environmental effects on autumn tree color
Download
Skip this Video
Download Presentation
Environmental Effects on Autumn Tree Color

Loading in 2 Seconds...

play fullscreen
1 / 48

Environmental Effects on Autumn Tree Color - PowerPoint PPT Presentation


  • 633 Views
  • Uploaded on

Environmental Effects on Autumn Tree Color Presenter: Jim Loken Topic Advisor: Dr. Dale Herman http://www.treeplanter.com/images/trees/Maple/red%20maple%20rubrum/acre%20rubrum%20leaves.jpg What do you already know? “Tree leaves change color every fall”

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Environmental Effects on Autumn Tree Color' - Audrey


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
environmental effects on autumn tree color

Environmental Effects on Autumn Tree Color

Presenter: Jim Loken

Topic Advisor: Dr. Dale Herman

http://www.treeplanter.com/images/trees/Maple/red%20maple%20rubrum/acre%20rubrum%20leaves.jpg

what do you already know
What do you already know?
  • “Tree leaves change color every fall”
  • “Leaves can have several different colors”
  • “The same tree might have different coloration depending on the year”
  • “Soil type can effect color change”
  • “Not all trees have the ability to change colors”
  • “It’s beautiful”
  • “Leaves are dying, pigments are changing”
  • “Fall is here”
  • “I’ve only noticed color change on deciduous trees”
outline
Outline
  • Legend of Autumn Colors
  • The Role of the Sun
  • Pigments
  • Physiology of Autumn Colors
  • Lee and Tukey
  • Schaberg, Van Den Berg, Murakami, Shane, and Donnelly
  • Take Home Message
the legend of autumn colors
The Legend of Autumn Colors
  • Native American legend
  • The legend of Jack Frost

http://www.hobbycraft.co.uk/LESSONS/pics/jackfrost.gif

the role of the sun
The Role of the Sun
  • Radiation Energy
  • Electromagnetic

spectrum

    • Visible light waves
    • Invisible waves

http://praxis.pha.jhu.edu/pictures/emspec.gif

pigments
Pigments
  • Chlorophyll
    • Absorb red and blue light
    • Reflect green colors
    • Not stable, continually synthesized
    • Located in the chloroplasts
    • Imparts a “masking” effect
  • Carotenoids
    • Absorb blue-green and blue light (an accessory absorber)
    • Reflect yellow colors
    • Very stable
    • Located in the chloroplasts
pigments7
Pigments
  • Tannins
    • Reflect brown color
    • Very stable
    • Located in the cell sap and cell walls
    • Most noticeably seen in dead tissue
  • Anthocyanins
    • Absorb blue, blue-green, and green light
    • Reflect red colors
    • Unstable
    • Sugar dependent
    • Accumulate in the vacuoles
    • Not found in all trees
color change main environmental factors
Color Change:Main Environmental Factors
  • Average temperatures are lowering
  • Day lengths are decreasing
color change main physiological factors
Color Change:Main Physiological Factors
  • Foliar sugar concentrations are increasing (especially important for red coloration)
  • Foliar nitrogen concentrations are decreasing
the storage of carbohydrates
The storage of carbohydrates

Seasonal Tree Carbohydrate Reserves

Fall

Winter

Spring

Summer

Fall

the results of cooler temperatures and shorter days
The results of cooler temperatures and shorter days
  • Photosynthetic capacity declines
  • Chlorophyll production slows to a halt
  • Existing chlorophyll breaks down
  • Trees begin to store food
  • Lower temperatures limit phloem mobility of sugars
  • An abscission layer forms
  • Colors change

Stoltenow, Sept 17, 2006

an abscission layer is formed
An abscission layer is formed
  • The xylem is still intact
  • Phloem tissues have been gradually severed
  • Remaining nutrients are trapped in the leaf

