Cutting Large Pine Tree Root

[Virraddon]

So this summer, I finally got around to putting in the stairs at the back of my property to lead up from the access road to my house. In doing so, I cut a large root from the ground. This seemed sensible at the time, but now it's keeping me up nights. (I'm completely ignorant when it comes to things like this, and the idea only occurred to me later.)

Some background: we're in the San Bernardino mountains in Southern California, sitting mostly on decomposed granite. We're at about 6000' and the woods here are fairly heavy (though we've had a drought for the last several years, of course). My yard is studded with about a dozen large pines (all Jeffrey or crossbred Jeffrey-ponderosas, I think), all well more than 80' tall.

The particular pine next to my stairs is about 2 1/2 - 3' in diameter and at least 100' tall. It's at the top of a small north-facing slope, and I cut into the hillside next to it (to install a set of brick stairs). Most of the branches are on the northern side as well, as the south side has a couple of slightly smaller trees hemming it in.

The root I was about 10" in diameter and was healthy. It was about 2' below the surface and the cut is about 3' from the trunk. In the last six months, the tree hasn't shown any signs of instability, and we've been through some heavy rains and pretty fierce windstorms.

So the question, finally: should I be concerned that taking out this one large root is going to cause this grand old tree to fall over? There are a couple of houses (one mine, one my neighbor's) that it could reach were it to come down.

Thanks.

 

[mike-ology]

Dear Virraddon,

I probably won't be the only one to recommend that you should consider hiring an well respected certified or consulting arborist to come out and have a look at the tree/property. What you did sounds like it could be a severe problem for the tree. There are exceptions to every rule, but removing a ten inch root from within 3 feet of a very large tree, located very close to your house, could have been a bad and possibly expensive decision.
In short, you should be concerned about safety for the property. It's good that you're asking. Do you know any local consultants? I mention it because you will probably want an objective, no conflict-of-interest consultation, rather than bids to remove if it is not a hazard. You might consider a TRAQ qualified tree risk assessor. But you should get someone qualified, someone you trust out there without hesitation.

Mike

 

[JeffGu]

I do landscaping/hardscaping and treework, and sometimes we have to deal with roots. I can attest to many species tolerating losing large roots this way without any noticeable ill effects, even many years later. However, I've never had to do this to a root quite that big, and never to a pine tree. I think Mike has given the best advice... start looking for a qualified risk assessor. From what you've said, I don't think it's going to topple over anytime soon, but better safe than sorry!

 

[Westboastfaller]

I am a wildlife DTA (Danger Tree Assessor) under Work Safe BC with a wildland fire module as well as Harvesting and Silviculcure module.

Our scale in the work force consists of "levels of disturbance" from: very low risk (VLR) to Level of Disturbance 4 (LOD 4)
Work Zones suck as living quarters, helli pads or the use of a medium or larger in work area as well as staging areas all fall into LOD 4

Now we have classes of deterioration. A class 1 conifer is a perfectly healthy tree: rated safe.
class 2 with no structural defects is safe.
(Example: live tree with top snapped off)
Class three conifer with no structural defects is safe (class three is dead but still has the fines on it/ needle tits present.

In your case an Assessor would mark it D for Dangerous.
I'm "search and destroy" I'm easy on spray paint and ribbon.

If it was a level 2/3 disturbance which is
most common in my experience and hardest to assess for. They say for pine greater than 25% of the lateral roots, rotton, damaged or gone is safe
providing there is no sign of root mat pull or recent lean to the work area.

A lot of trees may have 5 or 6 lateral roots

There is never a higher concern than there is when in close proximity to housing.

On a professional end I would be bound to my guidelines.

I can't use words like: many times, most often and usually. It dosen't mean a thing as its got to be 100%
That tree is already compensating for the lose and may eventually be stronger than before. I can guarantee that but I can't guarantee it won't blow down in the mean time.

You could possibly have a few stafety lines on it if you want that tree. I would have slack on them so it keeps compensating then eventually I'd take them down. That's what I'd likely do for myself.

Looking for root mat lift.
If the ground appears higher on one side, look for movment ('breathing') in the root area in the wind.

Good luck
Maybe saftey lines are an option. Seek out a pro. I'm only in Grade four.

 

[BC WetCoast]

The wildlife/danger tree assessment was never very viable in urban settings. TRACE (tree risk assessment certification was developed by the PNW ISA in conjunction with Worksafe BC) was developed. , which has now evolved into TRAQ and used across Canada and the US.

No assessor can guarantee 100% that a tree is safe or hazardous. The best you can do is assess the probability the tree or part of the tree will fail. The probability of a failure (whole tree or part) is going to vary according the species of tree, agent of failure (rot vs mechanical breakage) or past treatments on the tree.

