BACK TO THE FUTURE
WOODEN HIGH RISE BUILDINGS HELP FIGHT CLIMATE CHANGE AND DEFORESTATION

COMPILED BY LUCY MANESS WARNER
AUGUST 14, 2016

Today, on CBS News Sunday Morning with the eloquent and charming Charles Osgood, I saw his story on the new trend of building in wood, and high rises, no less. I wouldn’t have thought it to be a strong enough material for that, and the claim that it helps prevent the escape of increasing levels of CO2 into the atmosphere equally surprised me. It turns out that concrete gives off CO2 at a high rate, while wood stores it.

The key is that they are using an upgraded version of plywood which gains its’ strength from gluing together layers of wood, whose grain is applied in opposing directions, therefore each layer bracing the other under stress. That use of wood only requires smaller trees and can even include trees with rot or beetle damage, which today are useless for most purposes. Fashioning it into blocks, they create a stronger material which is also better for the environment.

In one of my dwelling places in Eastern North Carolina, Georgia Pacific – before they became a Koch company at any rate – regularly replants pine trees cut for paper, fiberboard, lumber, etc., so that the supply is constantly being replenished; as a result there isn’t the danger of demolishing forests at a terrible rate, and in a way that endangers species. Pine trees are “softwood” rather than hardwood like oak, and they grow rapidly, many feet tall over a ten-year period.

A very informative website covers this subject: http://forestry.arkansas.gov/directorysearches/documents/thinning_to_improve.pdf, by Frank A. Roth II, Extension Forester. Excerpts:

“What Is Thinning?

Some 30 to 50 years are required to grow a stand of
pine sawtimber to economic maturity. However, it is
usually necessary to cut some of the trees before the
stand reaches maturity. Cuttings made in
immature stands to stimulate the growth of the remaining
trees and thereby improve the yield of the stand are called
thinnings.

In any timber stand, the trees compete with each
other for light, soil moisture, and nutrients. The more
crowded the trees are, the more intense the competition.
In a very crowded stand, the growth rate is reduced and,
eventually, the weaker trees die. However, the volume
per acre of wood produced by a timber stand of a certain
age on a particular site is about the same over a wide
range of stand densities. This means that, if the number
of trees in a stand is reduced, the same volume of wood
can be produced with fewer trees while maintaining a
good rate of growth. . . . .

Pine Trees Grow Quickly

Most pine stands are even-aged. That is, all of
the trees are within a few years of being the same age. If
all trees are about the same age, then the larger trees
must have been growing at a faster rate. Improper
thinning operations, such as cutting to a diameter limit,
remove the larger, faster-growing trees for immediate
income and leave the smaller, slower- growing trees for
future growth.

On good sites, managed pine trees grow about 10
percent each year up to age 50, almost doubling in
volume and value every 7 years (see Table 1).



On modern building practices, see these two articles. --


http://www.popsci.com/wood-and-glue-skyscrapers-are-on-rise

ENVIRONMENT -- POPULAR SCIENCE
WOOD-AND-GLUE SKYSCRAPERS ARE ON THE RISE
AND THEY COULD HELP FIGHT CLIMATE CHANGE
By Jeremy Deaton
April 26, 2016

Drawing: Tall Wood Student Residence, In 2015, the University of British Columbia approved an 18-story residential building for students, which will be made almost entirely of wood. The Tall Wood Student Residence will rise 174 feet into the air, making it the tallest wooden building in North America.
Flow chart -- Ecofys, 2010 World Greenhouse Gas Emissions Flowchart; Excerpt from Ecofys's flowchart showing world greenhouse gas emissions for 2010. The full chart is available here.
Video -- Architect Michael Green TED Talk, 12:22 min.

Thanks to advances in wood construction, the next generation of skyscraper might be made of spruce, not steel. Architects are designing wood buildings that ditch concrete and steel in favor of a more environmentally friendly material—one that could help fight climate change.

Wood + Glue = Skyscraper Material

Glue might the best thing to happen to the lumber industry. Adhesives permit manufacturers to cheaply produce wood products that are no longer in the shape of trees. The particleboard in your IKEA coffee table, for example, is made from wood fragments that have been glued together.

