Incredible Wood

FROM THE WOODS

Incredible Wood

College of Agricultural Sciences Cooperative Extension

College of Agricultural Sciences • Cooperative Extension

AN EDUCATIONAL SERIES ABOUT FORESTRY FOR YOUTH ood is from trees keep producing more harvested from forests across also relates to how the wood is trees...but is that wood. the state to meet people’s cut from the tree and the tree’s all? Hardly! needs. growth pattern. Yet, many of W One reason we can use wood Wood is a natural, attractive, the products that are made for so many different things is versatile, and useful material from wood do not look like that there are many different WOOD STUFF that we use in thousands of wood at all. We use numerous species of trees. Each species ways. You may think you Just what is wood? Wood is wood products without ever of tree produces wood with its know many ways to use wood, the hard, fibrous, inner part of thinking of their connection own properties. For example, but you might be surprised. A trees and is mostly dead cell to wood. Here are the ways we some woods recent count walls. All wood is formed use the wood from are hard and listed over from the same five chemical Pennsylvania’s trees. some are soft; 5,000 products substances: cellulose, hemicel- some are flex- made with lulose, lignin, ash-forming ible and some LUMBER wood, and the minerals, and “extractive” are stiff. Ap- list keeps grow- chemicals. How these sub- Almost 70 percent of all the proximately ing. Wood is a stances vary in their volume trees harvested in Pennsylva- 30 of Pennsyl- truly renew- and characteristics is what give nia are used to produce lum- vania’s 108 able natural each species its unique ber. Lumber is simply tree species have commercial resource. If forests are cared wood properties. pieces of wood, importance; their wood is such as boards for and managed properly, Cellulose, hemi- or beams, cut cellulose, and from trees. lignins account More than 700 for about 97 per- sawmills across cent of all wood. Pennsylvania Cellulose and produce lumber. hemicellulose Most of our state’s are what make lumber (about 95 percent) up the wood’s is from hardwood trees. Hard- cell walls, and lignin acts like a wood trees have broad flat glue holding the cells together. leaves that drop every fall. The other two substances— They include red oak, sugar ash-forming minerals, and “extractive” chemicals—make up only about 3 percent of wood by weight. The ash- Wood is an forming materials are minerals incredibly the tree extracted from the versatile and environmentally soil. The extractive chemicals friendly are essentially the waste prod- material. ucts from when the tree’s cells were living. Extractive chemicals often give wood its color and odor. When people think of wood, Wood is a truly they think of its appearance. renewable natural Wood is attractive to look at, resource. If forests are cared for and managed and each species has its own properly, trees keep unique look or figure. Figure producing more wood. and durability are important. Pennsylvania’s hardwood lumber is known around the world for its quality and beauty. This valuable product is shipped to many countries in Europe and Asia. tissues, tickets, envelopes, Pennsylvania also boxes, bags, transfer papers, produces small art supplies, hospital gowns, quantities of soft- and newspapers, to name just Veneer, lumber, sawdust, wood lumber. Soft- a few, are all produced from wood strands, strips, and wood trees are those chips are used in the wood. that have needle leaves. Most manufacture of numerous engineered wood products Furniture is a major product needles stay green and at- of the wood industry. From HARDWOOD VENEER from Pennsylvania’s woods. elegant hardwood to tached to the tree year-round. economical softwood, wood Softwood trees include white Hardwood veneer is a very neered wood products from furniture can be found in pine and eastern hemlock. nearly every home or office. thin layer of wood sliced or Pennsylvania’s woods. Engi- Softwood lumber is largely peeled from logs or pieces of neered wood products are used for building construction, maple, white ash, and black lumber. It is usually made usually a mixture of wood siding, and paneling. cherry. The lumber from from the “highest quality” fibers or wood pieces mixed hardwood trees becomes fur- logs—those that have very few with glues. These products niture, doors, baseball bats, PAPER imperfections such as knots can be made with lower qual- and decay. The purpose of ve- ity trees and sawmill scrap toys, musical instruments, About 25 percent of all the neer is to cover a less attractive materials. They have many flooring, cabinetry, paneling, trees harvested in Pennsylvania or less valuable product with a useful applications. Laminated and many other items for go into paper and paper prod- more attractive wood. Veneer veneer lumber, laminated which attractive appearance ucts. There are several large covers tables, kitchen cabinets, paper mills in