↑"Black wood, [...] Builder’s wood,” the Treasurer said. “But it’s meant to contain and disrupt something like a self-propagating lifeform. Wall ’em in, and when the builder’s wood reaches maturation, it sends out spores. Existing wood, non-meat food supplies. Turns it into more black wood, provided the raw material is there and there’s any moisture. A lot of builder’s wood structures crumble, I think, integrity gone.”
“We’re surrounded by forest,” I pointed out.
“Yep,” he said. “But it’s going to take time. Pneumonia-like symptoms for everyone in the city that breathes it in, enough to keep them put. Minor complications with diet and eating. Wood grows in at the usual rate, you could give it a few days to a week before it gets as far as the city periphery. Keeps going until a gust of wind can’t carry a spore to the next bit of green. They’ll probably burn a circle to control its progress.”
“And if they don’t?” I asked.
“They will. They have to,” he said.
We’d never really fully discussed the extent the Infante might be willing to go to. The consequences he might put into action to silence a dissenting voice. - Excerpt from Gut Feeling 17.18