• Address:
  705 Spear Street
  South Burlington, Vermont 05403
  United States of America
  
  Phone: (802) 391-4135
  Email: femc@uvm.edu
  Website: www.uvm.edu/femc

Broad goal is to better understand mechanisms controlling foliar ion exchange (foliar leaching and uptake) in forest canopies.

• Comparison of chemistry of foliar leachate
  • Started: 1991-07-01
    Ended: 1992-12-30
    
  • Method Description: To identify the relative importance of foliage vs stems in canopy ion exchange, a comparison of chemistry of foliar leachate from normal and artificially defoliated branches, and evaluating the kinetics of ion exchange in each.

• Treatments and analysis
  • Started: 1991-07-01
    Ended: 1992-12-30
    
  • Method Description: Multiple paired branches from 2 open-grown trees were used to receive treatments. One branch per pair was manually defoliated in early July. Articificial precipitation at pH 4.4 was applied for three hours in branch chambers and foliar leachate collected every 15 min. Foliage and leachate samples were analyzed for all major nutrient cations and anions. Lab studies examined the ion transport properties of isolated leaf cuticles from the field foliage in order to calculate ion permeability rates.

• Contribution of leaf surface deposits to cano
  • Started: 1991-07-01
    Ended: 1992-12-30
    
  • Method Description: To evaluate the contribution of leaf surface deposits to canopy ion exchange a comparison of the chemistry of leachate from sugar maple foliage on small branches that had been previously washed with an acidic solution at pH 3.3, deionized water, or left unwashed. Thirty branches chosen from 4 trees were used. A total of 6 treatment compinations (3 prewashes X 2 acid mists) were used and the experiment was replicated 5 times for a total of 30 branches treated.

• Leachate sample collection
  • Started: 1991-07-01
    Ended: 1992-12-30
    
  • Method Description: Leachate samples were collected sequentially from each chamber over 15 min. intervals during the first hour and over 30 min. intervals during the second hour for a total of 6 leachate samples per chamber per replicate. Leaf and stem area determinations were made and chemical analyses. Leaf cuticle samples from treated foliage was collected for additional measurement of cuticular ion permeabilities. Leachate samples were analyzed for major ions.