Pennsylvania. Each American uses over doors, and floors. It also cov- 700 pounds of paper, in its Paper is made almost entirely ers many musical instru- various forms, every year! from wood pulp. When wood ments such as guitars, is ground up and broken pianos, and or- down, either mechanically or gans. Only about chemically, two main things 2 percent of all the remain: wood cells (referred to trees cut in Penn- as “fibers”) and lignin. Wood sylvania are made pulp consists of individual into veneer. wood fibers with the lignin removed. We use both ENGINEERED hardwood and soft- WOOD wood trees for PRODUCTS making wood Veneer, lumber, saw- pulp. The dust, wood strands, Veneer covers tables, many uses of strips, and chips are kitchen cabinets, doors, and paper are mind- floors. It also covers many used in the manufac- musical instruments such as boggling. Books, ture of numerous engi- guitars, pianos, and organs. lumber, fiberboard, ceiling Prepared by: Sanford S. Smith, tiles, strand board, and par- Wood in ice cream? natural resources and youth extension specialist, and Lee R. ticleboard are examples of Stover, extension wood prod- engineered wood products. ucts specialist. Appreciation to Holgate Toys, WOOD CHEMICALS OAKWORKS Inc., Paul Downs Cabinetmakers, and Pennsylva- Wood is also used to pro- nia House Furniture for their assistance with some of the duce chemicals. Cellulose, photos used in this publication. hemicellulose, and lignin This publication was produced are the source of most of with support from the Pennsyl- these chemicals. Wood vania Hardwoods Development chemicals become things Council, Pennsylvania Depart- ment of Agriculture. like cosmetics, rayon cloth, Believe it or not, wood is a component of that creamy ice cream cone and many other products that cellulose sponges, photo- Visit Penn State’s College of Agricultural Sciences “wood” surprise you, like cosmetics, rayon cloth, on the Web: http://www.cas.psu.edu graphic films, food addi- cellulose sponges, photographic films, food additives, salad dressing, shampoo, and toothpaste. Penn State College of Agricultural Sciences re- tives, and fillers for many search, extension, and resident education pro- types of plastics. Wood grams are funded in part by Pennsylvania coun- FIREWOOD best to use for firewood. ties, the Commonwealth of Pennsylvania, and the chemicals and components U.S. Department of Agriculture. Hardwoods burn longer are found in ice cream, salad Wood is also useful as a This publication is available from the Publications and give off more heat per Distribution Center, The Pennsylvania State Uni- dressing, shampoo, and fuel. Trees capture the sun’s versity, 112 Agricultural Administration Building, unit volume than softwoods. University Park, PA 16802. For information tele- toothpaste. Manufacturers energy to produce sugars. phone 814-865-6713. often use cellulose gum These sugars are used to INCREDIBLE WOOD Issued in furtherance of Cooperative Extension made from wood to thicken Work, Acts of Congress May 8 and June 30, produce cellulose, hemicel- 1914, in cooperation with the U.S. Department and smooth foods and other lulose, and lignin for grow- The next time you think of Agriculture and the Pennsylvania Legislature. T. R. Alter, Director of Cooperative Extension, The items. While very little of ing wood. When wood is about wood, think about all Pennsylvania State University. Pennsylvania’s wood actually burned, energy is released as the important products you This publication is available in alter- ends up in these types of heat. Tens of thousands of enjoy and use from it. Wood native media on request. products (our hardwoods homes in Pennsylvania heat is beautiful to look at and The Pennsylvania State University is committed to the policy that all persons shall have equal access are more valuable when with firewood. Wood fuel fascinating to work with. to programs, facilities, admission, and employment without regard to personal characteristics used as lumber), many of can also be used to generate Wood is an incredible mate- not related to ability, performance, or qualifica- these wood chemical-using tions as determined by University policy or by electricity. Smaller and rial useful in thousands of state or federal authorities. It is the policy of the products are produced in crooked trees that are not ways, and it’s a truly renew- University to maintain an academic and work environment free of discrimination, including the state. useful for lumber are the able natural resource. harassment. The Pennsylvania State University prohibits discrimination and harassment against any person because of age, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, or veteran status. Discrimination or harassment against faculty, staff, or students will not be tolerated at The Pennsylvania State University. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania State University, 201 Willard Building, University Park, PA 16802-2801, Tel 814-865-4700/V, 814- 863-1150/TTY.

