If I had one area in which I flatter myself to think I have some experience and knowledge, it would be in the magic of trees and woods. I've always loved trees, and as my Witchcraft practice has deepened, so have my feelings for and about them. There's little activity more enjoyable than a nice walk through a wooded area, and taking time to examine the various trees and other plants that make up the local flora and fauna. Of course, perhaps the best known use of trees in Witchcraft would be the creation of the magic wand from their branches, and it's this area in which I've had quite a bit of experience.
Traditionally, the wand has been made from the wood of a nut or fruit tree, which the belief (I'm assuming) that a tree which "gave forth" something would have the most efficacy as a magical tool. Hazel seems to have been the most common wood used, with Almond also mentioned, as well as Blackthorn and Hawthorn. Rowan is also a favoured choice, and in some cases Ash (which, though it doesn't give forth fruit, is well-known as the "World Tree" that lives in all three levels of existence.) I have experimented with all of these woods, and had varying levels of success with each. My own thoughts are as follows:
Hazel: This one comes up again and again as the "best" wand wood. As the tree of wisdom and knowledge, that certainly makes sense. In my own experience, it is indeed a powerful material to work with, but one with a certain "edge" to it. It's almost got a cold feeling; perhaps in the sense that the knowledge it provides is impartial, and may not be what you want or expect.
Rowan: Powerfully protective, it also has a "dreamy" feel and is known for the ability to enhance the psychic senses. In my own views, this would be a wise choice for benevolent, protective magic but not the best tool to use for offensive magic or blasting.
Hawthorn: The "thorn" in the well-known "Oak, Ash, and Thorn." Blackthorn's milder relative, this wood is one of my favourites, even though I've only recently begun to work with it. It's got an enchanting, inviting feel and works well with magic involving love. However, because of the heavy thorns, it's also got a powerful protective quality and, next to Hazel, would be a first choice for an all-purpose wand.
Blackthorn: Dense and extremely powerful, the most common choice for the famed "blasting rod." Some claim it has a negative or even evil aura, but this has not been my experience. Excellent for banishings, darker workings, but also for protection. Very difficult to get in the Americas.
Ash: A common tree, even in the South where I live, this is another of my favourites and was the wood my very first wand was made from. I've heard various attributes given to this tree, including that of protection from drowning, but in my own practice I've found that it would make both a fine all-purpose wand, and one that aids in shamanic work (because of its status as a tree of all worlds) and in protective charms.
There are many others, of course. I've used Oak with good results, though it's not one I commonly employ. Maple is common around me, and I've used that as well, but I don't find it has a particularly powerful energy. There are yet more I've yet to try, such as Elm, but which I plan on in the future. Part of my own search has been the question of whether or not to use woods that are "traditional" or woods that are local; for example, you'll not find a Hazel tree anywhere near me, but we DO have Ash and Hawthorn, so I wonder if the latter two might not be a best choice. At the moment, I am moving away from simply learning the properties of these woods, to being able to recognize all local trees by sight, and I expect that the study of these trees and others will be a work that I will continue for the rest of my life.