Chilean mesquite pruning question

[Osprey101]

Apologies in advance for the total noob question; I'm a homeowner, but I'm also a caver with climbing experience. Not that that makes me an arborist, but I simply can't afford a service to come out and do the work I need done. I'm a plant biologist by day, but these trees have me in a real bind.

We have two overgrown Chilean hybrid mesquite trees in the yard, here in metro Phoenix. One "pruned" itself a year and a half ago in a storm, and I was able to finish part of the job over time. The second one is more problematic, and that's where I could use some help.

The tree is mature, as large as I've seen mesquite get out here. The tree is leaning west, over the block wall, and I've tried to take out what limbs I can here and there to lighten the wind load as well as the weight.

My questions are:

1) How does one even decide what to prune on a mesquite this size? I'm concerned about taking out too much, but that's pure nonsense, I know. I just don't know how the pros decide what to remove; is it just a matter of opening it up by removing the limbs that are dead and "in the way," or is there some better approach?

2) The crown has done one of those things where it's starting to arch; rather than growing straight up, the crown is headed west, over the wall and putting more strain on the roots. Is there something I can do (top it?), or should I just let it go?

I really try to keep these two under control, but it's a losing battle. They're pushing 15 years in the ground here, and the previous homeowner watered them too much. Here's the tree in question; this is facing west, hopefully with enough of the block wall to give a scale.

 

[Bermie]

A general reply for you, since I don't have experience with your specific tree species, so I don't know if it is a high value tree or a pest, however some basic principles apply to every tree.

This tree would benefit from the attention of a professional to do a thin and reduction prune. I know you said you can't afford it, but how important is this tree to the aesthetics of your property, what would its absence or having substandard work done on it mean?

If the electrics in your house were outdated and causing concern for future damage, would you do it yourself, get a willing friend on the weekend or hire a professional?
Do your budget, get some estimates and let a pro do it. Be there for the operation and have them describe what they are doing, for your own knowledge! Consider it $'s spent towards the value of your property and your own education!

The 'landscape' including trees is often an intangible asset to any property, very difficult to assign a $ value but many properties benefit from the beauty and shade value, windbreak, noise reduction values of trees.

Your points:

1 - Yes, you CAN take too much off a tree at one time, to much removing of photosynthetic material will lead to excessive resprouting as the tree attemps to compensate for the loss of 'food production'...this can deplete stored energy reserves and lead to eventual decline as the tree attempts to restore the mass:energy ratio...again, a pro will know how to assess the tree, for species, growth habit, tolerance of pruning and provide a work plan to reach your desired outcome for the tree.

2. Excessive lean, weight on one side / stress on roots. While this is a concern, most trees adapt to overall stresses by the 'axiom of uniform stress', where stress is applied in one area the tree will adapt by laying down reaction wood in other areas to counter that stress, unless there has been outside intervention that alters the natural process, construction, mechanical damage, soil compaction, poor pruning etc. trees generally remain very stable overall. Visual cues such as fresh bark cracks or compression, lifting roots, bulges in the trunk or branches would indicate stresses that are not being compensated for.

Again, a pro can assess weight and lean in context of the trees location and surrounding infrastructure, and carry out weight reduction, thinning and pruning that will stabilize the tree sufficiently for its given location, and give you an idea of what will be involved for its ongoing maintenance.

Good luck...I like your tree!

 

[BC WetCoast]

Start with the basics
- dead and diseased branches
- broken branches
- crossing/rubbing branches
- branches growing into the middle of the canopy
- balance and shape

 

[Osprey101]

Thanks, all. Our mesquites survived the massive recent storms without losing a single branch- an oddity in the neighborhood, it seems. I still need to get up there and cut out a bunch of stuff- thanks for the guidelines, BC.

I do agree I should call in an expert, but funds are mighty tight right now. We bought this house well before the housing boom (before prices got insane), and we have no luxuries, really- no cable TV, the car's been paid for for ten years now, heck- we don't even own cell phones.

It'll all get done eventually. And for those of you that don't think the desert can grow "real" trees, well- I would have agreed with that statement a few years back. But these mesquites can throw 2-3 feet of branches in a month during the summer. They're really weeds, and the growth they produce is pretty soft; the first time a stiff breeze comes along, branches snap. Looks like we got off lucky this past week!

Thanks again, all.