Tree Architecture and Growth Part 1 Apical Growth

Tree Architecture and Growth Part 1

Apical Growth • Apical meristem = bud – Primary growth • Preformed • Indeterminant or sustained

Crown Form • Excurrent • Decurrent

Crown Architecture excurrent decurrent

Mechanisms • Branch angle • Geotropism • Weight (gravity)

Lammas growth • ‘unplanned’ bud break • Aug 1 “Lammas Day”

Epinasty • Epinastic control – angle and length of side branches – genetics and environment

Shade • Side shade – Trees do not lose form • Shade from above – high shade – low shade – becomes more diffuse – trees can lose epinastic control

Cross section

Live Crown Ratio

Live Crown Ratio

Shade • Side shade – Trees do not lose form • Shade from above – high shade – low shade – becomes more diffuse – trees can lose epinastic control

Multilayer vs. Monolayer Multilayer Monolayer

Horn, H. S. The adaptive geometry of trees. Princeton University Press, Princeton, NJ 144 pp

Release • Interaction of: – the environment (old new) – the silvical characteristics of the tree – tree condition

Tree Attributes • Amount of foliage • Amount of aphotosynthetic area • Sun leaves– Shade leaves • Epinastic control

Priorities for Photosynthate 1. 2. 3. 4. 5. Respiration Foliage – Fine Roots {Reproduction} Primary Growth Secondary Growth – Secondary Compounds

Lag in Response • Not enough excess photosynthate to add foliage