Standing trees as building supports?

I am totally new to permies, and the forum, so I hope I am doing this right. We are planning a new natural home, creating a hybrid of many of the techniques and systems out there. But one idea is can you go into a standing forest and choose large trees to use as roof supports and use them without cutting them and digging holes and re- Setting them in concrete. It would require killing the treas so the house did not get filled with saplings and the tree did not grow and lift the roof from the foundation. This might be impossible. But I am hoping someone would have some advise.

Kim,

I'm confused. Are you asking about tree houses or something else?

Hi Kim, welcome to Permies!

But one idea is can you go into a standing forest and choose large trees to use as roof supports and use them without cutting them and digging holes and re- Setting them in concrete.

This part seems reasonable; some large and elaborate treehouses exist, and your design would only be depending on the trees to hold up the roof, so should be no problem, assuming you choose appropriate trees and attachment mechanisms... You'll need to plan for the trees to move when it gets windy, though.

It would require killing the treas so the house did not get filled with saplings and the tree did not grow and lift the roof from the foundation.

This part seems like a *terrible* idea!

If you leave the tree alive and standing, the burden of keeping the tree upright is mostly on the tree. You'd need to make sure you don't damage it with excessive soil compression, poorly considered attachments, overly close bonfires... otherwise, observe and let it do its thing.

If you cut the tree down and use the timber, whether as roundwood or milled, you can within a reasonable degree predict and control the behavior of the timber.

If you kill the tree and leave it standing.. you've taken on the burden of keeping that dead timber upright, and now need to address a whole host of very problematic issues... but you're much less able to predict and control the behavior of the dead tree.

A dead tree left standing is going to come down, sooner or later; the roots will root away, largest to smallest... the bark will harbour swarms of wood-eating decay-accelerating insects and fungi... the canopy ranches above the roof may come crashing down before the tree itself, and will certainly catch the wind and contribute to the chance of the whole tree snapping in twain...

If you're set on using standing trees as part of your structure, I would suggest that you resign yourself to dealing with saplings/branches/the growth of the tree; the alternative you describe sounds a lot harder!

I saw several houses at Yestermorrow in Vermont that were done somewhat like you are suggesting. They don't kill the trees, because they choose species that work alive (I don't know if saplings are a problem with some species). The solid trunks of trees don't grow and move up (or probably that's most species). The parts that grow on a tree are the twigs and leaves and shoots. You've seen bits of fence or signboard engulfed deep into a tree trunk, and they're generally at the original height, right?

Google Yestermorrow, and besides that, I'm sure you can also find hundreds of other beautiful examples of what you're dreaming of.

<Oops, cross posted with a much more informative poster!>

In the species I'm familiar with, if any vertical movement of a given point on the trunk occurs, it must be a very slow process; as Rebecca says, old fences attached to trees are generally still at fence height.

Thing is, you already need to consider that the tree and ground are not fixed relative to one-another... however you go about accommodating wind movement of the tree, this may be enough to accommodate upwards growth if it should occur.

As far as attachment options go, the best method I'm aware of is a Gernier Limb or Treehouse Attachment Bolt... but these are very much Not Cheap:
http://treehouses.com/joomla/index.php/construction/garnier-limb-parts
http://www.treehousesupplies.com/Treehouse_Bolts_s/41.htm

We are not planning a tree house, but a home on the ground. And hope to build almost totally from materials from the land. The trees would would be on the inside of the house and not exposed to weather. I had thought that they would need to be debarked, treated in some way to avoid bugs and in some cases covered and surrounded with straw,cob and lime plaster. I had not thought about the tree roots rotting under the ground. ?? But I am not a builder, woods (woman) and I am also new to natural building. So maybe I need to re-think this whole thing. It seemed counter productive to me somehow to cut the tree, let it fall to the ground. Process it and dig a hole and put it back in the ground. (This is why I am asking advise) thanks so much.

I do totally see that the tree would not lift the house now, makes perfect sense. That part is cleared up.

I suppose Ill continue to study other means of supporting the roof. But I am open for any other suggestions you have.

I also found this image , which seems to have a tree in it.

Those are felled (cut down, dead) trees and limbs which have been peeled but otherwise left in their natural shape. If they were living, they would have to have retained their bark and the external cambium layer which is a living tree's circulatory system.

I believe you can see the cracks in the photo where the trunk has dried out.

ETA: I know a teacher from Yestermorrow and he explained to me his process of touring a property with a client in order to select for harvesting trees that "spoke" to the client in evocative aesthetic ways, but that would also work structurally within the edifice. The edifice is not constructed where the tree is rooted when alive, in most cases.

Don't get me wrong, I love the look and the extra strength of roundwood!

By chopping off the top of the tree you'd address half my concern about decay.


That picture seems to be from articles about the 'Hobbit House' that the Dale family built; a really appealing example. But it doesn't look quite like the pictures on Simon Dale's site, not entirely sure what's up with that...

In any case, on Simon's site there are some sketched 'plans' which mention a damp-proof membrane beneath the entire house, and dry-stone walls supporting the insulation. It's not clear what else the posts are sitting on, perhaps just the lower layer of pallets? In any case, his trees became posts! http://www.simondale.net/plans.htm

A side cut-away from another design is visible here, in this case the posts are on concrete piers: http://www.rrylander.com/


Perhaps there are extremely durable trees in a dry climate that would be suitable for use without the need to cut them down and protect the base from rot... But living in the pacific northwest, I'm used to things rotting pretty quickly, and I don't see any way to protect the roots/base of the tree without removing it from the ground.

