Coniferous Trees: Natures Evergreens
Coniferous trees are extremely important in the Earths biosphere. They are easily identified by their long, narrow leaves and their year-long foliage. Thanks to these traits, they are also known as evergreen trees. Though they are sometimes less celebrated than deciduous trees, which provide the yearly spectacle of leaf-shedding many people associate with fall, they are just as important forming the backbone of vast forests found in northern climates. The old growth forests of Germany, Austria, Canada, and other cooler locales are made up of thousands of ancient conifers. They come in many varieties, including pine, fir, yew, and more. There are over 500 known species of coniferous trees distributed all around the globe. Though conifers are most common in Europe, there are conifers adapted to warmer or tropical areas. Local conifers are found in China, Tasmania, and even Chile.
Reproduction and the Life Cycle in Conifers
Coniferous trees reproduce by way of their iconic cones. Cones come in male and female types. The wind catches hold of pollen produced by male cones; the dispersed pollen is carried to the female seed cone and deposited. Once this occurs, the pollinated seed within a given female cone is able to germinate. The seed contains a tree embryo. Upon maturity, the seed drops out of the cone and enters the ground, allowing the embryo and structures within the seedling to develop into a young plant. The plant eventually grows into a mature coniferous tree that has its own cones for reproduction. Both male and female cones may be present on any given conifer, with the smaller, male cones tending to be located lower on the tree than the generally larger female cones. Conifers are considered naked seed plants because their seeds develop in the absence of any fruit. This contrasts non-coniferous plants and trees, where seeds are contained inside recognizable fruits or flowers. Though evergreen cones are rarely sought out like fruits and flowers are, they can be used in a variety of artistic products. The wood of coniferous trees is used for paper, lumber, and a variety of goods.
Variety and Structure of Coniferous Trees
Some of the largest and oldest trees in the world are coniferous trees. The famous redwood sequoia trees of California are an example. This includes the worlds tallest tree, Hyperion, found in Redwood National Park. The oldest tree in fact, oldest living thing on Earth is the bristlecone pine called Methuselah that stands in the White Mountains of California. This amazing tree is almost 5,000 years old! Oddly, some of the worlds smallest trees are also conifers. Many conifers are used in the Japanese art of bonsai, which demands extremely tiny specimens. Though they appear in different forms, a conifer is comprised of familiar botanical structures: they have root systems, leaves, and stems that help move nutrients through the tree. Conifer leaves are specialized to prevent water loss, and conifer root systems are shallow but relatively widespread. The roots deliver water up the tree through chains of specialized tracheid cells in the wood. Nutrients flow much more slowly through coniferous trees compared to deciduous trees, because they lack the relatively wide pipes that run through the wood of deciduous trees.
Conifer Lecture: Detailed, illustrated notes from a college-level lecture on conifers. Extremely detailed discussion of each part of a coniferous tree, with lots of information on reproduction and useful facts on water transport. Detail photographs with notations.
Coniferophyta: Overview information about the phylum to which conifers belong. Focuses on reproductive and vegetative information.
The Pines: Overview conifer information. Particularly useful for its annotated detail photographs of the reproductive organs in male and female cones.
Bark, Wood, Roots, and Leaves: A detailed study of the different parts of trees, with several educational comparisons between coniferous and deciduous trees.
How to Identify Conifers: Detailed, scientific article discussing how to identify conifers under a microscope. Several detailed photographs of specimens showing the cell walls and other microscopic structures up close.
Identifying Conifer Trees: Helpful chart showing the basic presentation of coniferous trees and cones native to the state of Oregon. From the Oregon Forest Resources Institute.
A Field Guide to Conifers: Detailed field guide to identifying conifers in the northeast United States.
The Constant Conifer: From New Hampshire Public Radio, a brief reflection on the conifer, with some evolutionary background and fast facts about them.
Conifer Life Cycle: Accessible article focusing on the life cycle of conifers. Breaks down information into easy-to-understand chunks using several helpful diagrams, charts, and photographs.
Plant Cells, Tissues, and Tissue Systems: About the various kinds of microscopic biological systems found in plants, including the tracheid cells that are used in water and nutrient transport by coniferous trees. Also describes the vascular transport system in plants as a whole.
Choosing Landscape Evergreens: On soil and climate requirements for evergreens and their value in landscaping.
Redwood National and State Parks: Official website for the Redwood Parks in the state of California.
Oldest Living Tree Tells All: Interesting narrative about the history and controversy surrounding the Methuselah tree and efforts to learn more about it through scientific experiments.
NOVA Online: Methuselah Tree: Companion website for Methuselah Tree, the PBS documentary concerning the worlds oldest tree.