Why there's so few usable wood in the woods?

[CMB]

Subject

[Null Winter]

Story reason:
The woods are very much alive and actively resist being chopped down; comments from multiple characters and notes mention that all the work done in trying to chop down a single tree can be undone literally overnight. It takes an entire village working desperately to chop open a single small path.

Some of the piles you find are also likely rotten or too hard to use for crafting.

Gameplay reason:
Your character lacks the time and resources to commit to chopping down a mutant tree, so it is more efficient to loot logs from lumber camps and house stockpiles. This also keeps you from being complacent and amassing massive amounts of standard crafting components just by walking out your front door, like you live in some sort of well-made cube-shaped world of easy mining and crafting.

[CMB]

My brother in wood, there are literally piles of processed wood around the map - fences, fallen roof parts, wooden floors, furniture, there are also fallen dead trees that could be snapped by physical force using other trees as a pivot. Despite that, players is forced to use specially prepared wooden planks for something as brute as making physical obstacles.

[Null Winter]

This[tvtropes.org] and that[tvtropes.org].