Degree

Doctor of Philosophy (PhD)

Department

Environmental Sciences

Document Type

Dissertation

Abstract

Baldcypresss (Taxodium distichum (L.) Rich.) forests are crucial to the Southeast coastal region for the trees’ ecosystem services. Many organizations have been trying to restore the ghost and dead forests found throughout the Gulf region through restoration events. Baldcypress seedlings and saplings face several abiotic and biotic stressors, including but not limited to elevated levels of salinity, nutrients, temperature, and light intensity. These stressors can be the limiting factor in the success or failure of these massive planting efforts.

To assess which stressors were of most concern to the restoration efforts, we conducted common garden experiments with baldcypress seedlings grown under these abiotic conditions and evaluated them for their survival, growth in height and diameter, and carbon storage. Our studies found that nitrate nitrogen at levels mimicking Mississippi river diversions and full sun rather than heavy shading for portions of the day were some of the most detrimental effects that sub-one-year seedlings could face, leading to more significant mortality, poor growth, and poor carbon storage. Also, the presence of older saplings being potted nearby led to substantial decreases in mortality, greater growth in height and diameter, and greater carbon storage.

This work implies that restoration management needs to consider the abiotic conditions of the areas they intend to plant baldcypress seedlings. Further, they need to consider the age of the seedlings/saplings used. This work speaks to the need for restoration efforts to plant baldcypress seedlings in areas immediately adjacent to older baldcypress. This type of planting also mimics a natural way that forests expand. If we want our wetlands to be restored with healthy thriving trees and continue to store carbon, we need to plant more baldcypress in close relation to each other or mature trees and decrease the fertilizer runoff issues in forested wetlands.

Date

3-21-2023

Committee Chair

Hooper-Bùi, Linda

DOI

10.31390/gradschool_dissertations.6069

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