Suzanne's Mom's Blog

Photo: The Verge.
Daniel Janzen and Winnie Hallwachs, together with other conservationists, has brought forests back to the Area de Conservación Guanacaste (ACG) in Costa Rica — an area larger than the Hawaiian island of Oahu.   

Costa Rica, a beautiful country, has the right priorities. It has restored its forests and moved to renewable energy. Justine Calma at the Verge writes about the people behind the reforestation efforts and how climate change is starting to make their work more difficult.

“Ecologist Daniel Janzen wades into the field, clutching a walking stick in one hand and a fist full of towering green blades of grass in the other to steady himself. Winnie Hallwachs, also an ecologist and Janzen’s wife, watches him closely, carrying a hat that she hands to him once he stops to explain our whereabouts. 

“Together with other conservationists who have dedicated decades of their lives to this place, the couple has brought forests back to the Area de Conservación Guanacaste (ACG). It’s ​​an astonishing 163,000 hectares [~403,000 acres] of protected landscapes — an area larger than the Hawaiian island of Oahu — where forests have reclaimed farmland in Costa Rica. …

“ACG is a success story, a powerful example of what can happen when humans help forests heal. It’s part of what’s made Costa Rica a destination for ecotourism and the first tropical country in the world to reverse deforestation. But now, the couple’s beloved forest faces a more insidious threat.

“Across the road, the leaves are too perfect. It’s like they’re growing in a greenhouse, Janzen says. There’s an eerie absence among the foliage — although you’d probably also have to be a regular in the forest to notice. …

“There should have been bees, wasps, and moths along our walk, she explains. And plenty of caterpillar ‘houses’ — curled up leaves the critters sew together that eventually become shelter for other insects. …

“The bugs play crucial roles in the forest — from pollinating plants to forming the base of the food chain. Their disappearance is a warning. Climate change has come to the ACG, marking a new, troubling chapter in the park’s comeback story. … What’s happening here in the ACG says a lot about what it takes to revive a forest — especially in a warming world. …

“The dry season is about two months longer than it was when Janzen arrived in the 1960s. Climate change is making seasons more unpredictable and weather more erratic across the planet. …

“María Marta Chavarría, ACG’s field investigation program coordinator … explains it like this, ‘A big rain is the trigger. It’s time! The rainy season is going to start!’ Trees unfurl new leaves. Moths and other insects that eat those leaves emerge. But now, the rains don’t always last. The leaves die and fall. That has ripple effects across the food chain, from the insects that eat the leaves to birds that eat the insects. They perish or move on. And next season, there are fewer pollinators for the plants. ‘The big trigger in the beginning was false,’ Chavarría explains. …

“In 1978, Janzen … recalls in a 2021 paper he and Hallwachs published in the journal PNAS [his front wall was plastered with moths at night]. The title was ‘To us insectometers, it is clear that insect decline in our Costa Rican tropics is real, so let’s be kind to the survivors.’

“That observation in 1978 led the couple to focus their research on caterpillars and their parasites. In 1980, they used light traps to inventory moth species across the country, documenting at least 10,000 species. Since then, however, they’ve seen a steady decline in caterpillars. … 

“Hanging a white sheet and lights at the edge of a cliff overlooking a vast stretch of both old and new-growth forests, they photographed moths that came to rest on the sheet in 1984, 1995, 2007, and 2019. The first photograph is an impressive tapestry of many different winged critters. By 2019, that’s been reduced to a mostly white sheet speckled here and there with far fewer moths. Instead of an intricate tapestry of wings and antennae, the sheet looks more like a blank canvas an artist has only started to splatter with a brush. 

“Hallwachs and Janzen can see the same phenomenon now standing in broad daylight in the forest across from the field. Just because forests have come roaring back across the ACG doesn’t mean the struggle to survive is over. …

” ‘A lot of the reforestation projects are kind of assuming that trees are mechanical objects,’ Hallwachs says. But they don’t stand alone, not in a healthy forest. 

“Merely plant rows of trees, and the result is a tree plantation — not a forest. Bringing back a forest is a much different endeavor. It’s more about restoring relationships — reconnecting remaining forests with land that’s been cleared and nurturing new kinds of connections between people and the land.  

“In ACG’s dry forest, they didn’t have to plant trees by hand. By getting rid of the grass and stopping the fires, they cleared the way for the forest’s return. The first seeds blew in with the wind.

“Hallwachs and Janzen recognize them like old friends — stopping next to a Dalbergia tree that was one of the first to grow where they stomped out the fires. Its seeds are light and flat, allowing them to float on a breeze. When those trees start to grow, they attract animals in search of food or shelter. 

“Janzen measures each animal up by how many seeds they can hold and then spit or defecate onto the forest floor. ‘When you see a bird fly by, what you’re seeing is a tablespoon full of seeds,’ he says. ‘Every deer you see is a liter of seeds.’ ”

More at the Verge, here.