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## CONSIDERATIONS IN CALCULATING TREES TO PAPER

Jan 12, 2012

**What kind of paper are you talking about?**

Paper made in a “mechanical” or “groundwood” process (e.g. newsprint, telephone directories, base sheet for low-cost coated magazine and catalog papers)

**uses trees about twice as efficiently as**

paper made in the “kraft” or “freesheet” process (e.g. office and printing papers, letterhead, business cards, copy paper, base sheet for higher-quality coated magazine and catalog papers, advertising papers, offset papers).

**Is the paper “coated” or “uncoated”?**

The fiber in a coated paper (most often used for magazines and catalogs, with a clay coating that may be glossy or matte, or other finishes) may be only a little more than 50% of the entire sheet, because the clay coating makes up so much of the weight of the paper.

As a ballpark estimate, you can use .64 as the fiber estimate for coated papers compared to the entire weight of the sheet. (Fiber estimate calculation by Alliance for Environmental Innovation) So how many trees would make a ton of paper?

Claudia Thompson, in her book Recycled Papers: The Essential Guide (Cambridge, MA: MIT Press, 1992), reports on an estimate calculated by Tom Soder, then a graduate student in the Pulp and Paper Technology Program at the University of Maine. He calculated that, based on a mixture of softwoods and hardwoods 40 feet tall and 6-8 inches in diameter, it would take a rough average of 24 trees to produce a ton of printing and writing paper, using the kraft chemical (freesheet) pulping process.

If we assume that the groundwood process is about twice as efficient in using trees, then we can estimate that it takes about 12 trees to make a ton of groundwood and newsprint. (The number will vary somewhat because there often is more fiber in newsprint than in office paper, and there are several different ways of making this type of paper.)

**SOME TYPICAL CALCULATIONS**

1 ton of uncoated virgin (non-recycled) printing and office paper uses 24 trees

1 ton of 100% virgin (non-recycled) newsprint uses 12 trees

A “pallet” of copier paper (20-lb. sheet weight, or 20#) contains 40 cartons and weighs 1 ton. Therefore,

1 carton (10 reams) of 100% virgin copier paper uses .6 trees

1 tree makes 16.67 reams of copy paper or 8,333.3 sheets

1 ream (500 sheets) uses 6% of a tree (and those add up quickly!)

1 ton of coated, higher-end virgin magazine paper (used for magazines like National Geographic and many others) uses a little more than 15 trees (15.36)

1 ton of coated, lower-end virgin magazine paper (used for newsmagazines and most catalogs) uses nearly 8 trees (7.68) How do you calculate how many trees are saved by using recycled paper?

(1) Multiply the number of trees needed to make a ton of the kind of paper you’re talking about (groundwood or freesheet), then

(2) multiply by the percent recycled content in the paper.

For example,

1 ton (40 cartons) of 30% postconsumer content copier paper saves 7.2 trees

1 ton of 50% postconsumer content copier paper saves 12 trees.