Pine Communities Are Eventually Replaced by Oak-Hickory Communities After About

question 14

Multiple Choice

Pine communities are eventually replaced by oak-hickory communities after about 150 years of old field succession on the Piedmont Plateau of North Carolina because

• A) mature pines are susceptible to a fungal disease called pine blight.
• B) juvenile pines are susceptible to a fungal disease called pine blight.
• C) juvenile pines cannot grow in the low pH soil that results as pine litter decomposes.
• D) juvenile pines cannot grow in the shade of mature pines.
• E) mature pines require an association with mycorrhizal fungi which are excluded from this area by low pH soils.

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Definitions:

Marginal Benefit

The supplemental value or usefulness derived from using another unit of a good or service.

Marginal Cost

The increase in total cost that arises from producing one additional unit of a good or service.

Net Benefit

The total positive impact or gain subtracted by the total cost or negative impact, typically used in the analysis of business or policy decisions.

Marginal Benefit (MB)

The augmented satisfaction or usefulness obtained by consuming or producing one extra unit of a good or service.