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University of Michigan Biological Station

The University of Michigan Biological Station (UMBS) was founded in 1909.

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Assessing Understory Plant Growth in Response to Changing Light and Nitrogen Availability Associated with Northern Temperate Forest Succession

Plant Population
Terrestrial
Vegetation
Project Abstract: 
Understanding understory plant competition is vital in understanding forest succession and future forest composition. Competition varies over space and time depending on limiting factors and available resources. Successional disturbances affect competition, as these disturbances cause shifts in available resources. This study will assess seedling competition for light and nitrogen in an ecosystem level manipulation of forest succession at the University of Michigan Biological Station. I will use hemispherical photography as a direct measure of light availability, lysimeters, to assess soil solution nutrient content and N leaching, and an understory plant census to quantify seedling community composition and growth rates. This analysis will give insight into long term projections for species composition of future forests, as it is ultimately the seedlings and understory plants that determine future forest composition.
Investigator(s): 
Nicole Dear
Deborah Goldberg
Status of Research Project: 
Complete (archive)
Years Active: 
2011
Research sites: 
UMBS FASET Tower
Methods: 
This study will take place in a northern temperate forest at the University of Michigan Biological Station forest. The Forest Accelerated Succession Experiment (FASET) manipulation caused an increased rate of forest succession by stem girdling early-successional species (birch, and aspen), causing these relatively short-lived species to die in place and prompting re-allocation of limiting resources to later-successional species such as oaks and maples. I will quantify light with a LAI 2000 leaf area analyzer (LI-COR Biosciences). I will collect soil solutions from zero tension lysimeters (ZTL) weekly to assess available N losses and soil solution nutrient content. Quantification of N will come from lysimeter solutions and measure NH4+ and NO3-. Ammonium and nitrate are determined colormetrically via Bran-Leubbe or Smartchem analyzers. I will repeat a census of seedlings and compare changes in height, leaf number, stem thickness, understory plant cover and pathogen damage between treatment and controls. I will collect census data from three 1x1 meter quadrats in eight, 16 meter diameter plots distributed in treated and control areas. I will examine how changes in the plants are correlated with light and N. I plan to test the hypotheses by comparing composition and structure of understory plants in treatment and control plots.