Pasture Maintenance - invasive mesquites

I live in Texas where mesquite trees are an invasive problem. I am about to take over management of a small 130ish acre farm with about 80 acres of improved pasture that was planted with native grasses years ago. The problem is that, like most pasture in this area, the mesquites are slowly taking it back over. The last person to manage the land let it slip pretty bad, which is both a blessing and a curse. Most people around here manage with chemicals (or attempt to manage) and the good news is nothing has been sprayed in years. The bad news is that the mesquite trees are taking back over the land and it seems to really be impacting the grasses negatively.

I know mesquite trees are legumes and nitrogen fixers, but they also are competing for limited moisture, blocking sun light, and thick enough in many areas to prevent grazing because they are simply miserable to bump into. I understand that they thrive in many poor soils, which is probably why they are so prolific here. I am hoping to have management over this land for a very long time and want a sustainable, long term approach that is chemical free. I am hopeful that I can improve the soil quality over time and manage things such that the invasive nature of this tree is kept in check... but I am still left with the issue of getting this thick growth in check.

I am leaning towards mechanical thinning with grubbing, raking, reseeding the disturbed areas with native grasses, and then intensive rotational grazing combined with mechanical removal moving forward. I hate removing a tree... but I will still have considerable tree coverage in other areas.

1. Am I missing some benefit of the trees here? Am I wrong to consider them invasive?
2. Any better ideas for getting them under control?
3. Any great ideas for management moving forward?
4. Is there a better permies forum for this post?

I suppose fire is not on the menu for land management in this case. Back before the southwest was turned into cattle country, the grass got high enough before it dried out that it would carry a good hot burn and this kept mesquite mostly in the drainages and gallery forests along watercourses. Overgrazing and displacement of the people who originally lived there interrupted the fire cycle, and mesquite, being the opportunist that it is, took full advantage of the situation.

I don't think it's as much of a bad guy as the old-school ranchers would have us believe. Mesquite has incredibly deep roots, and brings up water from far below the zone where grasses and other plants can tap. Around every mesquite there is a zone of partial shade, nitrogen-rich litter, and higher soil moisture. The trick is balancing the density of trees to the pasture. My experience is SE AZ, where mesquite only achieves shrub size on the uplands and the trees are restricted to the bosques in arroyos and floodplains. I gather that the Texas rainfall patterns mean that you get full size trees with a closed canopy that's tougher to manage.

If I were in your shoes, I'd try coppicing and making biochar. The first round of felling might even produce some marketable timber, and after that if you cut every 3-5 years you'll just have little spindly mini-trunks that are easy to cut and process. The roots would stay in the ground and might even help get the pasture through droughts.

Mesquite is an interesting tree/plant. Yes, it is a legume, yes, it can be a problem if there are too many of them. It is part of the NATURAL landscape. Before you go eliminate ALL of them, if there are too many. I'd like you to observe a few somewhat isolated trees and the vegetation under them compared to the vegetation well away from the trees as the season changes from a wetter period to a drier period. First, compare the quantity of vegetation under the tree vs well away from the tree. Then, note the color of the grass under the tree vs the grass well away from the tree. If I'm correct in what you are seeing (and I've seen photographs/documentation of it) you might be trying to make sense of what you are seeing. I suspect that you may be seeing more grass under the mesquite and that it is greener than the grass well away from the tree. The reason being is that the tree is acting as a hydraulic pump. Mesquite roots are VERY deep. They are ABUNDANT to depths of 45 feet, they are REGULAR/COMMON to depths of 200 feet and have been DOCUMENTED/FOUND at depths over 500 feet [strip mine]. The mesquite trees are taking up water at these great depths and because of 'leaky roots' are releasing this water near the surface where the grasses take advantage of it. Mesquite might compete with water at the surface soil when there is water there, but it also provides water to other, more shallowly rooted plants (forage grasses) when there is no surface water. Control the mesquite numbers, but I wouldn't eliminate ALL of them.

I should have read Phil's post before I wrote what I did.  He is completely right. I added a couple things to look for to prove our point, but the trees aren't as bad as you think.

The only way to control mesquite is to keep the land mowed.

I have notice that land with goats does not have mesquite so my suggestion would be to take Phil's advice to coppice then go with bio-char and then get goats to keep the pasture free of mesquite.

The problem with coppicing in the field is now you’ve left a spike to poke a hole in a tire. Unless you dig around each one and get it below the surface. They make a skid steer attachment that pulls them up that works pretty good. The main reason people hate them is when this happens to your field you can’t cut hay.