Chaney, Oct 1994

physiology of autumn colors
Physiology of autumn colors
  • The abscission layertraps sugars and compounds called anthocyanidins in the leaf
  • Synthesis of anthocyanins is promoted
  • As the chlorophyll breaks down, the red colors are unmasked
red color development
Red color development
  • The shade of red an anthocyanin pigment provides is environmentally dependent
  • Anthocyanins are also influenced by pH
    • Low pH, acidic conditions promote red colors
    • As pH increases, these colors tend to get more purplish
  • Sugar and red maples, mountain ash, juneberries, and red oaks

http://harvardforest.fas.harvard.edu/research/leaves/images/red_osier_ts.jpg

anthocyanin more than just a pretty pigment
Anthocyanin:More than just a pretty pigment
  • Stress indicators
  • Antioxidant qualities
  • Osmotically active
  • “Light screen”

http://www.grapes.msu.edu/images/coverConcord06.jpg

yellow color development
Yellow color development
  • The loss of chlorophyll allows the yellow, more stable carotenoids to shine through
  • Birches, cottonwoods, some elms, and some maples
  • Most trees turn yellow

Copyright 2005 Martin Wierzbicki

brown color development
Brown color development
  • Brown colors result from the presence of tannins
  • Tannins occur most commonly in dead tissue
  • As chlorophyll breaks down species with less carotenoids often display a brown to golden-brown color
  • Some oaks and beeches

http://flyaway.smugmug.com/gallery/96774

slide18

Effect of Intermittent Mist on Development of Fall Color in Foliage of Euonymus alatus Sieb. ‘Compactus’

C.I. Lee and H.B. Tukey, Jr.

J. Amer. Soc. Hort. Sci. 1971. 1:97-101

misting study 1 objectives
Misting Study #1 Objectives
  • “To determine the effect of rainfall on the development of red color, leaf abscission, and dormancy”
methods august
Mist

40 3-yr old Compact winged Euonymus plants from rooted cuttings

Grown in greenhouse

Misted for 20 s every 30 min during daylight

Mist only applied to foliage

Temp: 23-30 C

(73-86 F)

Control

40 3-yr old Compact winged Euonymus plants from rooted cuttings

Grown in same greenhouse

Same environmental conditions

No Mist

Methods(August)

www.rgbonsai.com/burningbush.htm

2 months later october
2 months later (October)…
  • 20 misted plants and 20 non-misted plants were transferred to a dry 15-25 C (59-77 F) room
  • Observations were recorded

4 months later (December)…

  • The remaining 20 misted plants and 20 non-misted plants were transferred to a dry 15-25 C (59-77 F) room
  • Observations were recorded
non misted control observations
Red color developed in mid-Sept., and intensified with movement to the cooler room in Oct.

By early Nov., leaves had abscised and plants were dormant

Non-misted Control Observations
misted plant observations
Misted for 2 months

Leaves still green when moved to cool room in late Oct.

No red color developed

Leaves abscised by late Nov.

Main plant was dormant by Dec.

Misted for 4 months

Leaves still green when moved to cool room in late Dec.

Little red color development

Leaves abscised in Jan.

Main plant was dormant by Jan.

Misted Plant Observations
misting study 2 objectives
Misting Study #2 Objectives
  • “to demonstrate the effect of rainfall on anthocyanin development and to elucidate the mechanisms involved”
methods 12 week study
Mist

40 Compact winged Euonymus plants grown from rooted cuttings

Growth chamber 16 hr light periods at 16146 lumen/m2 (1500 ft-c) intensity

Misted for 30 s every 30 min for 5 light hrs

Mist only applied to foliage

Temp: 24 C (75 F) day

18 C (64 F) night

Control

40 Compact winged Euonymus plants grown from rooted cuttings

Grown in same growth chamber

Same environmental conditions

No Mist

Methods(12 week study)
methods
Methods
  • After 8 weeks, both misted and non-misted plants were transferred to a cold room
  • Here they experienced 4 weeks in the cold room at 5 C (41 F) with 16 hr photoperiods of 2153 lumen/m2 (200 ft-c) intensity
  • The goal of this transfer was to enhance anthocyanin development
methods27
Methods
  • Levels of substances involved in anthocyanin synthesis were measured every 2 weeks from the leaves during the entire study including:
    • Anthocyanin
    • Total sugar
    • Protein N/soluble N ratio
    • Potassium
n ratio k leaf content
N ratio & K leaf content