Thanks again for all the links and advise. If there are any others feel free to share. We are still open for all natural building techniques and just learning. But there is something so empowering about being able to go onto the land and erect a building from the resources right there. We are SO excited, but really want to do it right. Ill be watching for more comments.

I have seen a few houses made with posts with the bark still on them. It is a terrible nuisance. The bark is constantly catching and tearing clothing, skin, and hair: Especially of guests. There is always a pile of rubble around the base of the posts.

I have seen some houses using live pollarded trees as the main uprights in Bangladesh. The roof was thatch, and the top poked out through the thatch and then branched and grew leaves. I think they kept the tops cut back periodically, perhaps so the shade, etc. didn't make the thatch rot quicker, and to keep heavy branches from falling on it. I suppose some rainwater might find its way down through the roof along the trunk, but since the walls were one thickness of woven split bamboo and the floor was earth, I don't imagine it mattered much. The trees were the four corners and two ridge-poles, and the houses are always built on a raised mound, so the leaks would have been shed away from the center of the structure. It seemed like such a good idea at first glance that I was surprised not to see it more widely used, especially since the common village technique of sticking whole bamboo poles directly in the ground rots out after a few years. It might be because the trees needed to be planted in that pattern, trained to grow straight for a few years before being large enough to use.

Kim: I bet you could get some more specific feedback and suggestions if you provide some background info! Stuff like location, topography, climate, any specific requirements for your dwelling, and resources readily available: building materials, tools/equipment, skills...

A perfectly good design in one location can be a disaster in another; here on the west coast, cob/similar mud-based structures are particularly vulnerable to water damage due to the volume of rainfall. This means you need large overhangs, and some way to avoid constant moisture from rain splashing at the drip line; a local ecovillage uses a stone foundation that rises 2 feet above the ground on external walls.


Alder: Seems like a vastly preferable option vs unprotected posts straight into the ground! A nicely refined version of a basic wilderness shelter design, really... And far lower effort than a foundation etc. As long as you know up-front that you don't mind living with whatever inherent compromises are entailed.

With trees as corner-posts, any leaks down the trunk would be a lot less central and annoying than in a tree-centered design.... if you did want to use a live tree as a central pillar, I would be some sort of collar could be arranged to help seal the gap.


Joseph: Sounds pretty annoying! Plus, in many species of tree gaps behind the bark would make a perfect home for insect pests of all sorts... On the positive side, my cat would be ecstatic about his enormous new scratching post!

Here is a little bio to let you know more about us. I hesitated to have a long winded post. Not knowing what was expected on the forum. But to answer Dillon Nichols question. Scott my husband and i are mid 50's and are 10 year homestead veterans . Although we have worked farms and animals our whole lives. Scott is a woodworker and a chainsaw builder. We built our first homestead cabin out of cord wood. Then added on as the family grew and it ended up being 1900 square feet . Half stick built. But it was awesome. Our children are now girl 18 and boy 16. I have my elderly Mom who is mostly bed fast. (On with the story) We sold our homestead and moved to southwestern KY. It is zone 6 1/2 and tends to be dry. Even during rainy times the underground limestone caverns drain all the water away in a day or two. The ground is red sticky clay. Gets hard as a rock if you don't amend it heavily. We moved to an urban area to be close to my brother and have better health care for my Mom. Plus we were dis satisfied with some of the "mistakes" we had built around us on our first homestead. (Sometimes I wish we had not left our Ohio homestead) BUT,,, we want to get back out on the ground. Everyone is dis-satisfied with urban life and are screaming for, (trees,land,air,wild) BUT,, this time we want to be permaculture, natural building and really start working with nature rather than fight against it like you do on a typical farm. Back to the topic,,,, Scott has a great ability with building, heavy equipment etc,, but he has some pretty saver neck and back trouble and we are pushing years. 52 and 54. The kids can help this time. But we were hoping to find an easier more natural way to get under a roof. Thus my idea of using standing timber as roof supports. A note, we are looking for a 10 or more acre piece of land with at least half woods. But it is imperative to have good solid shelter and level floor for my Mother. We are a multi-generational family as well and our kids have no plan on moving out , but marrying in. so space and privacy is a prime as well, we need to be able to construct solid,durable structures as efficiently as possible. So, I am still hopeful we can (debark, treat secure and otherwise use standing trees as roof supports.) If we can figure out a practical way to do it.

Well, maybe I was wrong about more advice appearing if you gave more details... Having thought about this further, I still think dead standing trees are a bad idea for long term use and for inhabited structures, but am really liking the idea of live trees as supports that are outside the main building envelope, or are supporting outbuildings.

If you do go ahead with the dead, debarked, treated, standing tree, I'd love to hear how you go about it, and how it goes; best of luck!

Hi Kim...welcome...

Sorry that this one slipped by me, yet it seems you have bin well assisted thus far...

I will try to hits some of your questions and forgive me if this is new info.

So, to your main point...

NO...you can not just kill a tree while it stands and use it to build an enduring form of architecture....I would also revisit that trees grow from the top and outwards. They don't "push" anything in any direction....they encapsulate over time...

We are about the same age so admire your drive to build a natural home yourself.. Between you and Scott, and achieving a cordwood cabin, I think there is a good foundation of skills there.

At this point, I can't give much advice other than to suggest always to look to vernacular (indigenous) traditional/natural systems of building for a give region or biome type. There is many forms to chose from

Good luck and keep us all posted on your progress in finding a new homestead...

Regards,

j