When she thinks about a student going through college, Kristen Renn imagines a seedling growing into a tree: There are a lot of things that could go wrong along the way.

“One cataclysmic event can do it in,” said Renn, a professor of higher, adult and lifelong education at Michigan State University.

An entire forest of potential future graduates is now imperiled by the pandemic that has large numbers of students saying they will delay their higher educations, take time off, opt for community college or shift to studying part-time.

While attention has been focused on the impact of these choices on enrollment in the fall, each has also been shown to slow down or derail students on their way to degrees. For them, and for employers who need educated graduates, that means the effects of this crisis will be felt not just for one semester but for six or more years.

That’s how long it takes some undergraduates to finish college, if they ever do, even in the best of times. Now, just as happened in the last recession, it is likely to take them even longer and cost more, while — after years of hard-won progress — dropout rates rise and graduation rates fall.

“We’re so focused on the now and on the short-term future,” said Laura Perna, a professor at the University of Pennsylvania Graduate School of Education. “But there are serious long-term consequences to this.”

Most affected will be Americans who are already way behind their peers in completing higher education: those who come from low-income families and whose parents never finished college.

“This could add a year or two, easily, to a student’s time to degree,” said Renn.

That’s the inescapable lesson of history and research.

Worried about having to take classes online or not sure how they’ll pay, for instance, 10 percent of high school seniors who were planning to attend a four-year college or university before the pandemic now say they’re going to do something else, the consulting firm SimpsonScarborough reports. About half say they will enroll at a community college.

But high school graduates who put off college often end up never going, research shows. And only 45 percent of people who enter community college full time earn associate degrees in even six years, according to the National Student Clearinghouse Research Center.

Some of these students say they ultimately plan to transfer from community college to a four-year university and get a bachelor’s degree. But only 13 percent of community college students manage to achieve that goal, the Community College Research Center at Teachers College, Columbia University, says. (The Hechinger Report, which produced this story in partnership with The Washington Post, is an independent unit of Teachers College.)

“For some students [community college] will be like a detour,” Renn said, “and for others it will be an off-ramp.”

Of students who have changed their education plans, 15 percent say they will reduce the number of courses or the amount of training they take, another survey, by the nonprofit Strada Education Network, found.

But studying part-time also significantly lowers success rates. More than half of part-time students still hadn’t earned a credential six years after starting college, the National Student Clearinghouse Research Center says.

Even if graduating high school seniors say they are only delaying their educations and will eventually go to college, “their likelihood of actually enrolling a year or two years later is lower, and therefore their chances of getting a degree is lower,” said Watson Scott Swail, president and chief executive of the Educational Policy Institute.

Some may find jobs, start earning money and stay put, he said. Others will lose the helpful momentum of peer pressure. “You’re going to be behind your friends,” said Swail. “In your head, you’ve lost the race.”

Of course, many of these decisions about whether, where and how to go to college are being driven by new financial realities. While wealthier families still may largely be able to afford the cost of college, growing numbers of lower- and middle-income Americans — who were already struggling to pay — have now lost jobs or fear they will.

“What’s happening right now is putting families into a very precarious position for whom paying for college was precarious to begin with,” said Lindsay Page, an associate professor at the University of Pittsburgh School of Education who studies how students get to and through college.

“This is not going to affect families for a semester,” she said. “It’s going to affect them for a really long time.”

Some low-income prospective students now are working to help their families, said Yolanda Watson Spiva, president of the advocacy group Complete College America; others are seeing record unemployment rates and wondering whether there will be any jobs for them, even with degrees.

“It’s hard enough under regular circumstances to help students understand why college is important,” said Spiva. “Trying to get students to understand the value proposition of college now is going to be a more difficult and arduous undertaking.”

All of these new barriers and delays will likely further widen the nation’s broader socioeconomic divide, Page and other experts said.

“It’s middle- and lower-income students who I think will be wildly thrown off by this,” Renn said.

Already, only 12 percent of bachelor’s degrees awarded by age 24 go to people in the bottom quarter of income, new research from the Pell Institute for the Study of Opportunity in Higher Education finds, compared with nearly 75 percent that go to those in the top half.

“From high school graduation out toward college, we’re seeing covid make it even less likely that low-income, first-generation students of color do what we hope they will, which is get a bachelor’s degree,” said Liane Hypolite, an assistant professor of educational leadership at California State Polytechnic University, Pomona.

