Modules: Control

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Modules Control
Main or primary

• Biochemical control (role of apical meristems in
  the buds)
• Axis of priority
• Ways of offsetting (e.g., pruning, shearing,
  natural mechanical damage, age, size)
• Hydraulically re-enforced
• How branches are connected to stems or branchlets
  to branches.
• Pipes linked via pits versus directly
• Concept of modular or branch autonomy

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Integration at whole tree level

• Nutrient needs
• Water loss vs. water uptake
• Roots vs. shoots
• Mechanical support
• Sudden changes in environments
• Pathogen or insect presence
• Avoidance of irreversible impacts (e.g., early or
  late season frost or freeze)

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Integration Examples of context
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Root Nutrient, support story

• Root systems display a number of tradeoffs
  including
• Root distribution in both horizontal vertical
  directions.
• Advantages to deep (anchoring, access to ground
  water or deep water) vs. shallow roots (where the
  nutrient, water and O2 action are).
• Large vs. fine vs. mycorrhizal roots
• Root longevity vs. permanence (vs. aboveground
  growth rates parallels with foliage longevity)
• Root vs. shoot growth and long-term translation
  into root - shoot ratios.

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Integration Nutrients

• Nutrient limitations exist
• Tradeoffs occur
• Resources are allocated to maximize ..

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Nutrients Integration Examples
High Site
Low Site
1.8 N
1.2 N
1.2 N
0.9 N
Sites are defined by their climate, microclimate,
species composition and soils. The latter is the
most important. Site is measured by the height
of the dominant trees at age 50, 100.
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Nutrients Integration Examples
High Site, Evergreen
High Site, Deciduous
1.8 N
3.6 N
1.2 N
1.4 N
Deciduous trees, including larch, tend to grow on
sites with higher nutrient availabilities.
Relationship between short leaf longevity, high
rates of photosynthesis and, therefore, high leaf
N levels.
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Integration Equilibrium Flexibility
How much carbon do you invest in root system?
How do you partition carbon between support and
absorption roles? How does root and shoot growth
interact over time?
From Claus Mattheck 1999
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Integration Equilibrium Flexibility
Understory mountain hemlock
Plus tephra
Plus tephra full sunlight
Long-term results on next page for Abam
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This is a Type II Duff and Nolan Ring Width
Sequence
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What controls the distribution of growth or
quantities of growth

• Distribution of growth carbon allocation as
  affected by
• Hormones
• Resources
• Quantities of growth affected by
• Resources
• Age

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What is carbon allocation?
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How does a tree respond to the environment?

• Examples of rapid responses
• Cavitation - factors affecting water loss
• Light quantity
• Examples of intermediate responses
• Light quality
• Temperature sums
• Examples of longer-term (allometric
  relationships)
• Root-shoot
• Stem taper

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