Materials Science: Wood vs. Aluminum Bats (Basic)


On a recent outing to Seattle, a friend and I strolled past Safeco Field, home of the Mariners, our city’s major league baseball team. The outside walls of the ballpark were hung with giant portraits of the players: Justin Smoak, Franklin Gutierrez, Ichiro Suzuki – heroic, larger than life, powerful. I thought about all the children who looked up to these athletes and wanted to be like them. I also wondered how trees might play some part in that exchange. My friend informed me that professional players use only bats made of wood. According to the major league rules, a bat must be no more than 2-3/4 inches in diameter and no more than 42 inches long, and consist of a single, round piece of solid wood. There was my connection between this sport and trees.

When baseball was invented in the 1850s, bats came in all shapes and sizes and were made of hickory, an extremely hard and heavy wood. Today, the majority of wood baseball bats are made from deciduous trees harvested from Pennsylvania and New York. White ash (Fraxinus Americana) and sugar maple (Acer saccharum) are used because of their hardness, durability, strength, and ‘feel’. Trees that provide the lumber for baseball bats are around 50 years old. Metal bats, introduced in the 1970s as a cost-saving alternative to wooden bats that were prone to breaking, turned out to be more efficient than wood. In a study by J. Crisco and R. Greenwald at Brown University, metal bats outperformed wood bats in test comparisons. They clocked average ball speeds for wooden bats at 98.6 mph, and for metal bats at 103.3 mph. Claims that higher ball speeds put infielders at greater risk for injury have led to calls for restrictions on bat performance. Some athletic associations have banned the use of metal bats in high school play because bats made of wood seem safer. Learn the basics of wood vs. aluminum bats here.

Indoor Sports

The wooden floor underneath the action of indoor sports such as basketball gets far less attention than the athleticism displayed on court, yet it is a critical part of the safety and performance of the athletes. A sports floor must be durable, resilient to the pounding of heavy players, provide just the right amount of friction to prevent falls, and allow for slides and quick turns. As an athlete’s foot hits a sports surface, the force is translated into two forces, one absorbed by the floor, the other returned to the athlete. Artificial surfaces such as concrete and asphalt provide little force reduction for the athlete but maple sports floors absorb these forces, which reduces injury to the athlete. One study documented that athletes were 70 percent more likely to sustain a floor-related injury on a synthetic floor than on a wooden floor. Starting 150 years ago, Northern Hard Maple (Acer saccharum) became the sports floor of choice because of its resilience and traction. In the United States, each year, 17 million square feet of sports floors are annually installed, equivalent to about 85,000 trees that are 70 feet tall and 14 inches in diameter.


white-golf-ballThe materials that make up golf balls have evolved through the long and fascinating history of golf. Historically, these materials were linked to natural compounds, all of which were derived from objects in nature, particularly different species of trees.

The Scots, who originated the game in the 1400s, developed a variety of golf clubs: irons, putters, and woods. Woods are the longest clubs in the bag and are mostly used for long shots. The wood heads were made of persimmon (Diospyros) or maple (Acer) trees. The introduction of golf into America in the early 1800s led to the use of hickory (Carya) (native to the United States, but not to the United Kingdom) in the shafts of the clubs. These clubs were far stronger than other woods and became standard until steel shafts were introduced in 1925.

The first balls – called “featheries” – were leather-covered objects stuffed with boiled goose or chicken feathers., and then coated with paint. Feathers were first boiled and then placed in the pouch. As the ball cooled, the feathers would expand and the hide would shrink, making the hard, compact ball that would fly far and accurately.

Later, tree products entered into the golf ball. The “gutta-percha” ball was created in 1848. Gutta-percha is the evaporated milky latex from Malaysian Sapodillo tree of eastern Asia, Palaquium gutta. This and other related trees, such as the “bully tree” (Manilkara bidentata) of the West Indies, yield a hard rubber-like material called “balata.” Trees are tapped by cutting zigzag gashes in the bark, something like the harvest of maple sap to make maple syrup. The latex was collected in cups that hung from the trunk. That raw material turns into a tough, resilient, and water-resistant material.

The rubber was made round by heating and shaping it while hot. However, since the ball was spherical, it creating little lift and went only short distances. Accidentally, it was discovered that defects in the sphere from knicks and scrapes of normal use could provide a ball with a truer flight than a pure sphere. Thus, makers started creating intentional defects in the surface by hammering the ball to give it an evenly “dimpled” surface, which caused the ball to have a more consistent ball flight.

By: Nalini Nadkarni, University of Utah



Nadkarni, N. M. 2008. Between Earth and Sky: Our Intimate Connections with Trees. University of California Press. Berkeley, CA, USA.

Articles by Kenny Morley.

This entry was posted in and tagged . Bookmark the permalink.