2. Scots pine
Pinus sylvestris
Photograph: Fritz Schweingruber

3. parenchyma
Populus spp.
Photograph: Paul Schulte

4. Pinus spp.
Photograph: Paul Schulte

5. A growth-ring boundary in Chamaecyparis lawsoniana (Port-Orford cedar)
Source: Bu erfield and Meylan (1980)

6. T R E E - R I N G F O R M AT I O N

8. sections to read
CAMBIAL GROWTH
Cell division in the cambium
Production of xylem and phloem
Time of growth and amounts of xylem and phloem produced
Differentiation of cambial derivatives
Increase in cell size
Cell wall thickening
Loss of protoplasts

9. Why do trees form rings?

11. Pinus spp.
Photograph: Paul Schulte

12. Gymnosperms
(coniferous)

13. 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.

14. Cambium

15. Scots pine
Pinus sylvestris
Photograph: Fritz Schweingruber

16. ca
m
bi
um
phloem
xylem
Populus spp.
Photograph: Paul Schulte

17. Characteristics of the cambium
1
Self-sustaining
The cambium is a self-sustaining system, and retains its
functions for a long time (sometimes for centuries or millennia).

18. Bristlecone pine
Pinus longaeva
Photograph: mlhradio

19. Characteristics of the cambium
2 Resource-intensive
As the cambium grows, it consumes scare resources that cannot
be used for growth by the rest of the tree.

20. Limber pine
Pinus flexilis

21. Limber pine
Pinus flexilis

22. Characteristics of the cambium
3 Flexible
Cells produced by the cambium (called ‘cambial derivatives)
can be differentiated into the range of cells found in the
xylem and phloem.

23. Pinus spp.
Photograph: Paul Schulte

24. Photograph: Steven Vance

25. dormant cambium
1 - 10 cells
viscous protoplasm
sharp cell walls

26. 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.

27. Photograph: Ben Cooper

28. ca
m
bi
um
phloem
xylem
Populus spp.
Photograph: Paul Schulte

29. dormant cambium active cambium
1 - 10 cells 8 - 20 cells
viscous protoplasm fluid protoplasm
sharp cell walls semi-transparent walls

30. Cambial growth

31. Cambial growth

32. Cambial growth

33. Cambial growth

34. Cambial growth

35. Cambial growth

36. Cambial growth

37. Radi al file
Scots pine
Pinus sylvestris
Photograph: Fritz Schweingruber

38. Latewood
(prior year)
phloem
Early season
Immature earlywood

39. Latewood
(prior year)
Immature earlywood
Mid-season
phloem
Mature earlywood

40. Mature earlywood Immature
latewood
Late season
phloem

41. How does weather affect tree-ring formation?

42. 3
main pathways

43. T E M P E R AT U R E
Photograph: spaka acks

44. T E M P E R AT U R E
high growth
low growth
cold hot

45. T E M P E R AT U R E
high growth
frozen water
low photosynthetic rate
shorter growing season
low growth
cold hot

46. T E M P E R AT U R E
high growth
low photosynthetic rate
higher evaporation
low growth
cold hot

47. WAT E R
Photograph: circulating

48. WAT E R
high growth
low growth
dry wet

49. WAT E R
high growth
reduced cell division
reduced cell expansion
C02 starvation
low growth
dry wet

50. WAT E R
high growth
flooding
anoxic conditions
low growth
dry wet

51. DAY L E N GT H
Photograph: Chris Nixon

52. D AY L E N G T H
high growth
low growth
short long

53. D AY L E N G T H
high growth
flowering
dormancy
germination
low growth
short long

54. How do we know tree rings are annual?

55. The “pinning” method Photograph: Keith Weston

56. Band dendrometer

57. Band dendrometer measurements, white pine near Cloquet MN
Source: Alm and Brown, Minnesota Forestry Notes, 1964

58. Photograph: Baillie (1982)