Sunday, April 18, 2010

Harming Redwood Roots. From one that has "harmed" many.

I tried to answer this question in the "comment section", but wrote too many words. So, I put it here as a "Post".

"How close can a proposed building foundation typically be to an existing mature redwood tree without harming the tree and it's root system?"

First, you have to convince me that you have a very, very good reason for needing a building there. You should never build ANY kind of a building around a redwood. The redwood always wins!

I know this stuff is boring to the folks that don’t want to know anything about redwoods, but they “know that they love them”. But, please read! You WILL learn something, I promise!

I don't have nearly the experience that some have, but I have experience that not many have. I have cut and fallen redwoods, I have built roads with a Cat through them, I’ve dug out stumps. I’ve split every kind of a redwood split product that can be made out of redwood. I’ve built many structures from redwood. I’ve built many structures near redwoods. I have what is known as “Common Knowledge” about them.

Here's why you will lose if you build around a redwood: The common misconception about a redwood is that it only has a very shallow and weak root system. Nothing can be further from the truth. More later.

Fir trees usually have two major tap roots, that are usually found on the uphill side of them. They go deep down, and they anchor the tree very firmly to the soil. I know this from dynamiting them off of hillsides for road building. I dug a small hole between the roots, placed a small charge, and touched it off. That gave me a burrow between the tap roots, and under the center of the tree. Then I placed a bundle of dynamite under the tree, along with fertilizer and diesel fuel, I back-filled the hole with soil, lit the fuse and ran like hell. The tree would jump out of the ground about a foot. With its tap roots gone, it would fall right over.

Redwoods are not that simple. Even though they have “No tap root” they have dozens to hundreds of what I will call “anchor roots”. The anchor roots extend downward at a 30 to 45 degree angle, if the tree is on flat ground. They seek firm soil and they will extend downward until they reach it. These anchor roots can be found as deep as 12 feet, they quite commonly are found at 10 feet deep. On hillsides these anchor roots can extend almost straight down. That is why you can see redwoods growing above a cut road bank. You wonder how they stay there. I know from digging the stumps out of hillsides that they have the roots that seek the tight soil. In most all cases they have roots that go straight down on the lower side of a steep hillside. That may answer some peoples questions. Redwoods don’t have tap roots, they have MANY very sturdy “anchor roots”.

In combination with the anchor roots the redwoods have thousands of “feeder roots” that seek nutrition for the tree. These roots are very fine. From hair like, to pencil size. These are the roots that you see when you dig around the base of a redwood. These surface roots are what give people the misconception that “the redwood trees only have surface roots”. The feeder roots are very resilient and grow quite rapidly. They grow to where the food, and water is, in a very short time. (I was going to say a heartbeat, but we have enough anthropomorphizing of redwoods. Redwoods are not people, people. It‘s okay to love them, but they don‘t have toes) Redwood's feeder roots grow rapidly in the direction of needed nutrients. People just walk to the grocery store. Redwoods are much more adapted to where they live than we are. If the redwoods were people, I wouldn’t be surprised to find redwood roots coming up in the beer walk-in. They are not people, it does the tree a great disservice to think of them as such, please get real!

As I’m am sure you realize by now, the redwoods don’t make it to be thousands of years old without a sturdy and well adapted, and resilient, root system.

Now, to answer “Anon’s” question: Don’t cut into the plain of a thirty degree angle down from the base of the tree. Because that is the area of the anchor roots. On hillsides measure the angle down from the surface angle and add to it. On a 60 degree hillside you can dig straight down, if you are foolish enough to do that. I have! Stay without of that plain, and the redwood won’t even acknowledge your presence. You will not harm the tree even a speck! But you will be repairing your building a bunch. Don’t do it unless you need the building very badly.

I want to say that everything here is from my own direct knowledge. I have no education to rely on, so I would sincerely appreciate any corrections from the erudite.


J2Bad said...

Thanks for that. I'm trying to make friends with my redwoods, so I'm always glad to learn more about them.

Ernie Branscomb said...

To experience the true love of a redwood tree, you need to walk among them in a true, pre-global-warming, Humboldt county windstorm. You will learn a lot! Guaranteed.

Anon from Yesterday said...

Wow, thanks Ernie! Much appreciated!

Ekovox said...

"Redwoods are not people, people."

That's a pretty good synopsis to this entire situation.

Ben said...

