The 2008 Mesquite Harvest
September 1, 2008
Containing up to 17% protein, high in the important amino acid lysine, rich in calcium, magnesium, potassium, iron, zinc and water soluble fibers, mesquite pods are a powerhouse of nutrition. Because they produce copious amounts of pods without the need for irrigation, fertilizer, pruning or any other human input, there are few food sources more sustainable than our native mesquite trees. Having said that, it should be pointed out that the reason we now have such a large population of mesquite trees is due to human input – more specifically – white mans input.
For millennia fire swept through much of southern Arizona on an average of about twice per decade. Our native grasses adapted to this onslaught, developing the ability to bounce back quickly after a fire. In short, fire determined that grass would be the climax plant community of much of the 3,000’ to 5,0000’ elevations. Mesquite saplings are not able to withstand the constant onslaught of fire, so for thousands of years mesquite trees have been relegated to areas where fire didn’t often reach. However, given time to become established, mesquite can tolerate fire to some extent and with native animals continually dispersing its seed, mesquite was always able to gain new footholds here and there while losing them elsewhere.
Native Americans understood that grass supports a much wider array of game than mesquite and these folks may have played a role in aiding fires much as native peoples still do in many parts of the world today. Our native Masked Bobwhite quail is a good example of a game species whose population increases after a fire.
In the latter half of the 1800’s, white man came along and threw a monkey wrench into this finely tuned ecosystem in the form of cattle. Cattle were allowed to increase in numbers far greater than the fragile grasslands could tolerate and within a few decades much of the grass was gone (along with countless tons of topsoil), leaving insufficient fuel for its creator. Pressed for food due to lack of their natural food source (grass), cattle began to browse on mesquite pods.
It just so happens that mesquite seeds need to be scarified to germinate. Scarification is botanical lingo referring to the process of etching the hard ectoderm of the seed to allow water to penetrate and cause germination. Mold usually accomplishes this task, but being stepped on by a large animals hoof or rolling down a rushing arroyo can also accomplish etching. It turns out that passing through the digestive system of a cow or bull accomplishes scarification exceedingly well. In fact this ecosystem never saw a more efficient way of distributing mesquite, thanks to the fact that the seeds are passed out inside a pile of perfect growing medium. This – combined with insufficient grass to fuel fires – is how the very animal the ranchers brought here to eat grass are still to this day turning the grasslands into mesquite bosques.
This newly altered ecosystem is more of a curse than a blessing because; native wildlife dependent on vast grasslands are in decline, mesquite taps more groundwater than grass, grass serves to prevent soil erosion better than mesquite, grass slows rainwater runoff better allowing more to soak in and recharge the aquifer, grass is a better soil builder and of course grass supports much more game (another local food source – another column) and a wider array of non-game species.
On the plus side; we get to harvest more mesquite pods. When left with lemons, make lemonade.
Because mesquite trees flower and begin to set pods during the dry months just before the monsoon begins, the setting of pods is highly dependent on winter rains. The springs of 2006 and 2007 saw very few pods due to very dry winters. Although the winter of 2007/2008 was not exceedingly wet, there was sufficient rain to enable a decent pod set this year. Some trees in low lying areas or near the downspout of your rain gutters received enough extra moisture to set heavily.
Pods are ripe when they are easily pulled from the tree. If you have to pull hard enough to bend the branch, its not ready. Like most fruit, the pod will be sweeter and more nutritious when left to ripen on the tree. Look for pods that are not discolored and have no insect damage or bird droppings on them. If the pods have a black mold on them, discard them. These molds may contain carcinogenic aflatoxins. Brown spots are often due to mesquite beetles probing the green pod for juice. These pods will not be as sweet and should be avoided. Before pods can be milled they have to be dry enough to snap crisply when bent. If it has rained recently pods can absorb enough moisture from the air to be too wet to mill, even if they are kept inside. If your freshly harvested pods are not snapping dry, lay them out in the sun on a screen to dry before storing. To avoid rodent and insect damage, store in tightly closed containers.
Bruchid or bean beetles are a major pest on mesquite pods. There are three species in southern Arizona; Stater limbstus, Mimosestes amicus and Mimosestes alkei. The latter two lay eggs on the pod. When the eggs hatch the larvae burrow into the pod with adults emerging through the holes left by the larvae. The former species enters the pod through the burrow left be the latter two and lays eggs directly onto the seed. Many of the pods you harvest will have eggs on them with the larvae doing their thing well after you have put your pods into storage. This is why you may be greeted by hundreds of bruchid beetles when storage containers are opened days or weeks later. For this reason it’s often better to mill earlier rather than later. Contact me at katbambu@hotmail.com for information about milling.
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