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Plant interactions and limitations to growth. TULIP POPLAR. VIRGINIA PINE. MESIC SOIL. DRY SOIL. MESIC SOIL. DRY SOIL. GROWING TOGETHER. MESIC SOIL. DRY SOIL. Height. Mesic. Dry. Wet. Modified from Ellenberg, 1963. Niche Theory. Fundamental Niche Realized Niche. Height. Mesic.
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TULIP POPLAR VIRGINIA PINE MESIC SOIL DRY SOIL MESIC SOIL DRY SOIL GROWING TOGETHER MESIC SOIL DRY SOIL
Height Mesic Dry Wet
Niche Theory • Fundamental Niche • Realized Niche
Height Mesic Dry Wet
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
6 CO2 + 6 H2O C6H12O6 + 6 O2 SUNLIGHT Photosynthesis
“Stuff” Energy Photosynthate C6H12O6
C6H12O6 + O2 CO2 + H2O (Not balanced) ENERGY Respiration
Light • PAR • Photosynthetical Active Radiation • Sun foliage/ shade foliage • Shade tolerance
Sun foliage Ps Shade foliage 0% 20% LIGHT
Sun foliage Ps Shade foliage 0% 20% LIGHT
Shade Tolerance Shade intolerant Ps Shade tolerant Light
Water • Input • Soil • Stomates
Field Capacity Percent Soil Water Available Water Unavailable Water Heaviness of Texture From Brady, 1974
Precipitation PET AET Water Input
Hot Cold
Stomatal Behaviour • Internal moisture stress • Drought avoiders • Drought endurers
Law of the Minimum • Growth is limited by whatever factor is most need
Potential Growth Actual Growth Nitrogen
Law of Compensation • The addition of one factor can increase the efficiency that a tree uses another factor
With P Growth Rate Amount of N Law of Compensation
Rule of Efficacy • Diminishing returns Growth Amount of “X”
Nutrient Cycling • Availability • CEC • Weathering • Mineralization • C:N • Nutrient capital • Translocation
Nutrients • Nitrogen fixers • Mycorrhizae
Growing Space • Sunlight • Water • Nutrients • Physical space
Total growing space • Available growing space