Those who say they aren’t that bad tell that to your Texan rancher neighbor lol. Now if your neighbors are hunters they pay no mind.

I suggest the skidsteer attachment then when they come back off of a root piece it’s much easier to deal with.

I think the more accurate term is a pest tree as opposed to invasive.  West Texas Zone 8a is firmly in the historic range of the mesquite.  Here in far southwest Oklahoma we're on the very edge of the northern range.  The tree became invasive during the 1800's when cattle drives carried the beans from south Texas for horse feed.  Or so I've been told.  Cattle are often mentioned as being contributors to the spread, but to my mind horses and wild pigs are more likely culprits as cattle being ruminants chew their food twice.  Goats and sheep can help with control of seedlings.

Thanks to all of you for your responses! I apologize for lagging in mine... I've been out in the field and haven't been in front of a computer. I'll do my best to give a response to everything, but my apologies if I miss something. My head is swirling with a million thoughts and it's hard to get them all on the screen.

You have all given me a lot of things to think about and I really appreciate that!

To Phil: I don't think fire is probably my best bet. We actually have had a bit of rain and the burn ban has been lifted, but its a risky endeavor around here and very few people use controlled burns. I don't think this property would be conducive to that. I have read people have success with that taking care of the new sprouts, but it doesn't tend to kill mature trees. I suspect this is why mesquites used to be better controlled in Texas... they grew large in the riparian areas and could weather fires, but in the open rangeland fires kept them in check. I suppose Judy is correct in stating they are more of a pest than invasive species... though I might argue they are dominating microclimates they used the not be in.

The biggest problem with most of the suggestions made is that any sort of attempt to remove them that leaves the roots in tact, cause them to sprout from the base into a bush like tree that is even worse than before. So I could mulch them or cut them at the ground, but it wouldn't long before I would regret it.

To Mark: I haven't heard anything about leaky roots, and I would be interested to learn more. I assumed and have read that they compete for both deep and shallow water because of their root arrangement. I hadn't read anything about the upper roots distributing water outward. Is this a documented occurrence? It doesn't seem to me that the grasses do better under the trees. I was walking yesterday and would see both extremes... trees where it was remarkably better and trees where it was much worse. I love trees and even mesquites when mature. In places where they are mature and well spaced out it would seem they provide some well needed shade from the Texas sun... this gives some relief to the grass and causes livestock to congregate. If there is one tree in a field it is usually trampled underneath, but if they are spread out it seems to help with that problem. I can observe numerous properties where they are simply left to their own devices and I do believe those properties as a whole are less agriculturally productive that properties where they are managed.

I certainly don't intend to remove them all, nor do I think I could accomplish this if I tried, but I do feel like I need to get them under control if I am going to use the land for much more than hunting. Right now there are areas that are difficult to walk through they are so thick. Interestingly enough, in the riparian area that has mature trees there are very few young ones.

In response to Anne: I have wondered about mowing... the bar ditches here in Texas don't have mesquite and I don't ever see TxDOT spraying anything other than the edges of the shoulders, which is just round up I'm pretty sure. I also read a study that claimed if the new sprouts are mowed between 1-3.5" it effectively kills them, so if I can get them under control twice annual mowing would probably take care of it... not very permaculture-esque, but it would make a big difference. You did mention goats, but my experience has not been that they control them. Perhaps they would eat these new sprouts, and this would be worth looking into, but I have about 40 acres of land that was grazed pretty intensely by goats and the mesquites appear no different than the other 60 acres.

To Joe: I have heard of a lot of people using that attachment. I may give it a whirl. There are thousands of 1-3" trees across about 100 acres of pasture... I may see if I can rent a large tracked skid loader for a week or two and try to remove some of them.

To Judy: I had read the same thing about their spread. It sounds like the pods don't sprout and can remain viable for 20+ years after falling, they only sprout when digested by an animal... the study I read said deer, cows, and coyotes were the main spreaders of the pods in Texas. Coyotes really surprised me! I suspect the reason they are so proliferate in the field is that that animals are eating the pods in the riparian zones, then coming out to graze in the nice grasses. Then with no wildfire pressure and no upper canopy competition, the trees proliferate in the open.