Although college and university enrollment went up after the last recession, as more Americans sought education at a time when jobs were also scarce, there was a distinctive socio-economic divide, the National Student Clearinghouse Research Center found.

Students from wealthier families continued to attend the priciest institutions while more lower- and middle-income families chose community colleges, which the College Board reports cost about a third as much as the lowest-tier public four-year universities and one-tenth as much as the lowest-tier four-year privates.

Dropout rates rose, and graduation rates fell.

Since then, both statistics had begun to improve. The proportion of students dropping out between their first and second years, in any kind of university or college, fell two percentage points, and the proportion earning any kind of a degree within six years grew five percentage points as institutions put more resources into prodding their students to succeed — often under pressure from policymakers who tied their funding to such measures.

“We were making some good strides in supporting those students and improving completion rates,” said Bradley Custer, senior policy analyst for postsecondary education at the progressive nonprofit Center for American Progress.

How delicate these seedlings are, however, is evident from the fact that, even accounting for this progress, 26 percent of students still quit before their second year and 34 percent still haven’t graduated after their sixth.

Now there’s fear that financial problems could prompt institutions, some of which have already begun layoffs, to reduce support for students who need it. Student planning and advising offices consume $1 billion a year of university budgets, according to the consulting firm Tyton Partners.

“Those kinds of programs aren’t cheap, and colleges are really strapped right now,” Page said.

Already, fewer than a third of university and college advisers say they can always meet the needs of their students, Tyton Partners found in a survey of 2,500 administrators, advisers, counselors and faculty. The rest say their caseloads are too big to keep up with.

That could take a particular toll on first-year students and returning adults, many of whom need extra counseling. And if their institutions continue to teach online in the fall, as some have announced they will, it may be even tougher.

“Our students are out there floundering,” said Hypolite, who still advises graduating seniors at a charter school in Boston where she previously worked. “Once they hit a few roadblocks, without a person and a contact and a human being who can help guide them through the process, they’ll say, ‘I’m over it.’ ”

Spiva likens the job of advisers right now to that of contact tracers helping to find people exposed to the novel coronavirus. “We’re going to have to do some contact tracing to find our students, in some cases,” she said. And that will have to happen even with advisers’ already high caseloads and the possibility that their funding will be cut.

There are glimmers of optimism. The experience of juggling work and family while being shut down at home, for instance, may have made the broader public more sympathetic to the challenges faced by working students with children, and more willing to support services that might help them, said Perna, at Penn.

“There’s a lot of complexity that most people haven’t been aware of,” she said. “Everyone as they’re trying to do work is understanding that colleagues have families and other sorts of constraints. When you have those multiple responsibilities, there’s a precariousness to it. The whole house of cards can crumble.”

Public attitudes toward community colleges also may warm, said Karen Stout, president of Achieving the Dream, which works with those institutions to improve their graduation rates and the odds that their students can successfully transfer to four-year institutions. “And that puts pressure on policymakers to ensure that there are strong credit-transfer policies.”

But there are other problems. Should large enough numbers of students put off college but then show up on campus next spring or the following fall, for instance, it could create a sudden surge in demand for required courses that outstrips the supply, Page said.

“Students may be facing these course-level pileups and also advising-load pileups” that delay them on the way to their degrees, she said. “By the time they register, the class is full.”

And, in a vicious cycle, anything that slows them down diminishes the chances that they’ll ever finish, said Swail.

“It’s like a 100-meter dash or hurdles,” he said. “If you make the race a little longer, you add another 10 meters onto it, it just gets harder and harder to reach the finish line.”

Even students who do show up in the fall may not experience the usual in-person first-year orientation programs universities and colleges have built up over the past decade to get them accustomed to the campus and introduce them to each other, which have helped reduce the dropout rate, said Jennifer Keup, executive director of the National Resource Center for the First-Year Experience at the University of South Carolina.

But Keup sees hope, too.

The purpose of those programs, she said, is to take “a diversity of individuals you’re bringing to a campus and make it into a community” by finding things that first-year students can agree they share in common.

And, said Keup, “we’ve never had a more common human experience than we’re having right now.”

This story about college graduation rates was produced by The Hechinger Report, a nonprofit, independent news organization focused on inequality and innovation in education. Sign up for our higher education newsletter.