As part of the U.K. publishing industry’s eco-kick, Dorling Kindersley has released a series of green books “ greener than all those that have come before.

The four new titles are printed using non-toxic glue and vegetable inks on recycled card, and a tree is planted for every one pulped in the process. (And, for a limited time, David Suzuki comes free with every purchase.)

The Times Online notes, though, that while green publishing is certainly admirable, it’s not cheap, and until it becomes cheaper, it may not be sustainable financially:

Manufacturing the books will cost the publisher twice the usual price, largely because DK, part of the Penguin Group, is printing it in Europe instead of the Far East to cut down on unnecessary travel.

We are launching the range at a bit of a loss leader to see how it goes, said Gary June, DK’s chief executive.

We are hoping to pass some of the cost on because people will pay for ethical goods. The demand is there.

Most publishers are trying to go green. Hachette Livre’s Little, Brown imprint already uses nothing but Forest Stewardship Council-accredited paper, whereby a tree is planted for every one used. However, demand is outstripping supply.

June also aims to produce fewer books, cutting down on the number of unsold copies that are pulped.