Back about 1977-78, we had a windstorm unlike anything I have seen since. The sky turned green and the wind was so strong it blew the power poles over up at windy gap on the Alderpoint Road.
i was living in a little cabin at Astinsky's (now, once again, the Meadowwood) south of Phillipsville. My girlfriend and I had gone to the movies and so spent much of the storm inside unaware of the gusts. When we got out, the roads were covered with branches and when we got to Astrinsky's all we could see was a pile of branches. The next morning I returned to my cabin to find a redwood limb through the ceiling in my main room. The cabin next door had three but the cabin next to that had five limbs through the roof and one that had also gone through the floor! Three people were in that cabin through the whole thing. No one was hurt but they were absolutely terrified and afraid to leave as the whole area was being showered with branches.
A falling redwood branch is like a huge dart. The foliage acts to cause the limb to fall butt first. Terribly powerful, I still hate to drive through a redwood grove in a strong wind. I had a limb come down near me just a week or two ago.
Redwoods, in their long lives, must survive hundreds of those storms and perhaps they shed their limbs easily to reduce the resistance to the wind and prevent being toppled. I have noticed that the trees in groves support each other and that a road does create a gap that allows the wind to act with greater power on exposed trees. The downed trees at Fish Creek near Phillipsville are an example, though the road has been there for many years, even decades.
I favor the work at Richardson Grove as that stretch is terribly unsafe and the work seems to involve minimal damage. I don't like it that I am so at odds with many of my friends but I think there are bigger environmental fish to fry than the Richardson Grove project.

Mr. Nice said...

Just for hexaploid gymnosperm... atical correctness, Sequoia sempervirens has a fibrous root system. Redwood roots typically do not penetrate the ground further than six to ten feet but the root system can sprawl out one hundred feet or more. The reason why groves of redwood trees can hold it together is the trees interlink fibrous root systems with each other. Redwood trees will grow on a cliff where a doug fir would just topple over simply because they are anchored to other trees. In the case of Richardson Grove with the highway cut straight through the trees, the weak part of that root system is already covered by the road... those road roots are most definitely not what is anchoring those trees and cutting them a bit will not cause them to dry up and fall over. Look at the trees behind the trees next to the road... that is what is keeping the roadside trees up.

This is also why when dumb people plant a single redwood tree on their property it tends to reach out and find nearby structures. Just trying to snuggle up and make friends... not to get all anthropomorphic about them.

I'm okay with the project because I drive on that road all the time and have seen people scrub in the very portion they are adding the turn to. Now, this doesn't usually cause a pileup as SoHum/Northern Mendo drivers are typically better at maneuvering than the Arcata/Eureka metro driving school rejects, but you never know when there is going to be a deadly situation like a Eureka driver heading into a Southern Oregon driver or some such thing.

Ernie Branscomb said...

Mr. Nice, I always like hearing from you because you always seem to be on top of the issues, and you are always, well… so damn nice!

When I started this blog, I promised myself that I would write in terms that I could understand. That is the only way that I can be sure that somebody else might understand it. I know that you were getting a big kick out of using words that I might have to look up, but it confuses people, then I feel obligated to use common terms that people can handle. It’s just as easy to talk about redwood seed groups than to call them Hexaploid Gymnosperms , “Hexaploid Gymnosperms“ are the seed group of Sequoia Sempervirons more commonly, and more to my taste, called a Coast Redwood.

What you call a “fibrous root system” is actually over-simplified, but still confusing. I prefer to call that system,: “feeder roots, that seek nutrition for the tree. These roots are very fine. From hair like, to pencil size.” I go on to explain that there are also “anchor roots”. “The anchor roots extend downward at a 30 to 45 degree angle, if the tree is on flat ground. They seek firm soil and they will extend downward until they reach it.” These anchor roots can be found as deep as 12 feet, they quite commonly are found at 10 feet deep.”

I explained in one of my posts that the redwood leaves at the top of the tree are vastly different from the bottom. So much so that you would have to KNOW that they are from the same tree or you wouldn’t believe it. I can explain why, but for the purpose of this blog we are talking about roots. “Feeder Roots” and “Anchor Roots”, are also as different as the leaves of a redwood tree. Mr. Nice, these are things that I have seen with my own eyes. Big words can’t change that. You are right that redwoods will send out roots to a hundred feet or more. They send these roots out until they find food or moisture. The anchor roots are very real, as anybody knows that has tried to move a stump. They do extend down until they find soil so tight that they can’t grow any more. I’ve seen then as deep as twelve feet. They grow so swallow on tight soil that they may go no deeper than 4 feet, but they ARE there. In soft silty soils they will go way deep. The reason that I know about anchor roots is because I’ve had to dig down to them with a bulldozer blade to cut them before I could move stumps. Dynamite wont work, the only thing that you can do with a redwood stump that is in the way is cut the anchor roots.

Also, the trees behind the redwoods in Richardson Grove are NOT holding the trees in front of them up. There are deep anchor roots under the pavement that hold the tree very tightly. The only reason that I am belaboring this point is because most people know NOTHING about the “Anchor Roots“, and believe that the only thing holding the trees up are a vast tapestry of “fibrous roots. That’s wrong! But, thanks for supporting the realiegnment. And thanks once again for being Nice.

