Effects of Tree Shelters on Tree Seedling Microclimate and Seedling Chlorophyll Production: Two-Year Results
Matured riparian forests buffer streams and rivers downslope from the effects of upslope land use by improving water quality and providing carbon sequestration. Riparian forests also protect land upstream by minimizing the impacts of flooding and high winds. Restoring riparian forests has long been considered an agricultural best management practice as large-scale agricultural use intensifies nutrient loading into streams and causes a decline in water quality. There are many methods of riparian forest restoration, but the focus of this study is evaluating the practice of restoring planted trees using plastic tree shelters. Studies suggest trees within un-ventilated shelters benefit from elevated temperature and humidity while other studies 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 were collected in the spring of 2022 for height and diameter and again in the fall of 2022 and 2023. Internal tree shelter temperature and relative humidity was collected three times throughout the growing season in 2022 and chlorophyll content was collected at the end of the summer in 2023. Results demonstrate seedlings grown in unventilated shelters develop significantly less chlorophyll (p-value <0.001) and experience higher overall relative humidity (p<0.05), than seedlings in ventilated shelters. No significant differences in height, stem diameter, or shelter temperatures were found. Correlation between internal shelter climate, shelter type, and plant health could potentially lead to the development of more specific guidance when creating riparian restoration planting plans which utilize protective tree shelters.