Lee and Tukey, 1971

leachate analysis
Leachate analysis
  • Leachates were collected at the end of every misting day
  • Done to clarify if lack of anthocyanin synthesis in misted plants is due to leaching
  • The leachate was analyzed to determine content
  • Similar substances to those found in the leachate were then reapplied to leaf samples
leachate content
Leachate Content
  • Anthocyanin is derived from flavaniods via the shikimic acid pathway

Lee and Tukey, 1971

leachate effects
Leachate Effects

Control >

Flavanol >

Flavan >

Lee and Tukey, 1971

overall observations
Overall observations
  • Late season rainfall may inhibit fall color development due to the leaching of many substances necessary for anthocyanin synthesis
factors influencing red expression in autumn foliage of sugar maple trees

Factors Influencing Red Expression in Autumn Foliage of Sugar Maple Trees

P.G. Schaberg, A.K. Van Den Berg, P.F. Murakami, J.B. Shane, J.R. Donnelly

Tree Physiology. 2003. 23:325-333

objectives
Objectives
  • “To assess the environmental and physiological factors that influence the timing and extent of autumn red leaf coloration in sugar maples”
methods36
Methods
  • 16 trees were analyzed at a Vermont Research Station
  • Leaf samples were taken on 12 dates from June and October
    • Foliar Water content was measured
    • Foliar Carbohydrate levels were measured
    • Foliar Nitrogen levels were measured
    • Fall color was analyzed
observations of precursors to anthocyanin synthesis
Observations of Precursors to Anthocyanin Synthesis
  • Water levels were low compared to reported greenhouse grown sugar maples, but comparable to published levels for other native hardwoods
  • Carbohydrate concentrations were consistent with those reported for sugar maple
  • Nitrogen concentrations were much lower than reported averages
foliar nitrogen concentration august mean and seasonal averages
Foliar nitrogen concentration: August mean and seasonal averages

Best published foliar N range = 16.000 - 23.200 g kg-1

This average = 13.478 g kg-1

observations
Observations
  • The lower the foliar N, the earlier the red color expression, and the better the red color expression
  • Not all tree’s expressed red color at the same time
fall color analysis
Fall color analysis

Schaberg et al., 2003

observations42
Observations
  • Red color expression in trees may be a tree’s way of expressing nutrient deficiency
  • This may also explain why some trees in the study turned color before others

http://images.google.com/images?q=sugar+maple&ndsp=20&svnum=10&hl=en&lr=&start=120&sa=N

take home message
Take Home Message

The quality and extent of autumn color is affected by:

  • Late season rainfall (leaching and continued growth)
    • Lee and Tukey
  • Temperature
  • Day length
  • Nutrition (nitrogen)
    • Schaberg, Van Den Berg, Murakami, Shane, and Donnelly
what will the trees look like this year
What will the trees look like this year?
  • Wet spring
  • Dry summer
  • Average fall precipitation?
  • Nights have been getting cooler
it could be a good recipe for color but
It could be a good recipe for color, but…
  • What does the weather have in store?
  • How stressful was the summer?
  • Wind?
best case scenario
Best case scenario…
  • Warm days
  • Cool nights, but not freezing
  • Minimal precipitation

Stoltenow, Sept 17, 2006

a special thanks to
A Special Thanks to…
  • Dr. Dale Herman
questions discussion
Questions/Discussion???

http://images.google.com/images?q=sugar+maple+tree&ndsp=20&svnum=10&hl=en&lr=&start=160&sa=N

ad