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In a near future setting (technology has progressed more or less at the current pace) would it be possible to have a genetically modified tree that has both the density and textile strength of Schinopsis_brasiliensis (see also this answer in regard to it's exceptional qualities Creating wood actually as hard as granite) AND fast growing properties like Paulownia (one of the fastest growing hardwoods)?

Note that:

Paulownia grown on plantations generally has widely spaced growth rings, meaning that it is soft and of little value; wood with close growth rings is harder and of higher value.[citation needed] Paulownia is extremely fast growing; up to 20 feet in one year when young. Some species of plantation Paulownia can be harvested for saw timber in as little as five years.

Would 'fast growing' necessarily be mutually exclusive with 'extremely dense and with high bending strength' for a tree? Generally fast growing hardwoods have large rings. This leads to lower density and tensile weakness. On the contrary trees (even of the same species) with thinner rings are denser, with higher tensile strength but grow more slowly, usually due to less favourable climatic conditions.

The purpose of the company engineering the tree is to have a naturally fast growing hardwood that can sustain construction. To be shaped while growing. Imagine treehouses, bridges, monuments. Living architecture in general but brought more to the extreme (the living tree structure) and to a bigger scale than the examples in the link.
Economic sustainability is not an issue.
The purpose is not to have wood as construction material like with this method: Wood made denser and stronger. The tree must be alive and growing while being shaped.
Merging of trees, even of different species is fine. Grafting is also appliable. But the main structure of the tree should be of the genetically modified species (of which the company holds the rights).

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  • $\begingroup$ Would super-bamboo be acceptable instead? $\endgroup$ Feb 24 at 11:34
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    $\begingroup$ @StarfishPrime I'd rather stick with hardwoods. Let's say super-bamboo has been already registered by another company ^.^ $\endgroup$ Feb 24 at 11:45
  • $\begingroup$ that's a shame as there is already technology to shape living bamboo. $\endgroup$
    – Jasen
    Feb 24 at 12:09
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    $\begingroup$ Your use of "hardwood" is confusing. Do you perhaps mean wood from deciduous trees, as opposed to wood from conifers? Because some deciduous trees, like your paulownia example, or cottonwoods, have very soft wood, while some conifers have quite hard wood. $\endgroup$
    – jamesqf
    Feb 24 at 17:38
  • $\begingroup$ @jamesqf I apologize for the confusion. Let's stick with Oxford's definition: "Hardwood - the wood from a broadleaved tree (such as oak, ash, or beech) as distinguished from that of conifers." So yes, some of them can be soft. The GM tree am looking after should be fast growing but also dense, with high tensile, compression and bending strength. Like Schinopsis. Basically am ruling out bamboos, conifers, etc. $\endgroup$ Feb 24 at 17:44
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So here's the thing: all trees of a given size, under similar environmental conditions, can lay down about the same amount of material in a season. They're all basically leveraging the same building blocks in the form of their chloroplasts, and whilst there are small variations in photosynthetic efficiencies under some circumstances, there's no such thing as a substantially superior photosynthesiser, and that's what you'd need to solve your particular requirements.

Given your near future tech level, I'm going to assume that creating a better chloroplast remains science fiction, so something else has to be done instead.

You might consider some way of artificially nourishing the tree... force feeding it, effectively, and giving it the leafy equivalent of growth hormones. This sounds like something that would go alongside shaping and guiding living wood to form the sort of structures you want. By combining artificially increasing growth rates with a way to suppress the tree's tendency to lay down lower density wood during the summer seasons might enable you to force-grow dense timber. This seems likely to be quite a complex and expensive sort of task, with special groves of engineering trees surrounded by their support infrastructure and nutrient tanks which would have to keep operating for decades, most likely.

Do note that this sort of living structure will not have the same sort of density as the compressed would you linked above; the tree has its own internal infrastructure in the form of vascular tissues that are necessarily low density in order to let stuff through.


As an alternative though, consider a different kind of architecture that doesn't rely so much on heavy, solid structures.

I've always been a fan of banyan trees... they've an interesting structure that involves column-like aerial roots, and they can start out life as an epiphyte that grows over an existing tree and effectively smothers and crushes it. They can grow extremely large... here's a photo of the Great Banyan:

Great Banyan

This is a single tree with the largest canopy of any tree in the world at ~1.5 hectares. With a bit of persuasion, you could see how the horizontal branches and vertical prop roots could be bent into a useful shape upon which lightweight tensile structures could be built. Sure, it wouldn't have much in common with modern architecture, but why tie yourself to the same old designs as everyone else? Treehouses are awesome, fact.

