xylotomy

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The microscopic structure of the wood of a plant or group of plants.
• noun The preparation and microscopic study of sections of wood.

from the GNU version of the Collaborative International Dictionary of English.

• noun Art of preparing sections (transverse, tangential, or radial) of wood, esp. by means of a microtome, for microscopic examination.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun botany The art of preparing sections of wood (as by means of a microtome) for microscopic examination.