They can pop like an egg if not handled correctly or if there is no good place to drop them, proper layouts are key, but not always possible.
Imagine needing a D8 to gouge out a road for nearly every tree to land on, cost is high in time, money and can be environmentally unsound.
A tree deemed highly valuable can require several hours of prep, lots of dirt and vegetation displaced, not a good thing in an area that sees several feet of rain in a season.
The level of disruption is appalling, often there was nothing left but stumps, churned soil, permanently disfigured hillsides and massive heaps of debris.
The erosion was intense, the 1964 Christmas Flood was payback for decades of hellbent logging, major river streambeds like the Eel, Van Duzen and Klamath were buried under 20 to 30 feet of gravel.
Include the massive amount of large (LOL) woody debris, that took out the bridges, jammed up to cut the banks, toppling even more trees to become battering rams.
The rules began to change, too little, too late, such was the basic nature of OG Redwood logging. Who carries the blame? Ultimately, the consumer and the Government's greed for tax revenue.