Germination, Phenology, and Plant Allocation Patterns of Northeastern Tree Seedlings in Response to Future Precipitation Scenarios

Conference Year

January 2019

Abstract

Seedling germination, growth, and establishment is a sensitive period and a critical bottleneck in the regeneration of forest trees, yet little is known about how this process will be impacted by a shifting climate. Despite projected future shifts in species ranges, the germination and regeneration response of locally adapted (current) tree species compared to those predicted to be better adapted to future conditions is poorly understood. Understanding forest regeneration response under novel future climate scenarios is important as it may lead to compositional or functional shifts in forests with implications on forest health, productivity, and biodiversity. To examine the regeneration of forest trees under shifting climate, we test the response of fourteen currently- and “future-adapted” species grown from seed and bare-root seedlings under precipitation manipulation located in forest harvest gaps. Tree species were selected across a suite of functional traits from species currently common in northeastern US forests as well as from species projected to be better adapted to future climates. Two seedbed treatments (scarified and undisturbed) and four precipitation scenarios (projected shifts in rainfall frequency and magnitude) were used to examine species response in establishment, phenology, allocation, and water use efficiency. Results indicate a strong germination response to seedbed treatment with a mean increase of 128% (±58) in scarified treatments. Seedlings grown from seed and bare-root seedlings responded most positively to rainfall frequency while rainfall magnitude had less effect. Precipitation treatment most positively influenced growth and establishment of larger seeded species such as Pinus strobus, Fagus grandifolia, and Castenea dentata, but had no effect on Quercus rubra. The implications of this research may refine future species distribution models as well as provide tangible information for managers of northern forests seeking to maintain ecosystem function during a time of uncertain future global conditions.

Primary Faculty Mentor Name

Anthony D'Amato

Status

Graduate

Student College

Rubenstein School of Environmental and Natural Resources

Program/Major

Forestry

Primary Research Category

Biological Sciences

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Germination, Phenology, and Plant Allocation Patterns of Northeastern Tree Seedlings in Response to Future Precipitation Scenarios

Seedling germination, growth, and establishment is a sensitive period and a critical bottleneck in the regeneration of forest trees, yet little is known about how this process will be impacted by a shifting climate. Despite projected future shifts in species ranges, the germination and regeneration response of locally adapted (current) tree species compared to those predicted to be better adapted to future conditions is poorly understood. Understanding forest regeneration response under novel future climate scenarios is important as it may lead to compositional or functional shifts in forests with implications on forest health, productivity, and biodiversity. To examine the regeneration of forest trees under shifting climate, we test the response of fourteen currently- and “future-adapted” species grown from seed and bare-root seedlings under precipitation manipulation located in forest harvest gaps. Tree species were selected across a suite of functional traits from species currently common in northeastern US forests as well as from species projected to be better adapted to future climates. Two seedbed treatments (scarified and undisturbed) and four precipitation scenarios (projected shifts in rainfall frequency and magnitude) were used to examine species response in establishment, phenology, allocation, and water use efficiency. Results indicate a strong germination response to seedbed treatment with a mean increase of 128% (±58) in scarified treatments. Seedlings grown from seed and bare-root seedlings responded most positively to rainfall frequency while rainfall magnitude had less effect. Precipitation treatment most positively influenced growth and establishment of larger seeded species such as Pinus strobus, Fagus grandifolia, and Castenea dentata, but had no effect on Quercus rubra. The implications of this research may refine future species distribution models as well as provide tangible information for managers of northern forests seeking to maintain ecosystem function during a time of uncertain future global conditions.