In the story “The Man Who Planted Trees,” (1955) by Jean Giono, a Frenchman recounts an unusual experience he had while wandering in a remote region in Provence, in southeastern France, prior to World War I.
In this windswept deserted realm the wayfarer meets an old shepherd who, while his flock is grazing every day, methodically plants oak trees on the barren highlands. Over the shepherd’s lifetime, during which the wanderer stays in close touch with him, the old man replants an entire forest, 33 square kilometers. (It was known the area had been forested in ancient times.)
This act of relentless self-sacrifice over many decades, the storyteller explains, eventually brought back long-abandoned villages to the area.
The animated video of this allegorical tale, narrated by Christopher Plummer, won an Academy Award for Best Animated Film. The quiet shepherd’s name was Elzéard Bouffier. “I never saw him lose heart; nor was he ever deterred,” says the narrator. “And often, God knows, it must have seemed that heaven itself was against him.”
One scene may strike the listener as entirely fanciful, however. In it the narrator stops beside a gurgling stream that had been dry when he first met the shepherd. Over the years the old man’s surrounding plantings had caused it to flow again.
Surely, the viewer might think, this must be sentimental exaggeration: We can imagine a forest’s restoration bringing back fragrances, animals, the sound of breeze rustling leaves, happy children— even a reason for living. But how could a dried-up creek flow again because the surrounding forest has returned?
It turns out this really can happen. In a healthy forest the soil acts as a sponge. Filled with organic matter, leaves and bits of wood and air pockets, the sponge soaks up water then slowly releases it to the aquifer and nearby streams.
But when the trees are cut down and removed a certain amount of the soil washes away in the ensuing rains– the sponge becomes thinner as its most absorbent upper layers are stripped away and the passing of heavy logging equipment crushes the sponge, thinning it even more.
Removal of the protective forest canopy accelerates this process. Without treetops to break their fall raindrops plummet directly onto the exposed soil, causing splash erosion on a large scale. Tree trunks formerly slowed the force of flowing water too and tree roots held the soil. Leaves and litter that had lain on the forest floor, now washed downhill, no longer shield the underlying bare dirt from direct rainfall.
Snowpack formerly melting languidly in shade now vanishes rapidly under direct sunlight. A sudden higher volume of faster-flowing water increases erosion. The soil sponge, now covered with a fine-grained silt deposit, becomes hydrophobic— more impervious to water than before the trees’ removal; this accelerates runoff and lessens the absorption of water into the soil to recharge the subsurface supply.
This cascading effect all carries on until it reaches some equilibrium. Continue to deforest the land long enough and you have the scene depicted at the start of Giono’s story– a desolate country depopulated and forlorn. And dry.
Many places in the world have witnessed this cycle. At least as early as the Bronze Age deforestation of parts of the Mediterranean washed away deep soils and exposed rocky hardpan. Streams that once flowed remain dry some 3000 years later (with help from sheep grazing and such ongoing abuses as the depleted land still may sustain). But restoring forests can reverse this damaging process and, as if miraculously, bring flowing water back again.
The media is full of conservation controversies these days, some involving fights over threatened forestlands. Social media has brought to light some real-world Loraxes like Giono’s. But it might surprise some observers to realize that forest-defense efforts are as much about water as about trees.
We all know about the loss of wildlife and natural splendor that results from deforestation. Less well understood, however, is that most of our water supply comes from forests. With rangelands, forested watersheds are the source of more than 90 percent of California’s annual runoff.
And again groundwater, on which we depend far too heavily these days, is recharged by infiltration.
“I never tried to imagine his frustrations,” the wanderer says of Elzéard Bouffier, “but to achieve such an end he must have had to overcome many obstacles. For such passion to succeed he must surely have fought and conquered despair.”
From now on, with average global surface temperatures rising relentlessly, humanity will increasingly value every water source it can get — whether by restoring it through sustained labor over a lifetime, or better still by preventing the need to restore it in the first place.