Class 2, What are tree rings?

W H AT A R E T R E E R I N G S ?

slides

Photograph: dylancantwell

http://www.flickr.com/photos/dylancantwell/

http://www.flickr.com/photos/dylancantwell/

Lecture 2 - What are tree rings?

Definition of trees


Tree anatomy


Tree-ring terminology


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).

Photograph: Sco! Butner

Trees are perennial plants, which are plants that live for more than two years.

Trees have a single main stem (or trunk).

Photograph: daryl_mitchell

Shrubs have multiple stems (and are not trees).

Photograph: Chris Mullins

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

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

SapwoodCambium

Bark

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.

vascular cambium

tissue containing plant ‘stem’ cells

http://en.wikipedia.org/wiki/Lateral_meristem






http://en.wikipedia.org/wiki/Vascular_tissue

http://en.wikipedia.org/wiki/Vascular_tissue

http://en.wikipedia.org/wiki/Secondary_xylem

http://en.wikipedia.org/wiki/Secondary_xylem

http://en.wikipedia.org/wiki/Phloem

http://en.wikipedia.org/wiki/Phloem

Photograph: easagor

http://www.flickr.com/photos/crossroads_foundation/


Photograph: Crossroads Foundation Photos



Oldest wood

Most recentgrowth

Source: Hoadley, Identifying Wood

Cross-sectional (or transverse) plane

Radial plane



Tangential plane

Cross-sectional plane

BarkPith

Cambium

1 the small core of so! spongey tissue that forms the central longitudinal axis of a tree stem, branch or twig.

pith

2 the center of the tree.

Scots pinePinus sylvestris

Photograph: Fritz Schweingruber

Common beechFagus sylvestris


Heartwood

Sapwood

Photograph: sonykus

http://www.flickr.com/photos/scaglifr/

http://www.flickr.com/photos/scaglifr/

Photosynthetic wastes

Photograph: Dave_Gray

Tree-ring terminology

Gymnosperms(coniferous)

Gymnosperms have encapsulated seeds.

Douglas-firPseudotsuga menziesii

Red pinePinus resinosa

Eastern hemlockTsuga canadensis


Earlywood


Latewood


Total ring-width



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.

tracheids



large cellsthin cell walls

small cellsthick cell walls



Ray

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.

rays

Angiosperms(deciduous)

Angiosperms (like oak) have exposed seeds.

PalmCocos spp.


White oakQuercus alba

Photograph: Tie Guy II

Bur oakQuercus macrocarpa

English oakQuercus robur




Earlywood vessels



Latewood vessels

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.

vessel element

a hardwood with (1) relatively large vessels in the earlywood and (2) distinctly smaller pores in the latewood.

ring porous



Fibre

an elongated hardwood cell with thick walls that contributes greatly to the material strength of wood.

fibre

Photograph: Fri!s Schweingruber



Ray

Photograph: daryl_mitchell

American elmUlmus americana

a hardwood with vessels that are approximately the same size and distributed (fairly) evenly throughout the growth ring.

di!use porous

Sycamore mapleAcer pseudoplatanus


European beechFagus sylvatica


Trees without rings

Photograph: joanna8555

Photograph: stephenk1977

Trees without rings(approximate)

Mangrove spp.

Photograph: Kevin Hutchinson

Mangrove spp.

Photograph: tinkerbrad

Longleaf pinePinus palustris

Species range for longleaf pine

Class 2, What are tree rings?

Education

Transcript of Class 2, What are tree rings?