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Economic Significance

Trees have great economic significance to humans as a source of food, building materials, and paper. Almond, coconut, cherry, prune, peach, pear, and many other tree species are grown in orchards for their fruits and nuts. The apple tree is the orchard tree of greatest economic significance, and there are several hundred different varieties of apples. (Many of North America's best apples grow in New York state and Washington state.) Many trees are also useful for the wood they produce. Wood is used as a construction material and to make furniture. Wood is a valuable construction material because it is relatively inexpensive, easy to cut, and very strong relative to its weight. Many species of pines and other conifers are important sources of softwoods, and many broadleaf trees are important sources of hardwoods.

There are frequent conflicts between conservationists and loggers. In the United States, the coniferous rainforest of the Pacific northwest has been the site of one such conflict. In this region, loggers want to harvest coniferous trees from the forest just as they have done for many years, whereas conservationists seek to preserve the forest because it provides a habitat for the northern spotted owl, an endangered species.



Audubon Society and Staff. Familiar Trees of North America: Eastern Region. New York: Knopf, 1987.

Platt, R. One Thousand-and-One Questions Answered about Trees. New York: Dover Inc., 1992.

Raven, Peter, R.F. Evert, and Susan Eichhorn. Biology of Plants. 6th ed. New York: Worth Publishers Inc., 1998.

White, John, and David More. Illustrated Encyclopedia of Trees. Portland, OR: Timber Press, 2001.


Chaw, S. M., et al. "Seed Plant Phylogeny Inferred From All Three Plant Genomes: Monophyly of Extant Gymnosperms and Origin of Gnetales from Conifers." Proceedings of the National Academy of Sciences of the United States of America 97 (2000): 4086-4091.

Peter A. Ensminger


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—Physical attraction between different types of molecules.


—Physical attraction between molecules of the same type.

Cork cambium

—Undifferentiated plant tissue which gives rise to cork cells and secondary cortex.


—Identification and classification of woody plants.


—Plant tissue consisting of elongated cells which function in the transport of carbohydrates and other nutrients.

Vascular cambium

—Undifferentiated plant tissue which gives rise to phloem and xylem.


—Plant tissue that transports water and minerals upward from the roots.

Additional topics

Science EncyclopediaScience & Philosophy: Toxicology - Toxicology In Practice to TwinsTree - Tree Taxonomy, History Of Taxonomy, Modern Taxonomy, Cell Layers In A Tree Trunk, Growth Rings - Secondary growth