Definitions for jack pine
Random House Webster's College Dictionary
a scrubby pine, Pinus banksiana, growing on poor, rocky land in Canada and the northern U.S.
Origin of jack pine:
jack pine, Pinus banksiana(noun)
slender medium-sized two-needled pine of eastern North America; with yellow-green needles and scaly grey to red-brown fissured bark
an evergreen tree, Pinus banksiana, scrub pine