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Photo by Caleb Riston on Unsplash

The supply chain is often thought of in terms of units and space, inventory and throughput, distribution and delivery. Pallets are the components that integrate these processes together, and their ability for recycle and re-use are a significant cost and complexity saver for many companies. The flow of pallets is a constant in the modern supply chain and the machinery used to transport goods will typically break down a wood pallet over time. As a product made from a renewable resource, when old pallets are removed from the system, they are often replaced with new wood pallets.

These pallets are part of a larger system of forest products and practices, and the lumber supplied for new pallets has an interesting origin story that begins in the forest with the harvest of raw timber. That harvesting is part of a system of management called silviculture. This week’s post will dig deeper into the role that silviculture plays in the process of providing raw materials for the wooden pallet and container industries.

Humans & Wood

Human beings have relied on wood since before recorded time as a resource and tool. At first, that reliance was based on a natural resource in the wild that was bountiful and could be felled and transported with domesticated animals and burgeoning technology. As humanity’s population centers grew and their needs multiplied exponentially, trees and their cultivation became first an art and then later grew into the science of silviculture.

Silviculture can be defined as the art and science of growing and cultivating woodlands to meet the diverse needs and values of the landowners and a society in general. Those needs and values are balanced in concert with established sustainable goals like wildlife species preservation, managing water resources to help a forest thrive, mindful recreational activities of the general public, and of course timber production.

The practice of silviculture requires an understanding of ecology, soil preservation, entomology, botany, and in modern practices, crop science. It is typically delineated among three distinct processes that incorporate these mentioned fields of study:  regeneration, cutting, and protection of the resource for continued use.

Regeneration

The cultivation of trees follows a natural progression of replacing old timber with new growth over time. These old and new growths are also known as stands and the progression has developed into a cycling process over time called regeneration.

Regeneration can occur naturally or artificially; it depends on the needs and values of the participants involved. A plan is developed that starts with the preparation of the existing forest and ends with the establishment of appropriate goals for new seedlings and their development. The regeneration plan follows a pattern according to the type and species of tree and the forest environment as a whole. This rotational pattern is based on the growth of a defined generation of trees.

Timber Cutting

The cutting of timber during the development of a forest takes place at many different stages. These intermediate cuttings as they are known include both young and old tree growth and are designed to maximize the use of the forest as an asset.

This includes the strategic harvesting of trees for commercial use in industries like home building, architecture, and the pallet industry. The aim being to extract the most utility from the timber cutting process while harmonized with the overall health of the forest.

The results of this cultivation and harvest are guided by the various species in the woodland stand, and what is deemed as most beneficially attended to by the needs, values, and goals of those involved in ownership, trade, or use.

Protection

Of course, as the processes of regeneration and intermediate cutting are implemented, the stands and forest must be protected from many different natural and man-made events. These include everything from the possible introduction of new insects and animal species to fires generated both naturally and via human activities, to unforeseen weather events like hurricanes or climate changes.

The collaboration of industry and governments establishes initiatives like ISPM-15 to mitigate the migration of unknown insect species through the trade between countries. These insects can have a decimating effect on forests, and sometimes species of tree in particular.

The introduction of animal species must be well thought out and consider the ecological layers of the forest and how they are impacted by the interaction of a new species with the existing flora and fauna.

Wildfires have had a huge impact recently with both forests and the populace that live near them. In some cases, this has directly resulted from how a forest is managed overall and how climate change is altering the way that scientist and forest workers must prepare for these events as best as possible with the resources they have available.

Most often, people hear about and are familiar with processes like controlled burns and establishment of fire lanes in forests to help alleviate damages to the forest itself or the populations in and around them. Fire protection and science in regard to forests goes much further than what can be covered in this post.

Severe weather and climate change must be accounted for as well. The results of a severe weather event can be prepared for in a nearer term strategy. This is often accomplished in part with the positioning of stands in relation to one another, the makeup and development of the stand, and the utilization of the natural landscape in the overall plan.

Climate change, while in some sense a result of our own industrial activities, must be reckoned with over a longer period and mitigated both at forest level and globally. Whether man-made or not, the generational aspect of growing trees is most susceptible to climate change as an active force. This continues to change how foresters practice and execute the tenets of a silviculture plan.

