The vegetation map is now split to many files!
One for each sector, to be precise. You’ll be able to load and unload vegetation of only those sectors that concerns you, thus your computer won’t explode and will run smoother. The sectors are defined as Areas and are placed into sublayers of sector layers called (sector acronym)_vegetation, for example samopse_n_vegetation for Samopse north sector. In general, when you load/unload the whole sector layer structure, vegetation should load/unload with it.
If you want to work with a specific sector's vegetation, you have to lock that layer in Perforce. That is now easy thanks to the fourth square left of the layer's name.
When you click it, the green lock icon will show up and the layer will be locked by you. You can now edit the vegetation inside. If you won't lock it and still try to edit the vegetation you should be prompted that no changes will be saved.
Now the red lock icon means, that someone else has this layer locked. You can check the Perforce to find the culprit.
These vegetation maps are saved among layers (instead of under the LevelData as the global vegetationMap.dat) and have an extension .vga. The .vga file is the one you need to submit every vegetation change; .lyr file contains sector area definition only and thus no need to submit it.