The document discusses a study on how specific leaf area (SLA), a measure of leaf thickness, changes with canopy position and nutrient amendment treatment in trees. The study found that relative growth rate was higher in trees given a phosphorus treatment. It was hypothesized that SLA would decrease more slowly with increasing canopy position in phosphorus-treated trees. Methods involved measuring SLA of leaves sampled from different heights on 4 trees. Preliminary results found sun leaves had lower SLA and phosphorus trees maintained thinner leaves higher in the canopy. Future work planned to replicate the study and measure additional leaf traits.

1. How foliage traits respond to the
vertical gradient and nutrient
amendment
Alexander Young

2. Climbing
vs
Shotgun
Sampling

3. Courtesy
of
Shinjini
Goswami
Relative growth rate was 13% higher in P plots in mid-age stands (p
= 0.02) and 15% higher in mature stands (p = 0.07). (Shinjini
Goswami 2017) unpublished.
Relative growth rate increase with P treated Trees

4. Question
- Which canopy traits would change if trees allocate
more biomass to aboveground biomass?
- Photosynthetic pigment content
- Leaf chemistry
- Leaf thickness (Specific Leaf Area)
Hypothesis:
- Specific leaf area will decrease with canopy positions at
different rates for different nutrient amendment treatments.

5. Specific Leaf Area: Surface area (cm^2) / mass (g)

6. Why would leaf thickness change?
•Palisade mesophyll
• Chloroplast center
Palisade mesophyll
Shade leaf
Sun leaf
https://en.wikipedia.org/wiki/Leaf

7. Methods
-SRT technique
-Only 4 trees (pilot)
-Every 2 meters sample
with pole pruner

8. Methods
-SRT technique
-Only 4 trees (pilot)
-Every 2 meters sample
with pole pruner

9. Leaves from 24 m
Leaves from 14 m

10. • Sun leaves have lower SLA
Smaller leaves, but weighed
proportionally more
• The phosphorus tree
maintained thin leaves
longer through the canopy.
Phosphorus: p = 0.03
CanopyPosition(m)

11. Future Directions
For the Summer
• Get replication! (Collect in 3 stands)
Future Lab Methods and Measurements
• Specific twig length
• Chlorophyll a/b spectroscopy
• Foliar Chemistry through vertical gradient

12. Acknowledgements
MELNHE 2017
• Ruth Yanai
• Dani Fernando
• Melany Fisk
• Trey Turnblacer
• Grace Haynes
• Claudia Victoroff
• Caitlin Buchheim
NSF-REU: Tardigrades in the Canopy
• Dr. Meg Lowman
• Dr. William Miller
USFS White Mtn. Natl. Forest
• Bartlett Exp. Forest

13. Discussion
Why would nutrient
treatment impact the
way trees deploy leaves
as a function of light
environment?