[Sun] 1. A printer. 2. A person who wastes paper. This epithet should be interpreted in a broad sense; `wasting paper' includes the production of spiffy but content-free documents. Thus, most suits are tree-killers.
It is likely that both senses derive their flavor from the epithet `tree-killer' applied by Treebeard the Ent to the Orcs in J.R.R. Tolkien's "Lord of the Rings". See also elvish, elder days, and especially dead-tree version.