The glyph.
The Glyph of Strength was an ancient Ewok symbol. According to legend, it had magical properties to it, which made Ewoks nearby more resistant and hardy.
The glyph depicted a mountain with two moons above it. Ewok glyphs would often be carved on trees where Ewoks lived.
Sources
Ewok Village on StarWars.com (article) (backup link) (First mentioned)
