I agree in principle that reuse is the best imaginable outcome... but You underestimate the labor and cost of machines. I bet it costs $200 to pluck a single tree let alone ship it somewhere else usable.
It's probably blasting related to prepping for the eventual revival of an underground test platform.
I don't know all the logistics, but they probably don't detonate them directly under the base, and subterranean drilling might be less evident from satellite than top side wells.
Obviously a static sign is not aware of your current state, so it's message can only be interpreted as relevant to your likely state... i.e. the posted speed limit.
Imagine a major city in America that were politically dominated y China for 50+ years and it is hard to imagine this type of blowback not occuring eventually.
I promise I could give this to 10 people and get at least 7 wrong drawings.
Of the remaining 3, there would be erasor marks on 2. And the last one would technically hit the right numbers and linkages, but it would be a hand drawn sketch on a notepad.
Point is, these AI gotchas are always missing reality.