Cross section through an old & weathered log from an elm tree. The difference between the heart wood (dark) and the sap wood (light) is seen clearly. Sap wood is saturated with water and contains the living cells of the conducting tissue. After 10-15 years sap wood is converted into heart wood, which is a completely lifeless, dry tissue. Because it is dry and less likely to warp or crack, heart wood is preferred in the timber trade. Hardwood trees such as oak contain more heart wood than the softwoods, such as pine, and are preferred as timber. The concentric rings here correspond to annual growth rings, a count of which would indicate the age of the tree.

Photo website with Rights Managed and Royalty Free stock photos, images, illustrations and footage available for download immediately for commercial and editorial uses. Aflo is a leading independent supplier and producer of stock pictures and visual content. Search and find high quality images and video for design, print, web-use and publishing. Buy photos from our extensive collection of model released and property released sports images. Search some of the most beautiful travel and landscape pictures from our own photographers and license from our large collection of content, modern and archive, focusing on Japan. We provide free research. Register for personal account management and for full use of our Stock Photography website and start to download images now.