Consider, for example, the living root bridges that can be found in northeast India. They are often made from roots of ficus trees, not necessarily the same as the great banyan above, but similar. The roots are guided and plaited an interwoven with other structural materials over a period of years to construct things like this:

Living root bridge

Suitable domestication and genetic engineering of appropriate species could allow for large and elaborate living structures to be created, on and around existing architecture or trees that could be used as scaffolding.

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  • $\begingroup$ This looks promising. The Rangthylliang bridge was also in the link I posted about Living Architecture. I wonder if with a proper frame to bring water and nourishment higher in the frame it would be possible to grow also vertically way beyond the limits of a single tree. I agree with using multiple lighter structures as opposed to massive ones. And definitely the resulting architecture SHOULD be an entirely new design, otherwise... what's the point? :) $\endgroup$ Feb 24 at 18:04
  • $\begingroup$ @DuncanDrake if you have a suitable framework on which to support the tree and provide water for the roots above ground level, you could go all Hanging Gardens though the whole ensemble isn't living architecture itself. There's probably some interesting potential for hillside and cliffside developments in there, given a water source at the top... $\endgroup$ Feb 24 at 18:17
  • $\begingroup$ I was thinking more of a frame to guide the twigs of the developing structure, bring nutrients and water. Not as support. The whole living building should be capable of supporting itself. The frame could be made using another plant. $\endgroup$ Feb 24 at 22:11
  • $\begingroup$ Re: "there's no such thing as a substantially superior photosynthesiser": I'm a bit surprised by this statement -- I thought that C₄ carbon fixation was more efficient than C₃, provided there's sufficient light and heat? (The OP mentions Paulownia, which is one of the few tree genera using C₄.) $\endgroup$
    – ruakh
    Feb 24 at 22:41
  • $\begingroup$ Re "...a single tree with the largest canopy of any tree in the world at ~1.5 hectares...": Not. "Pando", an aspen tree in Utah, covers 43.6 hectares (per Wikipedia: en.wikipedia.org/wiki/Pando_(tree) ) Like the banyan, it has multiple trunks connected by a single root system. $\endgroup$
    – jamesqf
    Feb 25 at 3:36
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The hard part of wood is the darker part of the rings -- this is the slower growth wood, that's higher in lignin. The faster a tree grows, the more of the light colored, low density, softer wood is laid down between the dark, dense, hard rings.

Therefore, in general, a tree that grows very fast produces softer wood (balsa is a prime example -- balsa trees grow to harvest size in about five years, and produce wood so soft and light it's pretty nearly useless for anything other than flotation, naturally grown insulation, and model airplane frames).

Trees that produce very hard wood, by contrast (teak, ironwood and so forth) are generally very slow growing, laying down a minimum of the light, soft wood between dark, hard rings.

While it is surely possible to engineer (or selectively breed) trees for rapid growth, doing so will defeat the purpose of producing stronger, heavier wood (though you will get better strength to weight ratio, as is the case with fast-growing poplar, birch, and softwood species like fir and spruce).

To get the kind of wood you seem to be after, you'd need to engineer your tree to continuously grow the high density wood, rather than lay down softer material and harder material in cycles (usually a year due to seasonal variations). This might be managed to give faster growth than natural teak or ironwood, but will unavoidably be slower growing than poplars farmed for pulp or paulownia for saw timber.

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  • $\begingroup$ Could we not engineer it so that it'll grow in phases even in fast growth periods? Grow quick, enter the slow period automatically (but grow it fast!) or woodification or something similar. Rince and repeat per so much growth. $\endgroup$
    – Trioxidane
    Feb 24 at 12:23
  • $\begingroup$ Vegetable life doesn't have this level of time awareness. You could play with artificial light, temperature, and "rainfall" to simulate seasons more rapidly than one cycle a year, but you'll still get soft wood during the rapid growth part of the cycle. $\endgroup$
    – Zeiss Ikon
    Feb 24 at 14:20
  • $\begingroup$ What about just some hormones on a cycle that determine in a growing season how long rapid growth is allowed before slow growth is forced for some time? $\endgroup$
    – Trioxidane
    Feb 24 at 15:40
  • $\begingroup$ That's not genetic modification, that's real-time management -- and I'd question whether it would be cost effective. Not to mention the question of how to administer hormones to a tree. $\endgroup$
    – Zeiss Ikon
    Feb 24 at 15:48
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    $\begingroup$ Not necessarily. We have different hormonal systems in place compared to other species. This is eventually determined by DNA and gene expression. Doesn't seem too far fetched to add/change DNA to a plant that introduces hormonal cycles and desired growth. Just hellishly complex and currently far in the future (if ever). $\endgroup$
    – Trioxidane
    Feb 24 at 15:52
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Would 'fast growing' necessarily be mutually exclusive with 'extremely dense and with high bending strength' for a tree?

