In a limited area of the Sonoran desert there is a tree called the Ironwood tree. It grows only below 2,500 feet above sea level, but despite its limited range, it is a valuable and important tree to the desert. It can grow to 45 feet in height, providing a 15-degree difference in the heat beyond it and the heat under its shelter.
It creates biodiversity and creates food for the birds that live around it. Doves, quails, and rodents eat the seeds. Deer and sheep eat the foliage within reach.
The seeds grow in pods. The pods are hard and tough. When the pods drop from the tree, they don’t disintegrate. Instead they protect the seed inside. When the seedpod gets rained on, it begins to soften. The fibrous hull opens and the seeds are released. Birds eat them and move them to other locations.
The spreading branches of the Ironwood tree allow other growth below it to thrive. Ground cover keeps what little moisture there is protected. Other sheltered plants grow and provide cover, homes and blossoms for bees, insect, lizards, birds, and coyotes.
Saguaro cacti, which are fragile in the first ten years of their growth, thrive in the
shelter of the Ironwood. Saguaros are opportunistic and often seek nurse trees. Ironwoods are exactly that–they nurse the tender Saguaros and bushes by protecting them beneath their branches. The earth is cooler, damper and richer beneath the tree. The roots fix nitrogen and the other plants, which would starve if they were 100 feet away, thrive.
We all have the opportunity to be nurse trees. We don’t need to do anything else except follow our life purpose. Stand tall. Provide shelter. Stay cool when you want to feel overheated. Provide food with what you grow naturally. Encourage biodiversity. It’s a good life, and it can last 1,500 years.
—Quinn McDonald is a naturalist who learns a lot from walking in the desert. Alone.