Heavy Shade Forest

Old English hefig, weighty — cognate with heave. Used as a color modifier since at least the seventeenth century to indicate weight in saturation as much as value: heavy with pigment, heavy-bodied. In the engine's adjective grid, heavy sits alongside deep and plush in the dark-and-saturated quadrant. Closer to a fabric description than a pure value word.

Old English sceadu, shadow-or-shelter. As a color modifier, shade implies a sheltered-and-cool-and-shadowed quality, the visual register of Tuscan-cypress-and-Provençal-plane-tree-shade hand-sheltered-and-cool-and-shadowed Tuscan-cypress-and-Provençal-plane-tree-and-English-yew shaded-and-sheltered-and-cool surfaces under Tuscan-cypress-and-Provençal-plane-tree-and-English-yew dappled-and-cool-and-filtered afternoon-light. Sits at the modifier-and-mood end of the grid, parallel to shadow and gloam in usage.

The dense canopy of a temperate or tropical woodland — oak, beech, pine, eucalyptus, mahogany — wherever leaves close above to filter the light below. Forest green refers to the average reflectance of a healthy mid-summer canopy seen from below: a saturated, slightly muted green with the matte finish of layered chlorophyll. Deeper than fern, cooler than olive, with the ecological weight of a word that has named every wooded biome on Earth.