A new residence hall graces the campus of ‘Iolani School in Honolulu, Hawaii as part of a larger, multi-year expansion project for the culturally diverse, co-educational preparatory school that serves more than 2,000 students. VikingWoodTM, a natural, green, chemical-free thermally modified wood, manufactured by AHC Hardwood Group, based in Atlanta, Georgia, can be seen accenting the exterior of the five-story structure.

The residence hall was designed by G70 (formerly Group 70 International, Inc.) a Honolulu-based award-winning architecture, civil engineering, interior design, planning and environmental firm. According to Lance Hirai, AIA, G70 project architect, “Responding to the surrounding context, the architecture honors the original housing and style that occupied the site, but with a contemporary expression.”

HK Consultants, LLC of Aiea, Hawaii, suggested the cost-effective, sustainable, high-performance exotic wood alternative, often used for exterior applications. According to Mark Hee, exotic wood specialist and senior partner at HK Consultants, “When you have a lot of moisture in the air, a wood that is not kiln-dried properly is going to absorb moisture, and with moisture you get mold and mildew. This lets us take a wood that is normally very inexpensive that is treated through the thermal modification process to create a wood that can compete against more expensive exotic woods like ipe.”

Hirai explains how VikingWood thermally modified ash came to be specified for the residence hall exterior, “We were inspired by biophilia1 due to its benefits in enhancing student development. Connections to nature are reinforced through the use of natural materials like the thermally modified wood panels. We were keen on using natural materials to also maintain an honest expression of the architecture, as well as add warmth to the exterior, and with time, the wood will weather and serve as an example of how a building can age.”

A number of different exteriors were considered for the exterior facade of the residence hall, including composite materials. Several desirable characteristics of thermally modified VikingWood wood weighed into the decision, including the green, chemical-free nature of the wood.

VikingWood also acquires a rich, brown color during the thermal modification process and was finished with a clear WOCA exterior stain. According to Hirai, “We wanted to truly reflect the color of the thermally modified wood.” A clear stain was applied to experience the natural graying process, rather than a colored stain or a UV coating to inhibit the graying effect.

VikingWood is treated under extremely high temperatures (400oF+), which cook away the natural sugars found in wood, leaving a safe, green alternative to chemically preserved wood. Under this extreme heat, the hardwood is “thermally modified,” permanently altering the wood’s chemical and physical properties. The thermal modification process reduces the equilibrium wood moisture content down to a very low range of 5 to 6%. The thermally modified ash used for the ‘Iolani residence hall offers a Class 1 exterior durability rating.

Once sugars are removed from the wood and the moisture content is reduced, the conditions that can lead to decay and rot, as well as attract bugs, are virtually eliminated. This process produces a wood that is up to 85% more stable than traditional kiln-dried woods. Thermal modification also virtually eliminates the ability for the wood to reabsorb moisture from the atmosphere, which can be an important consideration when building in high humidity climates.

Hee adds, “It makes a lot of sense that this wood can hold up to the elements and the pests. It’s a natural, green alternative to composites and doesn’t gray out like exotics, even in the tremendous sun we have in Hawaii.”

Hirai summarizes, “The dormitory moves forward the school’s vision to ‘Create meaningful, sustainable, and reciprocal global relationships that stimulate the exchange of ideas, foster a deeper cultural awareness, and build students’ desire to improve the world around them’.”

‘Iolani School was originally founded in 1863 by King Kamehameha IV and Queen Emma as a boarding school that housed students from around the world. The new dormitory can accommodate 112 students in grades nine through 12 and marks the first time since 1959 that on-campus housing has been available for students. The last phase of expansion on the ‘Iolani campus is slated for completion by mid-2020.

1. biophilia (n) bio·phil·ia: a hypothetical human tendency to interact of be closely associated with other forms of life in nature. Merriam Webster Dictionary

After a multi-year capital campaign to build a new building, the Forest History Society (FHS) located at Duke University in Durham, North Carolina, has successfully completed a $7 million capital campaign and officially opened a new library, archives, and headquarters.

The grand opening, May 3, 2019, drew more than 160 supporters and donors from throughout the U.S. Atlanta Hardwood Corporation was among the in-kind donors, recognized at the event for contributing architectural mouldings for the new library and headquarters. Mouldings were milled in the AHC White County Mouldings facility in Cleveland, GA, which has been producing premium hardwood mouldings for more than 50 years.

