How much more carbon does an acre of trees sequester versus an acre of Jatropha?

Question

Just wondering about the negative effects of deforestation and the growing trend of biofuel, specifically Jatropha which has a 200 gallons per acre average rate of production. IF we hope to actually reduce carbon emissions, is this crop adaantageous or destructive to the world's goal of carbon reduction, given the massive amounts of land that would be needed to produce a sufficient supply of biodiesel from Jatropha.

Answer 1

Jatropha is a shrub that is easy to grow and has become a source of plant oil for producing biodiesel in.  Many  farmers are planting jatropha as a supplement to their other farming income.  

The plant needs little water or fertilizer and can grow in a range of environments. Its golf ball-sized fruits yield a yellowish liquid that can be made into biodiesel. Jatropha is not edible.  The main idea is to make use of its millions of acres of land where other plants will not grow as a result of depleted water tables.

Some companies are investing in jatropha as well.  In June, BP Plc said it would put $90 million into a biofuels startup that will develop jatropha in India.  In Australia, Mission Biofuels Ltd. has planted jatropha on 66,000 acres.

According to some estimates, the per-barrel cost of producing jatropha is about $43 -- half that of corn. Each acre of jatropha will produce about one ton of oil, and yield a profit of about $250 per acre.

The small jatropha tree or shrub continues to grow and thus is sequestering Carbon as it produces the oil that is burned as fuel and puts some Carbon back into the atmosphere. The net effect on the environment is a positive one, but comparing the sequestering of Carbon to trees is not really a valid issue, unless you are talking about cutting down forests to grow jatropha for oil production. In that case trees would sequester much more carbon..

Answer 2

I think the point is that Jatropha oil used as a fuel instead of fossil fuels is a different form of cycling with respect to emissions. Coal and fossil fuels from oil and gas are basically a mineralized carbon locked into the earth that formed and was removed by plants in their cycle of life, death and metabolism. You really don't want to release all that carbon back into the environment with the speed at which we do. This form of carbon mineralization still goes on at a slow pace, as it always has but not as quickly as we can burn the reserves that have been stored over millions of years. To grow a crop to burn as a fuel, like the oil plants is not the best idea, but it is a way to take and reuse the carbon the plant takes from the environment before it is locked into long term mineralization. Like taking the CO2 out of the air, and with the help of nutrients and the plant's metabolism, making an oil and directly using it as a renewable resource, not a non-renewable one (actually it should be termed a too slowly to use renewable mineralized one). Wood is similar and if we were using wood alcohol/ distillate it would probably be a bit more preferable to burning wood, which has a lot more negative by-products aside from CO2 emissions.