Unformatted text preview: Forests of the United States What is Wood Science? Study of that body of knowledge applicable to wood as a material, including: plant origin of wood properties and characteristics of wood and wood products Application of knowledge in conversion and processing of wood for use
Everett L. Ellis, Education in Wood Science and Technology [p. iii] Boston
August 14, 1765 "Forests are a key element in the broad sweep of United States history... There is no question that without its forests, the United States of America would have a decidedly different history, and would be a decidedly different place than it is today."
Douglas W. MacCleery, American Forests: A History of Resiliency and Recovery 304 million hectares (751.2 million acres) Approx. 33% of the land area of U.S. Forests of the World 4 billion hectares (9.96 billion acres) Forests cover approx. 30% of the planet's land area U.S.A. accounts for 7.5% of Earth's forest cover What is a Forest? There are more than 250 definitions! Definitions may be legal, political or ecological All require tree cover Most include a minimum percentage of canopy cover (overlapping crowns) definitions range from 5-100% canopy cover May require a minimum land area (i.e. 1 acre) U.S. Forest Service Definition
Forest land--Land at least 10 percent stocked by forest trees of any size, including land that formerly had such tree cover and that will be naturally or artificially regenerated. Forest land includes transition zones, such as areas between heavily forested and nonforested lands that are at least 10 percent stocked with forest trees and forest areas adjacent to urban and built-up lands. Also included are pinyon-juniper and chaparral areas in the West and afforested areas. The minimum area for classification of forest land is 1 acre. Roadside, streamside, and shelterbelt strips of trees must have a crown width of at least 120 feet to qualify as forest land. Unimproved roads and trails, streams, and clearings in forest areas are classified as forest if less than 120 feet wide. Think of various ways we describe forests... Old-growth forest Second-growth forest Ancient forest Original forest Healthy forest Plantation forest Natural forest Rain forest Virgin forest Anthropogenic forest Industrial forest Commercial forest National forest Temperate forest Tropical forest Boreal forest Non-industrial private forest Real forest (as in "not a real forest") Woodland The Rich Diversity of U.S. Forests Forest Types "Forest type" describes forests that prevail in a given region Name based upon dominant tree species within that region's forests For example, the dominant forest type in West Virginia is oak-hickory Tree: "A woody plant that attains a height of at least 20 feet at maturity in a given locality and usually (not always) has a single selfsupporting stem or trunk." It all starts with photosynthesis CO2 & H2O (both greenhouse gases) are combined to form simple sugars in the leaves The process is powered by solar energy What's inside the bark? Wood The portion of a tree's stem, branches, and roots located inside the bark Also known as the xylem Wood
"Changes and developments in wood usage make up a little-known but important part of U.S. history." W.G. Youngquist and H.O. Fleischer, Wood in American Life Growth of the Tree
Simple sugars produced in photosynthesis are transported down the stem through the phloem (inner bark) to newly forming cells of the xylem (wood) where they are converted into complex molecules (polymers) cellulose, hemicellulose and lignin. Cell Structure of Wood Long, slender tubes 100x longer than wide Functions in the tree: Fluid transport Strength The properties of wood make it very useful to humans Tree Taxonomy Taxonomy: Systematic classification of plants and animals according to their natural relationships All trees belong to the plant kingdom but hardwoods and softwoods belong to different phylum Species: The most basic unit of taxonomy; organisms possessing similar characteristics and are capable of interbreeding to produce fertile offspring There are an estimated 10,000 tree species in the world More than 1,000 species are native to the U.S. Only 180 tree species are native to Canada The 10 most common species comprise nearly half of the trees in the U.S. Hardwoods & Softwoods Hardwoods Belong to the plant phylum Angiospermae Broad-leaved trees Encased seeds, e.g. fruit, nuts, legumes, samara Not to be confused with deciduous trees Softwoods Belong to the plant phylum Gymnospermae "Naked seed" (e.g. cones) Leaves are needles Also known as conifers Not to be confused with non-deciduous trees Deciduous Plant: A plant that loses its leaves in winter or in the dormant season Not all hardwoods are deciduous, i.e. live oak. Some softwoods are deciduous, i.e. eastern larch (tamarack). Wood of the Hardwoods Hardwoods contain Most other specialized fluid hardwood cells are transport cells specialized strengthknown as vessel providing fibers elements or pores Wood of the Softwoods Almost all the wood cells of softwoods are of the same type tracheids that serve both functions of fluid transport and strength Forests of the World Hardwood & Softwood Growing Stock by Region
10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 East West million cubic meters Hardwood Softwood How much of the forested area of the U.S. that existed at the time of European contact remains forested?
A. Approx. B. Approx. C. Approx. D. Approx. E. Approx. F. More than Forested Acres in the U.S.
1200 1000 MM Acres 800 600 400 200 0 1630 1760 1800 1850 1900 1953 1963 1977 1987 1997 2006 Year Thoughts about History History is written by survivors. History is often written by "winners." Two eyewitnesses may remember or interpret the same event differently. History may be distorted for self-serving reasons. History may be distorted by later writers or writers from a different culture who interpret events through their own particular prism of biases. More... History, like science, in its purest form is a search for truth. Therefore, one must approach a study of history (and science) with an open mind and a healthy degree of skepticism. ...
View Full Document
- Spring '11
- Forest, forest Ancient forest Original forest Healthy forest Plantation forest, forest National forest Temperate forest Tropical forest Boreal forest, forest Natural forest, forest Anthropogenic forest, forest Second-growth forest