While the techniques and technologies available to provide regeneration, intermediate cuttings, and protection must be deployed effectively to ensure the goals of interested parties are met, silviculture in practice will evolve due to all the processes and forces mentioned.

The renewable resource of harvested trees will continue to supply raw materials for many industries, including the manufacture of wooden pallets and containers. This in turn will provide supply chains with the necessary wood pallets to keep products moving so the economic flow continues.

Forest-Overhead view
Photo by Ron Whitaker on Unsplash

Wood packaging such as crates and pallets are critical to international trade, and to the global economy. Consider that almost two billion wood pallets are used daily within the United States to store and transport goods, and that approximately $400 billion worth of American trade is exported each year using wood pallets and containers.

Wooden packaging is often made from recently milled timber, however. As a result, there is the potential for live insects to be transported unknowingly from one part of the world to another, where they can wreak havoc in stands of timber that have evolved without the benefit of natural defenses to hold invading species at bay. According to the U.S. Forest Service, many of the non-native bark- and wood-infesting insects now in the United States are thought to have arrived in untreated wood packaging.

The motivation for the establishment of ISPM-15 followed some high-profile infestations in North America as well as in other parts of the world. Infestations have been caused by Asian Longhorned Beetle, first identified in the United States in 1996, and the Emerald Ash Borer, initially discovered in Canada and the U.S. during the 1990s.

The Asian Longhorned Beetle was first discovered in 1996, where it was found to be attacking ornamental trees in Chicago and New York City. It subsequently was detected across most northeastern states and California. This insect is native to Asia, where it destroys many deciduous tree species, including maples, elms, and poplars. It is believed to have arrived in untreated wooden crates shipped from China.

The Emerald Ash Borer is another destructive insect that has inflicted considerable damage. It is speculated to have arrived in North America in the 1990s in solid wood packaging and was first detected around Detroit, Michigan, and Windsor, Ontario in 2002. It has killed millions of ash trees already and still threatens most of the 8.7 billion ash trees located across North America.

With the knowledge that wooden packaging can be a pathway for the international movement of forest pests from one country to another, new international standards under ISPM-15 were established in 2002 and fully implemented in 2006.

ISPM-15 requires that all wood packaging material (WPM) used for international shipments be heat-treated (HT) using conventional kilns or heat treatment chambers, fumigated with methyl bromide (MB) prior to export or treated with dielectric (microwave) heating (DH). All WPM treated to meet ISPM-15 requirements must be marked with a designated ISPM-15 stamp. In Canada, only dielectric heating and heat treatment are allowed. All producers of ISPM-15 stamped products must be approved.

In order to become approved, facilities are inspected and certified. After certification, the supplier is assigned a number and issued a stamp that is applied to wood packaging material to show it is compliant with the ISPM-15 standard. The stamp marking acts as a passport for wood packaging to officially enter ports of entry in foreign countries, and is recognized as sufficient proof that the wood products meet the ISPM-15 standard. There are more than 100 participating countries, worldwide. Lists are available of approved HT agencies and approved MB agencies in the U.S.

The U.S. Forest Service stresses that when properly implemented, ISPM-15 treatments “have been scientifically proven to be highly effective in killing quarantine pests.” In one study, the Nature Conservancy found that the infestation rates of pests in wood packaging decreased by up to 52% between 2003 and 2009, following the implementation of ISPM-15 in 2006.

As NWPCA notes, “Since the wide-scale adoption of ISPM-15 in the United States, there has been a significant reduction in[BG1]  new large-scale establishments of invasive wood-boring insects.”  The full collaboration of the wood packaging industry and plant health organizations in countries around the world has proven to be highly successful in controlling invasive species and thereby ensuring that wood pallets and packaging can continue to safely play their critical role in international commerce.

cross laminated timber

The W.A. Franke College of Forestry and Conservation at the University of Montana is just one of an increasing number of institutions looking to cross-laminated timber (CLT) for new construction. UM recently requested money from the state legislature to help fund the building of its new $45 million CLT building, to be built from wood grown, harvested, and manufactured in that state.

“It just makes perfect sense for a forestry building and tells the story, and it is a much more sustainable and reasonable way to go,” Alan Townsend, the Franke College dean, told The Missoulian. “And it can look really cool. It’d be a pretty iconic building on campus.”