The following is for Mr. Nice only. The rest of you won’t get anything out of it, but it is about the breeding habits of sibling redwoods. It’s X-rated,

By Deborah L Rogers
Coast redwood, Sequoia sempervirens, is a hexaploid gymnosperm of putative autoallopolyploid origin. In this first study of allozymes from the seed tissues of Coast redwood, six enzyme systems were examined in the megagametophyte and embryo tissues of nine control-pollinated (full-sib) families. Megagametophyte segregation patterns reflected considerable within-family segregation and a meiotic process that is consistent with hexasomic segregation. The array of gametic phenotypes observed precludes strictly disomic segregation. Staining intensity of banding patterns was an unreliable indicator of allozyme frequency, and scoring of phenotypes in this study was conducted conservatively. Observations do not refute the long-standing hypothesis of an autoallopolyploid origin.

Mr. Nice said...


For a simple explanation, read this article on redwood trees from 1969

Redwood trees do hold on to each other for stability. It is a proven fact. The best way to kill a redwood tree is to do something above ground. If the project involved removing pieces of the trunks and trying to patch that up with duct tape, I would fully oppose it.

"Observations do not refute the long-standing hypothesis of an autoallopolyploid origin."

This ploidy thing is because the type of genetics redwoods have is extremely rare in nature. Cultivated food crops commonly have oddly arranged genetics like this due to the breeding strategies used in crops. Natural chaos cannot replicate crop breeding due to the whole survival of the fittest thing. The autoallopolyploid deal is just one theory, there are also theories of other prehistoric ancestors and multiple ploidy-related events. My theory is that bigfoot ancestors cultivated redwood trees like hemp hybrids in order to make bigfoot houses and natural evolution has nothing to do with it. This also explains (to me) why redwood trees clone themselves so easily.

Ernie Branscomb said...

Mr. Nice
I enjoyed your link to “Ask Andy” he sounds very knowledgeable about the misconceptions that I talked about. He failed to mention the lower anchor roots are different that the top feeder roots, just like the top limbs and leaves of a redwood are different than the lower limbs and leaves. But, everybody knows about the limbs and leaves, right?

Id rather that you talked to a logger, or road builder, that had dug up a few redwood stumps though. You will find that they are very firmly anchored to the soil. I don't dispute that redwoods have surface feeder roots that spread so far I'm afraid to tell you, because you would probably find that inconceivable also. Some redwoods share the nutrients from a common root system, indeed they are of the same clone genetic stock.

I'm not trying to argue with you, indeed, I share your love of the redwoods. I'm simply trying to share with you that I find incongruities between the “common knowledge” about redwood roots and reality.

I enjoyed the link that you provided. I especially liked to Dagwood Cartoon with him with a pipe in his mouth. Also the Pogo Strip brought back a few memories. Heres a link to your article for others to enjoy.
Ask Andy. About Redwoods


M. D. Vaden said...


""How close can a proposed building foundation typically be to an existing mature redwood tree without harming the tree and it's root system?"

No general answer takes care of that question. It would depend on the age and size of the redwood, and the type of the building. Plus, the condition of the redwood.

My guess is that a building can survive at least 3 centuries near a redwood if it's not put too close, and the tree does not have any large defects in the crown; likely to break and crush the building.

If a building is supported on like pier blocks instead of a continuous foundation trenched through roots, existing redwoods can last decades if not centuries longer.

It is easier to start with a building and plant the redwood next to it, because there are more options for the depth and type of foundation. Roots can only exert a certain amount of pressure. Redwoods can even kill their own tissue due to weight under the oldest of the big redwoods. Redwoods have their limits.

Redwoods and the Achilles Heel

The closeness of a building to redwoods should be based on the size of debris that is likely to fall, or not fall, from the tree. If the trunk and branches are in good shape, and the top can be pruned at 10 year intervals to remove defects, a building could be put 8 to 12 feet from a redwood. With expectation of maybe 50 to 150 years use.

At 20 feet away from a redwood, a building could be expected to last 150 to 300 years if the frame is slightly stronger than normal, and the roof platform is doubled to withstand a few large limbs falling during storms.

No matter how well the building is built though, I would not sleep in it during a storm. Right now, there is a 70 Douglas fir about 10 feet from my office, and I don't stay in it during windstorms over 60 mph winds.


Anonymous said...

I have a question about redwood root shaving. I live on the East Coast in a 100-year-old house. This tree was planted about 50 years ago and is 75 feet tall and about 31/2 feet diameter. It is located about 10 feet from the house. Unfortunately the space between the tree and the house is our driveway and only egress from the property.
The tree roots have now buckled the driveway, raising it 4-8 inches, both splitting the drive and raising it up about 10 inches higher sloping it towards the house. Between the water collections against our structure, damage to our driveway and branches landing on our roof, we feel the tree needs to go.
Our neighbor, upon whose property the tree resides, wants to shave the roots and trim the tree.
While we all love the tree, are we tempting the fates?