Produced by Information and Communication Technologies in the College of Agricultural Sciences

CAT UH156 10M7/02nvo4255

Wood is useful as a fuel for heating homes and generating electricity. FROM THE WOODS Hardwood Lumber

College of Agricultural Sciences • Cooperative Extension

AN EDUCATIONAL SERIES ABOUT FORESTRY FOR YOUTH ennsylvania is known for its Hardwoods vs. softwoods beautiful and productive Hardwood trees have leaves that are forests. More broad, flat, and Pthan 108 different kinds of green in the summer trees (each one called a “spe- (left). Softwood trees have leaves cies”) grow naturally here. that are narrow, called needles, and Forests provide many benefits most species stay and materials that we need. green all year round Red oak Hemlock (right). Forests are places to camp, (hardwood) (softwood) hike, fish, and watch wildlife. Forests also provide us with we need. This is why forests chemicals, building products, Log preparation. Before the wood we use to make are “renewable.” and lumber. Lumber is simply it is sawn, a log is usually run many different products. logs (sections of tree trunks) through a debarker, which re- For some of our needs, we cut into pieces, called boards. moves the bark. Debarking Forests that are well cared for remove trees from the forest. prevents wear and damage to can continuously provide the These trees go through many the saw blade from soil or many benefits and materials processes to produce paper, HARDWOODS AND SOFTWOODS stones that might be stuck in The tree species of Pennsylva- or on the bark. nia can be placed into two The sawmill also may use a categories. metal detector to find old Hardwood trees are easy to recognize because in the summer their leaves are broad, flat, By-products and green, and in the fall the Nothing is wasted in leaves change color and drop the lumber industry. Bark becomes off. Over 85 percent of landscaping mulch, Pennsylvania’s trees are hard- and sawdust is used woods, and many are valuable as animal bedding or for particleboard for making hardwood lumber. production. Softwood trees have leaves that are narrow, called needles, and most species stay green all year round. Pennsylvania’s state tree, the eastern hemlock, is a softwood.

Sawdust FROM THE FOREST Tr ucks transport the logs harvested from the forest to the log yard at a sawmill. In the log yard, people and machines sort and stack logs by species, length, and quality.

Bark From forest to lumber . . .

