Forest Society Announces Development of Square Trees

Selective improvement leads to increased timber yield, more efficient processing, and greater carbon uptake in New Hampshire forests

April 1, 2008


Concord, N.H., April 1, 2008—The Society for the Protection of New Hampshire Forests, dedicated to land conservation and the wise use of the state’s abundant natural resources, hopes that a new development in the forests will promote both.


“After years—decades really--of effort, we are pleased to announce the successful development of a commercially viable square tree,” said Jack Savage, spokesperson for the Forest Society.


Working at a remote location on one of the Forest Society’s more than 150 permanently conserved forest reservations, forest research scientists started with a vision of the “ideal tree” and then worked to create it. A breakthrough came a number of years ago when the research team managed to get seedlings to adopt a shape other than round, which then led to the development of a consistently square trunk.


There are any number of advantages to the square tree. For example, square trees load more efficiently onto a logging truck for transport to the sawmill. Tests to date have shown that a standard logging truck can carry up to 25 percent more board feet per trip with square trees compared to standard round trees.


But the real improvements come once the logs get to the mill. Traditional round logs have to be squared up before being sawn into boards, yielding considerable waste wood. Those savings alone could improve efficiency up to 18 percent.


“Add onto that the fact that you can grow more square trees on a given acre of land than you can round ones, and you’ve got improved efficiency—and much-needed improvements in the financial margins—for the landowner, the logger, and the mill operator,” said Savage. “This is exactly the shot in the arm the forest products industry needs.


“Sustainable forestry has not only been an important element of our ‘wise use’ philosophy,” observed Savage, “but a key part of our land conservation strategy as well. Land owners who can generate revenue through good forestry are far less likely to convert their forestland to residential use. We think improving the efficiency of the forests will help protect them.”


“But this program is also about the environment,” Savage continued. “By carefully managing the increased yield of square trees, we can take up about 14 percent more carbon in our forests. Talk about additionality!”


Studies have shown that trees take up, or sequester, considerable amounts of the carbon dioxide that is emitted through the burning of fossil fuels, which is generally considered to be a key factor in climate change. By sequestering additional carbon, square trees can help mitigate global warming.



A few people have expressed concern over how one would measure a full cord of wood—after all, a stacked 8 x 4 x 4 cord includes a certain amount of air because of the irregularity of the cut and split firewood, and similarly stacked square trees fit neatly together. However, the square trees are destined for the sawmill, not the firewood processor.


“Besides,” said Savage, “so far we’ve only perfected the square trees in softwoods, like white pine and spruce, which aren’t typically used as firewood. The hardwoods, including oak, maple, and beech, have resisted the attempts at selective breeding

“Interestingly, the roots and branches are still round on the square trees we’ve cultivated thus far,” said Savage. “Inside the tree, however, the rings are perfectly square. I guess we’ll have to start calling them ‘tree squares’ from now on.”

Savage notes that square trees were developed using what’s known as ‘market-assisted selection’, or MAS, rather than the more controversial genetic engineering techniques. MAS involves identifying plants with desirable traits, then using conventional breeding techniques to introduce the genes into a host tree.

Our experiments followed several different avenues,” Savage continued, “including one in which one researcher attempted to cross a white pine with a Boxwood tree. That one never grew very big and the cell structure of the fiber lacked strength—it was really dog wood, even though it did grow square.”


According to Savage, the most controversial aspect of the program is the fact that the trees seem to respond best to the square breeding when they are grown in a ‘checkerboard’ pattern,” in which the trees selected silvaculturally for full maturity are kept in neat rows, equally spaced apart.


“We’re not entirely certain why this is,” Savage said. “It could be the pattern of sunlight, or the pattern of absorption of soil nutrients. But by trial and error we have learned this—the best way to grow a square tree is to grow it in a square forest.”

Savage acknowledged that not all lovers of the outdoors will be pleased with the notion of a forest laid out on a grid pattern, even if it does help attenuate global warming.



Impact on Wildlife

Savage said that the Forest Society is monitoring the effects of square trees on wildlife.


“For example, we’re watching closely how square trees will impact highly arboreal species, such as squirrels, fisher and porcupines,” he said. “Squirrels typically spiral up a tree, and there’s some concern that they will not be able to go as fast around the corners of a square tree, and thus be more susceptible to being caught by predators.”


Savage chuckled when asked about the impact of square trees on birds.


“Somebody tried to tell me that woodpeckers were pecking square holes in the square trees,” he said. “I think some of the scientists were trying to pull a fast one on us there.”


At most, Savage said, the holes woodpeckers peck in square trees are “a little more oblong” than those in round trees.


 “The potential of square trees is tremendous,” Savage said. “Through precise silviculture, we think we can harvest ready-made 2x4s, 4x4s, 6x6s, etc. We even have a timberframe company working out how to grow a ‘ready-to-build’ timberframe house.


“Those guys are really thinking out-of-the-box,” he deadpanned.


“At heart, we are all tree-huggers,” Savage concluded, “and I must admit that hugging a square tree is just not the same.”

Click here to hear a related story on New Hampshire Public Radio.

The Society for the Protection of New Hampshire Forests ( is the state’s oldest and largest non-profit land conservation organization. In order to preserve the quality of life New Hampshire residents know today, the goal of the Forest Society, in partnership with other conservation organizations, private landowners, and government, is to conserve an additional one million acres of the state’s most significant natural lands for trails, parks, farms and forests by 2026.