Specific Leaf Area

 

Laboratory 4

 

Forest Ecology - FOR 3213

 

 

Purpose: to learn how to measure specific leaf area (SLA) and compare the morphology of sun and shade leaves

Methods: Collect 5 leaves each from sun and shade sites from conifer and hardwood trees. You may choose any species, but select all the leaves from the same species of conifer and hardwood. Measure leaf area and oven dry weight (ODW) after 24 h at 70 ºC. The leaf area of hardwoods will be measured with an optical planimeter. Multiply the display value by 2 to calculate total two-sided leaf area. Measure conifer needles for radius ( r ) and length ( l ) and use the following equation to calculate area per fascicle (Af):

Af = 2rl (n + p ),

where n = number of needles per fascicle.

Report: Show data from the class in a table. Describe differences in SLA and explain why the differences exist. What morphological differences in the leaf are associated with the differences in SLA? What is the adaptive value of the differences? Are thin leaves better adapted to full sun or deep shade? Explain. The capacity to change leaf morphology from sun to shade environments is called plasticity. Are all species equally plastic in leaf morphology? Which species are plastic and which are not? Give examples.

 

Leaf Area

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leaf type species area per leaf, cm2 specific leaf area, cm2 g-1

broadleaf, sun

broadleaf, shade

conifer, sun

conifer, shade