PLANETARY HEALTH WEEKLY

If rivers can be granted legal rights (see my Blog #2) what about other natural features and ecosystems such as forests? It’s an idea first suggested nearly fifty years ago by Christopher Stone, an American law professor in his classic essay ‘Should Trees have Standing?’ If revisited perhaps it could help us revalue forests and all their inhabitants. It might even improve respect for their planetary significance.

While major forest fires are devastating both natural woodlands and timber plantations in several continents, another environmental crisis has been somewhat neglected in the international news. A major part of central and southern South America is currently in the grip of the worst drought in human memory, the cost running into billions. To climate scientists this is hardly a surprise, but an inevitable result of the deforestation of large areas in the Amazon basin in recent decades. On a warm day, even in England, the temperature in direct sun is much higher than under the shade of a tree; in the tropics this difference is greater. Not only does continuous forest cover maintain an even temperature at ground level, but even more important it restricts drying out of upper soil levels and maintains a general level of humidity. It’s a reason why trees in cities are becoming more and more important, but for the future of forests it is critical. The forest circulates moisture by transpiration through the leaves of the trees, building up dense clouds which release their moisture as rain. In many areas of tropical forest, the familiar afternoon deluge is a natural part of the cycle. Disruption of this cycle has serious consequences.

Limited breaks in a forest canopy – such as are formed by the fall of individual trees – are repaired fairly rapidly by natural processes, especially in the tropics. Seeds already in the soil germinate, seedlings already present grow faster taking advantage of the increased light, and a minimal new canopy is created within a season. This early repair canopy is often dominated by pioneer tree species, fast growing and relatively short-lived species that give way to the bigger forest trees whose seedlings need nursing (with lower air temperatures and higher humidity) under these early canopy species. Many major forest trees like mahogany cannot cope with high temperatures of direct tropical sun until they are well established as saplings under the shade of these pioneers.

Larger breaks in a forest canopy such as are being created across much of the Amazon, are much more difficult to repair. What has happened in Brazil is that cleared forest areas have become larger and larger, and even where diminishing yields have forced farmers to move on, the forest doesn’t come back. Repairing tropical forest – even where there is a will to do it – is not a simple job. In the late 1980’s I saw successful forest restoration projects in Vietnam. During the American War large areas of forest were destroyed by repeated spraying with defoliants under the trade name Agent Orange. To restore previously forested areas a fast-growing (and nitrogen-fixing) acacia was being planted while seedlings of big dipterocarp trees were being raised under shade in tree nurseries – the seed having been collected direct from trees still standing in undamaged parts of the forest. Once the acacias were well established, creating a provisional canopy, the dipterocarp saplings were planted among them. Where this process had already been in operation for several years a new dipterocarp forest was already becoming established. Saplings of other forest tree species, understory plants and herbs had all started to appear unbidden, their seeds apparently brought in by animals and birds.

When it finally registers that major deforestation has a disastrous effect thousands of miles and several international borders away, perhaps the idea of a regional intervention to protect and restore what has been lost may gain some traction. Urgent action is certainly needed before what many Brazilian scientists have warned may be a ‘tipping point’ in the entire ecosystem. The rights of forests (and the indigenous people who live in them) as legal entities could prevent them from being destroyed, stolen or transformed into farmland. This should be taken seriously and underpinned by international agreement; if rivers can have rights, why not forests?