Cupressaceae

Life History

The Cupressaceae represent a large family of conifers . Basic life history of the Cupressaceae follows the general life history of conifers in terms of issues as life cycle and reproduction and many other environmental characteristics. This page will be devoted to a several types of Cupressaceae that have interesting and distinguishing characteristics. The family as a whole is distributed world wide but predominantly located in the Northern Hemisphere. Many species reside in North American forests. In general, the trees of the Cypress family live in temperate climates and require a relatively significant amount of moisture.

One of the most important groups in the Cypress family are the Redwoods. The redwoods, which are also identified as the Sequioas, have the distinction as being the largest trees in the world. Many adult trees are estimated at weighing more than 2000 tons and many times the branching begins 40 meters from the ground. Also considered to be the longest living trees. Some stumps have been found with more than 3000 rings indicating the trees are over 3000 years old. The Sequioas have a limited range for the most part and are located primarily along the Pacific Coast in California and Oregon although some species like Metasequoia are found in China or are artificially planted in Europe or Asia.

One type of Redwood is the Sequoia sempervirens . One unique characteristic is the ability to produce asexually through the formation of a ring of young trees around the base of the adult tree. These young trees are formed out of the parent root system and therefore receive the nutrients and water gathered by the parent's roots like an umbilical cord as the young tree develops. Asexual reproduction allows the Redwoods to reproduce at a faster rate as cone and seed production can take several years and also ensures greater success as the young trees are fed by the parent. The Redwoods are long lived trees due to unusual resistance to wood-rotting fungi and thick bark about a foot thick that makes the tree resistant to forest fires. Unfortunately, this tall tree created desirable wood and was exploited by loggers in the beginning of the century. These trees were logged up until the 1930's when they were finally protected by the government. One disease of the Squoia sempervirens is caused by a fungus, Heterobasidion annosum, that attacks the root system and leads to the eventual death or the tree. This disease spreads easily to adjacent trees via root contacts. Diseased trees continually provide a desirable habitat for bark beetles, flathead borers, and engraver beetles, maintaining high populations of these pests. This results in more frequent and more damaging insect outbreaks.

The most famous Sequoias are the Sequoiadendron giganteum or "Big Tree". These are known to be the largest trees in the world, the trees are often over 100 meters tall and greater than 25 meters around in circumference. Statistics show that under natural conditions, one seed in a million will grow to an adult tree. The tiny wind blown seeds has proven to be a poor method of dispersal and seedlings are easily susceptible to the gray mold fungus Botrytis cinerea . Many seedlings are trampled by humans that go to admire the large trees in the Redwood forests. Luckily, seedlings grow well when artificially planted and maintained in arboretums. Unlike the Squoia sempervirens , the wood of the Sequoiadendron giganteum wood has less economical value because of its brittleness and softness. These massive trees are also resistant to fires due to the thick bark that is more than two feet thick and the tannic acid in the sap. Tannic Acid is an ingredient in some fire extinguishers and also has some healing effect on damaged areas of trees. Another feature of these trees is the large root system. Because these trees grow so large (300 ft), the roots that support the tree grow out about 200 feet from the trunk of the tree.

Another important group of Cupressaceae is the Juniper. There are some 60 species throughout the Northern Hemisphere. One main difference of Junipers is the cone which has fused the cone scales into a fleshy, berry-like cone. These groups of trees also grow at a much slower rate and are dioecious trees unlike other Cupress family members. Two important diseases affecting Junipers are the rust Gymnosporangium and the insect pest Juniper Webber which spins the foliage together and subsequently turns brown and leads to death.

The most widespread Juniper is the Juniper communis . It has the greatest natural distribution of any tree in the world as it is located throughout the Northern hemisphere. This tree is most well known because its "berries" are used to flavor gin.

Source: Oxford Encyclopedia of Trees of the World. Oxford University Press: Oxford, 1981.

Hugh Johnson. The International Book of Trees. Simon & Schuster, Inc.: New York, 1973.

Donald Peattie. A Natural History of Western Trees. Riverside Press: Cambridge, 1953.

Scott Leathart. Trees of the World. A & W Publishers, Inc.: New York, 1977.