Loading logs for 1 Transporting logs2 Sawmill 3 processing 4 Debarking

8 Kiln-drying lumber 7 Air-drying lumber 6 Grading 5 Sawing

nails, fencing, or other metal “By-products.” The bark paper, and any excess wood objects that were attached to Where do and other by-products, such as can become fuelwood. the tree’s trunk sometime dur- sawdust, slabs, or wood chips, Pennsylvania’s Grading. Hardwood lum- ing its growth. Undetected ob- were once considered “wood harvested ber is inspected and sorted for jects could seriously damage waste.” Today, they are no its appearance and beauty. the saw blade or injure a saw- trees go? longer waste. Bark becomes This is called grading. Imper- mill worker during sawing. landscaping mulch. Sawdust is fections or “defects” like usedBark asand animal sawdust bedding or for Sawing. knots, splits, and decay may In the sawmill, a particleboard (boards made large saw cuts the curved sides, Lumber greatly reduce the value of 70% from a mixture of sawdust and hardwood lumber. The saw- or “slabs,” off the bare log to glues pressed together). ing process removes or cuts make four flat surfaces. Aided Slabs and chips produce by lasers, computers, or just Paper away some defects, but not all. their eyes, the saw operators Products 25% (called “sawyers”) evaluate each log for the lumber desired. The Red oak Maple sawyers vary the spacing of the cut in the log to create indi- Other products 5%: veneer, bats, cabin logs, vidual boards. Other saws fence stock, etc. square off edges and cut boards to length. Lumber is cut into standard thicknesses and differ- Cherry ent widths and lengths.

White oak Drying lumber. After grading, lumber is often air- dried and/or dried in a lumber dry kiln. A lumber dry kiln is a large, low-temperature oven that dries the hardwood lumber over a period of several weeks. Kiln-dried wood is less likely to crack and twist out of shape.

HARDWOOD LUMBER PRODUCTS Many different products, including kitchen cabinets, flooring, household furniture, doors, window frames, decorative molding, pallets, and factory-made wooden buildings come from Pennsylvania’s hardwood lumber. Many of these products are manufactured right here in Pennsylvania.

Pennsylvania also exports From furniture to flooring, there are thousands of hardwood lumber products. some logs and lumber to other states or countries for Prepared by Sanford Smith, natural resources and youth specialist; further manufacturing. ful texture and color. Hard- Roy Adams, former associate professor of wood products; and Pennsylvania’s hardwood wood lumber is just one of Anni Davenport, former extension assistant in forest resources. the many products we re- lumber is among the finest Support for the printing of this document was provided by the in the world. It has beauti- ceive from renewable forests. U.S. Forest Service, the Department of Conservation and Natural Resources, and the Pennsylvania Bureau of Forestry.

Appreciation to Spectra Wood, Thomas Timberland, and Deer Park Lumber Co. for providing facilities for on-site photography.

This publication is available from the Publications Distribution Center, The Pennsylvania State Univer- THE BAT CONNECTION sity, 112 Agricultural Administration Building, University Park, PA 16802. For information telephone (814) 865-6713.

Major league Where trade names appear, no discrimination is intended, and no endorsement by Penn State Cooperative Extension is implied. baseball bats are Issued in furtherance of Cooperative Extension Work, Acts of Congress May 8 and June 30, 1914, in made from white cooperation with the U.S. Department of Agriculture and the Pennsylvania Legislature. T. R. Alter, Di- rector of Cooperative Extension, The Pennsylvania State University. ash lumber. This This publication is available in alternative media on request. wood is shock- The Pennsylvania State University is committed to the policy that all persons shall have equal access to resistant, strong, programs, facilities, admission, and employment without regard to personal characteristics not related to ability, performance, or qualifications as determined by University policy or by state or federal authori- and relatively ties. The Pennsylvania State University does not discriminate against any person because of age, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, or veteran sta- light—perfect for tus. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania State University, 201 Willard Building, University Park PA 16802-2801; Tel. (814) 865- slugging a homer. 4700/V; (814) 863-1150/TTY.