Lumber producers are now using über-powerful adhesives to assemble massive wood panels with the strength and durability of concrete and steel. Cross-laminated timber, as it’s known, is made of small planks bound together by a polyurethane adhesive. The pioneering technology has freed architects to dream up buildings that were previously inconceivable.

“Not only is [wood] attractive and warms up the building,” said Kris Spickler, a heavy timber specialist at cross-laminated timber manufacturer Structurlam, “I think architects really enjoy being able to use a product that they’ve used for interior spaces, and actually use it for the structure itself.”

Beyond its aesthetic appeal, cross-laminated timber boasts several other advantages. Wood construction sites generate less waste, noise, and traffic than conventional sites. And wood buildings can be erected more quickly than steel and concrete structures, keeping the projects cost-competitive. For example, Spickler pointed to a forthcoming skyscraper at the University of British Columbia.

“The building was competitively bid against concrete and steel. It wasn’t a show project,” said Spickler. “I think the speed an the affordability won out, and that’s why we’re building that 18-story.”

To observers, a wood skyscraper may sound like a fire hazard, but Spickler disagrees. Steel is vulnerable to melting in a blaze, twisting and contorting in the heat. Timber, on the other hand, will char on the outside, but flames will not penetrate its core. After a fire recedes, the wood beam will remain standing.

Wood’s greatest virtue, however, is not design potential or fire safety. The fibers of every plank help combat climate change.

Steel and Concrete Produce Carbon Dioxide

Steel and concrete come with a colossal carbon footprint. Cement, the binding agent in concrete, is made by heating limestone and clay in a kiln. Steel is made by heating iron, limestone and a carbon-rich form of coal called coke in a blast furnace. Carbon dioxide is an inevitable byproduct of both processes, from burning coal to generate heat.

According to a 2013 accounting from Ecofys, iron and steel account for nearly five percent of global greenhouse gas emissions. Non-metallic minerals, including the raw ingredients in concrete, amount to 6 percent. Together, these sources contribute about as much to climate change as all the cars and trucks on Earth.

Wood Traps Carbon Dioxide

When it comes to climate, wood beats conventional building materials on two fronts. First, wood boasts a smaller carbon footprint than steel and concrete. Logging, refining and shipping wood products eat up fossil fuels, but a producer will generate more pollution turning a lump of iron into a steel beam than turning a tree into a plank of wood.

Wood’s second advantage is its ability to trap carbon dioxide. Some scientists speculate the only way to keep warming under two degrees Celsius, the stated goal of the Paris Climate Agreement, is to provide for negative emissions. That could mean high-tech machines or materials that scrub CO2 from the air, or eco-friendly farming practices that trap carbon in the soil. So far, however, the most cost-effective tool for carbon removal is a tree.

Compare this to steel and concrete. "If we built a 20-story building out of cement and concrete, the process would result in.1,200 tons of carbon dioxide,” said architect Michael Green in a TED Talk. “If we did it in wood, in this solution, we'd sequester about 3,100 tons, for a net difference of 4,300 tons. That's the equivalent of about 900 cars removed from the road in one year."

Green’s back-of-the-envelope calculation lines up with more rigorous analyses. According to a 2014 study from researchers at Yale and the University of Washington, up to 31 percent of global carbon dioxide emissions could be avoided by building with wood instead of steel and concrete.

“If you build out of wood instead of concrete or steel or brick, then you avoid all that fossil fuel you would burn to make the steel, concrete and brick,” said Chad Oliver, Director of Yale’s Global Institute of Sustainable Forestry and lead author on the study. He noted that, because timber weighs less than conventional materials, builders also need less concrete to lay the foundation of a wood structure. When a wood building is finally retired, its component parts can be reused in other buildings, buried in the ground or used to produce electricity.

Smart Logging?

The prospect of leveling forests to erect skyscrapers and generate electricity is enough to make any tree hugger woozy. But Oliver says logging can form an essential part of smart forest management.

