Earthworks in high desert around existing trees?

Hey yall, I'm up in Northern Arizona, zone 6b. I just moved here onto a sage and rabbitbrush covered 1acre plateau plot. we have one juniper tree and a few juniper shrub/bushes.

I was hoping to do some small earthworks around the existing brush and tree to support their growth, and start some more native flowers and grasses come spring, just kind of focus on supporting and expanding the areas that already have some growth.

I just dont want to damage the roots and the growth thats already there, its basically flat land, there is a minor slope.
I was thinking of digging down and adding some mulch to create a basin, but i havent seen many examples or found much info yet on doing something like this with already existing trees and brush.  

Would appreciate some thoughts and opinions!

Can I suggest if the plants have done ok without help, maybe its best to leave them alone.
Mulching on top of the existing soil with either organic matter or stones would help if there was ever rain.
But some of these plants get dew etc, so mulch may not work as well.
From caring for junipers
"Junipers do well in northern Arizona with minimal help from us. Fertilize with a low nitrogen fertilizer or a slow release fertilizer in early spring just before growth starts.
Water soil thoroughly before and after applying to prevent burn.
Southwestern soils and water both contain salts, which can accumulate in the root zone over time.
This salt buildup forms where the water stops penetrating.
If you ? sprinkle? [ watering ] plants lightly and frequently, salts will build up in the top layers of soil and damage or kill your plant's roots.
Deep watering? or leaching?prevents this by flushing the salts past the root zone."

I heartily agree with John's suggestion about leaving the junipers alone. It is amazing how well they do on their own in rough conditions. Large swaths of Santa Fe, NM, are in zone 6b and this publication will give you lots of companion planting ideas that may help you achieve your goal of expanding areas that already have some growth:
https://www.ose.state.nm.us/WUC/LearningXeriscape/XeriscapeGuide_ScreenResolution.pdf

I will look into the referenced info. The area I'm in a lot are drying up and dying lately which is why I am thinking of sinking more rainwater when it comes.

Really sorry to hear about the die off, Gio Rivera:
https://www.fs.usda.gov/detail/kaibab/news-events/?cid=FSEPRD906836
Maybe a low area just outside the drip line of the tree will help as you suggested. The publication above offers some guidance to homeowners to help mitigate. Supplemental water plus sloped trenching (earthworks) toward the drip line might help give that tree the 18" it needs. I hope you can save your tree!

Will you create a roof to catch rian?
What level of rain are you getting anyway, I may be able to calculate what would work.

I found this;
Northern Arizona
Total precipitation during a year
Days Place                 Inches          Milli­metres
52 Canyon de Chelly               8.8          222
82 Flagstaff                              20.5        521
64 Grand Canyon Village      15.4        390
47 Page                               6.9         175
53 Pipe Springs Monument 11.4     290
73 Williams                               21.6       549
Which is your location?

Yes, i have a few small rooftops i'll be catching water with to start, but for now i am just looking to do some small earthworks + mulch around the sparse trees that i already have, add some native companion plants come spring.  I'm closest to valle/grand canyon junction, from my research we get around 8.9inches of rain annually.

I was thinking some sort of shallow basin around the drip line. potentially hoping to use them as nursey tree for some pinyon pines and a few other native trees.

Anothewr trick is to build a roof on the ground, so water can be diverted to a tree etc. Even with rocks on it so it does not blow away

Gio, you have been given some good advice.

I would like to suggest that you look at the work of Brad Lancaster:

https://permies.com/wiki/brad-lancaster

https://permies.com/wiki/51855/Rainwater-Harvesting-Drylands-Brad-Lancaster

Here is a thread with a similar question about damaging roots that you might find interesting:

https://permies.com/t/168639/close-tree-line-swale

Best wishes for greening you piece of desert.

with out seeing it ....

How flat is the site?  Is there ANY slope at all?

If there is some slight slope , maybe little boomerang swales?
That way you can "target" specific plants or areas.

If your  site is super flat ....
You can actually slope the valley of the dug out portion to enhance some slope to encourage the water to collect in one spot.
Its a hybrid between a Boomerang + Net-and-Pan + Zia Pit method ....
....you are going to have to create slope so water will run off and collect in one spot.
Then, mulch that area or something.
Does your site have rocks/stones/cobbles?  Use them as mulch.

Rocks do a few things?  
- They as mulch; it always seems to be moist under a rock.
- They are nearly impermeable, so rain sheets right off of them; the shed-rain deposits next to the "mulch".
- Might be some temperature and thermal mass advantages ... dew, etc.