Based on its earlier adoption in Europe as a building material, interest in CLT structures continues to grow in North America and around the world. Buildings manufactured with CLT panels are faster to construct, more energy-efficient and made from renewable material. Let’s take a closer look.

What is Cross Laminated Timber (CLT)?

Cross-laminated timber (CLT), a sub-category of engineered wood, is created by gluing together several layers of kiln-dried lumber. Laid flat, they are glued together on their wide faces, with grain in alternating directions at 90 degrees.

Panels most frequently consist of three, five, seven or nine alternating layers. Layer thickness typically ranges from ⅝” to 2” and board width from 2.4” to 9.5”. It is similar to plywood, however with significantly thicker laminations or layers.  The layered stacks are glued and then pressed vertically as well as horizontally to create panels, which can then be accurately sized and finished for installation.

Typical panel widths are 2, 4, 8 or 10 feet, while panel length may extend to 60 feet. CLT is different than glued laminated timber (glulam) in which all laminations are oriented in the same direction.

What is the History of CLT?

Cross-laminated timber was first introduced in the early 1990s in Germany and Austria. Since that time, it has continued to gain popularity for residential and non-residential building construction in Europe.

After slow initial growth, its popularity began to increase in the early 2000’s thanks to the green building movement, as well as through newfound efficiencies, product approvals, and improved marketing and distribution.

CLT usage in buildings has increased significantly in the last decade. Hundreds of impressive buildings and other structures built around the world using CLT bring to life the substantial benefits made possible by CLT. The European projects demonstrate that CLT construction can be competitive, particularly in mid-rise and high-rise buildings.

What are the Advantages of CLT?

According to www.woodworks.org, the major benefits of CLT are listed as follows:

Design flexibility: CLT panel thickness can be easily increased to allow for longer spans, and custom cut as required with CNC equipment to exacting tolerances.

Thermal performance: CLT’s thermal performance is related to panel thickness. Thicker panels require less insulation, and because panels are solid, there is little potential for airflow through the panel system. As a result, interior temperatures can be maintained with as little as one-third the amount of energy otherwise required for cooling or heating.

Cost-effectiveness: Even without considering the added benefits of faster construction time (up to 25% less time and up to 50% less labor) and lower foundation costs, CLT compares favorably to certain concrete, masonry, and steel building alternatives. According to a 2010 study by FPInnovations, CLT was 15% lower for mid-rise residential, 15 to 50% cheaper for mid-rise non-residential and 25% cheaper for low-rise commercial structures.

Less waste: Because CLT panels are custom manufactured for particular building projects, they generate little or no job site waste generated. Additionally, fabrication scraps, if created, can be used for other architectural elements such as stairs, or as biofuel.

Environmental advantages: Aside from superior thermal performance that saves building operators money on their heating bill, CLT is also valued because its production has a lower environmental footprint than the manufacturing of other construction alternatives, including the production of less air and water pollution and the generation of less CO2. The environmental case for CLT is enhanced as it acts to sequester carbon.

Fire protection: The thick cross-section of CLT panels provides superior fire resistance because panels char slowly. Once charred, the panels are protected from further degradation.

Seismic performance: Thanks to its dimensional stability and rigidity, CLT performs well under seismic stresses. Extensive testing has determined that CLT panels hold up exceptionally well with no deformation, particularly in multi-story applications.

What is the Outlook for CLT?

While mass timber is considered a more sustainable building material than steel or concrete, its uptake until recently has been limited due to negative perceptions regarding its strength and cost as well as building code restrictions that have limited its use in mass-market building types.

However, as one recent report notes, as the price of mass timber products continues to fall and local jurisdictions improve their code approval processes, the wood material is anticipated to become a more viable everyday choice for building commercial office buildings.

According to The Economist, mass timber is expected to account for US$1.4bn of the US$14trn global construction industry by 2025 and 0.5% of new urban buildings by 2050. With concerted investment in global manufacturing capacity and building projects for mass timber, however, The Economist believes that the share of the construction market could rise exponentially by 2050, capturing trillions in value.

Resources:

Canada CLT Handbook, 2019 Edition

Solid Advantages

U.S. CLT Handbook