“As a general rule, and this varies from place to place, the forests are getting more dense,” said Oliver. “You want some areas that are dense, but you don’t want to whole forest uniformly dense, because some animals live in that dense forest, but other animals live in an open forest. You need a diversity of conditions.” Loggers can foster biodiversity by thinning some parts of the forest and clearing others to create patchwork quilt of habitats where every species has a home.

Logging can also reduce the risk of forest fire. In a uniformly dense forest, flames grow hot and spread quickly through tightly packed trees. In a more varied setting, a fire might hit a meadow and slow down, allowing time for rain or cold to intervene and bring the inferno to a halt.

“If we harvested more of that extra [tree] growth instead of letting it rot or burn in overly dense forests,” said Oliver. “We could make a lot more products and use the waste for wood energy.”

“We can take smaller trees and laminate [them into] massive panels stronger than concrete and one fifth the weight.”

Cross-lamination allows manufactures to produce larger beams from smaller pieces of wood, meaning the raw materials can be supplied by shorter, more slender trees, including those threatened by rot, fire, and pine beetles. Trees that would otherwise decay or burn, leaking their stores of carbon into the atmosphere, can be made into the building blocks of skyscrapers.

“We have more trees right now in the forest that we can use than we did 50 years ago. So, we can sustainably grow this and harvest it and continue to use it,” said Spickler. “We can take these smaller trees and take the smaller cuts of them, and laminate panels that weigh 10,000 pounds—massive panels bonded together to be stronger than concrete and one fifth the weight.”

Climate change has already ignited revolutions in clean power and transportation. Spickler believes construction may be next. “This revolution has happened rather quietly and happened rather slow,” he said. “But I think we’re in a year right now where we’re going to see it explode.”

Jeremy Deaton writes about the science, policy, and politics of climate and energy for Nexus Media. You can follow him at @deaton_jeremy.



http://www.eenews.net/stories/1060032371

BUILDINGS:
Saving America's forests one wooden high-rise at a time
Brittany Patterson, E&E reporter
ClimateWire: Tuesday, February 16, 2016


Photograph -- The University of British Columbia's Earth Sciences Building in Vancouver is made of wood. The U.S. Department of Agriculture and the wood products industry are hoping to create a space for wooden high-rises in a U.S. market dominated by concrete and steel. Photo courtesy of FTP Edelman.


Correction appended.

MADISON, Wis. -- If the invention of steel forged the high-rise, the iconic building's future may be pine.

This fall, the future will be under construction in the United States. A 12-story high-rise built primarily of wood is set to go up in Portland, Ore., like giant Lincoln Logs extending more than 100 feet into the air. When finished, the project named Framework will be the tallest building in the country to be constructed with a promising engineered wood material, cross-laminated timber.

This feat of wooden engineering is something the Department of Agriculture as well as the wood products industry is hoping to use to start opening up the tall building market -- traditionally cornered by steel and concrete -- all while bolstering rural economies and fighting climate change.

"There is a huge amount of interest both from the architectural community and from the sustainability community relative to the carbon sequestration wood offers and the benefits it offers for managing forests," said Thomas Robinson, a principal architect with LEVER Architecture, one of the firms designing the Portland project.

Proponents of cross-laminated timber and other mass timber products say it could create demand for the woody material clogging overgrown forests, especially in the West. Creating a market for small-diameter trees or diseased or burned forests by turning it into a high-value building material would create jobs, something once-great rural paper mill towns desperately need.

USDA, the Forest Service's Forest Products Laboratory and a handful of the forest products industry groups have jumped in the cross-laminated timber game, throwing money at educating engineers and architects, promoting the product, and moving forward with research.

For the building's owner, the new space, which will be located in Portland's quirky Pearl District, needed to balance sustainability with practicality. When the team at project^ heard about a competition hosted by USDA calling on developers to use wood to build tall buildings, "the stars aligned" for cross-laminated timber, said Anyeley Hallová, a partner with the firm.

