Tree Identification

       In January I attended a class at the North Carolina Arboretum on winter tree identification. We were given a wonderful little book called, "Winter Tree Finder" by May and Tom Watts, which I recommend if you want to identify trees in the winter. The teacher of the class, Marc Williams, has two websites: www.botanyeveryday.com and www.plantsandhealers.com and offers courses online. 
         I decided to ask a question I have long pondered: is there a 'bright line' between whether a plant is a shrub or a tree? And the short answer is 'yes.' Basically a single trunk is a tree and a shrub has multiple trunks. Based on this criteria, he said a crepe myrtle is a tree. The first picture below is of a witch hazel (shrub) and below that is a red bud, which is a good example of a single trunk tree. 

w          He said bark is NOT very helpful in distinguishing between types of trees because the look of a tree's bark changes over the lifetime of the tree. 
         I did learn that the number of needles in a 'bundle' coming out of a 'fascicle' (point where the needle bundle fastens to the tree branch) DOES make a big difference in identifying the type of pine tree it is. I had always thought the number of needles in a fascicle was rather random, not knowing that ALL the fascicles on a tree have the same number of needles attached. 
          The scars are also critical in tree identification. There are leaf scars, vein scars and bud scale scars. Good clues to a tree's identity can be obtained by noting whether the leaf scars are alternate to each other on a twig, or opposite to each other. It also matters whether the leaf scars are 'whorled' or not. Leaf scar shape  matters as well; they can be heart-shaped, shield-shaped or C-shaped. TO be honest, I had never given the slightest thought to those 'marks' on the twigs of trees. Now that I know they contain important information I will pay them more heed. 
         I also learned that branches coming out of a trunk at a 90 degree angle are stronger than branches that come out at any other angle. Not that this helps with tree identification, but I thought it was interesting information nonetheless. See below for two examples of this.