Developing an Agroecological Approach
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How are physiological constraints which govern biomass scaling and vascular architecture maintained in managed orchard systems? - “a tree is a tree” - selective breeding programs cannot fundamentally alter the physiological constraints acting on tree physiology Do deviations from branching architecture relationships derived in natural forest ecosystems demonstrate a deliberate human manipulation (e.g., pruning) on the system? - branching ratio will vary with canopy height - higher order branches: optimize resource transport & growth - scaffolds, high influence from pruning (i.e. scars) Photosynthetic Biomass M p vs. Annual Growth Rate G Stem Basal Diameter D vs. Total Stem Biomass M S Before Tree Reconstruction After Developing an Agroecological Approach to Branching Architecture and Biomass Scaling Using Orchard Trees Zachary T. Brym, Utah State University, Department of Biology and Ecology Center Current Research Direction Anthropogenic – “Human Manipulation” – Domestic Fruit Trees - graft / scion union: disease resistance - dwarfing: increase xylem resistance, poor nutrient transport / water use efficiency - precocity: early maturation - pruning regiment: increased light, reduced vigor - unlimited nutrients and water - biomass approximation: trunk cross-sectional area, canopy volume, yield efficiency Evolutionary – “Natural Selection” – Forest Trees - grow tall to light source - reproduce late once established in canopy - maximize water efficiency - self shading “poor” light interception - biomass scales: M p ~ G, D ~ M s Agriculture Intensification Gradient Natural Selection High Leaf Mass : Wood Mass Fast Maturity Max Light Interception “Optimal Foraging” Vascular Structure Low Leaf Mass : Wood Mass Slow Maturity High Self Shading Water Wise Vascular Structure A Weecology Production Evolutionary Trade-offs Human Manipulation Low Reproductive Yield Low Initial Cost Low Economic Efficiency High Reproductive Yield High Initial Cost High Economic Efficiency Expected Branching Ratio: Biomass and Architecture Model - first test of this theory in agricultural system - first spatially explicit tree - tests the consequences of various horticultural management strategies (e.g. pruning) - explores avenues of research likely to increase the efficiency of tree growth - predict water use for diffuse- porous fruit trees Economics and Management Model - politico-economic parameters included to suggest sustainable horticultural systems - explore optimal management strategies adapted under social / climate change Extension Decision- making Model - growers, plant breeders, urban planners - graphical user interface for interactions in a survey-like fashion - generalizes physiological constraints, water-use and management decisions - What yield and resource use do we expect under predicted environmental conditions? Broader Impacts Opposing Forces Acknowledgements Thank you for the funding support from the Utah State University Graduate Student Senate Research and Project Grant and the Ecology Center Ph.D. Assistantship and Research Support Award and the field support from the staff and researchers at the Kaysville Experimental Orchard that make this project possible. Niklas K.J. & Enquist B.J. (2001) Invariant scaling relationships for interspecific plant biomass production rates and body size. PNAS, 98(5): 2922-2927 Niklas K.J. & Spatz H.C. (2004) Growth and hydraulic (not mechanical) constraints govern the scaling of tree height and mass. PNAS,101(44): 15661-15663 Data Collection H W LAI D L SLA M S H - canopy height W - canopy width D - branch diameter L - branch length - branch angle / declination C - branch bearing / heading P - parent branch ID N t,s,b - total count (twig, scar, spur) M L,S,R - biomass (leaves, stems, roots) - wood density LAI - total leaf area / ground area SLA - individual leaf area / leaf mass ( C P M R M L Orchard Tree Orchard Tree (Niklas & Enquist, 2001) (Niklas & Spatz, 2004) 2:1 3:1 5:1 9:1 y = 1.52x – 0.88 R 2 = 0.796
description
Developing an Agroecological Approach to Branching Architecture and Biomass Scaling Using Orchard Trees. A Weecology Production. Zachary T. Brym, Utah State University, Department of Biology and Ecology Center. Agriculture Intensification Gradient. Current Research Direction. - PowerPoint PPT Presentation
Transcript of Developing an Agroecological Approach
How are physiological constraints which govern biomass scaling and vascular architecture maintained in managed orchard systems?