I suppose my situation is no different than any other Texas land-manager. I just struggle because all of the information out there comes from people pretty deep into traditional agriculture methods and, while they still have wonderful contributions, I want to be sure I'm thinking holistically and long-term about the problem. I'm currently leaning toward physical removal of most of the small trees, leaving behind some large mature one as part of the natural landscape, and committing to mowing (or experimenting with a combination of goats and heavy rotational grazing) to keep new sprouts in check.

Blake Dozier wrote:was grazed pretty intensely by goats

How long ago was it when the goats grazed in that area?  It does not take mesquite very long to come back once the goat are taken off or even mowing stopped.

Our homestead had been a hay meadow turned into developed land.  Soon lots of the property had mesquite trees.

We had ten acres, a few cows and had to mow regularly to keep the mesquite trees under control.

My neighbor had horses and lots of mesquite trees.

Judy Bowman wrote:I think the more accurate term is a pest tree as opposed to invasive.  West Texas Zone 8a is firmly in the historic range of the mesquite.  Here in far southwest Oklahoma we're on the very edge of the northern range.  The tree became invasive during the 1800's when cattle drives carried the beans from south Texas for horse feed.  Or so I've been told.  Cattle are often mentioned as being contributors to the spread, but to my mind horses and wild pigs are more likely culprits as cattle being ruminants chew their food twice.  Goats and sheep can help with control of seedlings.

"Pest", "Invasive", "Noxious", "Weed", "Non-native", etc. They all have specific meanings that are different, but I personally don't often try to correct postings. In this case, invasive would be correct as the mesquite was eliminated (at least it sounds like it was) from  the area in question and has "invaded", although likely from a seed bank. You can - and do - have "native" species that invade an area. Native in itself is somewhat a generic term. I have a preference for "endemic" if I'm being particularly specific, although I do use the term "native" frequently.

What time of year do the pods mature? Green Deane writes that people can eat them too. If the pods are still on the trees, you may want to sample them before pulling specific trees. Some trees make better tasting pods, just like some pecans make better tasting nuts.

Joylynn Hardesty wrote:What time of year do the pods mature? Green Deane writes that people can eat them too. If the pods are still on the trees, you may want to sample them before pulling specific trees. Some trees make better tasting pods, just like some pecans make better tasting nuts.

Someone can correct me, but I think June-ish. I've never tried them, but certainly will. I will still have PLENTY of mature trees along a creek bed to satisfy these needs. These things are EVERYWHERE!

Anne Miller wrote:

Blake Dozier wrote:was grazed pretty intensely by goats

How long ago was it when the goats grazed in that area?  It does not take mesquite very long to come back once the goat are taken off or even mowing stopped.

Good question... there probably was a one year period where no goats were on the land, after clearing, before it was grazed steadily again. This would have given space for them to get established. I can definitely run goats on about 40 acres... I'll have some fence improvements for the other 60, but with the cost of remediating mesquite, the fencing expense would be well worth it! I'm going to add this to my high-ranking options for long-term planning.

The goat suggestion had me recalling growing up in Tucson. We had a back section where we kept a few goats when I was a kid (guess whose job was milking) and there were a few mesquites on it. The neighbourhood had been a bosque in pre-settler times, a sort of flat low area where runoff collected after storms. The soil is some of the best in the valley, which led to it being farmed before it was subdivided, and next door there was a massive velvet mesquite with multiple trunks over 50 cm in diameter, and with a spread of at least 20 m before part of it was trimmed for a house addition.

So the back lot had some scrubby mesquites on it, all having sprouted around the time I did. The goats chewed them down to the ground, and they kept resprouting. Natural coppicing at work. One managed to keep a trunk with a strip of bark on it, and I used to wonder if the goats intentionally held off finishing it because it provided a patch of shade. Then when I was a teenager we decided to build a bigger house, so the goats went away. Three of the stunted mesquites were out of the construction footprint, so they started to grow into trees, and I pruned them each to a dominant trunk or two. Thanks to their already-developed root systems, they got big fast and within another few years were providing plenty of shade.

By the time I sold the place nearly twenty years ago, my mesquites had some decent girth at the base and the biggest one out front was 10 m tall with a canopy spread of 15 m...from a starting point in the late '70s of barely up to my knee. Beneath it is a zone of dappled shade and high soil fertility where night-blooming cactus and chiltepins thrive.

Anyway, that's a long-winded tale of how you could reverse the trend by coppicing with goats. The first round will need to be a chainsaw and as low to the ground as you can get without wrecking the chain. Let some goats deal with the shoots that come back. It's a process, like just about any form of land management.

