Zhang Yuan carefully observed this so-called tree heart; it had some hollow sieve tubes in the middle, and its overall density was much lower than that of steel.
Yamamoto said something alarming, "These tree hearts are excellent material for the Riley Civilization, providing housing and food… but they are also a major crisis that could destroy the entire ecological chain!"
He scraped off a little bit of wood debris with a knife and lit it with a lighter.
Immediately, the burning created a wisp of faint smoke.
Zhang Yuan covered his nose, smelling a pungent odor similar to that of burning plastic, and pondered deeply.
Everyone had smelled the scent.
"It really does smell like plastic."
"What is plastic?"
Zhang Yuan explained, "It's a type of high-polymer material derived from petroleum, very cheap, and was widely used by Earth Civilization. However, after the exhaustion of petroleum, it was no longer viable, and we had to switch to using renewable materials on a large scale."
