Pine, spruce, fir, hemlock, cypress, cedar, larch--not all these trees are evergreens, although all have needle-like leaves and produce cones, so they are conifers.
Most of them wear needles throughout the year, but some needle-bearing trees are deciduous. The larch (or tamarack), for instance, sheds all its needles in autumn and grows new ones in spring. There are also a number of evergreen shrubs that are not needle-bearing, such as holly and rhododendron.
All the needle-bearing trees are conifers, that is, their seeds grow within the protection of cones. The technical term for the conifers is gymnosperm, meaning “naked seed”, since the seeds are formed on the surface of cone scales, rather than within embryo sacs like those of true flowering plants, known as angiosperms. Gymnosperms do, in fact, bloom, producing pollen from their male parts and egg cells in their female parts, but the reproductive structures are not as complex as the “true flowers” of the angiosperms. (There are a few gymnosperms with broad leaves—ginkgos and cycads.)
Many people refer to all conifers as pines, but in fact only the members of the genus Pinus (what’s a genus?) are pines, Other North American conifers include spruces, firs, hemlocks, cypresses, redwoods, cedars, yews, and larches. Following is a quick guide to the differences among the needles of the most common groups. Note that botanists also call needles “leaves”, since they serve the same functions as the leaves of deciduous trees.
Pines have long needles growing in clusters of two to five, depending on the species. White pine has five slender needles to a cluster and a white stripe down the side of the needle. Red pine, whose needles are thicker, has two needles per cluster. Other species have their own numbers of needles.
Hemlocks have short, flat needles with white stripes on the underside. Their needles grow in two rows pointing in opposite directions, creating a single flat plane of needles. (Hemlock trees are not to be confused with the knee-high plant poison hemlock, the source of the toxin used to kill Socrates. The tree species is not toxic.)
Spruce needles are short and squared, with four flattish sides. They grow in four rows along the twigs, sticking out in all directions around the twig. Similar in appearance are fir needles, but they are flat, white-striped beneath, and grow in rows that stand at right angles to each other.
Cedars and cypresses have scalelike “leaves” hugging the twigs or, in some species, short prickly needles. (Red cedars and other species of the Juniperus genus have small bluish cones that resemble berries.)
Larch needles are very soft and flexible and turn yellow before they are shed in the fall. Actually, most conifers shed their needles, but not all at once. If you look carefully at pines in the autumn, you will notice that about one-third of their needles have turned yellow. These needles fall, and in spring, the tree puts out new needles as it begins to grow again.
For instructions on making tree needle tea, see Trees in Winter.
