ΔE 5.8, very close: most people won’t see a difference side by side. Tree Ancient is more muted, warmer than Russet Shadow.
Yes, for most jobs. Very close match (ΔE 6). Tree Ancient is more muted, warmer than Russet Shadow.
The same difference applies the other way round: Russet Shadow is 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 Russet Shadow on the colour wheel See Tree Ancient on the colour wheel
All matches: Russet Shadow equivalents · Tree Ancient equivalents