Anthony Camaerei

Psychology

acamaere@lhup.edu

The purpose of the webpage is to acquaint the reader with a basic understanding of the biology behind wood and wood products as well as information and concerns regarding the importance of wood and wood by products and the impact these products have on society at large. 

Overview

1/3 of the earth is covered with forests and behind food-plants, wood and trees have the most impact on society. Knowing this you can already gain an understanding to just how important wood and its by-products are. However, before any discussion can be had with this topic it is crucial to understand what constitutes wood and some basic processes involved with its production. A textbook definition of wood is any plant that has accumulations of the secondary xylem. This covers quite a broad range of pants so to simplify we will only consider trees in this presentation other than bushes, shrubs, and so on. Moving on, the problem with this definition is what is a secondary xylem? To paint a clearer picture of what is being discussed consider the picture below.

The xylem as a whole, is vascular plant tissue that conducts water and minerals throughout the tree. The xylem can be further broken down into sapwood and heartwood. Sapwood is by definition the region of the xylem that actively conducts the water while the heartwood is the older, no longer functioning part of the xylem that is mainly used for support and also acts as a protective layer from decay. There is another part of the whole vascular system of trees called the phloem which is very similar to the xylem except it transports materials synthesized by the tree for storage. Some other important terms to be familiar with are the ray cells, which can be seen in the above diagram as the lateral lines extending from the center. These cells are part of the xylem system only transport water and minerals across the tree. Of course the bark is the external covering and protective layer of the tree. Without getting too technical there is also a layer not shown in this diagram known as the phellogen which produces the cork that I will discuss later.

Characteristics of Wood

Now that we have a basic understanding of wood/trees lets discuss some characteristics. Some terms that are of key importance in this area are porosity, which technically speaking, is the way large vessels are arranged in a given time. Grain is another important characteristic which simply put is the how the cells of the xylem are aligned. The last technical term I will discuss is the figure of wood which is collectively, the number of rays, porosity, and grain, as well as the presence/absence of knots in the wood.

The above characteristics refer to physical properties, meaning those that can be seen. Next I want to talk about mechanical properties, specifically density which in many cases is the most important when considering different types of wood to be used. An example of the importance of measuring density in wood is wood as fuel. typically the more dense a wood is the longer it burns, hence why charcoal burns for much longer periods of time then regular wood. You would not want to use a low density wood such as pine because it will burn too fast. More likely you would use an oak because the various cells constituting this wood are packed closer together. While on the track of wood for fuel and density, it is important to know what a cord is. A cord is a bundle of wood in any form measuring 8ft long by 4 ft high, by 4 ft deep. It becomes important when using wood for fuel because with relation to density, 3 cords of pine equals that of 1 cord of oak.

Other then fuel, densities are important for building and manufacturing goods. I will go this more in the next section when we consider types of woods.

Another characteristic of wood that I would like to discuss is the rings that are visible when a cross-section of the tree is taken, which can be seen below.

As you can see these "growth rings" hold much information that is important to botanists as well as archeologists, who by studying these rings can learn about earlier climates of a particular area, events that took place in that area, and general physical conditions of the tree itself.

Types of Wood

According to Encyclopedia Britannica there are roughly 3000 to 4000 species of wood producing plants. To cover all of them would be nonsense. So they have all been broken down into two main categories, those that bear cones called gymnosperms that produce our softwoods such as pine and spruce and the others that give us hardwoods called angiosperms. Examples of hardwood includes oak, beech, and teak. The majority of wood is hardwood which accounts for around 60% of all wood while the remainder is softwood.

The majority of the softwood lumber is for home construction and is typically pine. In the early colonial days white pine was the most important timber tree of the US and was commonly used in making ship masts. Now, yellow pine is more popular mostly because of the over cutting and a fungus that lead to the downfall of particular pines known as blister rust. Another common softwood in the lumbering industry is Douglas Fur, which is mainly used in the manufacturing of plywood because of its strength and also because it can be cut into large beams. A little known fact about the Douglas Fur is that its size rivals that of Redwood's in certain regions of the US.

Some uses of hard/softwoods

Red Spruce (Soft) - Mainly used in the construction of fine violins because of its reverberation effects

Hemlock (Soft) - The common wood used in making paper

White Pine (Soft) - As mentioned earlier, commonly used in framing houses and construction

White Oak (Hard) - Used also by builders for fine flooring and cabinetry

Hard Maple (Hard) - The Romans used it in spears and lances as well as bowling pins today

Hickory (Hard) - Was used in spokes and rims for wagons and tool handles

Since no one in the class appears to be a lumber jack I do not want to get  too deep in the process of milling wood, but rather, I want to provide the reader with some facts regarding the basic process involved as well as facts about wood and trees that is pertinent to this section.

Today it is estimated that 30-50% of the original forest have been cut down for a wide range of reasons from wars to fuel, all relating to money in some way. Of all the woodlands on earth only 13% is being managed to some degree and only 2% is protected reserve land. The rest of the woodlands are left to the mercy of man to do with whatever one chooses.

