chestnut
栗 centers on the chestnut, a specific type of nut with a prickly husk. The meaning is concrete and does not extend into abstract senses.
Japanese chestnut (Castanea crenata)
squirrel (any mammal of family Sciuridae)
potato starch
broiled sweet chestnuts
dogtooth violet (Erythronium japonicum)
chestnut (horse coat color)
chestnut-color; chestnut-colour
squirrel monkey (esp. the common squirrel monkey, Saimiri sciureus)
chestnut in its burr
American chestnut (Castanea dentata)
common squirrel monkey (Saimiri sciureus)
Siberian chipmunk (Tamias sibiricus)
black-capped squirrel monkey (Saimiri boliviensis)
European chestnut
crushed stone; hardcore; macadam
crushed stone; hardcore; macadam
dried chestnut
red squirrel (Sciurus vulgaris)
Taiwanese squirrel (subspecies of Pallas's squirrel, Callosciurus erythraeus thaiwanensis)
acorn squash (Cucurbita pepo var. turbinata)
栗 combines 覀 (a variant of 西, originally depicting a bag or container) with 木 (tree), suggesting a tree that produces chestnuts. The character likely originated as a pictograph of a chestnut tree with spiky fruits.
The top 覀 looks like a spiky chestnut husk, and the bottom 木 is a tree. Together they show a chestnut growing on a tree.
For リツ, imagine a chestnut tree that produces a rich, rhythmic harvest: the sound 'rits' echoes the rhythm of falling nuts. Rits -> リツ.