2017 Hubbard Brook presentation

1. Phenology of Leaf Senescence:
it’s LIT(ter)🔥!
Maddy Morley SUNY College of Environmental Science and Forestry
Griffin Walsh Yale University
Mentor: Dr. Ruth Yanai SUNY College of Environmental Science and Forestry 1
Adam Wild

2. Introduction
• Trees time their senescence to maximize their growing season while
reabsorbing nutrients before frost.
• Snapchat for Science: Comparing Leaf Retention on Nitrogen and
Phosphorus-Fertilized Birch and Maple Trees
Low Rank High RankTaking birch and maple canopy photos 2
Madison Morley

3. Leaf Retention Findings • N treated trees dropped
significantly more leaves than
N+P plot (p < 0.001).
• Maple leaf retention showed
no significant response to
treatment (p = 0.60). 3
Birch Leaf Retention
Maple Leaf Retention

4. Hypotheses
• Fertilized trees will drop more leaf mass later in the autumn
compared to the unfertilized trees.
• Old stand trees will drop more leaf mass later in the autumn than
younger stand trees.
4Adam Wild

5. Methods
• Four collection periods:
• October 8th
• Oct. 17th - 18th
• Oct. 22nd – 24th
• November 5th – 6th
Litter being sorted before
being dried and weighed
Systematic basket
placement in each plot 5
Gretchen Lasser
Madison Morley
Litter collection

6. Data Analysis
• Cumulative fraction
6
1 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑖𝑜𝑛
𝑇𝑜𝑡𝑎𝑙 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑖𝑜𝑛𝑠
1 + 2 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑖𝑜𝑛𝑠
𝑇𝑜𝑡𝑎𝑙 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑖𝑜𝑛𝑠
1 + 2 + 3 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑖𝑜𝑛𝑠
𝑇𝑜𝑡𝑎𝑙 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑖𝑜𝑛𝑠
1 + 2 + 3 + 4 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑖𝑜𝑛𝑠
𝑇𝑜𝑡𝑎𝑙 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑖𝑜𝑛𝑠Madison Morley

7. Results
Young
Mid-
aged
Old
7
Collection 1 (Oct. 8th)
- Young stand trees have
dropped more leaf litter
(p = 0.05).
- N treated trees have
retained more leaves
(p = 0.06).
Collection 2
(Oct. 17th-18th)
- N treated trees have
retained more leaves
(p = 0.01).
- P treated trees have
retained more leaves
(p = 0.07).
Collection 3
(Oct. 22nd-24th)
-N treated trees have
retained more leaves
(p = 0.02).
Collection (number)

8. Conclusions
• Nutrients (especially N) delay autumn leaf abscission in trees.
• The availability of nutrients promote a longer growing season.
• Trees in older stands retain their leaves longer than those in young-
age stands.
• Stands that vary in age have different species compositions and species have
unique timing of leaf fall.
• Remember Snapchat for Science!
8
• Sort the litter in some of the stands by species
• Add spring 2017 litter to our collection periods
Next steps

9. Acknowledgments
• Dr. Ruth Yanai
• Adam Wild
• Yanai’s B9 Lab Family
• Shan Shan
• Dr. Yanai’s High School Team
• 2017 MELNHE Field Crew!!!
9
Yang Yang
Alex Young
Gretchen LasserMadison Morley

10. Questions?
10
Mt. Washington!!!
…Cool!
Madison Morley