Mark A. Miller
Plant Common Name
Pines are considered to be some of the most economically important plants in the world. Lumber for construction and furniture, resins for turpentine, and wood pulp for paper are all products of commercially valuable pines. There are about 100 species which make up genus Pinus. These evergreen trees, and occasionally shrubs, are distributed across the Northern Hemisphere worldwide. Several species have naturalized in parts of the Southern Hemisphere.
The trunks and stems of these plants are often covered with conspicuous bark, which is variable and may be furrowed and plated or layered and scaly. Pine leaves are needle-like and clustered together in groups. The number of needles per cluster is often used for identification because these vary from species to species. Needle clusters may persist for a few to many years. Some pine species are self-pruning, which means they drop old branches as they grow.
Pine trees reproduce through separate male and female cones borne on the same plant. The male cones are oval or fat spike-like catkins (pendulous spikes) covered with pollen-producing structures. They are borne at the branch tips or on the current year’s growth. These wind-pollinated plants produce so much pollen you can see it in the air. The pollen it typically yellow but can also be tan, red, lavender or blue. The seed-bearing “pine cones” are the female structures. The scales of the cones are woody or flexible and have hooks or spines at the tips. Winged seeds are held between the cones and may be expelled while on the tree or after the cones drop. Female cones may take years to mature and are a major source of food for wildlife.
There are many different pine species. The bristlecone pine (Pinus longaeva) is a small, slow-growing, super long-lived species that is perfectly adapted to dry, high altitude mountain communities throughout the western United States. It is best known for its very long lifespan, over 4,000 years, and the twisted gnarled forms it takes on in the rigors of harsh, dry conditions. Slash pine (Pinus elliottii) is native to the flatwoods and coastal plains from the Carolina's to Florida and west to Louisiana. The medium-sized needles are borne in twos, sometimes threes and the hand-sized cones are brown, shiny, and offer considerable wildlife value. The Asian Japanese black pine (Pinus thunbergii) bears short, twisted, very dark green needles and is favored as an ornamental for its dense, pyramidal shape when young and open and irregular habit and twisting branches it develops with age.
Each pine is adapted to different areas, so choose the one that matches your climate and site. Generally, pines prefer full sun, open locations and soils with good drainage. They can be difficult to transplant, so they are typically planted as seedlings or small container-grown specimens. Some types are transient and give way to hardwood forest, while others are the climax species in fire-dependent community and need their underbrush to be cleared by fire or other means. Typically, pines are very susceptible to damage from construction, even a little compaction from equipment is enough to cause the decline and eventual death long after the construction has ended. All are important species for wildlife and people alike.