College of Agricultural Sciences • Cooperative Extension

AN EDUCATIONAL SERIES ABOUT FORESTRY FOR YOUTH ardwood veneer is a thicker veneer is more durable very thin layer of on plywood flooring. H wood sliced or peeled The most common types of from a hardwood log. It is a trees used for making attrac- unique and valuable forest tive hardwood veneer are red product. It is usually made oak, black cherry, black wal- from the “highest quality” nut, sugar maple, tulip poplar, logs—those that have very few and white ash. Only about 2 imperfections such as knots percent of all the trees cut in and decay. Hardwood veneer Pennsylvania are made into has many uses. veneer. The rest are made into hardwood lumber (70 per- VENEER IS EVERYWHERE cent) or paper and other wood The purpose of veneer is to fiber products (25 percent). cover a less attractive or less valuable product with a more A FASCINATING PROCESS attractive surface. Veneer cov- Veneer production begins ers tables, kitchen cabinets, with the harvest of trees in the doors, and floors. It also covers forest. There, tree trunks are many musical instruments cut into logs and separated such as guitars, pianos, and or- into two piles: logs for sawing gans. Using veneer helps into lumber (called sawlogs), manufacturers keep down the and logs for chipping to make cost of making wood products. wood fiber products such as This makes wood products paper. The sawlogs are sent to more affordable. The standard Only about 2 percent sawmills where workers sepa- of all the trees cut in thickness of hardwood veneer rate logs that may qualify as Pennsylvania are made is 0.6 millimeters (1/42 of an into veneer. veneer quality from the other inch). However, it may be cut logs. Veneer log buyers come thinner or thicker depending to the sawmill and look at on its final use. For example, these logs. They decide which and negotiate purchases. These The logs “cook” there for ap- thin veneer wraps best over logs meet the quality criteria logs are worth much more proximately 48 hours. The ex- moldings and furniture, while than other logs, and competi- act cooking schedule is differ- tion between buyers can be ent for each species of wood. keen. Once sold, truckers take Overcooking changes the the logs to a veneer plant. color of the log, while undercooking results in rough At the veneer plant, a debarker or uneven cutting of the ve- removes the bark from the neer. Mill workers, aided by logs. A metal detector then computers, adjust the tem- scans the logs to check for perature and cooking time un- pieces of metal, like fence wire, til the wood cells are softened. nails, and bullets. Metal must This makes it possible to slice be removed from logs because veneer from the log. After the it will damage the expensive cooking process, the logs move The purpose of veneer is veneer cutting machinery. A to cover a less attractive to a “slicing” or “peeling” area. or less valuable product, worker then loads the logs into such as particle board. a high-humidity steam cham- The slicing method, the most ber or into a hot water vat. commonly used in Pennsylva- The step-by-step process of making veneer

Debarked logs “cooked” to 1 Logs are sliced Veneer is dried and stacked soften the wood cells for slicing. 2 3

Stacked veneer ready for sorting Veneer strips are edge-glued 4 5 6 Final trimming and repair and trimming together into sheets

nia, involves moving a log off the log in a continuous need to be dried to prevent across a knife to produce indi- sheet. It is called rotary cut splitting, twisting, and crack- vidual slices of veneer. Sliced veneer. ing. A stainless steel screen veneer has a more attractive carries the veneer through a Initially, both sliced and grain pattern and is generally large dryer. The temperature, peeled veneer are high used on valuable furniture and in moisture. They cabinetry. The peeling method uses a rotary lathe, where the log turns against a knife and veneer peels off the log. This process is like unrolling toilet paper. The thin veneer comes