Process of Milling Wood

Now that you have some working knowledge of wood and its components, its characteristics, and the basic types, lets discuss how we get wood from standing trees. Logically wood is 1st cut, in this state, freshly cut wood is made up of around 50% water, however, to be used the water content most be lowered to around 10% so that the wood does not warp or decay. Typically wood most be dried from 20 - 300 days depending on the range of the humidity as well as the wood characteristics of the particular wood being dried. The entire process takes place in a mill either in a kiln or out in the open. A kiln is known to dry wood more efficiently and faster then other traditional methods because hot humid are is circulated throughout. In a kiln wood dries at a rate of 2.5 cm ranging from 2-50 days whereas out doors it can take up to 20-300 days for the same rate.

From there wood can either be treated with preservatives and milled (cut into boards) or stripped  and left "as is", hence the name, making what they call "round-wood". Round-wood is used for roofing, siding, fuel, posts, and timbers.

After the wood is made essentially ready for "use" we begin to get into the actual wood products of the next section. 

Wood can be used to produce many different products ranging from musical instruments to basic products such as charcoal, baseball bats, and bowling pins. In this section I am going to discuss some  important wood products both currently and historically.

Paper and Paper Making

Paper is one of the most widely consumed wood products that is used today. Papyrus is considered by many to be the 1st true paper used around 4,500 years ago by the Egyptians. They used a sedge plant found native in Egypt, Sicily, and Jordan. The Egyptians took thins slices of the cellular pith from this sedge plant matting different layers as they went then allowing it to dry. This allowed them to keep records and other important information and is continued to be used today mainly as decor.

Paper making as we consider it today dates back to 2nd century China where they used a process that is very similar to that which is used today using fibers from local plants. They ground the bark of these plants with water and allowed it to dry. Common plants to use in this region include rice, bamboo, and hemp. From China this process moved to Japan, eventually making its way the the Moors who in turn brought it to Europe. The art of paper making really took off with inventions such as Gutenberg's printing press from the mid-15th century which spread literacy and eventually lead to the Renaissance.

By this time making paper by hand was quite tedious so by 1798 the 1st machine which automated the process was built by Nicholas Roberts. However, being the 1st of its kind it was subsequently plagued with problems. In 1803 two British brothers improved on Roberts design and made a more reliable method. The paper-making machines today still bears their name Henry and Sealy Fourdrinier.

As technology advanced so did the quality of paper. In 1840 the paper-making process switched from using the bark of the tree to the pulp which provided a more abundant and inexpensive source to make paper. However, now that deforestation is becoming such a problem other sources are now being researched such as hemp which I will consider in the section labeled Controversy.

Cork

Even though plastics are beginning to replace cork today, it is still a very important product both currently and historically because it is both unique and cannot be totally synthesized through use of plastics. Cork is produced by stripping the bark of the Evergreen Oak common in Portugal (one of the countries biggest exports) and Spain. Once stripped from the tree, the bark is left out to "season" then boiled to remove chemicals then trimmed and sold at market. What gives cork its unique feel is actually parts of the cells in the bark that die during the process of making cork, these dead cells are replaced by air making cork extremely good as a floatation device as well as good for sealing jars, casks, and wine bottles that need to be breathable. Most of the time the trees that are "stripped" are not harmed and can actually be stripped every 10 years once the tree is at least 20 years old.

Traditionally, wood was used for its strength and workability for building, now it is also being used as a semi synthetic. Instead of cutting wood to make beams or for walling, as was done traditionally, people began making veneers, composition boards, plywood, and other textiles. Two basic methods are used to create these semi-synthetic woods, they can be created by either shaving or peeling a continuously revolving log. This method is known as the rotary method and is the most efficient method.

Veneers 

Veneer is basically composed of a thin sheet of fairly expensive looking wood glued to a piece of cheaper wood for either decoration or commonly in furniture and cabinetry. These pieces of veneer can also be laminated and used as very cheep material used also in cabinetry.  An example of veneer wood include entertainment centers, cabinets, and other "furniture" typically purchased at Wal-mart or other inexpensive outlet.

Plywood

Another typical wood product that is a semi-synthetic is plywood. It is composed of 3 or more layers of veneer glued together at right angles, always an odd number, for maximum strength and a very surprising light weight. Plywood constitutes about 20% of all manufactured wood and is very popular for builders for roofing, shelves, and sub flooring.

Rayon

Rayon itself is a term derived from taking the word "sun", converting it to ray then combining that with the "on" part of the word cotton. Simply put it is a name for all fabrics that come from cellulose. This material first came about when scientists wanted a way to create artificial silk. The process involved in creating rayon includes extracting particular saps and resins from bark pulp, heating it until it becomes "rubber-like" then dipping a needle into the solution and extracting it, the solution cooled and created a thread. There are two different processes that can be used to achieve this basic goal that I will further develop in my up coming presentation. These two processes are modern variations of techniques that were first developed back in 1664 when rayon based fabrics were first discovered (they were not patented until 1884). However, these fabrics had a huge impact as clothing for an entire generation and continue to be used today.