Blake Dozier wrote:
To Mark: I haven't heard anything about leaky roots, and I would be interested to learn more. I assumed and have read that they compete for both deep and shallow water because of their root arrangement. I hadn't read anything about the upper roots distributing water outward. Is this a documented occurrence? It doesn't seem to me that the grasses do better under the trees. I was walking yesterday and would see both extremes... trees where it was remarkably better and trees where it was much worse. I love trees and even mesquites when mature. In places where they are mature and well spaced out it would seem they provide some well needed shade from the Texas sun... this gives some relief to the grass and causes livestock to congregate. If there is one tree in a field it is usually trampled underneath, but if they are spread out it seems to help with that problem. I can observe numerous properties where they are simply left to their own devices and I do believe those properties as a whole are less agriculturally productive that properties where they are managed.

I certainly don't intend to remove them all, nor do I think I could accomplish this if I tried, but I do feel like I need to get them under control if I am going to use the land for much more than hunting. Right now there are areas that are difficult to walk through they are so thick. Interestingly enough, in the riparian area that has mature trees there are very few young ones.

.......

I suppose my situation is no different than any other Texas land-manager. I just struggle because all of the information out there comes from people pretty deep into traditional agriculture methods and, while they still have wonderful contributions, I want to be sure I'm thinking holistically and long-term about the problem. I'm currently leaning toward physical removal of most of the small trees, leaving behind some large mature one as part of the natural landscape, and committing to mowing (or experimenting with a combination of goats and heavy rotational grazing) to keep new sprouts in check.

It is documented, but I can't put my finger on a specific source at the moment. In reference to you seeing "both extremes", I think you have your answer, at least part of it, right here. When you see a single tree in a grazed pasture, it's going to appear 'nuked' under the tree and devoid of vegetation. That is where all the animals go for the tiny bit of shade that is in the pasture. If you only have 1-2 trees in a pasture, don't put your water and mineral right there. What that does is turn that spot into a nutrient sink (all the manure and nitrogen gets deposited here) as well as results in overgrazing at this point with undergrazing the further you get from the tree. Now, if you have several (enough) trees and the pasture isn't overused, that is when you are going to notice more and greener grasses under the mesquite trees. It's going to depend a little on the area you are in as to how pronounced the 'leaky root effect' will be, as well as the season, but it is there/does happen.

One more thing, and think about this, your situation is different from every Texas land manager out there. Also, your neighbor's situation is different from Texas land manager out there. No two situations are the same. They may be similar.

Well, golly gee.  I wasn't being ugly, as I rarely "correct" posts myself.  Since I can only go by "West Texas, zone 8a" which is right smack in the middle of the "historic" range of the honey mesquite I wasn't aware that the tree had been eradicated in the individual's particular area.  It certainly was never eradicated here. Just makin' conversation as I am no expert on anything.  Please pardon my imposition.

Mark Reynolds wrote:

It is documented, but I can't put my finger on a specific source at the moment. In reference to you seeing "both extremes", I think you have your answer, at least part of it, right here. When you see a single tree in a grazed pasture, it's going to appear 'nuked' under the tree and devoid of vegetation. That is where all the animals go for the tiny bit of shade that is in the pasture. If you only have 1-2 trees in a pasture, don't put your water and mineral right there. What that does is turn that spot into a nutrient sink (all the manure and nitrogen gets deposited here) as well as results in overgrazing at this point with undergrazing the further you get from the tree. Now, if you have several (enough) trees and the pasture isn't overused, that is when you are going to notice more and greener grasses under the mesquite trees. It's going to depend a little on the area you are in as to how pronounced the 'leaky root effect' will be, as well as the season, but it is there/does happen.

One more thing, and think about this, your situation is different from every Texas land manager out there. Also, your neighbor's situation is different from Texas land manager out there. No two situations are the same. They may be similar.

I've racked my brain thinking about roots and how that might work. Perhaps I'm not searching the right term, but I'm not finding anything about it. This article is a lengthy one, but it implies that roots change their hydraulic conductivity under drought through various biological means specifically to prevent moisture loss like this (check out figure 2 and surrounding text). I read the first 1/3 and ran out of time, so I skimmed the rest and will come back to it. Maybe there is something about this later in the article. I'll update the thread if I find anything and would love for you to share if you come across any info about it.