Short answer: yes, the faster a tree grows, the weaker the wood. There will always be a tradeoff between how fast you want it to grow and how hard you want it to be (the tree).

Long answer: just about nothing is truly impossible in biology. The growth rates and hardness of woods we see today are purely due to evolution in the wild and some selection from humans over the past few centuries. With sufficient genetic manipulation, you could force a tree to grow fast and hard, but it would require enormous amounts of energy to sustain, and I doubt you'd ever really obtain the speed of growth of Paulownia with the hardness of Schinopsis.

Another angle of attack that you could take that could work better: the (very heavily genetically engineered) tree grows fast, and is shapeable into a house or whatever structure you want, but is quite weak. But once you expose it to certain conditions (very cold temperatures, or high wind, or perhaps a parasite), the bark toughens immensely, creating a very rigid structure. This would mean that this particular tree is now stuck in this conformation, so you would no longer be able to grow an additional story to your tree apartment block. This is still very much the realm of pure theory, but it is more biologically plausible and doesn't run head first into hardness/speed of growth tradeoff.

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Chronomutant

Occasionally, trees will produce more than one ring in a year. The extra ring is called a false ring and it can be the result of drought stress in the middle of a growing season.

https://www.fs.fed.us/rm/highelevationwhitepines/Education/science-inquire.htm

Your fast growing trees have optimal conditions all the time. But their clock has been hacked - they are genetically engineered to think the hard times come every 2 weeks. They power down. Winter lasts 2 days and then they power back up. These trees lay down dozens of hard rings in a growing season.

They do not grow as fast as their unmodified relatives who lay down lots of soft white wood, but they are still fast.

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Duncan wood is produce from the Duncanoia tree. This is a heavily genetically engineered wood with the following modifications:

  • The entire photosynthesis cycle was heavily modified, bringing light conversion efficiency up from the paltry few percent to almost 70% in full sunlight. Researchers continue to tweak this, and have been getting about 1% improvement per decade now.

  • The tree has much larger sap vessels. This is needed to transport the sugars through out the growing parts of the tree.

  • Stomata have permeable membranes that allow CO2 to pass inward, but reduce water traveling outward.

  • The tree has highly alkaline sap. This disolves silicon dioxide out of native rock and sand. The dissolved silica forms a complex silicon oxide cellulose crosslinked complex. This complex accounts for the strength of Duncan Wood. In most varieties, pore space in the heart wood is filled with this material too, but it's not as well organized. Researchers would like to either eliminate this, resulting in lower density wood, or get it organized, giving better strength for the same cross section.

Downsides:

  • Temperature regulation is more difficult for the Duncanoia tree. Optimum growth is restricted to temperatures from about 12C to 25C, with photosynthesis dropping rapidly on either side. This is another subject to much ongoing reseearch.

  • Because the leaves are far more efficient, Dunconia is best grown in an atmosphere with 4-6% CO2. On most planets this results in the tree being only grown under large domes, where the air can be enriched with CO2 from degrading compost or fossil fuels. Grown in the open it is only a few times more efficient than other common trees. Dunconia is widely used as a mid stage plant in terraforming high CO2 worlds, as well as ones with active volcanos.

  • Duncanonia needs a continuous supply of silicates to grow strong wood. Optimum tree plantations need to be on a substrate is is mostly sand so that as the tree 'mines' the sand the whole area settles evenly. Drainage can be a problem as plantations sink.

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  • $\begingroup$ A very interesting answer! Is alkaline sap a real thing? The downsides should be tweaked for this tree to be employed in the setting (that takes place on Earth). May be planted within arcologies but CO2 requirements need some further gene working. $\endgroup$ Feb 24 at 20:08
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Short answer is No

At least not to any significant degree

The other answers have already said THAT you get hard and soft rings, but not WHY. Hard rings come from having less growth of vascular tissues. While the tree is growing quickly it needs a lot of hollow vascular tissue to pump water and nutrients between the leaves and roots. So, if a tree is growing quickly, its wood must be soft, but if it is growing slowly, its wood may be hard. This excludes the possibility of a hard wood coming from a fast growing tree.

When doing your research it is also important to know that hardwood is not the same as a hard wood. Hardwood trees are any species of deciduous tree and softwood refers to any species of coniferous trees, but many hardwoods are actually very soft.

You can see HERE that Paulownia is in fact one of the softest woods in the world.

Use Industrial Engineering instead of Genetic Engineering

While biology may be limited in how hard it can grow wood, there are certain man-made materials derived from wood that are extraordinarily hard. Nanocellulose can be produced by extracting and crystalizing the cellulose from the wood of any plant into one of the toughest materials known to man. Because the production of Nanocellulose begins with the pulverisation of the wood, the amount of starting vascular tissue is irrelevant.

