• Porosity
• Pore Groupings
• Pore Arrangement
PORE = VESSEL IN CROSS SECTION
POROSITY
• RING POROUS
• DIFFUSE POROUS
• SEMI- RING POROUS
(Semi-Diffuse Porous used in ID Book)
DEFINED BY SIZE DISTRIBUTION OF VESSELS
WITHIN ONE GROWTH RING
(about same size throughout or larger in earlywood)
and the
TRANSITION FROM EARLYWOOD TO LATEWOOD
(gradual or abrupt).
RING POROUS
• Earlywood zone with wide
vessels (pores)
• Earlywood zone about same
size each year.
• Abrupt transition to latewood
zone with narrow vessels
(pores), latewood zone variable
width
• Common in temperate US
woods, rare in tropical trees.
Ash, Fraxinus
Red Elm, Ulmus rubra
DIFFUSE POROUS
• Vessel diameter about the same in earlywood and
latewood
• Vessels throughout growth ring.
• Growth rings less obvious than in ring porous
woods
Yellow Poplar, Liriodendron tulipifera
Birch, Betula sp.
DIFFUSE POROUS
HOLLY, Ilex aquifolium
BLACKGUM, Nyssa
Which one likely has the higher specific gravity?
Holly with less vessel volume
SEMI-RING POROUS
Vessel diameter gradually decreases from earlywood to latewood
Diospyros virginiana
Persimmon
Carya illinoisensis
Pecan
PORE
GROUPINGS
• SOLITARY
• RADIAL MULTIPLES
• CLUSTERS
VESSEL GROUPINGS: Solitary
Handlens View of Red Oak
All vessels solitary
Microscope view (10x objective)
Tropical Vine. All vessels solitary
VESSEL GROUPINGS:
Solitary and in Radial Multiples
M
O
S
T
C
O
M
M
O
N
Handlens view of Birch.
Vessels solitary and in
short radial multiples
Microscope view (4x objective)
Mahogany. White ovals surround some
radial multiples of 2 and 3 vessels
VESSEL GROUPINGS: CLUSTERS
Cluster = a group of vessels, some
side by side tangentially as well as
radially.
Vessel clusters occur in combination
with solitary vessels and radial
multiples.
Not common.
In U.S. woods, see in latewood of
some ring porous species.
Handlens View of Black Locust
Latewood vessels in clusters
Clusters connected by axial parenchyma
PORE ARRANGEMENT
•
•
•
•
•
RANDOM
TANGENTIAL LY
RADIALLY
OBLIQUE / DIAGONAL
DENDRITIC / FLAMELIKE
NOTE: THESE VESSEL ARRANGEMENT PATTERNS OFTEN
INTERGRADE, ESPECIALLY RADIAL AND OBLIQUE / DIAGONAL
VESSEL ARRANGEMENT: Random
Handlens view of Birch (Betula).
Random arrangement of vessels
(vessels are solitary and in short
radial multiples )
Microscope view (10x objective)
Tupelo (Nyssa ). Random arrangement
of vessels (vessels solitary & in short
radial multiples)
TANGENTIAL ARRANGEMENT
Handlens view. Ulmus americana
Latewood in wavy tangential bands,
solitary row of earlywood vessels
Wide growth rings.
Microscope view (4x objective)
American Elm. Narrow growth rings,
earlywood solitary row, latewood with
tangential bands of vessels.
RADIAL to DENDRITIC
Handlens view. White oak.
Latewood with very small vessels in a
radial to dendritic arrangement
Handlens view. Chestnut
Latewood with very small vessels in a
radial to oblique to dendritic
arrangement
Arrangement of Vessels:
RADIAL to DIAGONAL / OBLIQUE
Handlens view. Tropical Hardwood
Vessels in diagonal pattern
Handlens view. Red Oak
Latewood vessels in radial-diagonal pattern