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Nature’s Packaging-Let’s Learn About Sawmills

Sawmills remain one of the most important tools for the creation of wood planks, taking raw timber materials and turning them into usable wood. The sawmill’s basic operation has not changed much since its creation. In this Nature’s Packaging post, we’ll learn how sawmills operate and their history.

What is a Sawmill?

In a modern mill facility, the raw timber can be debarked and bucked (cut to length) before entering the mill or those processes can be part of the intake process of the mill itself.

The next phase of the process is converting the logs into boards with the use of several motorized saws at various stages that start by cutting large timbers into several smaller rough sawn pieces. Those rough sawn pieces can then be “re-sawn”, which is when the wood is finished into boards of various thickness and lengths, and can also be planed for smoothness.

This is a quick general overview of processes and methods in a mill, there are many different specialty operations that can also take place in a sawmill and those will be covered in other Nature’s Packaging posts.

The History of the Sawmill

Prior to the use of sawmills, boards were cut manually using saws operated by men. The wood was rived and planed and then hewn.

Pitsaw operation

Typically, two men used a whipsaw or pitsaw to do this, one above and one person under it in a saw pit. The whipsaw, a long blade held on either side, was moved back and forth to cut the wood to just the right level.

There is evidence of mechanical sawmills that date back to the 3rd century AD.

Roman Hierapolis stone sawmill-3rd century AD

In the 11th century, the use of water-powered mills helped to ease the burden while producing more of the materials people needed as cities and towns grew. These water-powered systems were common in Spain, the Middle East, Central Asia, and Northern Africa. A few hundred years later, they were widely present throughout Europe.

Water wheel mill

In this version of a sawmill, a circular motion of the wheel helped to create the movement of the blade. Only the saw had power derived from the water, and the logs were typically still loaded by hand. A movable carriage eventually developed to speed this up.

In the 18th century, the Industrial Revolution created significant change for the timber industry. A circular saw blade was invented during this time, with credit going to Samuel Miller via a British patent #1152 in 1777.

The use of steam power in sawmill operations a century later meant that sawmills could operate at a faster rate to keep up with the ever-growing demand. The scrap lumber from the mill was often used to maintain a boiler.

In the 20th century, electricity was introduced and revitalized the way sawmills worked again. By adding electrical power and more innovation through computer technology, sawmills can produce lumber at a very fast rate by maximizing the number of optimal cuts taken in a single log.

How Today’s Sawmills Work

The same basic methods are still used in sawmills today though today’s mills are far more massive in size and capable of producing a large amount of lumber very quickly. They are expensive to run as most are highly computerized to make use of as much material as possible while still working to be efficient.

The process works as follows:

  • Trees are selected for harvesting, the trees of felled, and they are bucked to length, meaning just the logs are taken to the mill to be used.
  • The branches are removed in a process called limiting. The logs are loaded onto a truck and driven to a railroad or other location nearby for transportation.
  • The logs are scaled and debarked as the first steps. Then, the logs are sorted by species, size, and the end use for them, such as chips, plywood, or lumber.
  • The logs are then sized down to be able to be placed into the sawmill based on the desired end goal.
  • The cants (or unfinished logs) will then be broken down further. The fitches, which are unfinished planks, are then edged to remove any irregularities.
  • The finished pieces are trimmed, dried to remove moisture, planed to smooth the surface of them, and then shipped to their destination.

The Rise of Portable Sawmills

Portable sawmill

Portable sawmills have existed for over 100 years, but they gained real popularity in the 1970’s. These portable sawmill operations helped meet the exploding need for lumber products in the construction and forest products industries.

Because these portable systems can process material that would otherwise be wasted or underutilized, they are a unique solution for today’s industry and able to help reduce carbon emissions by processing materials onsite.

Portable thin kerf bandsaw mills are relatively easy to operate and can produce high-quality finished lumber from just about any species of tree. Initially, many property owners purchased portal lumber mills so they could clear a stand of trees quickly. They found that lumber was a profitable business, which encouraged them to expand their operations.

Today, portable mills are effective at not just producing quality finished products, they are also reducing the environmental impact of lumber production. A portable sawmill can harvest smaller sections within a stand of trees, and they lower the need to transport logs to another facility for processing, thereby removing steps from the process.

Portable sawmills can be helpful in urban areas. Trees that pose a public safety risk to pedestrians or that normally wouldn’t be processed in an urban environment can be removed and made into boards and other usable materials.

Portable sawmills can help foster more forest stewardship through more precise forest management and lessening the environmental impact of harvesting activities.

Sustainable Logging Practices

Sustainable Logging Practices

For some people, the words “sustainable” and “logging” simply do not go together. Historical logging practices were sometimes hard on forests and disrupted native ecosystems. Today, sustainable forestry practices that include logging and harvesting trees comfortably co-exists with the conservation of thriving forests.

Sustainable Logging:  The Beginning

Historical logging practices began with the axe, manual saw, and manpower. They were transformed by the introduction of powered machines. At first, as volumes of timber increased exponentially with these new capabilities, the harvesting practices remained tied to traditional practices for some time. The practice disrupted wildlife, native plant species, and the enjoyment of wild areas.

