LANDSCAPE ECOLOGY
SREM 3011
LECTURE 6
Dr Brendan Mackey
Department of Geography
The Australian National University
(1) Physiognomy,(2) life forms,(3) growth forms
and (4) structure
- vary in a predictable way with climate and other
environmental variables
- related to the growth of a plant
1,Net photosynthesis of foliage canopy
2,Structural support
3,Water/nutrient delivery network
4,Reproduction
Respiration
Translocation/storage of photosynthates
1,4,3
2,3
2,3,4
Plant Life Cycle
Germination
Growth Reproduction
Death
Annual growth cycle
Perrenial sexualvegetative
Optimum ranges for environmental factors at each stage
Temperature controls on plant growth:
1,Shoot growth
2,Stem/trunk growth
3,Leaf initiation/expansion
4,Root growth
In colder climates,eg,Boreal,temperature activates/
closes ‘active cycle’ ie,plant ‘shuts down’ in between
Eg,start growing season 5 days where MDT >50C
end growing season MINT <20C
Growing degree days
- accumulated temperature sum above a base temp-
erature
Initiation and rate of
growth etc,is temperature
controlled
(a) Seasonal cycles of foliation and stem growth of native eucalypts
temperate southern Australia (after Gill 1964,Ruiter 1964)
(b) Seasonal growth and stem growth in fertilized Pinus radiata
trees in southern Australia
Shoot/stem growth
root expansion/
starch storage
Mean Daily Temperature
elevation >,
temperature <
latitude <,
temperature <
Specht (1981)
Thermal response expressed as a fraction of the maximum dry
matter production) of a leaf canopy for plant communities
dominated by temperate C3,tropical C3 and tropical C4 species
(after Fitzpatrick & Nix 1970; Sweeny & Hopkinson 1975)
Three major east coast thermal groups
can be identified:
(1) Tropical subtropical group
shoot growth initiated >250C
(2) Warm temperate group
shoot growth initiated 150?250C
(3) Cool temperate group
shoot growth responds ~ 100C