I'm planning on using mesquite as a nurse plant for a soon-to-be-planted food forest. My question is whether I can coppice each tree branch by branch on a yearly rotation, in order to keep it from totally shading dwarf and semi-dwarf fruittrees, while still reaping the benefit of bean production? At what age does the coppiced branch produce pods (couldn't find that info after a brief search)? For example, if it's three years from coppice to pod from an established root system, my hope would be to have 3 or 6 stems so that I could cut 1 or 2 each year, ensuring annual bean production while decreasing the shade-out concern of the fruit tree, fixing nitrogen, and yielding animal fodder.
I have not managed mesquite specifically for coppice. However, growing up with a yard full of mesquite, I don't remember seeing smaller branches with beans, so I think your guess of 3-6 year old branches bearing beans might be in the ball park. Sorry I can't give a better answer. Hopefully others will chime in
posted 3 years ago
Thanks, Izzy. Since mesquite tends to cast light, dappled shade, I'm wondering more and more whether trees that need full-ish sun could still be productive under the nursing of a full grown mesquite tree. Somehow, I just imagine I'm going to want keep the mesquite at or less than an equivalent height to the citrus, pomegranates, apricots, peaches, etc. when the key food trees are full grown and bearing (10-15 ft or so).
I don't know exactly what coppicing is but I do cut a lot of mesquite for wildlife habitat improvement. Mesquite will not produce beans on new growth and like other trees will grow much denser when pruned. To get the most aggressive growth do your trimming while the trees are in leaves. My trimming is done to provide shelter/cover for wildlife, limbs from already multi-trunked trees are cut so that limbs can be laid to the ground but have enough cadmium layer to keep it alive and send up new growth, single trunked trees are cut off at the first branch to encourage multi branching, then after when the limbs get tall enough to be cut and laid over. For bean growth we allow trees to mature without any trimming or pruning. In my area very few mesquites will have enough shade to cause problems with any other plants unless they're growing very densely, thin all you would need to do is thin them out enough to plant your fruit trees.
posted 3 years ago
Ok! After my first reply I looked the definition of coppicing/pollarding, yes I do both. I've had more trees die from pollarding or coppicing while dormant than while actively growing, but either way absolutely will pizz off a mesquite, cause along with the new aggressive limb growth you'll get highly increased thorn growth.
Scott, do you actually have any hands-on experience yet handling Mesquite? It has really, really nasty thorns. I planted it myself for the opportunity to harvest the nutrient rich pods, but even that feels dangerous considering the thorns on it!
I think the thorniness must depend on the specific type. I climbed in mesquites a ton as a kid, both pruned and unpruned ones, and the sap and ants were a much greater deterance than thorns.
posted 3 years ago
The thorn growth is most aggressive on young trees while they have smooth bark, once they become larger and begin putting on rough bark the thorns are absorbed into the larger growth or begin growing into branches.
Your question about time to pod production from regrowth may be something that you just have to experiment with to figure out yourself. But in general a mesquite tree will begin to produce pods 3 years after planting but it may take 4 or more years to reach full production.
As far as I know a mesquite will grow back from the base if completely cut and will form a thicker shrubbier plant. I don't know how many times you can do this to a mesquite though. Pruning the tree branch by branch as you say that you would like to do on a yearly rotation sounds like a great idea to me. At the World Hunger Relief Farm in Waco leucaena is used in a similar matter in some perennial beds. The prunings can be used as mulch to add more nutrients and nitrogen, and the nitrogen contained in the root-mycorrhizal association beneath the tree are released. According to Bill Mollison there are specific roots directly in relation with specific branches above the tree. Thus when pruning leguminous trees (farmer's trees) a corresponding root will give a sudden release of nitrogen to the plants around it.
In addition to the nitrogen fixing abilities the Mesquites have wide lateral roots which accumulate nutrients from the surrounding soil and deposit the nutrients directly under the tree. Mesquite has been shown to increase N,K,S, Soluble salts, and organic matter directly under the canopy.
The mesquite trees are naturally smaller and provide a nice dappled shade for many plants and does act as a nurse plant in natural environments. I don't know where you are but I am assuming that you live in an arid or semi arid area and it is probably hot. I live in Central Texas and there are many honey mesquites here. Current research has shown that in Texas the sun is so intense that even plants that conventionally are supposed to get full sun actually do better with some shade. This is because there is a cap to a plants photosynthesis capabilities and so after a certain point the plant just can't utilize any for sunlight. So this may just be another bonus depending on where you live.
I plan to implement a similar production system as what you are describing. I recently harvested 150 lbs of honey mesquite pods. Mesquite bread is amazing. I am really looking forward to roasting some of the pods to make some mesquite coffee.