Last September, USDA, along with the Softwood Lumber Board and Binational Softwood Lumber Council, awarded the Portland project and another in New York City a total of $3 million to construct tall wood buildings to serve as demonstrations that wood can be the principal building material for multistory, nonresidential buildings.

"I think the reasons for interest on the part of [Agriculture Secretary] Tom Vilsack are many, one of which is the potential for jobs in America. Cities are thriving, but the countryside isn't, especially communities in highly forested areas," said Jim Bowyer, director of the responsible materials program at Dovetail Partners, a nonprofit environmental consulting firm. "USDA sees an opportunity for wood to play a bigger role in carbon mitigation, too."

Sometimes described as "jumbo plywood," cross-laminated timber (CLT) is made when smaller pieces of timber -- two-by-sixes and two-by-fours -- are glued together with the wood grain alternating at 90-degree angles. Sheets of the glued timber are layered together into large sheets, up to 18 inches thick, 10 feet wide and upward of 50 feet long, and can be used just like steel or concrete would as walls, ceilings or floors.

The material is strong, yet lighter than traditional building materials and full of carbon. Cross-laminated timber buildings go up in a small fraction of the time of those made from steel or concrete.

But some questions remain about building tall with wood. Won't it burn? Are wooden high-rises giant termite buffets? How does wood hold up against earthquakes or humidity? And these questions have to be answered before CLT is sanctioned by building code officials and can join steel and concrete as a truly competitive building material for high-rises across America.

Finding the 'sweet spot' for wooden high-rises

There is a lot of wood in Michael Ritter's office, which makes sense since Ritter is the assistant director of the wood products research group at the Forest Products Laboratory in Madison.

Wooden skyscrapers

Wooden skyscrapers are already popular in Europe, where 14 of the past 17 buildings using mass timber were built last year, like the one above in Austria. But the engineering feat is slowly gaining traction in the United States. Photo courtesy of FTP Edelman.

Samples of cross-laminated timber and other forest products litter his bookshelves. On a table sits a shoebox-sized model of an all-wood tornado safe house one could build for a few thousand dollars with wooden materials from Home Depot, a testament that the lab's job is to broaden the market and uses for wood products.

Ritter's latest project was to bring more than 120 researchers and engineers from the United States and abroad for a two-day rendezvous at the lab to discuss what the research priorities should be for CLT. The lab will soon release a report spelling out what those should be.

"I think that's going to be a real important outcome," Ritter said. "Both research and technology transfer are critical, and then communicating research activities and findings is also a priority."

Cross-laminated timber is not new, per se. In the last few decades, European builders, engineers and architects have quietly developed the material.

In the last five years, 17 buildings ranging from seven to 14 stories tall have been constructed using mass timber around the world, the majority in Europe.

The United States has been slow to embrace wood for building more than a few stories high. But some see the tides starting to turn.

Jennifer Cover, executive director of WoodWorks, an educational arm of the Wood Products Council that provides free education to architects and engineers on designing and building nonresidential buildings with wood materials, said in the last three years her organization has seen interest and requests for assistance skyrocket.

Currently, the group is providing technical assistance to 22 U.S.-based projects that are slated to build past seven stories with wood.

"The momentum is there for sure," she said. "Engineers are going to decide where the sweet spot is, where it makes the most sense. Seven, eight stories up to 13 to 14 seems to be very doable with wood as the primary material."

Research takes time

Designing a building using cross-laminated timber or other mass timber products is a different beast from more traditional wood design in part because of the way CLT is manufactured -- in large panels or plates. Based on the design of the building, a computer-controlled machine will control a robot that cuts slabs of cross-laminated timber so they will fit perfectly together. The slabs arrive to the job site, and the whole thing goes up like a big Erector set.

"The greatest hurdle is the perception that we know less than we actually do," Cover said. "We've definitely heard time and again that it isn't a huge learning curve after you get through that first project."

The Forest Products Lab began studying how the material holds up against earthquakes about four years ago with the goal of developing a design procedure for the material that is code-compliant for midrise buildings. The lab's research is not complete. But research from other countries like Japan finds the wood's flexibility allows it to perform as well as, if not better than, steel and concrete in an earthquake.

