Why do pine trees keep their needles all winter?

Answer 1

Soft wood,the sap stays up so they stay green !!

Answer 2

In addition to Ivorytower's post, this feature helps pine trees get a head start when the light improves. In the taiga where pines are abundant, the winter light is pretty dim. In the spring when light is more intense, these trees already have their needles in place and don't have to start by growing new leaves.

Answer 3

Pine needles have a lifespan of 3 to 7 years. Pines are well-adapted to drought conditions which occur in the dead of winter when no liquid water is available. They have thick cuticles, a low surface area to volume ratio and sunken stomata. The bundles of needles (fascicles) also pack closer to gether to reduc evaporation. Deciduous trees lose their leaves in winter becuase their leaves are not well-adapted for drought. Deciduous trees (most angiosperms) also have wide bore vessels that cavitate, whereas conifers like pine have only narrow bore tracheids with toroid pits that are less susceptible to cavitation.

Answer 4

The difference between a hardwood tree and a softwood tree is the shape of the leaf hardwoods are broad leaf and softwoods are needle hard woods go dormant in winter and soft woods grow all year.