The FHS is the world’s largest private library and archives of forest and conservation history. FHS is world-renowned for its unique holdings and for advancing scholarship in forest and conservation history through its publications, educational outreach efforts and research.

In addition to the expanded space for collections and archival materials, the new FHS headquarters has a state-of-the-art conference facility with live-streaming capabilities, a processing center that will enable more efficient digitization of historic photographs and records, and a soundproof oral history interview suite specifically designed for recording the lives and expertise of forest workers and leaders to capture information unavailable anywhere else in the historical record.

Since its establishment in 1946, FHS has published dozens of books and produced three award-winning films. Its most recent is the Emmy Award–winning America’s First Forest, a documentary about Dr. Carl Alwin Schenck and the Biltmore Forest School. Researchers all over the world can access FHS’s free research portal (at www.foresthistory.org), which contains more than 45,000 searchable topics and 22,000 photographs. Those needing further assistance may contact FHS library staff through the “Ask a Question” feature on the FHS website, or by phone at (919) 682-9319.

The FHS looks forward to growing its archival collections and offering new and engaging programs. Forest products organizations, family land owners, and others seeking a permanent home for their records, are welcome to contact Steven Anderson, president and CEO, by email at steven.anderson@foresthistory.org. The library is open to the public Monday through Friday, 8:30 a.m. to 4:30 p.m., for forest and conservation history research and exploration.

New Library Ceiling

Etched Glass Panels Installed in Reading Room

Library Shelves Being Stocked

View of the Library



By Hal Mitchell, President, Atlanta Hardwood Corporation

It’s not often that we see a revolutionary new process in the lumber industry. New developments in thermal modification may well be one of these processes.

The idea is relatively simple: heat lumber to above 320° F in a low-oxygen atmosphere to produce chemical and physical changes in the wood’s cellular structure. The heat treatment results in improved durability and increased dimensional stability. The improved stability allows for a superior flooring performance where minimizing movement is important.

Thermally modified lumber (TML) has been widely accepted in Europe for decades and is finally making its way to North American industrial production. While the treatment concept is relatively simple, the technology is complex and costly. Also, there is little history of treatment schedules (recipes) for most North American species. Each species and thickness requires a unique treatment temperature and duration to achieve proper modification levels. Entry barriers, lengthy learning curves, and lack of production standardization have kept American production relatively low.

There are two basic treatment systems: open and closed. Open systems use atmospheric pressure or a vacuum during treatment, while closed systems operate under high pressure. Open systems require drying the wood to nearly zero percent moisture content during the treatment phase to reach temperatures above 212° F. Open systems comprise most of the worldwide production. Closed systems require high pressure often above 100 psi. This allows for the material to retain moisture during treatment, which results in less shrinkage stress and lower degrade. Closed system cycle times are much faster, but the throughput is typically lower. Additionally, closed systems may not require as much heat to provide sufficient modification levels.

The treatment process uses only heat and steam, so it is completely “green” with no introduced chemicals. During treatment, the wood undergoes both physical and chemical changes. Some sugars are “burned” away (decomposed), leading to a reduction in food source for decay fungi. Wood color is changed through its cross-section to a darker color resembling walnut or tropical imports. The energy input also develops a much more stable product. Bond sites on cell walls provide for dimensional movement in wood as they attract and release water molecules with environmental changes.

One theory on the increased dimensional stability of thermally modified woods is that during the thermal modification process, enough energy is introduced to crosslink these sites and limit the woods ability to absorb water. Thermal treatment significantly reduces the available bond sites for water molecules, so dimensional stability is improved. Research indicates that dimensional movements due to moisture uptake can be reduced 50-90 percent (Jamsa and Viitaniemi, 2001).

Thermal modification reduces many of the mechanical properties of wood. Increased brittleness and decreased strength occur with bending strength reductions of 30 percent or more depending on treatment intensity (Kubojima et al., 2000). Hardness decrease is relatively limited at approximately 3 percent, but can vary tremendously by treatment levels. A “burnt” odor is produced during the process and can remain present in the wood. The unpleasant smell results largely from furfural production and can be limited if a vacuum is pulled during the final production phase. The odor will dissipate over time and can be negated once sealed.

