Seventy miles west of Cambridge, deep in a hardwood forest near the Massachusetts hamlet of Petersham, there is a Harvard classroom without walls, and four Harvard students who may set foot in Harvard Yard for the first time at Commencement.

The Masters of Forest Science Program, a part of the Graduate School of Arts and Sciences, is one of Harvard's smallest and least-known degree-granting programs. Usually consisting of a two-year research project, Harvard's is unique among academic forestry programs for its small size.

Small like four students, none of whom are even studying the Harvard Forest, a 1,200-hectare wilderness owned by the University that serves as their headquarters.

Students and researchers enjoy laboratories for nutrient analysis, physiological and population ecology, greenhouses, herbarium and a computer laboratory, according to the forest's Web site. Students and staff can live in apartments owned by the Harvard Forest.

Scientists have been studying Harvard's forest since 1907 and the woodlands are the center of two long-term studies funded by the National Science Foundation and the Department of Energy.

The studies aim to learn about how forests and landscapes react to climate change, pollution and human disturbances.

"The Harvard Forest lends itself to long term studies. Landscapes and forests change slowly," says David R. Foster, director of the Harvard Forest. "The forest has been here a hundred years, so there is a lot of long time data."

Long term studies are the heart of the forestry program, which does not require students to take any classes to get their degree, but instead has them do field research culminating in a thesis.

The Forest's Web site says, "Instruction at the Harvard

Forest is informal and personal. No

courses have to be attended and no formal examinations are held."

Faculty for the forestry program are drawn from Harvard's biology department.

The four students at the forest this year--there was only one student last year--say they revel in the chance to do research while still getting the advice of professors.

While other schools offer higher degrees in forestry--Harvard only offers a masters' degree in the specific discipline of forestry--students say Harvard's program offers the benefits of a more intimate working environment.

Jesse L. Bellemare, who went to the University of Massachusetts at Amherst, for his undergraduate work says, "The benefit is having lots of interaction with staff and getting the input from professors in the field."