DENDROLOGY WOOD ANATOMY LAB II


     I.  Make a freehand longitudinal section of one of the Pinus twigs you collected.  Section
through the pith throughout three years of stem growth.  Examine your section using a
binocular dissecting microscope.  Note the longitudinal relationship between the successive
annual growth rings.  Compare your observations with those you made on the Tilia stems.

     II.  Make freehand transverse sections midway between successive bud scale scars on
the other three year Pinus twig you collected.  Examine these sections in developmental
sequence using a binolcular dissecting microscope.  Note the transverse relationship
between successive annual growth rings.  Identify as many tissues as you can in your
sections.  Compare your observations with those you made on Tilia stems.

     III.  Using the remaining piece of three year old Pinus twig, make freehand longitudinal
sections in the radial and the tangential planes.  Examine these using a binocular dissecting
microscope.  Relate what you see in each plane of sectioning to each other, the transverse
section of the 3 year old Pinus twig and the twig as a whole.  Identify as many tissues as
you can in each section.

     IV.  Study the prepared light microscopy sections of Pinus wood.  Make sure you can
recognize the transverse (cross), radial longitudinal and tangential longitudinal sections.Relate what you see to your observations on your freehand sections of Pinus wood. 
Identify tracheids and ray parenchyma.  Make a three dimensional sketch of the anatomy
of a pine wood block to help you visualize how these three types of sections are used in
wood reconstruction.