Preferred Name
Christina Henriksen
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
ORCID
https://orcid.org/0009-0007-1377-1794
Date of Graduation
5-9-2024
Semester of Graduation
Spring
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Department of Biology
Advisor(s)
Bruce Wiggins
Heather Griscom
Christine May
Abstract
Continuous land development practices such as property development and large-scale agriculture impact watersheds when excessive nutrients from surface runoff enter streams, and over time, cause a decline in water quality. As these sources of pollution are diffuse, mitigation of nutrient loading can become quite difficult and costly to stakeholders such as farmers. To reduce the effects of nutrient loading into local streams and rivers, riparian forest restoration has long been the focus of many stakeholders wishing to improve water quality in landscapes which have been heavily degraded for agricultural use. There are many methods of riparian forest restoration, however, the focus of this study is evaluating the practice of restoring planted trees using plastic tree shelters. Some studies suggest trees within un-ventilated shelters benefit from elevated temperature and humidity while others indicate adding ventilation (holes) to shelters may result in the accumulation of more biomass than trees grown in un-ventilated shelters. The purpose of this study is to quantify the effect of ventilated shelters on seedlings. In the spring of 2022, 162 tree seedlings (Liriodendron tulipifera, Platanus occidentalis, Amelanchier canadensis, and Asimina triloba) were planted on an active cattle farm in Linville, VA. Seedlings were planted in ventilated and non-ventilated tree shelters. Field data for height and stem diameter were collected in the spring of 2022, in the fall of 2022, and fall of 2023. Internal tree shelter temperature and relative humidity was collected three times throughout the growing season in 2022 and chlorophyll fluorescence was collected at the end of the summer in 2023. Our data demonstrate seedlings grown in unventilated shelters have significantly lower values of chlorophyll fluorescence (p-value <0.001) and experience higher overall relative humidity (p<0.05), than seedlings in ventilated shelters. When planted in unventilated shelters, species such as A. canadensis grew significantly taller, while P. occidentalis and L. tulipifera seedlings grew significantly wider. L. tulipifera seedlings also died back and had a higher percent mortality when planted in unventilated versus ventilated shelters, although these results were not found to be significant. Our results also indicate species growth may also be significantly influenced by tree shelter size, as certain species such as P. occidentalis grew taller as tree shelter size increased (p=0.04). There is some evidence to suggest the increased levels of humidity in unventilated shelters has some effect on tree seedlings, but these effects are largely driven both by planting location and seedling species life characteristics.
Recommended Citation
Henriksen, Christina, "The effects of tree shelters on tree seedling growth, microclimate, and seedling chlorophyll fluorescence: Two-year results" (2024). Masters Theses, 2020-current. 267.
https://commons.lib.jmu.edu/masters202029/267