Fast growing woods may be less dense, but because they have more vascular space, they can put on mass faster than a slow growing harder wood. So, you can grow softwoods quickly, then process them into a substance that is even tougher than the hardest of hardwoods.

While this may be a less glamorous solution than growable buildings, it is much more practical for a number of reasons:

Many countries do not allow you to own the intellectual rights to a plant, and those that do tend to come with a lot of caveats. It is much easier to patent a material produced from a plant, than a plant itself.

Living buildings are a bad business model. When you buy land, you want to wait the least amount of time possible to have a usable building on it, and once you have a building, you want it to be permanent. As a person who wants to buy a building, you want the growing to happen offsite so you don't have to wait 10+ years to have a place to work/live, and once you have it, you want it to not be growing or else the rooms will be changing shapes and sizes causing flat surfaces to tilt, and furniture to have to be regularly replaced as the sizes of rooms change.

It is also much more precise. Manufactured materials can be molded into any shape you need down to the millimeter. While you can get certain plants to follow along the shape of a superstructure, plant growth is not very precise. Even genetic clones tend to have a lot of variance; so, your floors will never be level, your doorways never uniform. These little details can change the value of a building by a very large margin.

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Yes and no

Not going to an extensive answer here, but it is an interesting topic, so 2 cents on it

As already mentioned energy inflow to trees is one of the limiting factors for the growth, and artificial nourishment may improve the situation. However, it does not necessarily mean a 10fold increase, as the internal structure of a tree is a limiting factor again.

The tissue which produces the wood is a thin sheet between the bark and the core/wood itself. Bamboo and some other trees have different growing structures. So it may be possible to increase the surface of that tissue which grows, let's say if we shape that growing tissue on some primer, which goes like a spiral as an example, we can 10 fold the surface area, where wood is produced, and thus if we nourish it enough, it may be 10fold wood production increase.

Back to that bamboo cheater - it is hollow, and from material science, we do know that a pipe, or T-beams, etc are not much weaker than a solid equivalent but are significantly lighter, and that is exactly one of the bamboo tricks. So as for your structures be solid may be a wasteful excess, which is another way to say we can increase the surface area of productive cells in all sort of ways - it can be a hollow bone-like structure with channels and internally on walls of the mesh are cells which make wood and gain strength over time and then die out. So it all about increasing centers of growth and at the same time give the energy and building blocks to the cells.

It may be possible to make the wood itself be stronger and here where actual genetics may be involved in change the cell structure and what wood or more precisely which kind of composite material they do produce. (Cells may be elongated beyond natural necessities, produce carbon nanotubes to reinforce the structure, some polymers which soak the wood and solidify under some conditions, etc)

So there no single trick to use, but a set of approaches, maybe to the point u would not call it natural wood after looking at the material. Maybe most promising is the increase of the surface area of the tissue which produces wood and artificial nourishment. Those may increase the speed of the mass production, also give a preliminary shape to construction which then grows and increases strength. Primer can be another wood as an example - sheets of wood, wires/ropes of wood, or other materials, on which u spray cells and a cover for them and then pump nourishment through that structure.

Or primer structure can be much more sophisticated one and then the sky is the limit, or not, depends, but with it, u would be able to grow any shape in a year or half-year - but again it would play mostly 2-3 notes - nourishment and increase surface area and predetermined shape.

Again set of approaches, technology can give u what u want, but it won't be a single genetic trick. Also, there still will be some limits, one of the bottlenecks may be the speed of lignin forming, and others, it is the field of chemistry, those are polymers which have to be oriented properly, stitched together, etc and where constants of reaction speed play determining role and no genetics can help u, it not necessarily a problem and it looks like it is not a problem, but it needs to keep in mind that limits, bottlenecks, may come from the most basic processes happening in the thing. I would say with a good tech u can grow anything in a year and less, with less perfect ones in few years.

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I stopped reading after this amusing tidbit:

"In a near future setting (technology has progressed more or less at the current pace) would it be possible to have "

I can promise you this: for the next two years at least, with the idiotic leadership we have today, we aren't getting past covid.

And by the time we do, half of us will be dead.

Then you can have whatever type of tree you like.

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  • $\begingroup$ Wait and see - glory awaits us. $\endgroup$
    – MolbOrg
    Feb 25 at 0:41
  • $\begingroup$ The question is about trees, not politics. Also, near future can be decades ahead, which is definitely enough time to recover from such a major loss of life (see also post WW1/WW2 population) $\endgroup$
    – B-K
    Feb 25 at 2:19

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