For the OP, there are a number of factors to consider.
Species, ponderosa pines are one of the few species that has a tap root, depending whether your soil is deep enough.
A tree is more secure on coarse textured soils than fine textured soils.
Is there surface bedrock that the tree roots have to grow around? Is there sufficient soil around the tree for roots.
How dense is the canopy?

An assessor should give you a rating on how hazardous the tree is. It becomes your (the OP) job to determine what your level of risk tolerance is. Remember that we cannot eliminate all risk from our lives, so we accept a certain level of risk everyday (consider driving to work every day).

If you decide to accept the risk, then the most effective way to reduce the probability of failure would be to thin out the crown.

 

[Virraddon]

Thanks for the advice, all. I certainly do want to have an assessor come out and take a look--I just wasn't certain if this is something I needed someone to come out for, say, yesterday, or something that could be done when the weather clears a bit.

The ground is very coarse, being mostly decomposed granite; we run into roots just about everywhere we dig and it usually has to be done with a pickaxe. I don't know about bedrock, but we have no large dense stones anywhere nearby and we've never struck the bedrock. The canopy is relatively open--there are two other comparable trees nearby, and another dozen within a hundred feet in many directions, but the ground is clear.

This has been a great help.

 

[Westboastfaller]

Good post ^^^ lol..OK then a 'SAFE' tree.
No we can't guarantee a tree that fits the guidelines for 'safe' under any training. 'Safe 'healthy tree's uproot all the time. I don't have to have that on my shoulders. I only have to assess to the best of my knowledge and to an LOD 4 at best.

You definitely have to look at it all,
My decision may be based on my visual surroundings which would be patterns I see in my site assessment overview, some of which you covered.
It's just all trends and sitistics and it dosen't matter IMHO where I assess. My skills are sharp. Much of It is transferable between controlling my environment as a Faller and assessing for the saftey of others.
I definitely have a lot of respect for the ISA at this time. That certainly is their jurisdiction. They hold the power. The DTA has three different modules. The third is for Parks & Rec.
Like you say there is always a risk.
DTA's on fires allow 50% of the cross cut section missing up to 50% of the roots on gone an a LOD 3 with conifers.

Well if I was to start a 25% undercut and they traced it back to me I would be begging for my livelihood back no doubt.

 

[Woody912]

I saw this done to a hardwood( maple) the limbs on the root side died. Pines have much stronger espinastic (sp) control so maybe this does not apply to them

 

[Westboastfaller]

Now just concentrating on the specs here this time around as I didn't give any consideration to them yet.

On the positive side, if the trees have been in open areas for a long time especially on a hill they should have a very good root system. Do you see trees in the area of the same species blown over?
(Evidenced of past tree failure) we look at everything and answer the question marks. If the tree had shelter with other trees surrounding them and recent stand history has changed then the tree likley wouldn't stand a chance. Looking at height Diameter ratio > 100
Basically that's a ft dia to 100 ft high.
Your tree is approx at 2'6" - 3' Dia, putting it between 42&33 to 1 so that's good. It's definitely not high water table or saturated soils. Dosen't sound like fine textured soils/ restricted rooting depth?
Things that may need to be tested. Shallow soils Topography? Yes it's on a hill. evidenced of significant wind throws.
I see that as a Positive thing. It's been tested. I assessed 8OO km of Seismic line in 70 days two winters ago I showed up right after a rare 130 km (78 MPH ) January storm, that made me think realistically and wavered from the guidelines.
Crown conditions:

Stress cone crop
Thinning foliage
Chlorosis
rownded crown.
small live crown <20% or hight
Branch weight to one side?
*if the tree stood alone that would concern me more. The other tree that is close to it, thats described as a little smaller must have the common inner branches mainly missing due to been out in the open caused by a healthy outer crown free of competition. I would assume with out seeing pics, this is usually the case and may often be limb tied If the tree is healthy otherwise then it is only 'competition that kills the crown' at that age. I'n a sense it's much like one tree with a full crown and remove anyone of them and another will be unstable. You did keep that root about three feet long and that still offers a lot of support for both sides. Pictures would be nice. I would strap then together for extra precautions is what I'm thinking is the safest solution.
It's likley more dangerous to take that one than leave them all. Basically cut them all or leave them all.
Again pictures would be great.
Take some of this info and run it by a pro in your area. I also believe it's a far better scenario that the removel was on the north side and not the 'outer side' as that's its 'ancher side' both tree's will have a strong outside and a weak inside. Assuming the wind isn't almost always from one Direction?

Its all about exposure, wind makes weight and weigh makes strength.