The most common types of trees used for making attractive hardwood veneer are red oak, black cherry, black walnut, sugar maple, tulip poplar, and white ash humidity level, and speed of Prepared by: Robert S. Hansen, the dryer determine how Extension Forester, Bradford Not all wood is cut out to be veneer County, Sanford S. Smith, tender and flat the veneer is natural resources and youth ex- after drying. Once dried, tension specialist; and Lee R. clippers trim the edges and Stover, wood products extension specialist, Penn State any splits from the ends of School of Forest Resources. the veneer pieces. Appreciation to Lee Cummings, Oak Hill Veneer, and Interna- A NATURAL PRODUCT tional Timber and Veneer (ITV) for their assistance in the Sliced veneer is often edge- production of this publication. glued and spliced together This publication was produced to make larger sheets. Ply- with support from the Pennsyl- vania Hardwoods Development wood, door, and furniture Veneer is usually made from the “highest quality” Council, Pennsylvania Depart- companies use these spliced logs. Defects and imperfections such as knots and ment of Agriculture. decay (above) make veneer unusable. faces to cover other materials Visit Penn State’s College of Agricultural Sciences and make the final product on the Web: http://www.cas.psu.edu more attractive. Rotary cut sheets of glued veneer often covered with sliced Penn State College of Agricultural Sciences re- search, extension, and resident education pro- or peeled veneer is often pressed or laminated to- hardwood veneer to make it grams are funded in part by Pennsylvania coun- ties, the Commonwealth of Pennsylvania, and the made into plywood. Ply- gether. Plywood made from more attractive. Rotary cut U.S. Department of Agriculture. wood is made of several peeled softwood veneer is veneer may also cover This publication is available from the Publications kitchen cabinets, vanities, Distribution Center, The Pennsylvania State Uni- versity, 112 Agricultural Administration Building, curved windows, and chairs. University Park, PA 16802. For information telephone 814-865-6713.

Because veneer is so popu- Issued in furtherance of Cooperative Extension lar, there are many kinds of Work, Acts of Congress May 8 and June 30, 1914, in cooperation with the U.S. Department artificial veneer. Artificial ve- of Agriculture and the Pennsylvania Legislature. T. R. Alter, Director of Cooperative Extension, The neer is anything that at- Pennsylvania State University. tempts to look like real This publication is available in alter- wood veneer but is not. Ex- native media on request. amples of artificial veneer The Pennsylvania State University is committed to the policy that all persons shall have equal access can be found on desks to programs, facilities, admission, and employment without regard to personal characteristics where a pressed board or not related to ability, performance, or qualifica- plywood product has a pic- tions as determined by University policy or by state or federal authorities. It is the policy of the ture of veneer glued on it University to maintain an academic and work environment free of discrimination, including and then covered with a harassment. The Pennsylvania State University prohibits discrimination and harassment against layer of plastic or vinyl. any person because of age, ancestry, color, disabil- Other products may have a ity or handicap, national origin, race, religious creed, sex, sexual orientation, or veteran status. veneer pattern actually Discrimination or harassment against faculty, staff, or students will not be tolerated at The molded into the pressed Pennsylvania State University. Direct all inquiries wood itself. These treat- regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania ments increase the value of State University, 201 Willard Building, University Park, PA 16802-2801, Tel 814-865-4700/V, 814- the product, but they are 863-1150/TTY.

not as valuable as a real Produced by Information and Communication Veneer increases the hardwood veneer finish. Technologies in the College of Agricultural Sciences amount of usable © The Pennsylvania State University 2002 material from each Hardwood veneer is all- high quality log and CAT UH155 10M6/02nvo4255 makes attractive natural. It is made from the wood products more highest quality logs cut in affordable. the forest. It is a beautiful and useful forest product. FROM THE WOODS Paper !

