ΔE 23.0, loose: different enough that you should pick on purpose. Thornwood Green is a little lighter, much more muted, warmer than Vulkan Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). Thornwood Green is a little lighter, much more muted, warmer than Vulkan Green.
The same difference applies the other way round: Vulkan Green is a little darker, much more saturated, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Vulkan Green on the colour wheel See Thornwood Green on the colour wheel
All matches: Vulkan Green equivalents · Thornwood Green equivalents