What we have here is the cross section red oak log. And what I want to explain here is the three planes of direction in three-dimensional wood. This is a cross-section. The circles that we see are at least in this part of the world they're annual growth rings. Each year a tree puts on a certain amount of growth---goes dormant through the winter so thes--this is the circles that you see here. Center the log is called the pith, and this is looking down on the stump, as you just cut it. And so the length of the tree is coming out this direction--the height of the tree. That's the longitudinal direction. Radial direction is from the center of the log to anywhere out on the circumference. Straight line, that's the basic geometry radius of the circle. It is the way I remember it. That would be any of these surfaces here in the cracks would be radial surfaces. And then everything else anything, you know, all these other directions are basically tangential to the circle or something close to that, and so we're going to wind up calling those tangential planes, and those--if we were to just cut through here and expose those surfaces those would be tangential surfaces. And what we have is different properties, different strength properties, different shrinkage and swelling properties in each of those three directions. And variations of those, depending on what combination of cell orientations you create when you just create your r piece, depending on where it came from you're going to have different combinations of these surfaces. And so what we do as wood scientists is try to predict what how things are going to behave in those directions or at least try to manage them. And we're going to do a couple illustrations of those here. Get crushed. As a wood scientist, most of my job is dealing with manufacturers and loggers, harvesters, timber processors, consumers of wood products, you know, whatever somebody figures out to make out of wood, eventually I hear some sort of complaint along the way; it's just part of the process. And about, you know, eighty to ninety percent of the problems that I encounter over the years are related to moisture. Wood in a tree form is full of water. It's not 100-percent wood, and so everything that we do after we harvest the tree, we have to deal with that moisture either in the early stages or in use. Beginning to end, we are dealing with moisture. So somebody calls me with a problem, the first question in my head is "Where is the water?" And so I pass that on to you. Log cross-section--used to be a cherry tree and, as you can see, as it dried this check opened up, and that's because the wood is trying to shrink as it loses moisture. And it shrinks differently in each direction; shrinks longitudinally--it doesn't shrink very much, but radially and tangentially it shrinks a lot. And not the same amount in each of those directions, so we get splits and checks. Almost from the moment the log is cut, you have to start thinking about how to prevent this from happening. Either if it's going to go into lumber or some other product, this is what we're going to fight. If we don't either manage that process or predict it or control it in some way, really bad things are going to happen. And that's forever; it just stuff just happens.