Humboldt Oaks in the Mist

In November 2018 I had a long layover in Bogotá and had enough time for a quick visit to Parque Natural Chicaque, about an hour’s drive from the airport. This is probably the site closest to Bogotá where one can find Quercus humboldtii (Andean oak) growing in natural habitat. I had seen many street trees of that species, but had not yet observed it in the wild. One of the senderos (paths) in the park is called “Bosque de robles” (oak forest), so I was confident I would find what I was looking for. The path is a long loop and for a long stretch there was not an oak to be seen, and I was beginning to wonder whether this would be another instance of fuzzy nomenclature, where “roble” is used to name another tree (e.g., Tabebuia rosea in Panama). However, as I climbed to the highest point of the path, I came across cupules from aborted acorns lying on the floor and then the unmistakable trunks, leaves, and habit of Q. humboldtii. Acorn season was past (July, I was told) and acorns do not linger on the ground as they do in Bogotá: predators swiftly dispose of them. Known predators include a monkey (Alouatta seniculus, Venezuelan red howler), a squirrel (Sciurus granatensis, red-tailed squirrel), a wild pig (Pecari tajacu, collared peccary) and a rodent (Cuniculus taczanowskii, mountain paca). I found very few acorns. And there were very few scattered seedlings to be seen. The trunks of the oak bore an attractive red lichen, which I have not been able to identify.

On one of the tallest oaks, a platform and tree house has been built high in the canopy, 25 meters above the ground. A ladder affixed to the trunk leads up to it; one can spend the night there and also rappel down from it.

I chatted to a park ranger, who told me they identified two types of oaks in the park, roble blanco (white oak) and roble rosado (pink oak), and that the names were based on the color of the heartwood. He also said each type bore acorns of a distinct shape. However, only one native species of oak in Colombia is accepted—roble negro (black oak) is the related Trigonobalanus excelsa. I had already noticed a great variety of acorn shapes in the Q. humboldtii street trees in Bogotá, so this information also made me question whether more than one species have been yoked under this name.

But the payload from my day-trip to Chicaque came later and unexpectedly. As I was climbing back towards the beginning of the path, clouds closed in and mist started to leach light and color out of the forest around me. Then in a clearing I was confronted with the ghostly spectacle of a large oak emerging from the mist, in shades of charcoal and lead, like a life-size silver print.

When I returned to Bogotá I had some time before my flight to revisit some of the places where I had seen oaks. I had previously found fresh acorns in September and October, and in Chicaque, Andean oak acorns ripen in July. Now, in late November, some of the trees in Bogotá had recently dropped acorns. That is a wide window for one species to produce mature fruit in. If it is one species.