How Tree Roots Respond to Drought

I think that much of what you describe is true of the larger, mature mesquites... my shared observations were from immature trees that are 3-10 years old, have trunk diameters of 1-4", and are numbered in the thousands across a 60 acre and 40 acres pasture. I'm not convinced the long-term effects are visible yet as it is hard to find good patterns. I'll keep watching closely and thinking but I do know that I can observe properties in the area that have been cleared then left simply grazed with no mesquite controls for 40-50 years. As a whole, they do not seem healthier. The areas that were never cleared, often closer to creek bed and terrain, do generally seem healthier.

I understand what you mean about no two situations being the same. I am trying to think outside of the box and be deliberate about my decisions and really appreciate the alternative view points from everyone here!

Judy Bowman wrote:Well, golly gee.  I wasn't being ugly, as I rarely "correct" posts myself.  Since I can only go by "West Texas, zone 8a" which is right smack in the middle of the "historic" range of the honey mesquite I wasn't aware that the tree had been eradicated in the individual's particular area.  It certainly was never eradicated here. Just makin' conversation as I am no expert on anything.  Please pardon my imposition.

You weren't ugly at all and your comment made a valid point. I've got to find balance here... to try to eradicate something that belongs here would be an exercise in futility AND simply go against my principles and what is best for the earth. I have to find balance. I do think they are leaching into areas where they don't belong.

It's hard to communicate with a keyboard because the effort required to go from conversational to 'absolutely accurate' in all of our language use is exhausting. I think if we correct too much, it just makes people not want to post, but this wasn't one of those cases. You helped me think better and, also it will help me communicate better as I'm talking to people in the area about our attitude toward mesquites.

Phil Stevens wrote:The goat suggestion had me recalling growing up in Tucson. We had a back section where we kept a few goats when I was a kid (guess whose job was milking) and there were a few mesquites on it. The neighbourhood had been a bosque in pre-settler times, a sort of flat low area where runoff collected after storms. The soil is some of the best in the valley, which led to it being farmed before it was subdivided, and next door there was a massive velvet mesquite with multiple trunks over 50 cm in diameter, and with a spread of at least 20 m before part of it was trimmed for a house addition.

So the back lot had some scrubby mesquites on it, all having sprouted around the time I did. The goats chewed them down to the ground, and they kept resprouting. Natural coppicing at work. One managed to keep a trunk with a strip of bark on it, and I used to wonder if the goats intentionally held off finishing it because it provided a patch of shade. Then when I was a teenager we decided to build a bigger house, so the goats went away. Three of the stunted mesquites were out of the construction footprint, so they started to grow into trees, and I pruned them each to a dominant trunk or two. Thanks to their already-developed root systems, they got big fast and within another few years were providing plenty of shade.

By the time I sold the place nearly twenty years ago, my mesquites had some decent girth at the base and the biggest one out front was 10 m tall with a canopy spread of 15 m...from a starting point in the late '70s of barely up to my knee. Beneath it is a zone of dappled shade and high soil fertility where night-blooming cactus and chiltepins thrive.

Anyway, that's a long-winded tale of how you could reverse the trend by coppicing with goats. The first round will need to be a chainsaw and as low to the ground as you can get without wrecking the chain. Let some goats deal with the shoots that come back. It's a process, like just about any form of land management.

I LOVE that you have this experience to share. Exactly the type of wisdom I was hoping for. I do still think I need to remove some of them, simply because of the density, but I think once I get them to a reasonable level (maybe a more natural one), this is a wonderful longterm plan for creating a beautiful, functional, healthy pasture.

Blake Dozier wrote:

Mark Reynolds wrote:

It is documented, but I can't put my finger on a specific source at the moment. In reference to you seeing "both extremes", I think you have your answer, at least part of it, right here. When you see a single tree in a grazed pasture, it's going to appear 'nuked' under the tree and devoid of vegetation. That is where all the animals go for the tiny bit of shade that is in the pasture. If you only have 1-2 trees in a pasture, don't put your water and mineral right there. What that does is turn that spot into a nutrient sink (all the manure and nitrogen gets deposited here) as well as results in overgrazing at this point with undergrazing the further you get from the tree. Now, if you have several (enough) trees and the pasture isn't overused, that is when you are going to notice more and greener grasses under the mesquite trees. It's going to depend a little on the area you are in as to how pronounced the 'leaky root effect' will be, as well as the season, but it is there/does happen.

One more thing, and think about this, your situation is different from every Texas land manager out there. Also, your neighbor's situation is different from Texas land manager out there. No two situations are the same. They may be similar.

