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Exploring canopy structure and function as a potential mechanism of sustained carbon sequestration in aging forests

Fotis, Alexander T
http://rave.ohiolink.edu/etdc/view?acc_num=osu1503231521023889

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Evolution, Ecology and Organismal Biology.
Forests are thought to reach carbon (C) neutrality as they age such that photosynthesis is balanced by respiration. However, recent evidence suggests that C sequestration continues in forests that are centuries old. One potential mechanism sustaining C accumulation in old growth forests are age related changes in canopy structural complexity. Among these is rugosity, a measure of the horizontal variability of vertical variation in leaf area distribution. While rugosity has been found to sustain forest productivity across a 200-yr chronosequence of deciduous forests in Michigan, the mechanism linking this structural metric to forest function (e.g. C sequestration) is not well understood. The objectives of this dissertation were to study the drivers of canopy structural complexity and explore the novel mechanisms by which canopy structural complexity might influence forest productivity. At the University of Michigan Biological Station, i) portable canopy light detection and ranging (LiDAR) was used to characterize canopy structure in space and time, ii) long-term hemispherical photography was used to quantify within-canopy light distributions and its among-year variability, iii) branch and leaf materials were collected to measure tree responses to canopy structure and light distributions, and iv) canopy light microhabitats were manipulated from an aerial work platform and in situ morphological and physiological responses of trees subjected to different treatments were quantified. More complex canopies (high rugosity) were found to have greater amounts of empty space and reduced light variability in the midcanopy while total light interception was unchanged relative to less complex canopies. This high spatial light variability may have induced differential branch growth and lead to greater among-year light variation. Leaves of trees acclimated morphological and physiologically to the prevailing light conditions regardless of how much the irradiance changed between growing seasons. However, American beech trees (Fagus grandifolia) was unable to acclimate morphologically and physiologically to very large (50% change) increases in light between two consecutive growing seasons. Stands with high stem densities had reduced inter-annual variability in canopy structure, and areas with more variable tree sizes and those with communities dominated by early successional species had the highest canopy structural complexity. Aboveground net primary production (ANPP) was highest in areas with high canopy structural complexity and lower inter-annual variation in canopy structure. In summary, canopy structure in space and time was found to affect within-canopy light distributions and its among-year variability, determines leaf phenotypic acclimation, and influences ANPP of the forest.
Peter Curtis, Ph.D (Advisor)
Gil Bohrer, Ph.D (Committee Member)
James Bauer, Ph.D (Committee Member)
170 p.
Ecology; Forestry; Plant Sciences; Remote Sensing
Canopy structural complexity, leaf morphology, leaf physiology, carbon sequestration, light distribution

Recommended Citations

Citations

  • Fotis, A. T. (2017). Exploring canopy structure and function as a potential mechanism of sustained carbon sequestration in aging forests [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503231521023889

    APA Style (7th edition)

  • Fotis, Alexander. Exploring canopy structure and function as a potential mechanism of sustained carbon sequestration in aging forests. 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1503231521023889.

    MLA Style (8th edition)

  • Fotis, Alexander. "Exploring canopy structure and function as a potential mechanism of sustained carbon sequestration in aging forests." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503231521023889

    Chicago Manual of Style (17th edition)

osu1503231521023889
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This open access ETD is published by The Ohio State University and OhioLINK.