College of Agricultural Sciences • Cooperative Extension

AN EDUCATIONAL SERIES ABOUT FORESTRY FOR YOUTH aper! It’s everywhere. metal tablets, and even leaves fibers for papermaking. Also and linen fibers (for printing It’s all around us. You to write on. during this time, various types things like money and maps). are looking at paper of machinery and processes But what exactly is wood P The Chinese invented the first right now. No other manufac- were developed in Europe and pulp? When wood is broken true paper about 2,000 years tured material is so widely America for grinding or down, either mechanically or ago. Their paper was made available, versatile, and so im- chemically breaking down chemically, two main things from a watery paste of portant to our everyday exist- wood and producing paper. are left: fibers (composed ground-up mulberry bark, ence. We read books. We print Wood was in mostly of two kinds of cellu- hemp, and out Web pages and computer abundant sup- lose) and lignin. The fibers are cloth rags. files. We dry our hands on ply, and the actually the remains of the They pressed paper towels. We wrap gifts. use of wood tree’s cells. They are small, this paste to We take notes. These are just a rather than about 1/8 of an inch in length remove the few of the ways we use paper. rags made it and 1/150 of an inch in width water, then You may have heard that much cheaper (about 1/10 the thickness of a sun-dried the paper comes from trees, but and easier to human hair). When a piece of resulting mat that’s just part of the story. make paper. paper is torn, you can see tiny of compacted Hand-copied text on cloth rag paper from a 15th century This was the wood fibers along the ripped BOOK COURTESY OF: RARE BOOKS AND MANUSCRIPTS, PENN STATE LIBRARIES fibers to HISTORICAL WRAP Italian manuscript beginning edge. Lignin is the glue, or make a sheet of the mass-produced cement, that held the fibers in The ancient Egyptians devel- of paper. It wasn’t until an paper industry, an industry place in the wood. Wood pulp oped a paperlike substance invading army captured a that played an important part is nothing more than a huge nearly 4,000 years ago. Chinese paper mill 600 years By weaving together later that the papermaking the reeds of papyrus process was carried west to plants into the Middle East, Africa, and Papyrus mats, and Europe. was similar then to modern For many years throughout day paper, pound- but much the Western world, paper was ing them, less only made from discarded versatile. they produced rags and clothing. Cotton and a thin, tough linen fibers produced a fine, sheet for writing on. strong paper, and the use of This product was called other plant fibers for paper- papyrus, and our English making was forgotten during word “paper” has its origin in the Dark Ages. However, pa- that Egyptian name. Before Modern paper machines per was always in scarce sup- are nearly as long as a papyrus, people used clay tab- ply due to the constant short- football field and can lets, stones, wooden create a sheet of paper age of used cloth. The first pa- boards, cloths, 6–14 feet wide and 40 per mill in America, estab- miles long in an hour. animal skins, lished outside of Philadelphia, Pennsylvania, in 1680, also in the development of our quantity of individual wood used old rags to produce pa- country and the world, and fibers with the lignin re- wood fibers per. By 1802, there were still does! moved. The natural color of nearly 200 such mills in the wood pulp ranges from dark United States. SIMPLY PULP brown to light gray. When a piece of During the mid- Today, almost all paper is Before wood pulp is produced paper is torn, you 1800s, European can see tiny wood made from wood pulp; how- from a tree, several steps must fibers along the papermakers redis- ever, some specialty papers are be taken. First, trees are cut ripped edge. covered the use of tree still produced using cotton and transported to a paper fibers. However, chemical methods are more widely used Here’s how paper is made. . . and are more energy-efficient. The chemical methods involve cooking wood chips in large tanks. These tanks, called digesters, are similar to pressure cookers. Various chemicals, called the cooking liquor, help break down wood chips into a Naturally dark brown wood mushy mass of fibers. Regard- pulp (right) is useful for making Pulpwood yard stores Pulpwood is debarked 1 the raw material 2 and chipped paper bags and boxes. After less of the method used to bleaching and softening (left) produce pulp, it is always pulp produces higher grades of paper and other products. washed and screened (to remove impurities) before it becomes paper. mill. Most of the trees used for papermaking in Pennsylva- Wood pulp is also made from nia are smaller trees that have chipped sawmill waste wood little potential for making or from used paper. The recy- lumber. At the mill, the bark cling process for used paper is Wood chips are cooked 3 in a digester and broken 4 Pulp is washed, is removed from the trees. similar to making “virgin” pulp down into pulp bleached, and softened

Pulp is mixed with water Paper machines rapidly 5 and pumped onto a 6 press, dry, and smooth moving screen the pulp

Computers monitor the Paper machines produce 7 entire process 8 large rolls of paper