The stability enhancement can allow wood products to be used in new and improved applications including flooring. Treatment will limit the dimensional change of wide plank flooring. This idea is often used by European plank flooring manufacturers when decay is not an issue as the dimensional stability can be greatly enhanced without reaching full modification and color change. Where stability is extremely important, such as basement or porch flooring, thermal modification will provide significant performance improvement. Of course, no wood product is 100 percent stable, so often micro-beveled edges are used in areas subject to large humidity changes. Moisture content is lowered in treated wood. Typically, thermally modified wood is dried to 4.5-6 percent. Lower moisture content is a good attribute when lightweight installation is needed such as garage doors and shutters.

Current markets, particularly in Europe, consist heavily of three products: cladding, decking, and flooring. Softwoods comprise the majority of the worldwide production, but hardwoods are gaining popularity. Historically, untreated American hardwoods could not be used in cladding or decking, but with the thermal treatment process, they perform well.

TML characteristics are similar to the untreated species characteristics. After treatment, finish quality often improves, grain patterns remain the same, and the sapwood and heartwood often become difficult to distinguish. Increased brittleness requires sharp tooling and often eased or beveled edges are preferred due to chipping. The material glues well with non-water based adhesives.

Stainless steel fasteners are often necessary for installation. Flooring installation requires extra caution with the degree of brittleness. Brittleness is dependent on treatment level and species, tongue breakage is a concern.

Finishing typically requires oil-based products, but there are specially formulated water-based products that are becoming popular as well. The wood oxidizes (grays) quickly to a silver patina unless treated with a UV inhibitor. While the finish life is improved due to increased wood stability, the UV inhibitors will typically need to be reapplied annually in areas with direct UV contact.

North America currently lacks the support of a thermally modified wood industry association to promote increased production and utilization of thermally modified wood; however, the American Wood Production Association (AWPA) is working to provide standardization. To ensure that TML manufacturers are properly treating their material and not overstating the performance properties, there will need to be a collaborative effort to provide user standards. Mechanical and durability tests will need to be performed on the North American species; some of this work is currently underway by the University of Minnesota Duluth at the Natural Resources Research Institute (NRRI). Product quality can vary due to initial lumber quality, treatment recipes, and kiln types. It will be imperative that specifiers, installers, and consumers are educated on proper installation techniques and performance expectations to prevent market failure and “overselling” of performance capabilities.

We have a unique opportunity to create new and improved uses for North American lumber through the thermal modification process. This opportunity is rare in our industry, and we must be diligent to ensure manufacturers and customers have realistic expectations of the TML.

Hal Mitchell is President of Atlanta Hardwood Corporation based in Mableton, Georgia. He has been with the AHC Hardwood Group since 1999 and has a Master of Science Degree in Forest Products Marketing and Management from Virginia Tech. AHC operates a closed-system thermal modification plant in Cleveland, Georgia. He can be reached at 800-476-5393 / 706-865-3166 or via email. To learn more about Atlanta Hardwood, visit hardwoodweb.com.


Jamsa, S., Viitaniemi P., 2001. Heat Treatment of Wood Better Durability Without Chemicals. In: Rapp, A.O., Review On Heat Treatments of Wood. Cost Action E22. Proceedings of Special Seminar, Antibes, France, pp. 17-21.Kubojima, Y., Okano, T., Ohta, M., 2000. Bending Strength and Toughness of Heat-Treated Wood. Journal of Wood Science 46, pp. 8-15.

Mableton, GA – Atlanta Hardwood Corporation, located here, which recently rebranded as AHC Hardwood Group, has been continually pioneering new hardwood markets since its founding 65 years ago. Recently, AHC installed a state-of-the-art, high-pressure thermo-modification kiln at their moulding plant in Cleveland, GA. The company’s new product offering, VikingWood™, is ideal for exterior applications, including siding, cladding, porch flooring, shutters, doors, rain screens, decking and window framing. Thermo-modification improves stability, repels moisture and is chemical free (www.vikingwood.org) providing green options for architects and builders looking for alternatives to chemically-treated wood products.

Atlanta Hardwood was founded in 1952 by James W. Howard Sr. in Knoxville, TN. Howard started as a lumber broker selling to furniture manufacturers in eastern Tennessee. In the mid-1950s, he moved to Atlanta and leased kilns on Glenwood Avenue near downtown. His brothers, Sid and Lee, joined the company, which became known as Howard Lumber and Kilns. By 1960, they had built a plant nine miles outside of town in Mableton, GA, and Atlanta Hardwood became the sales arm for Howard Lumber. In 1966, they opened a second plant in Huntersville, NC, to service the furniture industry. In 1992, James’ son, Jim Howard, became chief executive officer and principal owner.