I've racked my brain thinking about roots and how that might work. Perhaps I'm not searching the right term, but I'm not finding anything about it. This article is a lengthy one, but it implies that roots change their hydraulic conductivity under drought through various biological means specifically to prevent moisture loss like this (check out figure 2 and surrounding text). I read the first 1/3 and ran out of time, so I skimmed the rest and will come back to it. Maybe there is something about this later in the article. I'll update the thread if I find anything and would love for you to share if you come across any info about it.

How Tree Roots Respond to Drought

I think that much of what you describe is true of the larger, mature mesquites... my shared observations were from immature trees that are 3-10 years old, have trunk diameters of 1-4", and are numbered in the thousands across a 60 acre and 40 acres pasture. I'm not convinced the long-term effects are visible yet as it is hard to find good patterns. I'll keep watching closely and thinking but I do know that I can observe properties in the area that have been cleared then left simply grazed with no mesquite controls for 40-50 years. As a whole, they do not seem healthier. The areas that were never cleared, often closer to creek bed and terrain, do generally seem healthier.

I understand what you mean about no two situations being the same. I am trying to think outside of the box and be deliberate about my decisions and really appreciate the alternative view points from everyone here!

I'm looking and can't find quite what I'm looking for, but here are two terms that give a glimpse of what I'm talking about. "Root exudation" and "guttation".  I know guttation is a process occurring in leaves and not specifically roots, but when you couple that with root exudation and the process seen there, that serves to partially explain my "leaky roots" observation.  

Mark Reynolds wrote:
I'm looking and can't find quite what I'm looking for, but here are two terms that give a glimpse of what I'm talking about. "Root exudation" and "guttation".  I know guttation is a process occurring in leaves and not specifically roots, but when you couple that with root exudation and the process seen there, that serves to partially explain my "leaky roots" observation.  

This wikipedia article on Root Exudates is interesting.

It doesn't sound like it refers to water being released, but a chemical mixture that manipulates the environment directly around them root zone. It would be fascinating to learn how these chemicals interact with the other plant roots in the area and if it is symbiotic or parasitic. Perhaps there are some benefits.

While all of this is interesting and worth exploring, I have to admit that I'm not convinced that the mesquite trees are capable of bringing groundwater up and making it available for grasses. I think it is more likely they are depleting water from both the deep reservoirs and the shallower subsurface soils. They do provide some shade from the hot Texas sun and it seems this would help with evaporative losses.


Speaking of the Texas sun... I'm off to go spend some time in it. The high is upper 80s today, so it feels like winter here! Looking forward to checking in on other comments tonight.

Blake Dozier wrote:

Mark Reynolds wrote:
I'm looking and can't find quite what I'm looking for, but here are two terms that give a glimpse of what I'm talking about. "Root exudation" and "guttation".  I know guttation is a process occurring in leaves and not specifically roots, but when you couple that with root exudation and the process seen there, that serves to partially explain my "leaky roots" observation.  

This wikipedia article on Root Exudates is interesting.

It doesn't sound like it refers to water being released, but a chemical mixture that manipulates the environment directly around them root zone. It would be fascinating to learn how these chemicals interact with the other plant roots in the area and if it is symbiotic or parasitic. Perhaps there are some benefits.

While all of this is interesting and worth exploring, I have to admit that I'm not convinced that the mesquite trees are capable of bringing groundwater up and making it available for grasses. I think it is more likely they are depleting water from both the deep reservoirs and the shallower subsurface soils. They do provide some shade from the hot Texas sun and it seems this would help with evaporative losses.


Speaking of the Texas sun... I'm off to go spend some time in it. The high is upper 80s today, so it feels like winter here! Looking forward to checking in on other comments tonight.

Found it! Well, not the mesquite pictures, but the exact process I am talking about. It even has a couple references.

https://nph.onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2011.04039.x

It's possibly a bit on the 'grandiose' side as to the effects, but it outlines the process and what I was describing with an explanation.

The accepted term for this process, (It's not 'leaky roots') is Hydraulic Redistribution.

Hydraulic redistribution (HR) is the passive movement of water between different soil parts via plant root systems, driven by water potential gradients in the soil–plant interface.

Many suggested biochar but maybe a wood chipper might turn them into something that will hold water and make soil better.
Doesn't tell you how to get rid of them but how to use them when they are removed.
Biochar can be some work to set up compared to a chipper.

