Ethanol from trees?

Question

All the maples and birches produce a sucrose rich sap though only one or two types of maple, and birch are commercially viable for sugar (syrup) production. But, all saps contain sugars of some molecular form. My question is: Could deciduous trees be a viable source of sugars for ethanol production? There are only a few months in the year when sap can be taken from maples which constrains production, but there are millions of maple trees. Unlike sugar cane, the tree is not harmed by reasonable sucrose harvesting methods. Could ethanol be produced from deciduous trees in a cost efficient manner?

Answer 1

Ethanol can be produced from any plant material that we let the yeast work on.

Tapping maple trees is not a cost effective process. It takes 40 gallons of sap for 1 gallon of syrup with a good tree. Most the ratio is larger. Then it takes energy to boil off the water. Collecting the sap is not economically feasible, even with the plastic tubing running downhill to tanks. That is why maple syrup sells for $50 a gallon.

Field crops that are not used for food for humans or animals is a better idea, such as switch grass. Algae is another thought. It can be used for ethanol or methane .