Lauren Kendle Winter Ecology Spring 2012 Background Information An analysis of 60 species indicated that there were photosynthetic processes in the bark Aspen Trees had the highest level of bark chlorophyll ID: 723918
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Slide1
Distance and Bark Photosynthesis In Aspen Trees In The Front Range
Lauren KendleWinter EcologySpring 2012Slide2
Background Information
An analysis of 60 species indicated that there were photosynthetic processes in the barkAspen Trees had the highest level of bark chlorophyll (
Wittman
and
Pfanz
, 2011
)
Photosynthesis in the bark is reduced to a quarter of summertime production during the winter
(
Solhaug
and Haugen, 1998)
Chlorophyll is arranged in the tree to maximize
photosynthesis
(
Pfanz
et al., 2002)Slide3
Question and Hypothesis
Question: Are Aspens able to adjust the amount of chlorophyll in the bark if there is a tree or an object blocking the direct sunlight?Hypothesis: The closer the object or tree is to the Aspen should result in more chlorophyll because so the tree can compensate for the decreased amount of sunlight. Slide4
Methods
Paint Chip Analysis Measured at breast height on the sun-facing sideTook PictureRecorded information from locationSlide5
Methods continued
Photoshop to standardize photosSampled Green PigmentationAveraged Green PigmentationUsed R for analysis of dataMany limitations of in data collectionSlide6
ResultsSlide7
Results Continued… excluding group 1 Slide8
Results
Hypothesis was not supportedFor the Categorical DataP value = 0.672 R-squared -0.04042For data for blocked trees onlyP Value = 0.248
R-squared = 0.05Slide9
Discussion
The Data did not support the hypothesisMaybe confounding variablesAge of treesAspectAmount of sunlight blockedHuman influence in second sample site
Aspens are highly competitive species and optimize the light received by increasing chlorophyll per unit of area
(
Aschan
et al., 2001
)Slide10
Further questions
Is the age of the tree related to the chlorophyll content?Would changing the methods produce different results?Machine measurement of CO2 or O2 What other factors may influence the chlorophyll content?
Soil
Water
AspectSlide11
Conclusions
Hypothesis was not supported in this studyNot enough information collectedNo significant relationships based on the data collectedMethods may not have adequately assessed levels of photosynthesisSlide12
Literature Cited
Aschan, G., C. Wittmann, and H. Pfanz. 2001. Age-dependent bark photosynthesis of aspen twigs. Trees, 15:431-437
Foote, K.C. and M.
Schaedle
. 1976. Physiological characteristics of photosynthesis and respiration in stems of
Populus
tremuloides
michx
. Plant Physiology 58:91-94.
Pfanz
, H., G.
Aschan
,
R.Langenfeld-Heyser
, C.
Wittman
, and M. Loose. 2002. Ecology and
ecophysiology
of tree stems:
corticular
and wood photosynthesis.
Naturwissenchaften
89:147-162
Roakowski
, P., Y. Li, and P. B. Reich. 2011. Local
ecotypic
and
speicies
range-related adaptation influence photosynthetic temperature optima in deciduous broadleaved trees. Plant Ecology, 213:112-125.
Solhaug
, K.A. and J. Haugen. 1998. Seasonal variation of
photoinhibition
of photosynthesis in bark from
Populus
tremula
l.
Photosynthetica
35:411-417.
Wullschleger
, S.D., D. J. Weston, and J. M. Davis. 2009.
Populus
response to
edaphic
and climate cues: emerging evidence from systems biology research. Critical
Reivews
n Plan Science, 28:368-374.