Shades of Green: Earth's Forests -- Wood & Forest Products

Every day we use products derived from forest plants. Oils, resins, waxes, gums, rubber, food crops, medicine, and other substances all come from trees, but by far the most widespread are wood and paper products.

Logs are floated downstream to mills where they will be processed. Photo by Maya Walters.

Wood is arguably the most important plant product we use, and we have been using it for centuries. Different types of forests provide us with a variety of different woods. The boreal forests supply pine, fir, and spruce. Temperate forests produce oaks and beeches, and the valuable hardwoods such as Teak and mahogany grow in the world's tropical forests. The majority of timber is processed into boards or pulp for paper.

Coniferous forests produce the most timber per hectare, and these trees are preferred for making pulp because of the long fibers in the wood. Tropical hardwoods are used to make everything from toilet seats to bagpipes. And of course wood is used in construction.

The early stages of construction of a log house. Photo courtesy Al Walters.

Wood is one of the oldest building materials. It is still used extensively in construction, despite more and more products made from steel and concrete. Increasingly, solid wood materials are being replaced by products such as chipboard, laminated board and plywood. These are made by glueing together several thin strips of wood, known as veneer. Huge amounts of plywood, manufactured mostly from softwoods (coniferous trees), are used in housing construction.

Above: The chemicals used to produce paper have caused extensive damage to waterways. Below: Much fish and amphibian habitat has already been destroyed in this manner. Photos courtesy Al Walters.

All woods have their own properties that make them suitable for different products. Only one specific variety of willow has the right weight and resilience to be made into cricket bats. Many woods are used to make musical instruments, but only a few trees produce wood that is suitable for xylophone keys: only certain high-density woods will create a satisfactory musical note when struck. Light-density woods, on the other hand, absorb sounds and can be used in rooms to reduce echoes. Wood is also a poor conductor of heat, so it is commonly used for handles of pots and pans.

One third of all timber cut is used to make paper, cardboard, and other wood pulp products. Logs and wood chips are first broken down into pulp, which is then often transported to other factories to be made into paper products. Water pollution from pulp and paper factories has become a well-known environmental problem. The chemicals used for making pulp and paper, and chemicals such as chlorine which are used to bleach paper, have polluted rivers and ultimately the oceans.

On this page: The leaves and trunk of a rubber tree, a common tree on "extractive reserves". Seventy percent of the rubber produced every year goes to make tires for vehicles. Photos by Maya Walters.

Since timber is such a valuable commodity, forests are being exploited all over the world. Companies that are often based in foreign countries get licences to log. The forests are cut down, the company takes the profits, and moves on to another forest. An alternative to this process is to harvest relatively "minor" products such as fruits, oils, and fibers. There is a much smaller market for these crops than for wood, but they can be harvested every year, whereas once a forest is cut for timber, it can't be used again for another 80 or more years. It does not destroy the forest to extract these minor products.

However, it isn't clear how profitable these "extractive reserves" could actually be. There have to be enough different "minor" products available on a tract of land to make up for the fact that each one is worth relatively little. The area of land also has to be large enough, and have low enough species diversity, that there are enough plants producing each product. One palm tree is not going to grow a fruit crop large enough to sell. If prices drop too much, the managers of the extractive reserves often turn to logging as a fast way to make money.

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