At the southernmost end of the Americas, one family of trees has staked its claim amidst fierce winds and a tough climate: the southern beeches. This tree family shares its roots not with the beeches of North America, but rather with a group of species found primarily in New Zealand and Australia, dating back from the era of the Gondwana Supercontinent. In the forests of the Patagonia National Park project, the most common member of the southern beech family is the lenga (Nothofagus pumilio).
A deciduous tree, the lenga reaches an average of 30 meters (~100 feet) in height. Its leaves are small and green with sharp, toothed leaf-margins. Come autumn, the lenga puts on a striking color show across the mountainsides. As the weather begins to chill in April, its leaves change from green into a fiery array of yellows, oranges and reds.
To make some family generalizations: the lenga is a mountain tree, while its closest relative, the nirre (Nothofagus antarctica), is a river tree. The lenga thrives from the warmer, dry boundaries of the steppe all the way up to the timberline, at around 2000m of elevation. Along the exposed subalpine slopes that mark the upper reaches of its habitable range, the lenga tree sometimes grows into wild, twisted, wind-blown shapes. These formations are called krumholz, German for “twisted wood.” The nirre looks similar to the lenga, but smaller and shrubbier. It tends to grow along waterways, and in lower lying lands, but can also grow alongside lenga on the mountain slopes.
The southern beech forests are home to a broad range of species, making the lenga hum with life from its roots up to the green canopy above. The lenga is quite often found draped in tufts of Old Man’s Beard (Usnea barbata), a lichen whose name aptly describes its hairy, bedraggled look. As many as 93 plants, 85 lichens and similar numbers of mosses have been identified in the lenga forests. Beneath their boughs, lengas also provide shelter for some of the most charismatic and ecologically significant animal species that inhabit the region, including the Magellanic Woodpecker, the Culpeo fox, and the highly endangered huemul deer. The huemul sometimes browses on lenga, but also eats, and obtains key nutrients, from the shrubs, grasses, and flowers that thrive in this forest’s understory.
These thriving biotic communities have long been under attack by human development. Myriad hillsides in this region are strewn with the fallen trunks of burned southern beech trees. When the Chilean government sought to settle the remote Aysen Region in the mid-20th century, it offered land titles to anyone who “improved” land—and burning to clear land for agriculture seemed an “improvement.” Many of these hastily-set fires escaped control and burned steep hillsides, which settlers had no plans of ranching. Sadly, these forests have recovered slowly, given the short growing season and slow decomposition. Southern beech forests in this area have evolved without any natural forest fires, making human-set fires particularly disruptive.
Here in the future Patagonia National Park, the lenga forests will be permanently protected, providing an ongoing safe harbor for all species that live beneath the forest canopy. Removing the livestock from this former ranchland has reduced the pressure on the remaining forest areas, where cattled used to crowd out species such as the huemul. Moreover, we are actively restoring damaged forests in key areas. And the Visitor Center and Museum, currently under construction, will tell the story of the lost lenga forests, and potential for regeneration, to the park’s thousands of visitors, in hopes that they consider their own impacts on the earth’s remaining forests.