An evergreen tree is defined by foliage that remains green and functional throughout the year. Unlike deciduous trees, which shed all their leaves seasonally, evergreens maintain a continuous covering of leaves through a gradual renewal process. This strategy allows them to photosynthesize continuously, even during colder or drier periods when other trees are dormant. While the term often suggests cone-bearing conifers like pine and spruce, the evergreen category also includes broadleaf plants, such as holly and magnolia, which reproduce with flowers instead of cones.
The Defining Foliage Needles and Scales
The most recognizable feature of an evergreen is its specialized foliage, which primarily takes the form of needles or scales. Needle-like leaves, common to pines, firs, and spruces, are long, thin, and often sharp or pointed. Pine needles are typically found in bundles of two to five, held together by a papery sheath. Spruce needles, however, are attached singly and are often four-sided. Needles are an adaptation to conserve water and survive in harsh conditions, with colors ranging from deep green to blue-green.
The second major type of foliage is the scale-like leaf, characteristic of trees like arborvitae, cedar, and juniper. These small, flat structures overlap tightly like shingles on a roof, often pressed against the stem. Scale leaves give the branches a feathery or flattened appearance and are highly effective at minimizing water loss. Evergreens shed their foliage gradually over several years, ensuring the tree never looks bare.
Overall Tree Structure and Branching
Evergreen trees often exhibit a distinct structural shape, differentiating them from the sprawling canopies of deciduous trees. Many conifers, especially younger ones, grow in a symmetrical, pyramidal, or conical form, featuring a single, dominant vertical trunk called the leader. This shape, known as excurrent growth, is structurally advantageous because it allows heavy snow to slide off the branches easily, reducing the risk of breakage. The branches typically grow in whorls, forming circular patterns around the trunk at regular intervals, which helps determine the tree’s annual growth.
Branching on many evergreens is dense and often starts low on the trunk, contributing to a full, uniform profile. Trees like cypress and spruce maintain this defined, conical shape for much of their life. Others, such as some pines, may develop a more rounded or open crown as they age. Junipers, arborvitae, and yews often display a more random branching habit, lacking the distinct whorls of pines and spruces.
Cones and Reproductive Features
The reproductive structures of many evergreens are visually defined by cones, which come in male and female forms on the same tree (monoecious). The cones most people recognize are the female seed cones, which are typically larger, woody, and designed for protecting the developing seeds. Examples vary widely, from the large, elongated cones of a pine to the small, rounded, woody cones of a cypress.
Male cones, or pollen cones, are significantly smaller and less noticeable, often appearing as tiny, yellowish or reddish structures clustered near the tips of the branches in the spring. These smaller cones release a fine, yellow dust of pollen carried by the wind to fertilize the female cones. Some evergreens, such as junipers and yews, have evolved cones that look like fleshy, blue berries or red, cup-shaped fruits, with the scales fused together, making them less obviously cone-like.