests and forestry. For not only do natural forests occupy a tiny fraction of the country, but they are essentially off-limits to timber cutting, with minor exceptions. And yet South Africa is self-sufficient in wood and actually exports to neighboring countries. How does it do this? Through forest plantations.

I saw lots of forest plantations during my visit to South Africa, and they were similar to what you see in the southern United States and in Europe and in many other parts of the world: monocultures of exotic species (mostly pine, eucalyptus, and acacias) grown in straight lines. They looked very different from the diverse Afrotemperate forests with their giant yellowwood (Podocarpus) trees.

Native forest, Harkerville Forest Flora Trail, Knysna. Photo by Doug Boucher.

They were clearly not there to delight the eye and soothe the soul, nor to protect the habitat for wildlife and wildflowers, nor to sequester carbon and reduce global warming pollution. Their role was to produce wood, period. They are so efficient in that task that South Africa, with only 1.1 percent of its land in plantations, is more than self-sufficient in wood.

Planted pines north of Kynsna. Photo by Doug Boucher

But by the limited criterion of wood production, plantations are very successful – far more so than natural forests. Around the world, plantations tend to yield 3 to 10 times as much wood per year as even well-managed natural forests.

As pointed out in our new report on wood products and tropical deforestation, Wood for Good, plantations make up less than 5 percent of the world’s forest area, but represent a considerably larger share of its wood product output — for some kinds of products, the majority. And their output will grow rapidly in future years as new plantations in tropical and south-temperate countries (e.g. Chile, New Zealand, the southern part of Brazil) reach maturity.

One point that Wood for Good makes very strongly is that natural forests should never be cut down to establish plantations — that the damage to biodiversity, sequestered carbon, ecosystem services, and forest peoples’ livelihoods far outweighs the benefit in terms of wood production. But it also shows how on degraded, already-cleared land, such as abandoned cattle pastures or invasive-grass-dominated areas in southeast Asia, plantations can be environmentally and socially beneficial, particularly when controlled and managed through community forestry.

Nor do plantations have to follow the industrial straight-line-exotic-monoculture pattern. In fact, a meta-analysis by Daniel Piotto in the journal Forest Ecology and Management showed that trees in multi-species plantations tend to grow faster in diameter than in monoculture, particularly if the plantation includes nitrogen-fixing species. And Catherine Potvin and Nick Gotelli have shown that many native species in tropical countries, grow very well in mixed-species plantations.

In 1835, in his Guide through the District of the Lakes, the poet William Wordsworth decried the conversion of natural forests to plantations in these words:

“To those who plant for profit, and are thrusting every other tree out of the way, to make room for their favourite, the larch, I would utter first a regret, that they should have selected these lovely vales for their vegetable manufactory, when there is so much barren and irreclaimable land in the neighbouring moors, and in other parts of the island, which might have been had for this purpose at a far cheaper rate.”

 Maybe it’s not a very scientific statement, but sometimes the poets say it best.

Portrait of William Wordsworth by Benjamin Robert Haydon. Source: Wikipedia