plant interactions and limitations to growth. growing together dry soil mesic soil virginia...
TRANSCRIPT
Plant interactions and limitations to growth
GROWING TOGETHER
DRY SOIL DRY SOIL
DRY SOIL
MESIC SOIL MESIC SOIL
MESIC SOIL
VIRGINIA PINETULIP POPLAR
Height
Dry WetMesic
Modified from Ellenberg, 1963
Niche Theory
• Fundamental Niche
• Realized Niche
Height
Dry WetMesic
Site Sensitive / Site Insensitive
• No tree ‘likes’ a bad site
• Where you see a tree is where it reproduced and survived
• Many examples of trees in the ‘wrong’ place
Communities
• Mutualism– Animals – plants- plants and animals
• Competition– Primary model for this course
• Facilitation– Focus of much current research
Mutualism
• Organisms depend on each other• Communities become a ‘reproducing’
entity• Common in animals
– Food pyramid– Plants don’t eat each other
Competition
• Survival of the fittest
• Gene – environment interaction
• Probabilities
• Ultimately natural selection
Facilitation
• One plant ‘helps’ another with no detriment to itself
• Interaction must be close to selective neutral for ‘helper’
• Role of mycorrhizae
Climax theory
• Historic role of ‘superorganism’– No way for natural selection to work
– Many examples showing this does not hold
– Has greatly (negatively) impacted forest management
Growth Factors• Light
• Water
• Nutrients
• Others?
Photosynthesis
• Chlorophyl in the foliage
• Chloroplasts
• Sun foliage/shade foliage
Photosynthesis
6 CO2 + 6 H2OC6H12O6 + 6 O2
SUNLIGHT
Photosynthate
C6H12O6
“Stuff”
Energy
Respiration
C6H12O6
+
O2
CO2 + H2O
(Not
balanced)
ENERGY
Light
• PAR–Photosynthetical Active Radiation
• Sun foliage/ shade foliage
• Shade tolerance
20%
LIGHT
0%
PsSun foliage
Shade foliage
20%
LIGHT
0%
Ps
Sun foliage
Shade foliage
Shade Tolerance
Ps
Light
Shade tolerant
Shade intolerant
Water
• Input
• Soil
• Stomates
Per
cen
t S
oil W
ater
Heaviness of Texture
Field Capacity Available Water
Unavailable Water
From Brady, 1974
AETPET
Precipitation
Water Input
Rainfall Consistent
Cold Hot
Stomatal Behaviour
• Internal moisture stress
– Drought avoiders
– Drought endurers
Nutrients
Law of the Minimum
• Growth is limited by whatever factor is most need
Nitrogen
Poten
tial Grow
th
Actu
al Grow
th
Law of Compensation
• The addition of one factor can
increase the efficiency that a tree
uses another factor
Law of Compensation
With P
Amount of N
Gro
wth
Rat
e
Rule of Efficacy
• Diminishing returnsG
row
th
Amount of “X”
Nutrient Cycling
• Availability• CEC• Weathering• Mineralization• C:N• Nutrient capital• Translocation
Nutrients
• Nitrogen fixers
• Mycorrhizae
Temperature
Growing Space
• Sunlight
• Water
• Nutrients
• Physical space
• Total growing space
• Available growing space
Total growing space
• Depends on time and place
– Macro and Micro conditions
Available Growing Space
• Grow
• Regeneration
Thinned
Unthinned
Latewood
Earlywood
No Available Growing Space
• Repartition
• Competition
Priorities for Photosynthate
1. Respiration
2. Foliage – Fine Roots
3. {Reproduction}
4. Primary Growth
5. Secondary Growth – Secondary Compounds
• Photosynthesis > Respiration ?–GROW
• Photosynthesis < Respiration ?–DIE
• Photosynthesis = Respiration ?–NOT A LONG TERM
CHOICE
Volume
• Wood formation (total volume) is:
[ (Photosynthesis-Respiration)]
- Allocation
Where Does It Go?
Respiration Increment
Dominant Tree 26% 42%
Co-dominant Tree 29% 41%
Suppressed Tree 50% 8%
[ash stand in Denmark]