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What is a conifer tree?

Conifer trees are softwood trees with needle-shaped leaves and seed-producing cones. A tree that produces cones that bears its reproductive structures in the cones is called a Gymnosperms, and they belong to the phylum Coniferophyta family. Unlike flowering plants, these cone bearing trees have male cones that produce pollen which is blown by the wind to reach female cones that bear naked seeds. They are also known as the world's tallest and largest trees. The tallest conifer trees are the redwoods, also known as the giant sequoia sempervirens. The conifer trees and shrubs group includes pine trees and other cone bearing trees. The pine family trees are the largest family member of the conifer species, with over 900 different members in the division pinophyta growing worldwide today. An example is the great basin bristlecone pine. Because pine cones are attached to branches by flexible stems, they tend to fall to the ground when they are ripe, spreading seeds far from their parent tree. Pines and other conifers make the tallest trees that are especially important in northern regions where trees cannot survive winter cold because they can remain dormant until conditions are right for growing again. The most widely-known conifer is the evergreen Christmas pine commonly used to decorate homes during the holiday season in winter. Many conifers are woody plants of economic importance since they produce wood used commercially in construction materials such as plywood and many types of furniture. And last but not least, many species of cone bearing trees have resin inside their trunks, making them naturally resistant to fire, so they only burn on the outside, leaving the inside untouched. ## What are some Australian conifers? The most well-known Australian member of the group Coniferales is the King Billy pine (Athrotaxis selaginoides). This tree can be found in Tasmania and Victoria. These trees are very old, some up to over 3,000 years old. King Billy trees grow straight upwards with twisting branches that form a cone shape. They have thin greyish-green needles that are about 10 cm long. The cones are red when they mature but turn brown as they ripen. King Billy pines store lots of water inside their trunks, so they rarely need any rainwater during dry periods. Therefore, this means that many of these trees can survive even if there is no soil or moss to anchor them down. Their thick bark also protects the tree from fires, so they can stay alive even if their roots are burned. The King Billy is also called a resurrection tree because it can be burnt down to its stump by hot fires, but new shoots will sprout again from the base of the trunk. It takes between 60-80 years for these shoots to grow into mature trees. King Billy pines are widely used in Tasmania as windbreaks and ornamental trees around homes because they are very hardy and long-lived once established. ### Wollemi pine An exciting discovery in 1994 changed how people thought about conifers. While studying fossils, scientists found that there were pine tree species alive at the same time as dinosaurs. The Wollemi pine was one of these ancient trees. It has since been grown and planted around Australia (great news because it is becoming endangered in its natural habitat). Wollemi pines look like small bunches of dark green broccoli growing out of rock crevices or cliff faces. These pines are very slow-growing and produce miniature needles about 2 cm long. They also drop their needle-like leaves once a year (just like deciduous trees, which lose their leaves every autumn) but usually only drops 1 to 3 leaves at a time. When grown in a place with plenty of sunlight, Wollemi pines can grow as tall as 15 m, which is about the same as a 3- to 4-storey building. ### Bunya pine The Bunya pine is a conifer tree native to the subtropical rainforest in eastern Australia. It produces large nuts (5-7cm long) that fall from bunches on its branches, hence another common name for it - the Bunya nut tree! The nuts are only edible by animals like parrots with curved beaks. Humans can still eat them, but they taste bitter because of their hard outer covering (equivalent to an acorn shell). This Australian conifer has very large needles up to 25 cm long. These needles are arranged in pairs around small 'twigs' or stems that sit at right angles to the main trunk. The cones grow up to 30-40 cm long with scales tapering to a point. They are striped brown and green when young but turn woody and dark brown as they mature. ### Hoop pine (Araucaria cunninghamii) The hoop pine is native to the subtropical rainforest in eastern Australia. It has stiff leaves about 2 cm wide, longer than the bunya pine, which has small 'birthing' scars on its underside where the bunches of seeds fall from its branches. The male cone produces yellow pollen, while the female cone produces red seeds. These pines can grow up to 40 m with trunks reaching 1 metre in diameter with smooth bark, different from other conifers. ## Why are conifers important? The answer lies in their needles. Most conifers shed these "paddles" from time to time, allowing other plants to grow on the bare ground beneath them. It is a good thing because it helps new species grow and evolve to use different parts of the ecosystem for food and shelter. Conifer trees are also important for animals. Birds, porcupines and squirrels especially love pine seeds because these animals can hide the seeds inside their fur or store them in their large cheek pouches, where they will be safe until conditions are right for germinating. ## The difference between evergreens and conifers Evergreen trees stay green all year long, even when it's cold outside. Most species have special cells inside their needles filled with an oily sap which helps keep the needles plump and juicy even in freezing temperatures. Evergreens can also close their "windows" to help them retain water so their needles do not dry out as quickly as deciduous trees during hot, dry periods. They also have a layer of dead bark on the top of their trunks which acts as a barrier to prevent moisture from evaporating too quickly. The spruce tree is one example of an evergreen coniferous plant, but several others exist. The Douglas fir, hemlock, larch, juniper, and yew are also evergreens. ## What is an evergreen tree? Evergreen trees and shrubs stay green all year round, so they are not deciduous. These trees can be conifers or broadleaf. However, the word conifer does not mean the same as evergreen. ## What do deciduous, biennial and perennial mean? A deciduous plant means it loses its foliage in the fall and regrows it in the spring, just like maples, oaks, birches, and elms do each year. These plants have a two-season life cycle with one major growing season (when they sprout) and one dormant period (when they leaf out). In comparison, biennial trees and shrubs live for one full growing season from spouting to dying back but does not re-sprout after dying back. A biennial plant grows leaves, flowers and seeds in the first year but then dies during its second season. Biennials like dandelions only take two seasons to complete their life cycle rather than three (like most perennials do).