It’s home to volcano rabbits, giant mushrooms and ancient lava fields. It supplies 23 million people with water. Its stunning natural beauty obscures years of power struggles and contradictions.
Welcome to the Bosque de Agua (Water Forest), where everything you thought you knew about how to take care of a forest dissipates with the morning mist.
Planting trees can be bad. Leaving land untouched can be worse. And yes, a healthy forest can be made to thrive smack in the middle of one of the world’s largest urban areas — if the conditions are right.
Last week on the outskirts of Mexico City, some colleagues and I spent half a day following Jürgen Hoth, project director of CI Mexico’s Water Forest Initiative, on a hike through his beloved forest, where he has lived, hiked and studied for the better part of 30 years.
On the slopes of extinct volcanoes, native pine and oak forests and grasslands form an “L” connecting Mexico City, Toluca and Cuernavaca, which together are home to more than 23 million people. These ecosystems filter and store fresh water essential for sustaining these cities — a “free” service that one study found could cost US$ 30 billion to replace.
Despite this critical service, the area is threatened by land conversion into agricultural fields, as well as the steady city growth that Hoth referred to as an “urban tsunami.” (Get a 30-second glimpse at CI’s work in the Water Forest in the video below.)
The intersection of human and nature needs in the Water Forest is so important that two years ago, Conservation International moved its Mexico office here from southern Mexico in order to get more involved. There were already plenty of organizations working on water supply issues in central Mexico, and others focused on the environment — but virtually no one was looking at how they were connected.
As good as it gets
We set off on our hike from Coajomulco, a hillside indigenous village whose residents own the land we planned to cross. This community has a long ancestral tradition of forest stewardship, relying on the woods for charcoal, mushrooms, wild game and other products.
Hoth and Juan Eslava, the president of Coajomulco, acted as our guides. As we stumbled up muddy hillsides and peered into lava caves, Eslava pointed out edible berries, stomping through the thick yellow grass to deter rattlesnakes.
“This is as good as it gets,” Hoth announced as we reached a particularly healthy-looking patch of forest. Sunlight filtered through the pines onto the bunchgrass, which grows in large clumps that shelter the volcano rabbit, the world’s second-smallest rabbit species — and which is found nowhere else on Earth. Cartoon-like red mushrooms emerged from the grass as birds called to each other in the trees overhead.
As Hoth explained, this forest’s story could have been much different.
The domino effect
Enter Desierto de los Leones National Park. Established in 1917, this was Mexico’s first national park, and is only 15 kilometers (9.3 miles) from where we stood.
In the 1970s, air pollution in Mexico City was at its worst; the city had an average of 280 “emergency” air quality days per year. The rain became 1,000 times more acidic than normal, which among other impacts, weakened the park’s oldest trees by removing the soil nutrients.
This created the perfect conditions for bark beetles, which are now devastating pine forests across the western U.S. and Canada. The Mexican government responded by cutting down infested trees, but left a lot of them in the forest to rot.
In 1998, when a massive forest fire tore through the park, it ravaged everything — and killed otherwise fire-resistant pine species — because there was so much accumulated fuel.
Fire plays an important role in the ecological cycle, improving soil and promoting the release of seeds from certain pine species. In this region, fires naturally occur about once a decade. However, due to more than 70 years of forest fire prevention, the park’s trees grew older and weaker, and more dry vegetation debris built up. This created the perfect conditions for a fire to decimate the national park.
“All this was the result of well-intended but ill-conceived forest management measures,” Hoth explained. “And yet a few kilometers away, we’re standing in one of the healthiest fir forests in central Mexico — which local communities have been burning and logging at low intensities for years.
“However, given that these practices take place on protected lands — even if owned by native communities since time immemorial — local people frequently end up in jail for breaking a law that has little to do with nature´s dynamics. We really need to listen to nature and rethink how we prescribe what needs to be done to maintain different ecosystems.”
Start with questions
This idea underlies Hoth’s — and CI’s — basic philosophy for working in the Water Forest: Start by asking the right questions.
Many of the so-called conservation efforts recently undertaken in the region have little basis in science. For example, government authorities have planted many trees on native grassland. Long-term water catchment studies have shown that doing this can reduce the land’s annual water yield by more than 40%. Trees suck up valuable water from the soil, and due to their dense planting, the excessive shade creates “green deserts” where other plants simply can’t grow, such as mosses and lichens whose otherwise dense mats help form the forest’s “sponge” that absorbs and stores water.
Traditional knowledge will be invaluable to setting up an effective forest management plan. The families of many indigenous and local people have spent generations living and working in these forests. It’s a testament to their understanding of the forests’ value that even in these impoverished communities, where landowners could get as much as US$ 3,000 per square meter for selling their land, many owners are refusing to sell.
CI is working to combine its scientific expertise with traditional knowledge to chart a better future for the Water Forest — a future in which communities and governments are able to maintain and improve the natural functioning of this ecosystem while enabling the sustainable use of its resources by the local communities that depend on them.
In Hoth’s words: “Let’s invest in science. Let’s do several years of trials and studies. In the end, we’ll be in a better position to inform policy by not blindly doing things that just seem like they will work.”
Molly Bergen is the senior managing editor of Human Nature. To learn more about the Water Forest’s importance for Mexico City, read this blog from Jürgen Hoth.