Louise Gabel packed 24 years of teaching into cardboard boxes last week. They line her fourth grade classroom now, stuffed with the mementos of a career spent in one place, Claremont Elementary School.

The boxes will be shipped out soon, because Gabel won't be returning to the South Arlington school in the fall. She's not ending her career. The school is.

A victim of declining enrollments in Arlington and other area school systems, Claremont closes for good today after serving nearly 14,000 youngsters since 1952--some of them now ministers, secretaries, accountants, teachers and physicists--through the first stages of public education.

The occasion is being marked by parents, students and faculty at a picnic today at the school, a sprawling two-story brick building recessed in a shaded valley beyond street view. It will be a bittersweet affair for the 330 pupils and 47 faculty and staff members who will part at its end. In September, pupils not going on to intermediate school will be bused to Abingdon Elementary, a more modern school with open-space classrooms just a mile away. The teachers and other staff will be reassigned to schools throughout the county.

"We look at it as a merger, a move, not as a closing," principal Ann Fenton said, as she typed the pages of a short booklet to include the history of the school and odes to Claremont written by fifth graders.

Many students, with the adaptability of youth, view the closing and impending merger as an adventure. "Computers, Coke machines, air conditioning, and bigger play fields--that's what we're gonna get at Abingdon," boasts 12-year-old Gene Bell, a fifth grader in Peggie Davis' class.

"Prettier girls," someone shouts from a small gathering at the back of a classroom.

"Nicer boys," an indignant girl interjects.

Gabel, however, views the closing with less enthusiasm. "A lot of us are very sad," she said, frustrated because she does not know what school she will work at in the fall. " Claremont has been sort of like a second home for some of us."

To Gabel, the closing is another step toward the end of an era when every student walked to a neighborhood school and spent most of the day in a traditional four-walled classroom. The promise of more modern facilities at Abingdon doesn't console her.

Seated in her first-floor classroom, stuffy and hot on a late spring afternoon even with all its windows open, Gabel looked around her. Walls and bulletin boards are bare now except for stray tacks and snatches of tape, scarred chairs and desks aligned in no distinct pattern, windows tinted with chalk dust.

"You couldn't ask for a larger room with closed walls," she says. "It's messy now, but . . . "

Claremont had been open for only six years when Gabel, then a young woman looking for work compatible with mothering, began her teaching career. Like many of the schools shut down in recent years, Claremont was built by a community of young, well-educated families, most of them white, with more children than the Arlington school system could accommodate then.

Claremont was the kind of school, strongly committed to teaching the academic basics, to which families like John and Stevanne Karlinchak felt comfortable sending their children. All eight of the Karlinchak children attended Claremont, beginning with Denise, now 26, and ending with Stephen, now a 16-year-old Wakefield High student.

"We moved here originally because of the elementary school . . . so that my kids could walk to school," recalled Stevanne Karlinchak, who still lives a block from Claremont with her youngest children. "I'm glad that it wasn't closed when my children were going there."

In 1964, the school system added four classrooms to Claremont, but a decade later found it overflowing again with an influx of foreign-born students. Since then, even with the still growing foreign-born student population, overall enrollment in Arlington schools has been dropping from 27,000 in the late 1960s to 14,500 this year. Since 1971, the decline has led to the closing of 19 schools.

Last month, the Arlington School Board voted to close two elementary schools in 1984 and Claremont at the end of the current term. Abingdon, with only 200 students in a building that can hold 550, will easily accommodate the Claremont students.

Here is how fifth grader Brendan Holland eulogized Clarement and looked to the future: "Teachers are packing, making things ready/ Kids are cleaning, which is hot and sweaty/ Carrying books that weigh a ton/ I hope it will be just as good at Abingdon."