Class 5, Tree-ring formation
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Transcript of Class 5, Tree-ring formation
Scots pinePinus sylvestris
Photograph: Fritz Schweingruber
Photograph: Paul Schulte
Populus spp.
parenchyma
Pinus spp.
Photograph: Paul Schulte
A growth-ring boundary in Chamaecyparis lawsoniana (Port-Orford cedar)
Source: Bu!erfield and Meylan (1980)
T R E E - R I N G F O R M AT I O N
CAMBIAL GROWTHCell division in the cambiumProduction of xylem and phloemTime of growth and amounts of xylem and phloem producedDi"erentiation of cambial derivativesIncrease in cell sizeCell wall thickeningLoss of protoplasts
sections to read
Why do trees form rings?
Pinus spp.
Photograph: Paul Schulte
Gymnosperms(coniferous)
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
Cambium
Scots pinePinus sylvestris
Photograph: Fritz Schweingruber
Photograph: Paul Schulte
Populus spp.
xylem
phloem
cambium
Characteristics of the cambium
Self-sustainingThe cambium is a self-sustaining system, and retains its functions for a long time (sometimes for centuries or millennia).
1
Bristlecone pinePinus longaeva
Photograph: mlhradio
Characteristics of the cambium
Resource-intensiveAs the cambium grows, it consumes scare resources that cannot be used for growth by the rest of the tree.
2
Limber pinePinus flexilis
Limber pinePinus flexilis
Characteristics of the cambium
FlexibleCells produced by the cambium (called ‘cambial derivatives) can be di!erentiated into the range of cells found in the xylem and phloem.
3
Pinus spp.
Photograph: Paul Schulte
Photograph: Steven Vance
dormant cambium
1 - 10 cells
viscous protoplasmsharp cell walls
Source: Marchand, P. J. 1996. Life in the Cold: An Introduction to Winter Ecology, 3rd ed. University Press of New England. Hanover, NH. 304 pp.
Photograph: Ben Cooper
Photograph: Paul Schulte
Populus spp.
xylem
phloem
cambium
dormant cambium active cambium
1 - 10 cells 8 - 20 cells
viscous protoplasm fluid protoplasmsharp cell walls semi-transparent walls
Cambial growth
Cambial growth
Cambial growth
Cambial growth
Cambial growth
Cambial growth
Cambial growth
Scots pinePinus sylvestris
Photograph: Fritz Schweingruber
Radial file
Latewood(prior year)
Early season
phloem
Immature earlywood
Latewood(prior year)
phloem
Immature earlywood
Mid-season
Mature earlywood
phloem
Immature latewood
Late season
Mature earlywood
How does weather affect tree-ring formation?
3main pathways
Photograph: spaka!acks
T E M P E R AT U R E
cold hotlow growth
high growth
T E M P E R AT U R E
cold hotlow growth
high growthfrozen water
low photosynthetic rate
shorter growing season
T E M P E R AT U R E
cold hotlow growth
high growthlow photosynthetic rate
higher evaporation
T E M P E R AT U R E
Photograph: circulating
WAT E R
dry wetlow growth
high growth
WAT E R
dry wetlow growth
high growthreduced cell division
reduced cell expansion
C02 starvation
WAT E R
dry wetlow growth
high growthflooding
anoxic conditions
WAT E R
Photograph: Chris Nixon
DAY L E N GT H
short longlow growth
high growth
D AY L E N G T H
short longlow growth
high growth
flowering
dormancy
germination
D AY L E N G T H
How do we know tree rings are annual?
The “pinning” methodPhotograph: Keith Weston
Band dendrometer
Band dendrometer measurements, white pine near Cloquet MN
Source: Alm and Brown, Minnesota Forestry Notes, 1964
Photograph: Baillie (1982)
