Source: Paul Schulte

September 18

How does weather a!ect tree growth?

Red mangroveRhizophora mangle

Red mangroveRhizophora mangle

Photograph: Kevin Hutchinson

Red mangroveRhizophora mangle

Trees without rings(approximate)

Bur oakQuercus macrocarpa

GEOG5839ARE TREE RINGS ANNUAL?

The “pinning” methodSource: Keith Weston

Band dendrometer

Band dendrometer measurements on a white pine near Cloquet MN

Source: Alm and Brown, Minnesota Forestry Notes, 1964

Atomic bomb test in Almogordo, New Mexico, July 16, 1945.

How do we knowtemperate or boreal trees are

ANNUAL?WHY?

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 di!erent species.

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.

h"p://esp.cr.usgs.gov/data/atlas/li"le/

Dormancy

Bud break

Leaf outFlowers visible

Fruit drop

Source: Steve Ryan

DORMANCYThe buds of most temperature trees are protected by a covering of scales during the dormant period.

BUD BREAKA leaf bud is considered "breaking" once a green leaf tip is visible at the end of the bud.

LEAF OUTA leaf is considered "unfolded" once its stalk or base is visible outside of the bud.

FLOWERS VISIBLEFor bur oak, the male flowers hang loosely from the branch and are called catkins.

FRUIT DROP‘Fruit drop’ occurs when mature acorns are ripened and have dropped from the tree.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb

dormancy

bud break

leaf out

flowers visible

fruit drop

dormancy

Every species has its own phenological ‘calendar’

Cambial activity is not continuous in space or in time.“ ”Kozlowski and Pallardy

Physiology of Woody Plants

GEOG5839WEATHER, CLIMATE & TREES

temperature water day length

Source: spaka"acks

H O W D O E S T E M P E R A T U R E A F F E C T T R E E G R O W T H ?

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.

6CO2 + 12H20 ➔ 6O2 + 6H20 + C6H1206

carbon dioxide water sugaroxygen water

cold hotlow growth

high growthfrozen water

low photosynthetic rate

shorter growing season

low photosynthetic rate

higher evaporation

T E M P E R A T U R E

Source: circulating

H O W D O E S M O I S T U R E A F F E C T T R E E G R O W T H ?

Source: Karen Rice

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.

PINE NEEDLEleaf stomata

CO2 CO2

H2O H2O

LEAF CROSS-SECTIONabundant water

CO2CO2

CO2CO2

CO2CO2

H2OH2O

H2O H2OH2O

LEAF CROSS-SECTIONwater shortage

CO2 CO2

dry wetlow growth

high growthreduced cell division

reduced cell expansion

C02 starvation

flooding

anoxic conditions

W A T E R

Source: Chris Nixon

H O W D O E S D A Y L E N G T H A F F E C T T R E E G R O W T H ?

short longlow growth

high growth

flowering

dormancy

germination

D A Y L E N G T H

G(t) = gE(t) • min[gT, gW]

A#er Evans et al., Journal of Geophysical Research, 2006

total growth rate

growth ratedue to radiation

growth ratedue to temperature

growth ratedue to soil water

Growth is controlled by the scarcest resource (limiting factor), not the total amount of resources available

LAW MINIMUMTHE OF THE

Source: Neil Pederson

GEOG5839ECOLOGICAL SIGNALS

Tree-ring display at elementary school

Photograph: Tom Swetnam

Dr. Hal Fri"sUniversity of Arizona

Fri"s, Tree Rings and Climate, 1976

Source: Fritts et al., Ecology, 1965

MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE

INCREASING VARIABILITY IN ANNUAL PRECIPITATION

DECREASING EFFECTIVE PRECIPITATION

Low

High

Forest interior Semiarid forest border

c.f. Fri"s, 1976

MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE

INCREASING VARIABILITY IN ANNUAL PRECIPITATION

DECREASING EFFECTIVE PRECIPITATION

Low

High

Forest interior Semiarid forest border

Average ring-widthArborial dominance

c.f. Fri"s, 1976

MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE

INCREASING VARIABILITY IN ANNUAL PRECIPITATION

DECREASING EFFECTIVE PRECIPITATION

Low

High

Forest interior Semiarid forest border

PERCENT ABSENT

RINGS

c.f. Fri"s, 1976

MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE

INCREASING VARIABILITY IN ANNUAL PRECIPITATION

DECREASING EFFECTIVE PRECIPITATION

Low

High

Forest interior Semiarid forest border

CORRELATION

BETWEEN

TREES

c.f. Fri"s, 1976

MORE DAYS WHERE MOISTURE IS LIMITING TO PROCESSES IN TREE

INCREASING VARIABILITY IN ANNUAL PRECIPITATION

Low

High

Forest interior Semiarid forest border

CORRELATION

BETWEEN

TREES

DECREASING EFFECTIVE PRECIPITATION

c.f. Fri"s, 1976

Source: Fritts et al., Ecology, 1965

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

Source: United States Geological Survey

A species may grow and reproduce over a certain range of habitats; that range is described as its ecological amplitude.

h"p://esp.cr.usgs.gov/data/atlas/li"le/

h"p://esp.cr.usgs.gov/data/atlas/li"le/

THE PRINCIPLE OF ECOLOGICAL AMPLITUDETrees that grow near the margins or limits of their ecological amplitude are o#en more sensitive to changes in their environment.

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