Download - Rapp vmc maple_121713
Maple syrup production declines
following masting Joshua Rapp
Tufts University and Harvard Forest
Acknowledgements
People Elizabeth Crone
Dash Donnelly
Casey Mangnall
Natalie Kerr
Data and Support
Masting as a reproductive
strategy
Episodic and synchronous
production of seeds across a
population
Sugar maple seed fall in The Bowl Natural Area, White Mountain National Forest
Graber and Leak, 1992
Definition:
Masting as a reproductive
strategy
Density-dependent benefits to
fitness
Escape seed predators
Attract seed dispersers
Pollination efficiency
Why not just make the same number of seeds each year?
Masting as a reproductive
strategy
Resource Budget Model (RBM)
Proximate mechanisms variable reproduction
Reproductive litter fall can equal or exceed vegetative litter fall in mast years
Flowering before leaves come out requires stored resources Non-structural carbohydrates: energy reserves of a tree
Reproductive litter fall can equal or exceed vegetative litter fall in mast years
Flowering before leaves come out requires stored resources Non-structural carbohydrates: energy reserves of a tree
Reproductive litter fall can equal or exceed vegetative litter fall in mast years
Resource Budget Model
6CO2 + 6H2O C6H12O6 + 6O2 light
Resource Budget Model
6CO2 + 6H2O C6H12O6 + 6O2 light
Resource Budget Model
6CO2 + 6H2O C6H12O6 + 6O2 light
Resource Budget Model
6CO2 + 6H2O C6H12O6 + 6O2 light
Resource Budget Model
Why Sugar
Maple?
• Bimodal seed
production
• Maple syrup
production as a
potential proxy of
carbohydrate stores
• Potential effect of
seed production on
maple syrup yield
2011 2012
Does masting affect syrup
production?
1. Resource stores
(NSC) should be
high just before
flowering.
2. Masting should
deplete NSC
Resource Budget Model -
Predictions
Sugar Maple Seed Production in Vermont
Maple syrup production in Vermont –
detrending the data
Masting and syrup production in Vermont
What about the weather?
What about the weather?
Relative importance (left, top) and shrinkage-adjusted coefficients (left, bottom) from model averaging analysis. Adjusted R2 (below) best model including seed production in the previous year only, weather only, or both seeds and weather.
Summary – masting and maple
syrup
• Masting depletes sap sugar
and leads to lower maple
syrup yields
• Seed production is a better
predictor of syrup production
than weather during the
tapping season
The take
home… NSC =
Theory informs practice
Importance of life history in considering climate change effects on maple syrup industry