If not, mesquite wood chips are used for BBQ flavor:
https://www.fireandflavor.com/products/fire-flavor-mesquite-smoking-chips-2lb-bag?srsltid=AfmBOoreeb7l0FZFZa3P9dWOvXUB95v8w_FwOOG-Svzz08eCkRJPxOXO
$7 for 2 lbs. with free shipping but the price varies.
https://www.firewoodnm.com/oldwoodshop/Mesquite-grilling-smoking-chips-and-chunks-12lb-bag-p103651769
8.25 for 12.5 lbs.

Mark Reynolds wrote:

Found it! Well, not the mesquite pictures, but the exact process I am talking about. It even has a couple references.

https://nph.onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2011.04039.x

It's possibly a bit on the 'grandiose' side as to the effects, but it outlines the process and what I was describing with an explanation.

The accepted term for this process, (It's not 'leaky roots') is Hydraulic Redistribution.

Hydraulic redistribution (HR) is the passive movement of water between different soil parts via plant root systems, driven by water potential gradients in the soil–plant interface.

This is fascinating! I really appreciate you taking the time to find the source... I love learning about things like this!

It sounds like it happens at night. In line with my application, it does mention, toward the end of the article, studies with trees and grasses. It appears they believe that the day-time competition for moisture typically outweighs the benefits of nighttime redistribution. Here is an excerpt:

Deep-rooted species may shed water overnight through HR, potentially benefiting other species, but they also compete with their neighbours for water during the daytime. Ludwig et al. (2004) reported an intense competition for water between Acacia tortilis and three grass species in its understorey. Grasses effectively took up water redistributed by A. tortilis but when tree roots were experimentally removed, preventing access to redistributed water by grasses, the biomass of the latter was greater. Thus, although grasses effectively took up redistributed water, competition between tree and grasses outweighed the potential positive effect of HR. Other studies using grass species have reported similar results (Table 2). However, in mesic ecosystems where water is not as limiting, positive effects have been reported (Dawson, 1993). Grass species usually have shallow root systems (Schenk & Jackson, 2002a) and a great capacity to extract soil water, which makes them great competitors, especially in dry ecosystems where water sources are scarce (Armas & Pugnaire, 2011). In association with a species engaged in HR, the amount of water redistributed may not be enough to meet the grass requirements, and depletion of water by the nurse during daytime would exert a greater negative effect on the grass. In this case, competition would be the predominant outcome of the interaction (Ludwig et al., 2004). On the other hand, grasses usually senesce when soil water potential becomes low and HR may benefit grass species by lengthening the period before soil moisture depletion and senescence occurs (Meinzer et al., 2004), although direct evidence of this effect is scarce (Hirota et al., 2004).

I thought that last sentence was pretty interesting... implying the book might not be closed. Isn't it crazy how much we know and how it just leads us to see how much we still don't! Haha.

Thank you for sharing this and helping grow my knowledge and understanding! Its got me wondering how fast the tap root on a mesquite tree grows and how soon it could potentially do something like this.

craig howard wrote:Many suggested biochar but maybe a wood chipper might turn them into something that will hold water and make soil better.
Doesn't tell you how to get rid of them but how to use them when they are removed.
Biochar can be some work to set up compared to a chipper.

If not, mesquite wood chips are used for BBQ flavor:
https://www.fireandflavor.com/products/fire-flavor-mesquite-smoking-chips-2lb-bag?srsltid=AfmBOoreeb7l0FZFZa3P9dWOvXUB95v8w_FwOOG-Svzz08eCkRJPxOXO
$7 for 2 lbs. with free shipping but the price varies.
https://www.firewoodnm.com/oldwoodshop/Mesquite-grilling-smoking-chips-and-chunks-12lb-bag-p103651769
8.25 for 12.5 lbs.

There was a guy in this area for a while that would remove old mesquite growth at a discounted rate and they made smoker pellets out of them! Chips are a good idea... then I could mulch with them. Most of what I am removing will be too small for people to buy them to cook with or burn as firewood, but I hadn't thought about chips being able to be shipped. That's a good idea! I might even have potential access to a chipper, though the volume I have to do would be pretty substantial. Most of the guys around here rake them into a big pile and leave them.

I had wondered about some hugelkulture in the pasture. It would give some terrain, some microclimates and be a way to handle the trees in bulk (it would also mean the bits of dirt I didn't get out wouldn't cause problems).

craig howard wrote:Many suggested biochar but maybe a wood chipper might turn them into something that will hold water and make soil better.
Doesn't tell you how to get rid of them but how to use them when they are removed.
Biochar can be some work to set up compared to a chipper.

