W H AT A R E T R E E R I N G S ?
slides
Photograph: dylancantwell
Lecture 2 - What are tree rings?
Lecture 2 - What are tree rings?

Definition of trees
Lecture 2 - What are tree rings?

 Tree anatomy
Lecture 2 - What are tree rings?

                Tree-ring terminology
Lecture 2 - What are tree rings?

                                   Trees without rings
What are trees?
Trees are not limited to a single order
or even division of plants.

“Tree-ness” is defined by a
specific growth form.
Trees are woody plants (a category that
also includes shrubs and some vines).
Trees are perennial plants, which are plants
                         that live for more than two years.




Photograph: Sco Butner
Trees have a single main stem
(or trunk).
Shrubs have multiple stems
               (and are not trees).




Photograph: daryl_mitchell
Plants are often required to attain
                            a minimum height at maturity to
                            qualify as trees (usually between 3
                            and 6 meters tall).



Photograph: Chris Mullins
secondary thickening Woody plants are capable of
                     secondary thickening, adding new
                     yearly growth layers of cells onto the
                     accumulated growth of previous years.
Basic tree anatomy
Heartwood

              Sapwood
Cambium


               Bark
tissue containing plant ‘stem’ cells



vascular cambium 1 a lateral meristem in the vascular tissue of plants.

                   2 the source of both the secondary xylem (inwards,
                   towards the pith) and the secondary phloem
                   (outwards), and located between these tissues in
                   the stem and root.
Photograph: easagor
Photograph: Crossroads Foundation Photos
Most recent
               growth




Oldest wood
Cross-sectional
                                    (or transverse) plane




Source: Hoadley, Identifying Wood
Radial plane




Source: Hoadley, Identifying Wood
Tangential plane

Source: Hoadley, Identifying Wood
Cross-sectional plane
Bark
Pith




       Cambium
pith 1 the small core of so spongey tissue that forms
     the central longitudinal axis of a tree stem, branch
     or twig.
     2 the center of the tree.
Scots pine
                                  Pinus sylvestris
Photograph: Fritz Schweingruber
Common beech
                                  Fagus sylvestris
Photograph: Fritz Schweingruber
Heartwood




            Sapwood
Photograph: sonykus
Photosynthetic wastes
Photograph: Dave_Gray
Tree-ring terminology
Gymnosperms
 (coniferous)
Gymnosperms have
encapsulated seeds.




                      Douglas-fir
                      Pseudotsuga menziesii
Red pine
Pinus resinosa
Red pine
Pinus resinosa
Eastern hemlock
Tsuga canadensis
Earlywood




            Eastern hemlock
            Tsuga canadensis
Latewood




           Eastern hemlock
           Tsuga canadensis
Total ring-width



                   Eastern hemlock
                   Tsuga canadensis
Tracheids




                                              Scots pine
                                              Pinus sylvestris
Photograph: Fritz Schweingruber
tracheids 1 elongated cells that function in food conduction
          and structural support.

          2 most common type of cell in conifers. Much less
          frequent in deciduous trees.
large cells
                                               thin cell walls

                                    small cells
                                  thick cell walls



                                                                 Scots pine
                                                                 Pinus sylvestris
Photograph: Fritz Schweingruber
Ray




                                        Scots pine
                                        Pinus sylvestris
Photograph: Fritz Schweingruber
rays 1 fla ened bands of tissue that extend horizontally
     in a radial plane through the tree stem.

     2 transport sap and wastes produced by
     photosynthesis.
Angiosperms
(deciduous)
Angiosperms (like oak) have
exposed seeds.
Palm
                                  Cocos spp.


Photograph: Fritz Schweingruber
White oak
                         Quercus alba
Photograph: Tie Guy II
Bur oak
Quercus macrocarpa
English oak
                                  Quercus robur
Photograph: Fritz Schweingruber
Earlywood vessels




                                                      English oak
                                                      Quercus robur
Photograph: Fritz Schweingruber
English oak
                                  Quercus robur
Photograph: Fritz Schweingruber
Latewood
                                   vessels



                                             English oak
                                             Quercus robur
Photograph: Fritz Schweingruber
vessel element 1 a type of hardwood cell that has a relatively
               large diameter, thick cell wall and perforate
               (open) ends.

                2 combines to form ‘vessels’, long passageways
                used to conduct water and soluble nutrients.
ring porous a hardwood with (1) relatively large vessels
            in the earlywood and (2) distinctly smaller
            pores in the latewood.
Fibre



                                          English oak
                                          Quercus robur
Photograph: Fritz Schweingruber
fibre an elongated hardwood cell with thick walls
     that contributes greatly to the material
     strength of wood.
Ray


                                        English oak
                                        Quercus robur
Photograph: Fri sSchweingruber
            Fritz Schweingruber
American elm
                             Ulmus americana
Photograph: daryl_mitchell
diffuse porous a hardwood with vessels that are
              approximately the same size and
              distributed (fairly) evenly throughout the
              growth ring.
Sycamore maple
                                  Acer pseudoplatanus
Photograph: Fritz Schweingruber
European beech
                                  Fagus sylvatica
Photograph: Fritz Schweingruber
Trees without rings
Photograph: joanna8555
Photograph: stephenk1977
Trees without rings
    (approximate)
Mangrove spp.

Photograph: Kevin Hutchinson
Mangrove spp.
Mangrove spp.
Longleaf pine
Pinus palustris
             Photograph: tinkerbrad
Species range for longleaf pine
Class 2, What are tree rings?

Class 2, What are tree rings?