Someone posted on Facebook that each day a forty foot tree takes in 50 gallons of dissolved nutrients from the soil, converts that into ten pounds of carbohydrates and releases 60 cubic feet of pure oxygen into the air. 
     I wasn't sure whether to be impressed or not. I mean, I have no idea how much oxygen I need to breathe each day. This might be a massive amount of oxygen in relation to my needs as a human, or it might be rather puny. So I did a little research and found an article by Luis Villazon in the BBC Focus magazine. According to this article, a human breathes about 9.5 tons of air in a year. Oxygen, however, is only 23% of the air we breathe (by mass) and we only take in about 1/3 of the oxygen that is available to us in the air of each breath. That means we need 740 kg of oxygen per year. 
      So, how many trees do I need to support my personal oxygen habit? According to Villazon's article I need 7 or 8 trees. Another article says I only need about two trees to produce my oxygen. But, of course, this depends on various other factors. Redwoods, aspens and oaks tend to produce more oxygen than other types of trees. But, THIS depends on where the tree is in its lifecycle as trees what are still growing produce more oxygen than trees who have reached their mature size. 
      As for the 'how' they produce oxygen, the scientists are in agreement on this: through the process of photosynthesis when trees take sunlight, add carbon dioxide from the air --  this produces oxygen. But it sounds like magic to me!

Above, from left: catkins on display, leaf catching the sunlight, trademark curly corkscrew of branches

I never noticed the 'walking stick' tree/shrub until a friend drew my attention to it yesterday. Obviously 'walking stick' is a misnomer as something so twisted wouldn't make good raw material for a walking stick. But the corkscrewing branches do add great interest to a winter landscape when the tree has lost its leaves. 

The 'walking stick' has various names: contorted filbert, corkscrew hazel and Harry Lauder's walking stick. There is also lack of consensus as to whether it is a tree, a 'tree-like shrub' or a deciduous shrub. One point of agreement is that they all bear yellow catkins that start in late autumn and get bigger in the spring. This shrub, which can grow to 10 feet tall, is a relative of the birch and will thrive in sun or partial shade. 

The leaves on most trees come and go depending on the season. Deciduous trees bear leaves that dazzle us with color and delight us with shapes. The flowers on some trees, horsechestnut and magnolia come readily to mind, provide us with their own delights -- but are short-lived. 

When you are choosing trees for your property, you might want to give thought to bark for ornamental purposes. Bark, after all, will be there 365 days a year. A dependable source of texture and color. Some barks have a 'solid' appearance, akin to a wallpaper in the landscape. Other tree barks add interest because of the patterns created when they peel. 

Trees with peeling barks include: crepe myrtle (some debate whether it is a tree or a shrub), Chinese quince, sycamore, eucalyptus, shagbark hickory, birches, aspens and Kousa dogwood. Within the category of trees with peeling barks are some of my very favorites -- the paperbarks. There are paperbark maples, river birch and Melaleuca(tea tree). I've had the pleasure of photographing several of these interesting barks (below). 

Pictured above from left: Paperbark Maple, Paperbark Melaleuca, Eucalyptus