Oak & Pecan Tree Root Systems

[C Scott]

I am searching for info on Texas Live Oak and Pecan Trees root data. This primarily concerns whether they both have deep tap roots and what is the effect on residential foundation structures.

I believe both types have deep tap roots and then the normal radiating surface root zones. Can someone point me to a good reference source?

 

[John Paul Sanborn]

FOr the most part the deep tap root is a myth. Most tree roots exist in the first 8-12 inches of soil. most tap rooted trees will shead the taproot as they mature. Some trees that evolved in savanah environments have a secondary root system that is deeper. It will activate when drought causes the levels of O to rise at those levels. There are cases of some trees putting down sinkers for long distances, but they are following paths of these tow limiting factors.

Roots need both O and H2O to live. the deeper you go the less O there is. So this is the biggest limiting factor. What makes them invade sewers is that they leak O, H2O, and high N wastes.

The biggest problem with foundation failure is the underlaying soil. If it is a dynamic clay that expands ewith hydration and contracts with drying, then tree roots can exaserbat this problem by scavenging mor water in drough periods.

 

[TheTreeSpyder]

In the models presented of late, of the stretched tissues growing as if exercised to provide support as needed in a slow motion self adjusting system of finding path of least werk/most support; it would make sense because out horizontally instead of down would be the most leveraged position of anchoring in all directions supporting both from compression as well as stretching forces.

Straight down root systems woud tip over more easily with high leverage, leaning, shifting C.o.B. and massive weight; stretching the roots right out of the ground easily.

:alien:

 

[DadF]

I dug a 6" dia(nursery standard) pecan tree this spring with a Big John 80" spade. The spades dig a root ball 56" deep. When I tried to raise the tree and rootball out of the ground I just about didn't it out. There was a portion of the tap root sticking out beyond the spades about 2' and the remainder had broken off in the ground. The end of the break was about an inch in dia so you can guess that there was probably another 2-6' of tap root still the ground. With 6' foot of tap root on the spade and who knows how much in the ground I'd have to guess that there was at least a 10' tap root. True Guy the soil was fairly sandy and it was not a mature tree by any means. Happily it still put a normal amount of leaves out this spring and seems to be doing OK so far. I'm keeping my fingers crossed

 

[TREETX]

Pecans are what I would consider tap rooted. Never seen one cause foundation problems. Ash, mulberry, and cottonwood come to mind there.

I would say live oak is not tap rooted. As far as their rooting in central TX, I would say it depends on soil. In clay soils of the blackland prarie to the east, rooting seems to be shallow these trees seem to be much more vulnerable to compaction/construction damage. Those just to the west, in the hill country seem to root pretty deep in the limestone of the Edwards Plateu as well as shallow. I have pushed them with a dozer and the seem shallow but have excavated sites and found roots 12 feet deep. Maybe it is a follow the water thing. In limestone, it is either just running off or percolating down. Anyway, live oak in the limestone is very construction/compaction resistant.

Pecan has no place being in someone's yard. It is a POOR urban lanscape tree. I don't care if it is the state tree. They belong in reprarian zones away fom people. If ya want nuts, head to the grocery store.

.02

 

[Guy Meilleur]

Originally posted by TREETX
Pecan has no place being in someone's yard. It is a POOR urban lanscape tree. .02

In NC pecan is an EXCELLENT landscape tree if it is sited and managed correctly. Yes all trees in the genus Carya tend to develop taproots.

re house foundations, site any tree away from the house to avoid conflicts.

 

[TheTreeSpyder]

Our local pecans strip down so much in the witer and fill so much inn the summer; lending heat and shade at fairly right seasons, that i think they have a good utility to the South, though wouldn't favour up against house.

 

[TREETX]

Compared to all of the GOOD trees out there to plant, why choose a pee-can?

Messy and breaking is what they do.

 

[Guy Meilleur]

Originally posted by TREETX
Compared to all of the GOOD trees out there to plant, why choose a pee-can?Messy and breaking is what they do.

Preventing broken trees is what arborists are supposed to do. Basic reduction cuts on sprawling branches prevents breakage. It's really pretty simple.
Messy? All the leaves shed at the same time, unlike many oaks, etc. Some twigs will shed occasionally, but the customer who complains about that has it pretty good if that's all that's wrong with their yards.
They provide good shade at the right times, good food for very little investment. A great tree for southern exposures, if a competent arborist who is not philosophically opposed to light crown pruning is available every 3-5 years.

 

[TREETX]

Originally posted by Guy Meilleur
Preventing broken trees is what arborists are supposed to do.

Yup, that is why I don't recommend planting pecans.

They are not bad WITH an ARBORIST's attention - making them lighter in the crown. Via many small cuts with a polesaw (figured you would like that Guy).

Too may around here try to make them lighter via just a few cuts with a chainsaw

 

[Guy Meilleur]

Originally posted by TREETX

Too may around here try to make them lighter via just a few cuts with a chainsaw

Any tree can get whacked.
Sounds like a missed educational opportunity. Are there more trees in your area than you can personally do?

 

[DadF]

Hey y'all-sorry for starting this about planting a pecan. There are a couple of things that you have to remember: First is that this is a land grant university and the whole campus is considered a teaching lab for evryone, second is that there are very few pecans in Indiana so when we have a chance to get one we do. At this point on this campus we have one other pecan and a pecan/hickory cross. Not really enough to give most students a fair shake at being exposed to them. Yes I have been where pecans are grown and realize that they are treated much as black walnut and hickories are up here-just another nuisance nut tree when they are in the yard, but they do have their pupose and in some cases can make or break a landscape setting in the proper area. SO to each his own and lets just keep trees growing whenever possible.

 

[Reed]

Ya can teach a pecan to limit it's height and girth. It's one positive use of root girdling when young and easily influenced. There's a couple old timers here in town that have employed "rooting" in yard trees - hybrids that bring top dollar in harvests. I have three Choctaws @ sixteen years only 12 ft in height. The one "free planting" is thirty ft.

That's an interesting graft, the pecan/hickory. I have three surviving Monterey lemon/Rio Grande orange citrus crosses. Highly frost resistant but a tart fruit. Thinking one limb would yield the orange, all fruit bares the effects. Does the hickory reflect in the pecan nut characteristics?

 

[DadF]

It's not a graft. As far as I understand it's an actual hybrid. Don't know all of the history on the tree but imagine I could find out. I do know that the nut production has been sporadic on both of them. This year however the pecan/hickory has had a bumper crop and has caused some sidewalk clearance problems where it's planted at. The nuts look like regular pecans only about twice the size. Haven't cracked any open yet to check the meats but have wondering whether they would be viable seeds. Anyone out there have any thoughts??