Original mod:
https://mods.factorio.com/mod/fewerTrees

Original mod Description:

Fed up with huge forests in your games? Want less trees? I did.

This mod is a bit redundant now, with the Trees option in the terrain settings, but it will remove a number of trees when a new map segment is generated based on a percentage.
The preview pictures show a default forest, a 70% culled forest and a 100% culled forest.
Also has an option for culling rocks, so it's not entirely useless.

Change the settings via the new Map Settings button when creating a new game.

Changelog:
0.2.5:
- Updated for 0.17 but there are some trees and rocks not included yet.
0.2.4:
- Fixed a bug that stopped the mod from removing a number of the new rocks in 0.16.
0.2.3:
- Updated for 0.16. Seems to work fine.
0.2.2:
- Now accepts decimal values for removal.
0.2.1:
- Fixed a bug where the remove rocks option wouldn't remove the purple-desert rocks.
0.2.0:
- Now comes with mod-settings support.

Updated mod to work with Factorio 1.0