Lastly, the fibers are either directly from wood. In recy- mechanically or chemically cling, the wood fibers in the extracted from the wood and paper must be separated again then separated from the lignin. or “repulped” in water. It is In the mechanical method, also necessary to remove the grindstones tear wood fibers chemicals, such as adhesives and ink, on used paper. The apart in water, or the trees are Rolls of various weights Sheets of paper are 9 and colors are stored in 10 shipped to buyers chipped up into small pieces recycling process shortens the warehouses first and then ground down to length of the individual fibers, Prepared by Sanford S. Smith, natural resources and youth extension specialist; James C. Finley, associate professor of forestry; and Lee R. Stover, wood products extension specialist, Penn State School of Forest Resources. Appreciation to Glatfelter, Weyerhaeuser, and Comic Swap, Inc. for their assistance in the production of this publication. This publication was produced with support from the Pennsylvania Hardwoods De- velopment Council, Pennsylva- nia Department of Agriculture.

Visit Penn State’s College of Agricultural Sciences on the Web: http://www.cas.psu.edu

Penn State College of Agricultural Sciences re- search, extension, and resident education programs are funded in part by Pennsylvania coun- ties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.

This publication is available from the Publica- tions Distribution Center, The Pennsylvania State University, 112 Agricultural Administration Building, University Park, PA 16802. For infor- Paper products are all around us, including your favorite comic books and mation telephone 814-865-6713. magazines, newspapers, boxes, office paper, envelopes, paper towels, toilet paper, Issued in furtherance of Cooperative Extension packaging, gift wrap, and so much more. Work, Acts of Congress May 8 and June 30, 1914, in cooperation with the U.S. Department so wood fibers can only be the slush moves along on usually rewound and cut of Agriculture and the Pennsylvania Legislature. T. R. Alter, Director of Cooperative Extension, recycled several times before the screen and then through into smaller rolls or packs, The Pennsylvania State University. they are too short for mak- a series of heated cylinders then shipped to printers and This publication is available in ing paper. That’s why it is to press, dry, and smooth it, manufacturing plants to alternative media on request. The Pennsylvania State University is committed necessary to mix new pulp ensuring uniform thickness. become products. There are to the policy that all persons shall have equal with recycled pulp to make Rolls of paper are the fin- thousands of different paper access to programs, facilities, admission, and employment without regard to personal characteris- paper products. ished product. They are products—everything from tics not related to ability, performance, or qualifi- coffee filters to facial tissues cations as determined by University policy or by It’s easy to recycle paper state or federal authorities. It is the policy of the University to maintain an academic and work and it makes good sense! and magazines. Throughout MODERN PAPERMAKING environment free of discrimination, including The papermaking process the papermaking process, harassment. The Pennsylvania State University prohibits discrimination and harassment against begins by washing, bleach- tests ensure paper quality. If a any person because of age, ancestry, color, dis- roll of paper does not meet ability or handicap, national origin, race, reli- ing (to whiten or “brighten” gious creed, sex, sexual orientation, or veteran if necessary), and beating (to quality standards for the status. Discrimination or harassment against faculty, staff, or students will not be tolerated at The soften) wood pulp. Starches, desired finished product, Pennsylvania State University. Direct all inquiries it is recycled back into the regarding the nondiscrimination policy to the colors, and other chemicals Affirmative Action Director, The Pennsylvania process. State University, 201 Willard Building, Univer- added at this early stage cre- sity Park, PA 16802-2801, Tel 814-865-4700/V, ate different types of paper. That’s the whole story of 814-863-1150/TTY. After mixing the pulp and Produced by Information and Communication papermaking. Paper is ma- Technologies in the College of Agricultural Sciences chemicals with water, this terial that’s similar to the air “slush” moves into large © The Pennsylvania State University 2002 we breathe. It’s all around CAT UH153 5M6/02nvo4255 papermaking machines. Here, us, we use it continuously, the slush is pumped evenly and we yet we never think onto a fast-moving (58 feet about it! Can you imagine a per second), fine-meshed world without paper? screen. As water drains off,