While clearcutting is still practiced today, it is more controlled and meant to optimize renewal growth.

As environmental and climate awareness began to rise, bitter confrontations with the logging industry became far too common.

In 1972, the U.S. embarked on a new path. With the passage of the Clean Water Act, environmental policies were written into law across the nation. Local, state, and federal regulations emphasized healthy forests and responsible management.

But logging couldn’t simply stop. The industry supplied, and continues to supply, much-needed timber and other forest products to consumers around the world. The harvesting of forest products provided the economic foundation for communities across the country.

Reconciling those competing needs resulted in the birth of sustainable logging practices. Old-style clear-cutting both destroyed forests and ended the economic viability of the land. Sustainable practices allow both to flourish.

Sustainable logging practices benefit everyone, from the employees of logging companies to the campers enjoying a weekend in the woods.

Sustainable forestry even has the potential to help mitigate climate change.

Sustainable Logging Overview

The main principle of sustainable logging is to balance the economic importance of forest products with the ecological importance of healthy forests. This requires a comprehensive strategy for every potential logging site.

One way to approach sustainability is to design harvesting to mirror the effects of nature. Forests are altered by wind, fire, flood, and other natural events. Trees die and are replaced in forests with no human intervention.

Sustainable forestry also depends on choosing harvesting sites wisely. Old growth forests that are not normally harvested commercially should be left alone, preserving ecosystems and habitats that have flourished in place.

For land with a history of logging, sustainable logging begins with foresters learning as much as possible about the natural patterns and existing conditions of each tract of trees.

Sustainable Logging Practices

No two tracts of land will be logged in exactly the same manner. Sustainable logging brings together a team of experts who compile a comprehensive analysis of the area. Biologists, geologists, ecologists, and more lend their expertise to each project.

Each project has its own profile. But similar sustainable logging practices are adapted for sites across the country and, increasingly, around the world.

Patchwork Logging

While a company used to clear-cut an entire forest, sustainable logging is far more targeted and precise.

Harvesting trees from a small area allows the surrounding forest to adapt to the clearing like it would to a natural event. Keeping harvested areas far enough apart maintains habitat and biodiversity.

Tree type and growth, soil conditions, and other factors determine how many trees can be harvested from an individual area. In places where fire or damaging storms are common, the overall environment may be able to regenerate a larger area.

Patchwork logging leaves trees within a harvested area to better mimic natural conditions. It also allows for the preservation of tree species that are endangered or play an oversized role in ecosystem balance.

Sustainable logging is done in cycles. Some models propose that a cycle be no shorter than 80 years. This allows the forest to recover and continuously produce harvestable trees.

Areas that have been harvested are planted with saplings. The emergence of wild grasses attracts wildlife to the clearing, and the ecosystem evolves and grows.

Selective Harvesting

Selective harvesting removes individual trees, thinning the forest to allow existing smaller trees more space and light to grow. This type of sustainable logging is especially beneficial in tropical areas that don’t have natural events that mimic areas of clear-cutting.

Selective harvesting preserves undergrowth. This helps prevent soil erosion and maintain the health of the larger ecosystem.

Both patchwork and selective sustainable logging use fewer and smaller roads and less equipment, reducing damage to the surrounding forest. Careful attention is paid to the protection of unharvested trees.

Other Benefits of Sustainable Logging

Sustainable logging offers additional environmental benefits. Harvested trees and areas are kept well away from waterways to minimize erosion and runoff. Sufficient space is left between harvested areas to provide an uninterrupted habitat for wildlife.

Sustainable logging also provides a safer working environment. Fewer people and less equipment in each area help reduce the chance of accidents.

Sustainable Logging:  Forest Management and Climate Change

Sustainable logging can play a major role in forest management. An unlogged forest is not necessarily a healthy forest. The work that goes into profiling a forest or tract of trees before harvesting provides valuable information.

That information includes soil, geography, and tree health analysis. Invasive species are documented, as are biodiversity, wildlife habitat and density, erosion, and any disease or damage present in the area.

Logging is sometimes the first step in returning a forest to good health. Removing diseased, damaged, or low-quality trees helps the higher quality trees grow. This is called an improvement harvest.

The branches and other wood left behind by this careful removal provides wildlife habitat while it decays and enriches the soil. Removing invasive trees, vines, and other plants provides better conditions for the remaining trees.

Sustainable logging practices are used and adapted by forest managers to improve the overall health of their woodlands, even if no trees are harvested for lumber.

Sustainable forestry is also becoming the focus of climate action. Sustainable logging can result in more trees as well as healthier trees able to capture more carbon.

Tropical forests are an area of particular interest for climate action. 1.5 million square miles of tropical forest are currently being selectively logged. Widespread adoption of selective harvesting practices would allow these forests to maintain much of their carbon stores and biodiversity while continuing to anchor economies.

Sustainable logging practices combine common sense, careful study, and new technologies to improve the health of forests around the world. At the same time, they provide economic stability for many communities and meet the continuing demand for lumber and other forest-based products.

 

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