- “a tree is a tree”- selective breeding programs cannot fundamentally alter the
physiological constraints acting on tree physiology
Do deviations from branching architecture relationships derived in natural forest ecosystems demonstrate a deliberate human manipulation (e.g., pruning) on the system?
- branching ratio will vary with canopy height- higher order branches: optimize resource transport & growth- scaffolds, high influence from pruning (i.e. scars)
Photosynthetic Biomass Mp vs. Annual Growth Rate G
Stem Basal Diameter D vs. Total Stem Biomass MS
Before Tree Reconstruction After
Stem Midpoint Diameter D vs. Number of Supported Twigs
Developing an Agroecological Approach to Branching Architecture and Biomass Scaling Using Orchard Trees
Zachary T. Brym, Utah State University, Department of Biology and Ecology Center
Current Research DirectionAnthropogenic – “Human Manipulation” – Domestic Fruit Trees
- graft / scion union: disease resistance- dwarfing: increase xylem resistance,
poor nutrient transport / water use efficiency- precocity: early maturation- pruning regiment: increased light, reduced vigor- unlimited nutrients and water- biomass approximation: trunk cross-sectional
area, canopy volume, yield efficiency
Evolutionary – “Natural Selection” – Forest Trees
- grow tall to light source- reproduce late once established in canopy- maximize water efficiency- self shading “poor” light interception- biomass scales: Mp ~ G, D ~ Ms
Agriculture Intensification Gradient
Natural Selection
High Leaf Mass : Wood MassFast Maturity
Max Light Interception“Optimal Foraging” Vascular Structure
Low Leaf Mass : Wood MassSlow MaturityHigh Self ShadingWater Wise Vascular Structure
A Weecology Production
Evolutionary Trade-offs
Human Manipulation
Low Reproductive YieldLow Initial CostLow Economic Efficiency
High Reproductive YieldHigh Initial Cost
High Economic Efficiency
Expected Branching Ratio:
Biomass and Architecture Model
- first test of this theory in agricultural system- first spatially explicit tree- tests the consequences of various horticultural
management strategies (e.g. pruning)- explores avenues of research likely to increase
the efficiency of tree growth- predict water use for diffuse-porous fruit trees
Economics and Management Model
- politico-economic parameters included to suggest sustainable horticultural systems- explore optimal management strategies adapted
under social / climate change
Extension Decision- making Model
- growers, plant breeders, urban planners- graphical user interface for interactions in a
survey-like fashion - generalizes physiological constraints, water-use
and management decisions - What yield and resource use do we expect
under predicted environmental conditions?
Broader Impacts
Opposing Forces
AcknowledgementsThank you for the funding support from the Utah State University Graduate Student Senate Research and Project Grant and the Ecology Center Ph.D. Assistantship and Research Support Award and the field support from the staff and researchers at the Kaysville Experimental Orchard that make this project possible. Niklas K.J. & Enquist B.J. (2001) Invariant scaling relationships for interspecific plant biomass production rates and body size. PNAS, 98(5): 2922-2927
Niklas K.J. & Spatz H.C. (2004) Growth and hydraulic (not mechanical) constraints govern the scaling of tree height and mass. PNAS,101(44): 15661-15663
Data Collection
H
W
LAI
D L
SLA
MS
H - canopy heightW - canopy widthD - branch diameterL - branch length - branch angle / declinationC - branch bearing / headingP - parent branch IDNt,s,b - total count (twig, scar, spur)ML,S,R - biomass (leaves, stems, roots) - wood densityLAI - total leaf area / ground areaSLA - individual leaf area / leaf mass
(
C
P
MR
ML
Orchard
Tree
Orchard
Tree
(Niklas & Enquist, 2001)
(Niklas & Spatz, 2004)
2:1 3:1 5:1 9:1
y = 1.52x – 0.88R2 = 0.796
