If I get the visa (L) in August 2015, can I use it for travel in Feb or Mar of 2016?

Jeff, if the L type only has one entry on it, then I'm afraid you can't use it in the next year because the single-entry L type is usually only valid for three months. You can try to apply for a 6-month or 12-month multiple-entry L type or even the 10-year multiple-entry L, so that you can use it during a long time. What's more, the fee is the same for single entry and multiple entries.