hemlock, (kokuji)
栂 is a Japanese kokuji for the hemlock tree, specifically the species Tsuga. Its meaning is tied directly to that tree.
栂 is a Japanese kokuji created by combining 木 (tree) with 母 (mother), possibly chosen for its sound contribution (つが/とが) to represent the hemlock tree. The exact reasoning behind the component choice is uncertain.
A tree (木) that is like a mother (母) to the forest, providing shelter and shade: the hemlock tree.
For つが, imagine a hemlock tree with two (つ) moth (が) cocoons hanging from its branches: つが.
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southern Japanese hemlock (species of conifer native to Japan, Tsuga sieboldii)
mountain heath (Phyllodoce nipponica)
Japanese Douglas fir (Pseudotsuga japonica)
northern Japanese hemlock (Tsuga diversifolia); hemlock spruce
western hemlock (Tsuga heterophylla)
Aleutian mountainheath (Phyllodoce aleutica)