Another cause for concern -- one Bowyer calls "quite legitimate" -- is how the material performs against fire. Here, too, the research seems to indicate wood outperforms steel, which is highly susceptible to heat.

"As wood burns, it forms a char layer, which is an extremely effective insulator," he said. "Even through an intense fire, wooden beams will remain standing, whereas steel beams will heat up and bend over them."

Research is being conducted to see how much exposed wood can be subject to fire before it contributes to a blaze.

"The research is a very rigorous process," Ritter added, setting a sample of cross-laminated timber made with three-quarter-inch laminate on the table. "So even though we're scheduled to do the final phase of the research on seismic design, it may still take six years, seven years down the road to get it in the code."

A building codes problem

Kenneth Bland, vice president of codes and regulations with the American Wood Council, said although the industry wants to build taller with wood, the codes aren't there yet, and that is preventing wide-scale adoption.

Most homes are constructed with a wood frame. In the nonresidential space, however, anything taller than six stories has been appropriated to steel and concrete through building codes.

One challenge is that getting new codes approved by the International Code Council, the nonprofit that develops building standards, is a three-year cycle. Bland and his staff submitted a proposal for a nine-story mass timber code, which was denied. The next opportunity to submit a new proposal will be in 2018, for the 2021 codes.

Code officials may be opening up the lines of communication. Last month, the ICC board of directors voted to create a Tall Wood Ad Hoc Committee, which will study tall wood construction and may develop code changes to be submitted for the 2021 International Building Code.

Inside the biggest installation of CLT in the U.S.

Outside of the testing and scheming to bring cross-laminated timber to the mainstream, early adopters have found the material adds something timeless and natural to their structure, while the environmental benefits bolster sustainability goals.

Melodic piano music envelops visitors as they step into biotechnology company Promega Corp.'s Feynman Center, located at the company's Madison headquarters. A mix of laboratory, manufacturing and meeting spaces, the 260,000-square-foot building was completed in 2014 with the hope of balancing functionality with comfort, said Jennifer Romanin, director of in vitro diagnostic operations.

The space goes to great lengths to accomplish that. Many aspects of nature -- from 18,000-pound boulders to a lush two-story-tall living wall that grows and blooms year round -- greet visitors when they arrive. The biggest component of the building, however, is its primary building material: 14,133 cubic feet of cross laminated timber, what is believed to be the largest installation of the material in the United States.

The total carbon benefit between carbon stored in the wood and greenhouse gas emissions prevented is estimated at 692 metric tons.

"Especially here in the Midwest, I think we see a lot of wood, but to see the structure the way it was designed, and all the wood in the columns and beams, I think that is what helps it stand out," Romanin said. "One of the words we used to describe what we wanted to evoke was 'timeless' -- what about wood isn't timeless?"

The option to use cross-laminated timber was introduced to Promega by the architectural company with whom it worked and trusted. Still, there were questions about fire safety and the performance of the wooden material. The Forest Products Lab continues to monitor how moisture is affecting the building through the use of remote sensors. So far, everything looks normal.

All the cross-laminated timber used at the Feynman Center originated in Canada, which highlights another challenge for the material: a lack of manufacturers based in the United State.

There are only a handful of facilities in the country that make CLT, including one in Oregon and one in Montana.

"In the business of supply chains, competitive bidding is very important," Bowyer said. "It's a chicken-and-egg thing. Prices will come down, the price of shipping will come down, but only if we get more producers."

The Portland project is hoping to source at least some of its cross-laminated timber from the Oregon plant. The USDA grant will help pay for seismic and acoustics research and testing on the building, with the findings and the experience of the project made available for others to learn from.

"There are lots of things we're still working on, but there's a huge amount of interest," Robinson with LEVER said. "We have these products, and we can create more value for them in the communities that they are harvested, and that can create a more virtuous cycle between rural and urban parts of the country."

Correction: An earlier version of the story listed LEVER Architecture as the lead firm for the Framework project. Project^ is the firm leading and coordinating Framework.