Source : Webster's Revised Unabridged Dictionary (1913)

Tamarack \Tam"a*rack\, n. (Bot.)
   (a) The American larch; also, the larch of Oregon and British
       Columbia ({Larix occidentalis}). See {Hackmatack}, and
       {Larch}.
   (b) The black pine ({Pinus Murrayana}) of Alaska, California,
       etc. It is a small tree with fine-grained wood.

Source : WordNet®

tamarack
     n : medium-sized larch of Canada and northern United States
         including Alaska having a broad conic crown and
         rust-brown scaly bark [syn: {American larch}, {black
         larch}, {Larix laricina}]