Chapter 7 Forests

Forests Complex association of trees, shrubs, and plants Each one contributes to the life of the community Forests cover one-third of the United States A wide variety of products comes from trees

Forests Two major types of forests Evergreen: do not shed their leaves mostly conifers; produce lumber called softwood Deciduous: shed their needles or leaves every year produce lumber called hardwood

Forests of the United States Eight major forest regions in United States Depending on type of forest, forest soils differ from place to place

Northern Coniferous Forest Largest region in North America Most dominant type of tree is the evergreen or softwoods Some areas contain mixtures of softwoods and hardwoods Region characterized by swamps, marshes, rivers, and lakes Climate is cold

Northern Hardwoods Forest Reaches from southeastern Canada through New England to northern Appalachian Mountains Region extends westward beyond Great Lakes region Populated by several important hardwood species beech, maple, hemlock, and birch trees

Central Broad-Leaved Forest Contains more varieties and species of trees than any other forest region Composed mostly of hardwood trees: oak, hickory, beech, maple, poplar, gum, walnut, cherry, ash, cottonwood, and sycamore Conifers include Virginia pine, pitch pine, shortleaf pine, and red cedar

Southern Forest Located in southeastern part of the United States south from Delaware to Florida west to Texas and Oklahoma Region with most potential for meeting future U.S. lumber and pulpwood needs Most important trees are conifers Hardwoods include oak, poplar, maple, and walnut

Bottomland Hardwoods Forest Occur mostly along Mississippi River Among most productive U.S. forests Productive because of area’s high soil fertility Contains mostly hardwood trees oak, gum, tupelo, and cypress

Pacific Coast Forest Located in northern California, Oregon, and Washington Most productive of forest regions Provides more than 25 percent of annual U.S. lumber production Composed mostly of conifers redwoods, giant sequoias, Douglas fir, ponderosa pine, hemlock, western red cedar, Sitka spruce, sugar pine, lodgepole pine, noble fir, and white fir Important hardwood species include oak, cottonwood, maple, and alder

Central Broad-Leaved Forest Located mostly east of Mississippi River and south of northern hardwoods forest Production of high-quality wood some used to construct high-quality furniture some used in construction and to make industrial pallets

Rocky Mountain Forest Divided into many small areas Extends from Canada to Mexico Composed primarily of conifers western white pine, ponderosa pine, lodgepole pine, spruce, fir, larch, western red cedar, and hemlock aspen only important commercial hardwood

Tropical Forest Some located in southern Florida and southeastern Texas Major trees in region are mahogany, mangrove, and bay Although important ecologically, these species have little commercial value Some of U.S. tropical forests are in Hawaii Wet forest region produces a variety of trees used in the production of furniture and novelties The dry forest region of Hawaii produces many trees with little commercial value

Tree Types Trees may be described in terms of the lumber they produce Softwoods: needle-type evergreens Douglas fir, balsam fir, hemlock, white pine, cedar, southern pine, ponderosa pine, and Sitka spruce

Tree Types Hardwoods: deciduous trees birch, maple, poplar, sweetgum, oak, ash, beech, cherry, hickory, sycamore, walnut, and willow deciduous trees lose their leaves in fall or winter

Douglas Fir Perhaps most important U.S. tree Makes up approximately 20 percent of timber harvested each year Douglas fir forests produce 5 or 6 times more wood than other species Popular as construction lumber and for manufacture of plywood

Cedars Eastern red, eastern white, and western red Cedars have unique properties resist decay makes them useful as fence posts, shingles odor repels insects used to line chests and closets

Maple Maple lumber classified as both hard and soft Hard maple lumber is heavy, strong, and hard used for butcher blocks, workbench tops, flooring, veneer, and furniture Soft maple only approximately 60 percent as strong used for same applications Some species produce sweet sap that is made into maple syrup

Oak Two general types of oak in United States white oak red oak hard, heavy, and strong pores plugged with membranes, making wood nearly waterproof used for structural timbers, flooring, furniture, fencing, pallets red oak highly porous and not especially resistant to decay must be treated with wood preservatives when used outside used for furniture, veneer, and flooring

Cherry Found from southern Canada through eastern United States Cherry wood dense and stable after drying desirable and popular in production of fine-quality furniture expensive and in limited supply

Tree Growth and Physiology A tree begins life as a seed Seed germinates, shoot grows up, and roots grow down and out Trees grow in height and diameter Growth layer called the cambium Produces annual rings

Tree Growth and Physiology Trees contain specialized transportation tissues xylem: carries water and minerals from roots upward to rest of plant phloem: carries food made in leaves to rest of plant

Forest Management Art and science of tree production is silviculture Assumes that forest environment can be managed to be favorable to production of trees Silviculture is practiced with varied intensities Private forest lands are intensively managed National forests are managed with less intensity

Managing a Stand of Trees A stand of trees is managed to produce the desired trees in the desired area It may be necessary to change the environment to favor a particular tree Management decisions are made to favor the growth of the desired species A variety of practices are used plantings, selective harvesting, clear-cutting, etc.

Regenerating a Stand Two types of forest regeneration: natural and artificial Natural regeneration Young trees begin to grow without being planted Harvested area reseeds itself Artificial regeneration Seeds or seedlings are planted at harvest site Often called direct seeding Often results in uniform distribution of trees Gives managers control over species

Timber Management Forest management is an active process Unwanted trees need to be “weeded” Stands of timber need to be thinned Side branches need pruning When stand is ready, it is harvested A harvesting plan is always followed maximizes yield from stand

Types of Harvest Several timber-harvesting methods; each has advantages and disadvantages

Clear-Cutting Controversial method of harvest loss of scenic value erosion desertification habitat loss to native organisms Produces even-aged stands Trees are all of the same age Leave unharvested buffer zones of trees near streams to protect water quality and provide wildlife habitat

Seed Tree Method Mature trees of desired species are protected from cutting in scattered locations throughout forest Purpose of these trees is to provide seed for regeneration and protect seedlings Site preparation is necessary Brush and seedlings are cleared to minimize competition with seeds Shelterwood method is similar When seedlings are established, mature trees are also harvested

Coppice Method Silviculture system where trees are clear-cut and forest regenerates from stump sprouts Care must be taken to protect against soil erosion Tree species generated by coppice method are fast-growing Oaks and aspens often managed this way Trees usually used for fuel or pulpwood Method also has great promise in production of biomass

Selection Cutting Timber harvest method used to identify and harvest trees near end of their productive lives Important to harvest these trees while still vigorous Need to make use of the trees before they become victims of decay or disease

Salvage Harvesting Harvesting of diseased trees or damaged trees Often used after natural disasters Trees dying from insect damage and diseases can still be used for lumber products Examples of natural disasters include forest fires, high winds, insect infestation Once damage has occurred to trees, they need harvesting as soon as possible After two or three years, trees often produce poor-quality lumber

Impact Statements Harvesting requires filing of an environmental impact statement Science-based study details the expected effects of human activity on the environment Must be completed before timber harvests on federal land Study analyzes variety of impacts road building, soil stability, effect on plants and animals, presence of threatened or endangered species

Forests as Valuable Resources economic value biological value habitat value value from climate moderation energy value value for grazing value for recreation value of watersheds

Protection of Forests To preserve this resource, forests must be protected from several threats pests diseases fires mismanagement / deforestation

Forests and Erosion Soil erosion is number one source of water pollution in North America Forest lands are susceptible to erosion after fires and harvesting that disturbs soil Soil conservation efforts can minimize erosion Place straw bales, plastic sheeting, and other types of silt traps to slow water flow