Tree ID by alternate zig-zag buds

Buds are located at the end of stems (terminal buds) and along stems (lateral buds). Here are photos of  lateral buds that alternate along a zig-zag stem. The change of direction occurs when the terminal bud dies and one of the lateral buds that lies behind the stem tip becomes the new terminal bud but grows in a slightly different direction. Known as sympodial growth, this gives the stem a zig-zag appearance. This is easy to see in Limes, Elms and Mulberry but more difficult to see in Beech and Plane. If the terminal bud does not die growth is in a straight line and this is known as monopodial growth, as in the Ash. 

Tree ID by alternate zig-zag buds – Click on any photo to enlarge it. Click on any name in red to learn more about the species. To go back to the BUDS key click HERE

In Britain most tree growth occurs in spring and summer. During the growing season the tree produces buds ready for next years growth. These buds remain dormant during the winter and open in the following spring. Inside each bud are tiny preformed leaves, shoots or flowers. Terminal buds are formed at the end of the shoot. Lateral buds are formed at the junction of the leaf and shoot. Leaves and lateral buds are formed at particular points on the shoot called nodes. As the shoot grows in the summer, the terminal bud releases a hormone which prevents lateral buds forming. The concentration of this hormone is high at the tip but as the tip grows away it becomes low enough for lateral buds to form at a node. The tip then continues to grow until another node can grow and so on until growth ends for the year.