Redwood Trust, which a few years back branched out into buying GSE loans, announced this week that it was throwing in the towel on that business, cutting 25 percent of its workforce in the process.Although it will no longer buy Fannie Mae and Freddie Mac mortgages from correspondent originators, it will remain a buyer of jumbo product. As one source close to the company noted: Redwood “just couldn’t make the math work” in that line of business. At Sept. 30, the publicly traded real estate investment trust employed 221 full-time workers. The layoff will claim roughly 54 jobs, most of them in Denver where its GSE acquisition initiative was based.