Alternative Title

comparing dominant species in a deciduous forest isn't so "clear cut"

Publication Date

2018-05-14

Document Type

Honors Project

Degree Name

Bachelor of Arts

Department

Biological Sciences

Advisors

Danielle D. Ignace

Keywords

Ecology, Succession, LICOR 6400, Plant physiology, Ecological succession, Plant succession, Photosynthesis-Measurement

Abstract

Forests occupy a large portion of the terrestrial land surface and account for almost half of all primary productivity on earth. Forest productivity is determined by a number of factors, including stand age, species composition, and environmental factors. Forests can serve as an incredible sink for carbon storage. Studying the sink/source dynamics of a forest post-clearcut is especially pertinent given the broader context of ongoing global climate change. This study delves into a commercial clearcut site in Harvard Forest, USA, six years post-clearcut, in order to quantify the physiological mechanisms that determine successional success for a snapshot in time post-disturbance. Six dominant species were identified based on species abundance studies, and various physiological data was collected. Photosynthetic capacity curves were collected using the LICOR 6400 XT, and analyzed to yield photosynthetic parameters. Leaf tissue was analyzed to identify the percent content of nitrogen, carbon, and the presence of the 13C isotope, indicating water use efficiency. When synthesized, the data suggests that although hayscented fern has a lower maximum capacity of photosynthesis, its ability to store nitrogen indicates that it will be a successful herbaceous understory species in the mature forest. Raspberry, a woody shrub, has high rates of photosynthesis, but its affinity for edge sections with high light suggests that it will not be able to succeed into the mature forest. Red maple and pin cherry are excellent pioneer species with high maximum photosynthetic rates. Red maple especially is able to support high growth rates and use less nitrogen, indicating that it will be a strong competitor through succession in to the eventual forest community. All woody species had low water use efficiency, indicating that in early successional stages, photosynthetic gas exchange is prioritized over water use efficiency.

Rights

2018 Madeleine Ann Meadows-McDonnell. Access limited to the Smith College community and other researchers while on campus. Smith College community members also may access from off-campus using a Smith College log-in. Other off-campus researchers may request a copy through Interlibrary Loan for personal use.

Language

English

Comments

45 pages. Includes bibliographical references (pages 42-45)

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