Anonymous said...

Nice to have found this guys seem like you know what you're talking about. we just bought a home in the bay area (on the Peninsula) and it comes with a giant redwood in the backyard. I found out that the prior owner planted it 55 years ago and it's now about 120' tall and is about 9 feet from the house. i see it's buckling some of backyard retaining walls and also some of the concrete on the hardscaping and it's canopy is directly over the house...hmmm...what to wife wants to take it down before it does more damage and potentially messes with the foundation over the coming years.

Anonymous said...

Great to see this blog. Another question about Coast Redwood roots: Our leach field is about 50 feet from a redwood we planted 19 years ago. The leach field is uphill on a 12% slope from the redwood, soil is fairly heavy clay. There are two 18-inch oaks and a 10-inch cedar between the redwood and the leach field, a 24-inch ponderosa about 15 feet from the leach field, and various mature oaks surrounding the leach area.

Would the redwood roots be likely to go through the roots of these other trees and reach the leach field in the next 50 years or so? If so, are the roots from this younger tree more likely to cause failure than roots from the pre-existing oak, cedar, or ponderosa that are closer to the leach lines?

Ernie Branscomb said...

Wow Anon, I could only guess on this one... My bet is always on the redwood. Their roots will always seek nutrients and moisture. Too much moisture will drown them, but it sounds to me like you will have a very happy redwood downhill from a septic system.
Most roots will end up in the leach field. Trees and leach don't mix. you will probably have a variety of root problems in your leach lines, including the redwood tree.

deborah said...

interesting thread. i just bought an 82 year old house in La Honda, CA last fall, there are three hugh Coastal Redwood trees close to the house (three ppl could wrap arms around and barely touch fingers)The house was literally built around one, and another is inches from the deck,the third in front is about three feet from the corner. Then there are several smaller trees about. I was considering redoing the roof next year- perhaps I should have it reinforced? The house sits straight and the lower back section is poured concrete. There doesn't seem to be a problem after all these years they are simpatico. but the roof worries me now..... i was sleeping just fine - thanks guys.......

manofflowerz said...

Thank You Earnie! I just found this blog when looking for info about redwoods and if they easily fall over in storms. I have looked a lot of different web-sites and none of them thus far have mentioned "anchor roots." So, I was very glad to learn about this. I have to admit though, that I may have made a mistake in planting these three redwoods. I knew little about the trees at the time and I was collecting California Native trees and shrubs at the time. So naturally I wanted a small grove of redwoods. I love them dearly, but neighbors are a problem, and I mean neighbors who literally know nothing about trees and or nature. Very kind people, but they would be better off living in a "shopping mall." Anyway, my point is not to complain but to share my gratitude to your wealth of knowledge and experience around redwoods.

Anonymous said...

I have 9 redwoods on a slope at the rear of my home. They have been there 22 years. I planted azaleas and rodys as well as perenials under the other drip line on the slope. Is it ok to cut into the small 1/4-1/8 inch surface roots to give my plants breathing room?

Anonymous said...

The drought seems to have hit one or two of our redwoods now with brown tops and isolated brown branches. Does one cut off the brown dead top of the redwood, and prune away the bropwn branches, and just water profusely?

ANy help would be appreciated. (We are in NorCAl)

Rachel Faulkner said...

Hi! So my husband and I just bought a house in central California where the previous owners planted 3 redwood trees around the pool no further than 3 feet back. We took them all down this weekend to prevent damage to the pool, but we are wondering if the root system will continue to thrive and if so, how would you recommend killing the stumps with out digging them out. I am affriad that digging them out so close to a pool will cause more harm than good with so much shifting soil. They were not huge redwoods, probably 15 feet for the smaller one, 35 and 40 feet for the other two. Everything is on flat level ground and we only found one large root on the surface. We cut them flush with the dirt and were planning on laying a weed barrier and covering them with rock. Do you think that will be enough or do we need to do more? Thank you for your time!

Ernie Branscomb said...

It sounds like you are on the right track. You must keep the redwood from gettting any light to kill it. It will probably send out shoots anyway, so keep your eye on it and address any issues that come up,

Anonymous said...

My neighborhood has many redwood trees and my neighbor had four removed last year. Will their roots continue to grow as their stumps are left? The trees were about 50 years old and am not sure if the roots are still growing in my property 10 feet from the stumps.

Dr Elsar Amos Orkan said...

If the roots are in wet earth, they would grow!

Anonymous said...

Hi Ernie, I am digging on one side of a redwood about 10 feet away. I have struck a couple of roots that are 2-3 inches in diameter and about three feet below the base of the tree. Would I be ok in cutting them?