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Party at the Oak by the River

October 3, 2019

I am the lucky gal who gets to travel the world saving trees from extinction as part of The Morton Arboretum’s Global Tree Conservation Program. I conduct research that will help land managers and conservationists make the right decisions to protect threatened species. I also work with local collaborators to raise awareness of threats and promote sustainable practices.

Last fall, for example, I was in the Cabo Region in Mexico, the same “Los Cabos” area where people go to party on spring break and drink margaritas. Most people are not aware of a party that happens each November, less than 60 miles north of where the resorts and beaches are located, within the Sierra La Laguna Biosphere Reserve. This party takes place right by the river, under a magnificent Arroyo Oak tree (Quercus brandegeei). Each year, this amazing tree produces thousands of tiny acorns that slowly grow and mature for months. Then, at the end of the rainy season, the acorns ripen and a party like no other begins! Birds of  many species get first dibs while the acorns are still on the branches, while small rodents and even beetles wait eagerly for fruit to fall. Because farm animals roam free in these lands, cows, goats, sheep, and pigs congregate to enjoy the feast. These acorns are an important source of protein for local wildlife and farm animals, and even the ranchers join the party at the oak by the river. They bring buckets to collect the acorns, which they make into a type of coffee or a pudding. 

The Arroyo Oak needs some acorns to be spared, to germinate so that new trees will grow. Most existing trees are hundreds of years old. Moreover, this oak species only occurs in the Cabo Region, which means that if it doesn’t reproduce here, it will go extinct when the old trees die.

This is where I come in. As part of a collaborative project with Mexican scientists, we are conducting research to explore why there is no regeneration happening and to test the effect of farm animal grazing on seedling survival of this rare and endangered oak tree species. It’s possible that climate change and shifting rain patterns could also be impacting these enigmatic trees. The results will help establish guidelines that promote conservation and sustainable use of the Arroyo Oak. In addition, we are collecting acorns and distributing them to botanic gardens to ensure that there are “living collections” of this species throughout Mexico. Hopefully these collaborative efforts will ensure that every year in November, for many years to come, there will be a party at the oak by the river

Silvia Alvarez-Clare, PhD. is a tree conservation ecologist at The Morton Arboretum.

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