typical dry matter is ~50% carbon by mass there are 10,000 m2 per hectare fast-g

Question

typical dry matter is ~50% carbon by mass

there are 10,000 m2 per hectare

fast-growing trees will produce ~10 metric tons of dry matter/hectare-year (with optimal placement and areal density)

slow-growing trees will produce ~1 metric tons of dry matter/hectare-year (with optimal placement and areal density)

Now we will consider Arizona State University offsetting.

a) Is there enough open space on the Arizona State University main campus to offset the fossil fuel CO2 emissions (direct energy and electricity) with your fast-growing trees?

b) If there isn’t enough space, how much more is needed?

Some key factoids:

o Main campus is ~642 acres

o Assume that 30% is open space (not covered by building)

o Main campus emits ~68,000 metric tons of carbon per year

o There are 2.47 acres per hectare o

Area of Tempe is 40 square miles

Explanation / Answer

Fast growing trees will sequester 5 metric tons of carbon per hectare in one year.

Assuming that 30% of the campus, i.e. 192.6 acres or 77.94 hectares, is available for the trees, so the amount of carbon sequestered would be:

5 x 77.94 = 389.7 metric tons per year

Since the campus emits 68,000 metric tons of carbon per year, there isn't enough space to offset the fossil fuel emissions. The space needed to offset the CO2 should be:

68000 / 5 = 13,600 hectares i.e. 13522.06 hectares more than the present space

So, the additional area needed is 13522.06 hectares or 33487.86 acres or 52.32 square miles of open space.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.