Today, AHC includes nine operating facilities, including four drying yards, a moulding plant, several affiliated southeastern distribution warehouses, and a logistics company. AHC’s lumberyards are located in Crystal Spring, PA; Huntersville, NC; Clarksville, TN; and Cleveland. AHC kiln yards are strategically located near the Appalachian timber region and east coast ports.

In 2010, AHC acquired Craig Lumber, which is now the import division of AHC Hardwood Group–AHC Import Lumber (www.ahcimportlumber.com). Both the import and export divisions operate in Huntersville.

In addition to mouldings produced in a state-of-the-art facility in Cleveland, known as White County Mouldings, the yards offer S2S, planing, gang ripping, specialty sorting, export packaging and overseas freight services. According to Vice President of Remanufacturing Operations Zack Rickman, “Offering a diverse range of products allows us a competitive advantage. On a single truck, we can deliver domestic and exotic products from lumber and blanks, to millwork in both solid and finger-jointed form.”

AHC has a diverse inventory of 75 species of domestic and imported premium Hardwood. Through its import division, AHC’s inventory includes some of the most desired species from around the world. The company also sells worldwide to customers, direct from the source. Their offerings include African Hardwoods, such as Bubinga, Black Limba, Sapele and Zebrawood, and South American Hardwoods, such as Peruvian Walnut, Red Grandis, Ipe and Jatoba. By offering customers both domestic and imported species, AHC Hardwood Group is able to streamline ordering and offer mixed loads for efficient, cost-effective purchasing.

In January 2016, Hal Mitchell was promoted to president of AHC Hardwood Group and is responsible for overall operations at all company facilities. He frequently tours each facility and helps troubleshoot any issues. His motto, inherited from company founder James Howard, is “expect and inspect” and Mitchell believes his managers must have autonomy to make decisions as long as they are consistent with the company principals, culture and goals. “This year,” Mitchell noted, “AHC implemented two new corporate initiatives to improve business processes and company performance. We’ve learned to focus on a couple of key initiatives per year.” He continued, “By incentivizing all managers and supervisors to focus on better inventory controls and recruitment/retention plans, we’re enhancing our performance and profitability.”

According to CEO Jim Howard, “We don’t bet the ranch, but we are continually striving for improvements. We’ll invest in technology if we see a payback. All of our trucks now have tracking software and we have recently invested in a thermo-modification kiln and a planer mill upgrade.”

The state-of-the-art thermo-modification kiln was installed at the moulding plant in Cleveland in mid-2016 to produce their newest product offering, VikingWood. Through the use of a high-pressure chamber, the thermo-modification kiln burns all of the sugar out of the lumber, causing chemical reactions at the cell wall bonding sites, so they can no longer absorb water. After thermo-modification, what’s left is a board resistant to decay that could be used in exterior applications because of its stability and resistance to moisture. When lumber is processed through a thermo-modification kiln, it has a dark chocolate color, so lighter looking species like Ash or Poplar can sometimes be substituted for Walnut. “This is a whole new market for American Hardwoods,” said Mitchell, “and AHC is excited to be on the forefront.”

Besides thermo-modification, a second corporate initiative in the past 12 months has been the founding of a logistics business called AHC Logistics. Six-year veteran, Chris Rider, heads up the company’s logistics team headquartered in Huntersville. AHC Logistics not only serves AHC’s freight needs, but also is a licensed third-party logistics freight provider. Rider noted, “We have 11 trucks in our fleet, not counting local distribution trucks, and we handle all of AHC Hardwood Group’s import and export-based logistics. In addition, we are currently supporting two of our lumberyards, as well as the shipping needs of White County Mouldings.” As a third-party provider, AHC Logistics also specializes in handling building material freight hauled on flatbeds such as stone, steel or softwood lumber.

Company-wide, AHC employs approximately 300 individuals. Today, the people strategy is as important as long-term capital investments. AHC invests in ongoing training programs and has a long-standing relationship with North Carolina State University and Virginia Tech. Numerous managers and officers, including Mitchell, started their careers as interns. This past year, AHC also completed several large capital projects to expand its niche product offerings and services and to drive product quality.

Howard noted, “AHC is proud of our company heritage and family-friendly culture. We’re a family-owned business offering quality Hardwood products with values based in integrity, loyalty, determination and a strong work ethic. As a successful multi-generational company, we have a long-term vested interest in sustainable forestry. We believe in the future of the forestry industry and hope that our values and commitment to it encourage others to think of us for their Hardwood needs.”