Back to the earth works:
If site is really really flat, the key to digging a water collection ditch, is the original grade must maintain its "flatness" on one side of the collection ditch (where the water will sheet, or flow from).
If you get a monsoon storm or hard rain, and the supposedly "flat" ground starts to sheet, or develop a thin layer of ponding water, it will obviously move into the ditch/lower ground.

If you have enough slope, and are hell bent on "not disturbing roots" .... then soil might be able to be dug up in barren/lifeless spots, and deposited into the boomerang / diversion beam / mini-swale shapes by hand with wheelbarrows and handtools around the target plants

Thank you both I'm going to check out those other threads. I do have both of brads books that I'm currently studying as well, super appreciate the input yall!

Gio, I am attempting basically the same thing. There are lots of juniper and pinyon on our 9 acres. Juniper seems to be struggling less than pinyon. There are many healthy trees and many that are visibly struggling. We are on a a significant slope as well. I picked a struggling tree to experiment on. I figure if my 'help' ends up harming the tree, it might have been on its way out anyway. I definitely disturbed the roots a bit, but pumped some water in to fill the basin at the outset to hopefully offset. Will leave it be from here on out and see what happens.

Hey parker, thanks for the reply + picture, nice basin! Best of luck with your experiment, would be curious to see updates as time goes by.

Very helpful to see your picture Parker. If you are willing to consider another opinion, please consider bringing the water all the way out to the drip line. One thing I have noticed regarding tree wells that focus the water near the trunk instead of out by the drip line of the tree is that the trees are rarely saved. Looking at the tree as though from an aerial view, the place where the rain water drips down the tree canopy and into the soil to nourish the tree is at the outer most ring of the needles. That edge is where the tree takes in water, like the open end of a straw. The interior water collection by the tree trunk cannot take in the water like the drip line.
I highly recommend that you make a ringed trench as your water basin and leave the roots alone in the center and keep that inner area dry. The tree can drink water at the surface of the outer trench. If you have 2 or more trees where the drip lines overlap, make one outer trench that both can share (like an island). All my trees have outward expanding drip lines as they grow. I don’t water at all inside the drip line. The trees that have this drip-line-attention are truly thriving.
From your picture, it looks like the outermost dry wood pieces are at the drip line. That is where I would carefully make a shallow depression to give the thirsty tree a drink. Since the fine young roots may have been cut while digging out the well, perhaps an experiment with another tree using this drip line approach would enable you to compare outcomes.
Good luck and I hope your hard work to help these trees succeeds!

I would echo Margaret's thoughts on the tree wells.

Those are established trees, with roots extending OUT past the drip line of the canopy.

Your site seems like boomerang swales would be a good option.

This is a helpful watering guide from Denver Water

Amy Gardener wrote:Very helpful to see your picture Parker. If you are willing to consider another opinion, please consider bringing the water all the way out to the drip line. One thing I have noticed regarding tree wells that focus the water near the trunk instead of out by the drip line of the tree is that the trees are rarely saved. Looking at the tree as though from an aerial view, the place where the rain water drips down the tree canopy and into the soil to nourish the tree is at the outer most ring of the needles. That edge is where the tree takes in water, like the open end of a straw. The interior water collection by the tree trunk cannot take in the water like the drip line.
I highly recommend that you make a ringed trench as your water basin and leave the roots alone in the center and keep that inner area dry. The tree can drink water at the surface of the outer trench. If you have 2 or more trees where the drip lines overlap, make one outer trench that both can share (like an island). All my trees have outward expanding drip lines as they grow. I don’t water at all inside the drip line. The trees that have this drip-line-attention are truly thriving.
From your picture, it looks like the outermost dry wood pieces are at the drip line. That is where I would carefully make a shallow depression to give the thirsty tree a drink. Since the fine young roots may have been cut while digging out the well, perhaps an experiment with another tree using this drip line approach would enable you to compare outcomes.
Good luck and I hope your hard work to help these trees succeeds!

Thank you for the suggestions, Amy. I will certainly put your advice into practice next time I'm up for digging a basin!

Thank you, Parker, for making this "teachable moment" possible for everyone reading this thread. I can't tell you how many trees I tortured and killed before I learned about the drip line. I'm sure many trees will be saved by this discussion.
Gratefully yours,
Amy

Hi all, I’m a long time lurker here and decided to throw in my 2cents. I have lived here in north eastern AZ my whole life and can say from experience that giving a juniper extra water will almost certainly kill it. A little input goes a long way with these very hardy trees