Ancient giant silicon-based tree hypothesis

The ancient giant silicon-based tree hypothesis was first formulated by Russian YouTuber and conspiracy theorist Ludin Rusi (Людин Рɣси ) in 2016, which proposes that many geological formations are actually remains of an extinct clade of huge botanical species.

Origins
The tree grew large and strong and its top touched the sky; it was visible to the ends of the earth. It's another example of Biblical literalists trying to reconcile their beliefs with reality. However, trees that are both giant and made out of rock is not mentioned. Furthermore, it does not account for the living state of those trees before they turned into stone upon dying.

Silicon biochemistry
Silicon life, even if possible, would not be compatible with carbon-based life. Due to its bigger size, silicon atoms can hardly establish double bonds, as carbon can. As a result, many silicon analogs of carbon cannot form, making its chemistry much poorer than that of carbon, which illustrates greater molecular stability, and therefore the independence of carbon analogs, that isn't vulnerable to contamination with cross-reactants ever abundant in the case of carbon.

It is also dubious if aerobic respiration could be possible. Both carbon and silicon have a valence of +4 but oxidize differently. Carbon's smaller atomic size lets it form stable double bonds with oxygen, and the resulting CO2 is a gas. Silicon is too large to form stable double bonds and forms single bonds with four oxygen atoms, leaving the oxygen atoms to bond with another silicon atom. This atom bonds with three other oxygen atoms, which all bond with silicon, and so on ad infinitum as a crystal.

Structural problems
Earth's gravity posits biophysical limits to plant growth. George Koch et al. of the Northern Arizona University calculated that at most, trees can theoretically reach a height of 130 meters. There is no evidence that trees with fantastical biochemistry could grow any taller than that. However, it does not consider whether or not gravity exhibits properties instead of them coming solely from density and buoyancy variations.

Things we can praise it for
The author did at least have the awareness to call his idea a hypothesis and not a theory.