A xylotheque (from the Greek xylon for "wood" and "theque" meaning "repository") is a wood collection.
But just as a library is something more than merely a collection of books, a xylotheque is something more than just collection of wood. Almost all rather developed countries with worries about their flora have at least one xylotheque with their flora and one with flora from other places in the world.
The xylotheque with a largest number of samples is the Samuel James Record Collection of the Forestry School of Yale University in New Haven, Connecticut, which houses 60,000 samples. The second largest xylotheque belongs to the Royal Museum of Central Africa in Tervuren, Belgium. As of September 2004, it had 57,165 samples. The Thünen Institute of Wood Research in Hamburg has more than 37,000 samples. 
Other important xylotheques are:
|RBG Kew (UK)||20,000|
|Dehra Dun (India)||15,000|
|Saint Petersburg (Russia)||8,000|
A xylotheque is useful to understand the scientific and economic value of the existing woods. At the same time, their samples are used to study the xylotomy, physical and mechanical wood properties, such as durability and preservation. The existence of xylotheques has also immediate applications for anyone who needs to make a morphological-visual analysis of wood. These include technicians, specialists and woodworkers, and also those involved in industry and commerce.
Even a modest wood collection has value, as each of its samples is a compendium or monography that encloses a vast information. They are very important in museums, schools and universities for didactic and docent value.
A xylotheque becomes really interesting and its use is essential as a study tool and a reference to investigations about identification, use and substitution of woods in real state and movable of our cultural patrimony, as well as in preservation and restoration.
- "Woods of the World in the Thünen Institute". Johann Heinrich von Thünen Institute. Retrieved 2013-10-09.
- International Wood Collectors Society
- Xiloteca Manuel Soler (One of the largest private collection of wood samples)
- Wood Collection Xiloteca Imanol Artola (Zumárraga, España)
- Wood Collection