Something tells me you may not have tried putting mesquite through a chipper :-)  Making biochar from it can be as simple as piling it up in a pit or trench, lighting it on fire, and putting it out before it all turns to ash.

And in terms of holding water and making soil better, you're going to have a hard time getting more bang for the buck than biochar.

Phil Stevens wrote: Something tells me you may not have tried putting mesquite through a chipper :-)  Making biochar from it can be as simple as piling it up in a pit or trench, lighting it on fire, and putting it out before it all turns to ash.

And in terms of holding water and making soil better, you're going to have a hard time getting more bang for the buck than biochar.

Mesquite would be pretty rough on a chipper. These are young, so I think that would help... but still, it's a pretty stout wood.

I don't want to take up too much of your time, Phil, but could you expand a little more on the biochar idea? I'd have to be very careful with fire, but if its something I could do on site after raking the mesquite into a pile I might could swing it. Say I dug a few trenches, pushed the limbs in, lit them on fire... could I just snuff them out with backfill after burning for a bit? Would I then leave it or spread it out over the field? How would this compare to, say, low Hugelkulture beds (or some crude form of it) that weren't used for veggies but just bermed up in the pasture to grow native grasses and slow down water flow?

A trench or pit burn is the lowest cost way of making a decent quantity of high-quality biochar. You could even just do a top-lit pile, but your yield will be lower and it will pose a bit more of a risk to surrounding vegetation.

First, you dig your hole. Ideally, the sides will be angled about 60-70 degrees from the surface plane. Make it big enough to accommodate branches without cutting, in order to save yourself work and double handling. Make an initial pile of small-diameter branches with a kindling bundle on top. Light the bundle and let the pile start burning from the top down. When it's fully aflame, start putting on more branches, a few at a time.

The feeding rate is determined by watching the fire. You want hot flames all across the top and no visible smoke above. The flame cap is keeping oxygen from turning the embers all the way into ash, and at the same time it's burning up all the volatiles and particulates coming off. If the flames die down, you'll see ash start to form. This is a cue to add more wood, but not too much at once...overfueling can lead to excess smoke by either cooling the active combustion zone, or by overrunning the available oxygen.

If you do get smoke, the colour is telling you which type of overfueling event is happening. White smoke is unburned volatiles from cooling the flames, while black smoke (soot) is a hot fire limited by oxygen. Both modes can be fixed by backing off and waiting, but with cold overfueling I like to goose the flame cap back into action with fine, dry fuels. In your situation I would recommend having a pile of dry yucca leaves...here I use tī kouka (cabbage tree) which is a relative. Dry grass or twigs also work well.

Once you get into the rhythm of tending your fire, that's what you do until you run out of branches. Or daylight. Or patience. I usually set aside four hours to do a burn. When you're done, just push the pile of dirt over the top and tamp it down well. You could douse it with water, but that will take a lot and I'm guessing you have better things to do with it. Wait at least a week before uncovering, two if you can stand the suspense. Otherwise there's a very good chance it will relight itself as soon as air hits it.

Now you've got your basic biochar. The remaining step is to inoculate it with some good microbial life. Lots of ways to do this, from mixing with compost or animal manure, peeing on it, diverting greywater through it, or feeding it to livestock. The latter method is great because they also do the work of spreading on the land. Otherwise, you can just mix it into the soil where you want it, or leave in on top and let hooves and time work it into the topsoil.

Blake, I agree, they are often where they don't belong.  My place has some good examples.  Looking out the back door there is 160 acres that was formerly in cotton, thankfully now in CRP.  It looks like it should.  There is mostly native grass, remnants of two old shelter belts, and along areas that drain there is a nice mix of a few mesquite, hackberry and native plum.  Looking out the front there is 160 acres that had cattle running on it for many years.  Unfortunately we tend to overgraze here so the grass is out of balance and the mesquite's are thick.  I see acreages like this often and would dearly love to see them go to goats.  30 years ago we brought the first sheep to Greer County since the turn of the century.  That ran on a native grass pasture that had been cleared of mesquite.  It stayed cleared.  When we got out of the business there were horses put on it.  Once again, the mesquites are thick.  So, yea, balance is the key.  Ranchers here seem to be moving from spraying to having them dug.  There are people who provide that service.  Sometimes they burn them, but often just leave brush piles.  I like seeing this because it provides wildlife habitat.  Surprisingly, they do break down.