PRESERVED WOOD

The remarkable history and uncertain future of preserved wood in ports

By Ryan Pessah, Director of Government Relations

Western Wood Preservers Institute

While there are some who believe it is a relic of the past, the reality is that preserved wood is — and should be — a critical part of the maritime infrastructure here in the 21st century.

The very roots of preservative treating for wood harken back to maritime history. In the early decades of the 19th century, a lawyer turned inventor named John Bethell in England earned a patent on a diving apparatus to make underwater repairs on wood ships. This work led him to another perplexing maritime problem: how to keep timbers in ships from rotting.

After trying a number of methods, Bethell found success with a process The growth in preservative treating for wood expanded with the need for durable, long-lasting infrastructure in the U.S.

to impregnate wood with a new distillation called creosote, and in 1838 he earned a patent for pressure treating wood. Within a few decades, the process made its way to the U.S. where it was used to protect wood in ships, port facilities and rail ties.

The growth in preservative treating for wood expanded with the need for durable, long-lasting infrastructure in the U.S. What started with ships and port facilities soon moved into emerging industries such as railroads (rail ties) and electricity distribution (utility poles). Preserved wood offered an economical and proven way of keeping these products in service while protecting them from extreme conditions.

Remarkable history

In the maritime industry, the remarkable development of ports across the Pacific during World War II and the post-war expansion thereafter was

Due to concerns of the past and the uncertainty of the future of preserved wood in aquatic and sensitive environments, the preserved wood industry has responded by improving performance on many different levels of protection.

built upon preserved wood pilings and docks. At first, the idea was to make the wood last as long as possible, and no thought was given to the impacts of extra preservative in the environment, or the amount of wood installed. True to form, old pilings, utility poles and other preserved wood structures remain in place 50 to 70 years later, oftentimes long after their useful life or as industry has moved on.

It is now clear that property values and trends change faster than preserved wood deteriorates. The modern practice of tearing down good piers, buildings, and other infrastructure along with the removal of old creosote pilings should be done with the understanding that it doesn’t change the past or solve an ecological problem. All materials should be vetted for their impact over their entire life cycle along with the project’s expected life span.

For instance, what is the impact if a material is only expected to be used for 25 years instead of 50 due to rising sea levels, obsolescence, or other changes. Sustainability for ports is assured as globalization will continue to see the shipment of goods between continents and along coasts for centuries to come. Sustainability for forests in North America are assured as the industry overcomes past mistakes and embraces the need for renewable resources more than ever before.

Ports that handle bulk and container shipping are trending away from exposed wood structural elements. This is mainly due to the perceived negative perception of old preserved wood that are considered an eyesore decades later, as well as government regulations intended to keep toxic chemicals from waterways. These regulations mistakenly assume zero impact from wood alternatives, which is impossible.

There is no doubt that preservative treated wood exposed to ultraviolet light and water will degrade over time. Also, there will be a release of some of the preservative into the environment. Acknowledging this has led the preserved wood industry to research the potential risks and create models to assess whether the preservative release will have an impact on the environment in case-by-case scenarios. To our knowledge, no other building material does this.

Uncertain future

Due to concerns of the past and the uncertainty of the future of preserved wood in aquatic and sensitive environments, the preserved wood industry has responded by improving performance on many different levels of protection. First is the ability to select from a variety of preservatives depending on the situation and needs of the project. Today, there are five oil-borne and six water-borne preservatives available for applications in aquatic and sensitive environments.

Second is in limiting the preservative available to move into the environment with Best Management Practices (BMPs). The BMPs ensure there is little residual preservative on the surface of the wood that can migrate into the environment.

Third is the availability of models that can be adjusted with site-specific data to assess selected preserved wood options and evaluate potential impacts.

Fourth is the improvement of standards and treating quality control to use an appropriate amount of preservative that protects the wood while at the same time balances the protection of the environment. Lastly is the ability to create additional durability by applying polyurea coatings, fiberglass wrappings and other heavy duty means of protecting the preserved wood.

The preservative treating industry’s willingness to adapt to current regulations and perceptions ensures preserved wood will continue to be an option for ports, not just in the immediate future but far into the future. As ports broaden their view to consider the entire life cycle and the sustainability of materials, preserved wood will once again become the preferred material of choice for structures.

When such a shift will happen, we are not certain. What is certain is that until then, preserved wood will remain an essential part of the maritime industry. It might not be in pilings, but you will continue to find it boardwalks, piers, posts, signs, docks, fenders, decks, poles, fencing and every other application at a port.

Ryan Pessah tracks and addresses legislation and regulations proposed by government institutions in 17 western states that impact the preserved wood industry; coordinates activities with lobbyists in California and Washington state; and works directly with state departments (transportation, parks, etc.) to influence and increase production and use of preserved wood.