ΔE 8.6, close: similar, with a visible difference side by side. Park Green Flat is a little darker, more muted than Forest of Shadows.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Park Green Flat is a little darker, more muted than Forest of Shadows.
The same difference applies the other way round: Forest of Shadows is a little lighter, more saturated.
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 Forest of Shadows on the colour wheel See Park Green Flat on the colour wheel
All matches: Forest of Shadows equivalents · Park Green Flat equivalents