According to a study conducted by California high schools, the average weight of a physics textbook is 4.8 pounds. Taking into account the most common modern paper-making techniques, it takes 12 trees to produce one ton of paper, according to Conservatree. This means each tree outputs about 167 pounds of paper. This figure represents paper made using the "mechanical" or "groundwood" process.
Using the average figures for average textbook weight and average tree output, a result of 0.028 trees per textbook can be reached. Similarly, it is found that 34.8 textbooks can be produced from each tree. On a campus of 10,000 students, each with 6 textbooks, a total of 1,680 trees worth of paper is being used.
These calculations are based on average figures, and a number of variables can affect the result. The most obvious of these variables is textbook and tree size, with larger textbooks requiring more raw materials and larger trees producing more wood suitable for production. The paper-making method also plays a substantial role, as modern "mechanical" techniques are about twice as efficient in their wood usage as the traditional "freesheet" process. Additionally, paper that has a glossy coating may use about half as much wood fiber per pound as uncoated paper, because its clay coating makes up a large part of its weight.