12. Y ?
HHow do we know
W
temperate or boreal trees are
ANNUAL?
13.
14.
15. Phenology is the study of the timing of recurring
biological events, their relationship to biotic and
abiotic forces, and the inter-relations among phases
of the same or different species.
16. Bur oak (Quercus macrocarpa) is a common tree along rivers in Minnesota and the upper Midwest.
Select trees of this species can live for up to 450 years.
19. DORMANCY
The buds of most temperature trees are protected by a
covering of scales during the dormant period.
Source: Steve Ryan
20. BUD BREAK
A leaf bud is considered "breaking" once a green leaf tip is
visible at the end of the bud.
21. LEAF OUT
A leaf is considered "unfolded" once its stalk or base is
visible outside of the bud.
22. FLOWERS VISIBLE
For bur oak, the male flowers hang loosely from the branch
and are called catkins.
23. FRUIT DROP
‘Fruit drop’ occurs when mature acorns are ripened
and have dropped from the tree.
24. Every species has its own phenological ‘calendar’
leaf out
flowers visible
fruit drop
bud break
dormancy dormancy
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb
25.
26. “ Cambial activity is not continuous in space or in time.
Kozlowski and Pallardy
”
Physiology of Woody Plants
38. Stomata are microscopic pore on the epidermis (surface)
of land plants. Stomata act as gateways that allow plants
to exchange CO2 and O2 with the atmosphere.
46. total growth rate
growth rate due to temperature
G(t) = gE(t) • min[gT, gW] growth rate
growth rate
due to soil water
due to radiation
A er Evans et al., Journal of Geophysical Research, 2006
47. THE LAW OF THE MINIMUM
Growth is controlled by the scarcest resource
(limiting factor), not the total amount of
resources available
58. High
Low
Forest interior Semiarid forest border
DECREASING EFFECTIVE PRECIPITATION
INCREASING VARIABILITY IN ANNUAL PRECIPITATION
MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE
c.f. Fri s, 1976
59. High
Av
era
ge
rin
g-w
Ar idt
bo h
ria
ld
om
ina
nc
e
Low
Forest interior Semiarid forest border
DECREASING EFFECTIVE PRECIPITATION
INCREASING VARIABILITY IN ANNUAL PRECIPITATION
MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE
c.f. Fri s, 1976
60. High
S
NG
RI
N T
Low B SE
PERCENT A
Forest interior Semiarid forest border
DECREASING EFFECTIVE PRECIPITATION
INCREASING VARIABILITY IN ANNUAL PRECIPITATION
MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE
c.f. Fri s, 1976
61. High
E S
R E
T
N
EE
TW
BE
N
T IO
LA
R E
O R
Low C
Forest interior Semiarid forest border
DECREASING EFFECTIVE PRECIPITATION
INCREASING VARIABILITY IN ANNUAL PRECIPITATION
MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE
c.f. Fri s, 1976
62. High
E S
R E
T
N
EE
TW
BE
N
T IO
LA
R E
O R
Low C
Forest interior Semiarid forest border
DECREASING EFFECTIVE PRECIPITATION
INCREASING VARIABILITY IN ANNUAL PRECIPITATION
MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE
c.f. Fri s, 1976
64. “ Thus the physiological processes, such as photosynthesis,
respiration, assimilation, and cambial activity, are largely a
function of favorable or unfavorable climatic regimes, and
”
hence the trees exhibit a high amount of similar variation
in relative year-to-year fluctuations of their ring widths.
Fri s et al., 1965
Ecology
69. THE PRINCIPLE OF
ECOLOGICAL AMPLITUDE
Trees that grow near the margins or limits of their ecological amplitude
are o en more sensitive to changes in their environment.