Also, you must supply a description of the location of the quadrat. Assign a number to each tree on your map which corresponds to the number of the tree on the table. The standard method is to measure at breast height. Use a tape measure. Measure and record the circumferance.
Tree height is a little more difficult.
Stand a meter stick at the base of a tree. Walk far enough away from the tree so that you can easily see the top and bottom of the tree. Hold a meter stick at arms length from you and measure how tall the meter stick at the base of the tree appears to be. Next, while still holding the meter stick at arms length, measure how tall the tree appears to be. Divide the apparent height of the tree by the apparent height of the base-of tree meter stick and you will have the real height of the tree in meters.