Wooded terrain could not reliably replace prepared defenses. Tanks could pass among trees or knock them down, while explosives gave military engineers another way to clear an approach. Chainsaws had been developed early in the twentieth century and were in practical use well before 1939, so tree felling had changed. Engineers already building with timber and concrete should have understood how quickly a wooded obstacle could be altered. The planning failure came from treating forests according to an outdated view of what terrain could do.
Notable Point · 6:25-7:58
Forests and engineering assumptions
The forest critique uses tanks, explosives, chainsaws, and military engineers to show how outdated assumptions can hollow out a defense plan.