Facility and contact information for AHC Hardwood Group is listed below

– AHC Hardwood Group: 800-476-5393, 706-865-3166 / Email: ahc@hardwoodweb.com.

– AHC Import Lumber 800-476-5393, 706-865-3166 / Email: ahcimports@hardwoodweb.com.

– AHC Export Lumber, 800-476-5393, 706-865-3166 / Email: ahcexport@hardwoodweb.com.

– White County Mouldings 800-476-5393, 706-865-3166 / Email: wcm@hardwoodweb.com.

– Hardwoods of Tennessee 877-989-9663, 931-802-2534 / Email: info1@hardwoodweb.com.

AHC Hardwood Group is a member of several lumber associations, including: the National Hardwood Lumber Association; International Wood Products Association; Appalachian Hardwood Manufacturers Inc.; Hardwood Distributors Association; Hardwood Manufacturers Association; Southern Cypress Manufacturers Association; American Hardwood Export Council; Penn-York Lumbermen’s Club; Indiana Hardwood Lumbermen’s Association; and the Tennessee Forestry Association. More information is available by visiting www.hardwoodweb.com.

When walking into the front lobby of the Cristo Rey Jesuit High School in Atlanta, Georgia, you are immediately struck by a lobby that perfectly balances sophistication with an open welcoming atmosphere. The lobby is part of a much larger capital campaign that allowed Cristo Rey to expand by renovating a former Oxford Industries building. Much like the school’s approach to its education priorities, the renovation breathed life into a building that no one was sure what to do with and made it shine.
Cristo Rey is no ordinary Catholic school. It offers a very unique high school education experience, giving Atlanta’s economically disadvantaged students a way to prepare for college, the workforce, and life. Cristo Rey’s unique program offers students a college preparatory curriculum, but this intensive program doesn’t come free. “When all of our students come here to register for school, we also register them as our employees,” explains Bill Garrett, President of Cristo Rey. Students attend classes while also working for one of the school’s corporate partners, earning a large portion of their tuition. Parents are also expected to chip in, on a sliding scale. “Two-thirds of our operating budget is provided by students working with our corporate partners,” explains Camille Naughton, Vice President of Advancement and Corporate Partnerships. The remainder of the costs are covered by parent contributions and philanthropy.

The lobby of their new education building was an important design element. The lobby needed to set the tone of success for the school,” Naughton explained. “We are very pleased with the design. The lobby needed to be sophisticated, polished, and professional while also giving being warm and inviting and I feel that’s exactly what was achieved.” She continued, “What an amazing gift AHC Hardwood Group has given us.”

AHC Hardwood Group frequently donates wood for non-profit community projects. Chief Executive Officer Jim Howard feels strongly about giving back. “As a company, it’s important that we support programs in our local communities”. He explained, “By donating exquisite hardwoods for community projects, we are able to provide high quality environmental and architecturally interesting building products, showcasing the warmth and versatility of wood, and help support the community.”

Details, a local corporate interior design firm, proposed a high visibility wood treatment for the lobby. AHC Hardwood worked with Details Owner and Designer Jillian Carr Mitchell to select the perfect wood. “With over 45 wood species to choose from, we worked to find the right combination of look and function for the project,” explained Stewart Sexton, Import Lumber Senior Product Specialist for AHC Hardwood Group. “We chose White Limba for its clean lines and contemporary feel.” The design plan called for a wood with straight grain, consistent color, and a modern look overall. The golden colored sapwood also coordinated well with the anigre furniture used in the space. “We are really pleased with how the wood wall project came out,” said Naughton. “When people come into the lobby, they are immediately drawn to the wall. Many even reach out and touch it.”

The lobby is just the start of the variety of ways that Cristo Rey sets the tone for success. With their first graduating class leaving for college in 2018 with a 100% acceptance rate and over $12.8 million in financial aid and scholarships, Cristo Rey Atlanta is well on its way to leaving their mark.

Cristo Rey Atlanta thanks the 2018/19 corporate sponsors for their continued participation and support. The Cristo Rey Network is comprised of 32 high schools that serve over 11,000 young people from low-income backgrounds, living in urban communities with limited educational options. If you would like to learn more about the Cristo Rey Jesuit High School in Atlanta, visit their website: CristoReyAtlanta.org,