Can a Prototaxite be used for a wood equivalent?

Question

Prototaxites.

Giant, finger-shaped mushrooms.

Painting by Mary Parrish, National Museum of Natural History.

These monsters existed before trees did, and while there are a few theories on whether they actually existed as depicted above, for the sake of the fact that I'm going with an alien planet, I'm going to assume that's how they were.

What I'm wondering is could a fungoid-like in such a configuration be used instead of wood? IE, could you dry it, cut it into planks, build a boat out of those planks, build a house, etc.

For ease of answering presume it follows terrestrial biology as much as practical, and has been given conditions in which it could grow.

Answer 1

This is the closest thing I could find to fungi being used in a way similar to wood, Mushroom furniture.

Ross begins with a carbon-based agricultural byproduct, like cornhusks or sawdust, and adds a bit of mycelium tissue. The culture comes from Ganoderma lucidum, a mushroom that forms chestnut-colored saucers on surfaces it colonizes. Most importantly, it grows at room temperature, ideal for a lab aiming to keep energy costs low.

The mycelium feeds on the sawdust over a couple of weeks and forms a vast web of fibers. Ross then transfers the growing structure to a mold, and the fibers grow to fill the form of the container, be it brick- or chair-shaped. Next, Ross pops the structure into an oven to denature proteins and kill the fungus.

Its strength ranges from cork to balsa wood depending on various factors, and when making furniture, the inventor uses wooden legs for support.

So I don't think earth fungi would be very good as a replacement for wood.

However the cells of fungi are made of chitin which can have some strength if made thick enough. For the exo-fungi, instead of having the cells creating thin fibrous strands, have the cells lock together like bricks. To make it a bit different from wood, have them being flexible and leathery while alive or recently cut, but when properly dried they stiffen up and act more like wood. This would let people or aliens bend and twist them into many different shapes before drying to give them an organic, almost grown look to them.

Answer 2

Fossil mushrooms are rarities. Mushrooms are the fungal equivalent of flowers - spongy, ephemeral, disposable bodies generated to serve a reproductive need. You could not use mushrooms for wood.

The prototaxites were not mushrooms. They were large and substantial. I deduce this from the presence of growth rings in the fossil prototaxites.

https://www.researchgate.net/figure/Transversely-sectioned-Prototaxites-fossil-This-overview-image-originating-from-a_fig1_51174561

The presence of rings means this structure endured shifts in growing conditions over time. This thing was there for many seasons. On earth, that means it weathered storms and wind: no small feat for an upright thing this size.

There is an analogous modern fungus: the bracket fungus aka "shelf fungus".

The shelf is also a spore-making body but a permanent one, and it also can persist many seasons, laying down growth rings with the seasons. Bracket fungi are as tough as wood.

https://herbarium.usu.edu/fun-with-fungi/shelf-fungi

Woody shelves may be several years old. They add a new layer of spore tissue every growing season. The old layer is covered by the new one. These layers look like growth rings in a tree. One author reported counting 37 rings. Ten layers may mean the shelf is 10 years-old if there is only one growing season (spring). If there are two growing seasons per year (spring and fall), it may only be 5 years-old.

One of the largest shelves weighs 300 pounds…

Woody shelves are impossible to break with your hands and difficult to cut. This toughness results from the kinds of hyphae (filaments) that are used to construct the shelf. Easily crushed mushrooms are made of thin-walled hyphae. Some of the hyphae in woody shelves are thick-walled and the hyphae are interwoven making them tougher. They resist tearing or splitting because there are no planes to split along in the tissue.

A bracket fungus large enough could be used for wood. The medium to small ones are used to make real shelves and durable beads.

It is reasonable to assume the prototaxites were of a composition similar to modern bracket fungi and so suitable for use as a wood equivalent.

Answer 3

Earth fungi are made of chitin, which is plenty durable enough to build housing and furniture out of, although it will not be as strong as actual wood, and you will not be able to build tools out of it, although you could say they are made of a denser chitin than earth fungi.

Of course as aliens fungi-like things and not actually earth fungi you could just say they are actually made of cellulose instead of chitin (or both), there is no reason they have to be made of chitin only, it is a fluke of evolution. Biologically there is not much difference between the two materials as far as production goes so you would be fine having them made of cellulose (wood).

Nearly anything organic will burn so it is fine as fuel. However it will burn like a light wood not a dense one.

the real trick is they will not be all that common since they are not primary producers they need to get the energy to grow from something else, like dead plants, so using them for fuel will be tricky just logistically.

Answer 4

If we are talking about creatures similar to those of our world developing and evolving for ages in other planets, there is nothing keeping those fungus from using hard materials for a skeletal support structure.

On Earth fungi have chitin, as has already been described on the other answers. An alien fungi might also use bone (why not?), cartilage, glass (some sponges have glass structures), cellullose (which is chemically very similar to chitin), iron-mineralised scales (such as this snail), or a combination of those. By combining every form that has been tested and tried by nature in our own world, the alien fungus could be harder than anything on Earth, and grow larger than sequoia.