In the previous section I discussed various wood products that stood out to me as some common yet important ones worth mentioning. In this section I will talk about the importance of wood in a broader scope.

Fuel

Since man first harnessed fire, wood has been among the biggest sources of fuel and continues to be so today. In "Plants and Society", it is noted that 1.5 billion people depend 90% on wood as their sole source of fuel and cooking and of an additional 1 billion people depend on wood for 50% of their heating and cooking fuel. Another interesting statistic is that of all harvested wood throughout the world, 50% of it is relied on for fuel and this is the chief reason for the tropical rain forest crisis that I will cover later in the page.

As technology advanced people found they could use wood and through a burning process create charcoal. This process has been around for around 7,000 years. Without getting too technical, the wood is transformed into nearly pure carbon which when burnt can reach very high temperatures and was chiefly used in the smelting of metals. In the middle ages nearly all of Europe's forests were destroyed creating charcoal for smelting metal to be used for cannons and other weapons.

Resins

Another important by product of wood is resins. The resins from trees in particular, are very important. They act as a waterproofing agent for the tree as well as help the tree resist disease and fungi, and aid in furniture protection. When fossilized these resins become amber which to many is considered a botanical jewel.

Commercial uses of resins include turpentine, rosin, which is a by product of the turpentine creation-process commonly used by musicians who have bowed instruments (i.e. violin) and baseball/softball pitchers to get a better grip on the ball. Another common use of these resins are the stickiness on Band-Aids. Some people argue that one of the reasons for the British unwillingness to allow American Independence was for our vast pine forests which bare these resins particularly the ones used for waterproofing ships.

Wood-Pulp

Among the chief importance of wood is wood pulp. 50% of all the harvested wood is used specifically for wood pulp which is in turn used mostly in paper. Another statistic concerning the importance of wood-pulp is that 1/3 of all paper consumption. This doesn't seem too drastic except for the fact that 1 billion trees are specifically cut for paper use annually which equals 44 million metrics tons of use in the US alone. The pulp from wood is made by grinding the wood with water. Typically wood chips are used and put in a chemical solution to dissolve the lignin contained in the wood, which is 25%-35% of the product. The lignin contained in wood gives it a very dark brown color that darkens with age making it unsuitable for use with paper. Some dark color remains even after this process which is why most pulp used in paper-making is bleached.

In the 80's the process of bleaching the wood-pulp contained high amount of chlorine and when mixed with the chemical process of making wood-pulp created a deadly chemical known as dioxin which is very toxic in even small amounts. The problem was that these plants dedicated to the production of wood-pulp was being dumped into the ecosystem and causing vast problems because the chemical would be stored in fat and passed throughout the food-chain. However, by 1994 the industry was forced to reduce the dioxin content only trace.

Wood in Culture

Many cultures throughout time have used wood or some type of wood by product in the advancement or in plain every day life. However, to some cultures the by products they "create" from wood are very much a part of what makes them a culture. A prime example of this is the Pennsylvania Dutch who carried with them a certain level of superstition from the old world when making their way to the new world. Wood found its place in their particular superstition of warding off evil spirits and bringing good luck through the making of hex signs.

Each different color and designed used in the hex sign had a special meaning and they are even used to represent family crests. The signs themselves first appeared 300 years ago in Germany and were subsequently brought with families and individuals traveling to the new world.

Wood also penetrates into culture for particular tribes living in the rainforests. One tribe known as the Mapuche believe that they are the guardians of the forest and are being threatened by outlanders coming into their home and cutting down their forest. I will discuss more about this in the controversy section.

Hemp as Paper

As I mentioned earlier in the page one source of controversy surrounding paper making is the use of other sources than wood pulp from contemporary trees. One suggestion is to use hemp. As with everything involving the cannabis sativa plant that hemp comes from, as well as marijuana, it is illegal. The main argument for replacing typical wood pulp for hemp is its significantly longer life as paper. Regular paper lasts about 25-100 years depending on the process and type of wood used. However, Hemp has a life of around 1,500 years making it bar far more durable then contemporary paper. Another benefit from switching to hemp paper production is its ability to be to grown in just about any climate and soil type. An interesting fact about hemp paper is that our declaration of independence is actually written on hemp paper.

The Tropical Rainforest

There is so much controversy and debate centered around the tropical rainforest, its cutting, and its future that I will devote more time to focus on this aspect during my upcoming presentation. During that time I will share some facts and paint a picture of what the current situation is as well as what the future outlook is for the tropical rainforest regions of the world.

As you can see wood is one of the most important natural resources that has such a wide scope I cannot begin to come close to compiling a complete list of every application. I do hope that through this web page and subsequent presentation you have gained a better understanding of wood and its many by products. Many of the topics I put forth in this web page will be better developed and other topics that I might have neglected during the creation of this page will be addressed. I look forward to sharing with everyone what I have learned about wood and wood by products and will do my best to answer any questions you may have.

Thank you,

Anthony Camaerei!

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