The Mesquite Bosque
An artist's rendering of forest at the foothills of the mountains
Tumacácori's mesquite bosque
How It Was
The mesquite's history and value to desert dwellers goes far back in time. Mesquite bosques (Spanish for small forests) reach their greatest development near desert rivers or where their long roots can reach ground water. This rich woodland plant community on the floodplain of the river provided the mission community with wood, medicine, and foods that were essential to life.
The tiny mesquite flowers, rich sources of pollen and nectar for wildlife, are crowded onto long spikes called catkins. Although the principal bloom normally occurs in spring after the winter rainy season, a second bloom of lesser intensity may occur in response to the summer monsoon rains.
When fertilized, the flowers form long green fruits that resemble string beans. These grow and mature through the summer months. The ripe beans are tan or streaked with red, and are sweet. A second harvest of mesquite beans is usually possible in the fall as a result of the summer bloom; this is why you sometimes see mesquite beans persisting on some trees well into winter.
The beans can be eaten at all stages of their growth. They were an important food for the O'odham, who ate them as a vegetable when green, and ground the pods into flour when ripe. They are favored by many animals, including hares, pocket mice, kangaroo rats, pack rats, and javelinas. Small bruchid beetles lay their eggs on mesquite beans so that the larva can bore through the pod and into the seed, where they pupate. The mature beetle then eats its way out of the seed and pod, leaving the little holes so often seen on mesquite beans.
(text adapted from Ruth Greenhouse, Desert Botanical Garden
How It Is Now
The term mesquite bosque describes a closed canopy woodland dominated by mesquite trees on river flood plains. It is now a rare ecological community due to wood cutting, land use for development, and water pumping for human use, livestock grazing, and agriculture. Mesquite trees depend on the availability of ground water within a certain distance below the surface of the landscape in order to grow to heights sufficient to create a closed canopy.
Last updated: July 23, 2020