The Woodside School, a one-room clapboard house, stands in a field of clover bordering the trees and is flanked by two small outhouses. The swinging barn doors on the back porch stand open to the warm autumn air.

Inside, 35 children from nearby farms -- all with the last names Hertzler, Swarey and Stoltzfus -- labor over their desks. The girls wear black stockings, simple dresses with black aprons, and white nets over long, coiled hair. The boys wear long-sleeved shirts and black pants with suspenders. All of them are either wearing sturdy black shoes or are barefoot.

A wood-burning stove crouches in one corner. An 18-year-old woman teaches them health and the 3 Rs at the school through the eighth grade, all the education she says they need for a simple, rural life style.

But outside, as hawks soar above amber fields of dried corn stalks and draft horses strain before the plow, modern society is inexorably closing in on these simple people.

The life style of the Old Order Amish community here on the border of Charles and St. Mary's counties is threatened by a shortage of its most vital resource: affordable land.

The minimum acreage needed to support an average Amish family with eight children ranges from 50 to more than 100 acres, depending on soil fertility, authorities say. While there is land available, these mostly tobacco and dairy farmers say that the market value of $1,500 to $2,000 an acre, according to St Mary's assessment official William Lawrence, is out of reach of most.

Dispersing to find affordable land in less thickly settled areas would leave the Amish vulnerable to the outside, they say, separated from the sociotheologic network that is the focal point of the community.

The Amish immigrated to Pennsylvania from repressive Switzerland as early as 1727, taking their name from Jakob Ammann, one of their Swiss Anabaptist forefathers. In 1940, the first settlers came to Maryland from Lancaster County seeking cheaper land. The original seven families have since been joined by more than 100 more, gathered largely in the area between Rtes. 6 and 236. According to the Old Order Amish Almanac, three of Maryland's four religious districts are in the Mechanicsville-Charlotte Hall area, with one other in Oakland on the western border.

John Hostetler, who left the Pennsylvania Amish community in which he was raised and now holds a PhD in sociology, says that the Amish population boom is a nationwide phenomenon: The U.S. total of 45,000 in 1962 doubled to almost 90,000 in 1980, said the Temple University professor, who predicted it will continue to double every 23 years.

This rate of population growth, coupled with skyrocketing land prices, has already forced some Amish families to leave Maryland. One of the two bishops in the area (supplemented by 13 ministers) has already seen four of his eight children move back to Pennsylvania. The bishop, his long beard, gray against weather-etched skin, paused after milking his goat to recount passing the 47-acre tobacco farm down to his eldest married daughter three years ago. "Land is so high, we can't all farm," he said, "so I let the children take the farm over." Now in his 50s, he builds picnic tables and chairs for a living.

His daughter came to the door of the farmhouse holding her 8-month-old son, whose orange plastic pacifier contrasted with her homemade dress fastened with straight pins (buttons are banned as ornaments). "There are some moving out now," she said, echoing her father. "Farms that haven't been Amish are being bought by our people."

As do all Old Order Amish, the bishop's family shuns electricity, telephones, automobiles and plumbing, preferring to minimize dependence on the outside world by using wood and coal stoves, kerosene lamps, horse-drawn buggies and windmills to pump water from wells. The Amish sell livestock and crops to the outside, however, necessitating minor compromises: Some farmers have resorted to tractors for plowing, and phone booths dot the major paved roads.

Dr. William Marek, deputy state health officer for St. Mary's County, marveled at the Amish people's "ingenious ways of complying with state regulations." For instance, he said, they use gasoline engines to refrigerate the stainless steel milk tanks. The Amish have family doctors and use the local hospital for serious illnesses and injuries.

Modern devices have filtered into other Amish trades in Maryland as well. The table saw and drill press in King's Buggy Shop on Rte. 236 are powered by an internal combustion generator. The metal wheelrim, however, is still heated in the glowing coals of a stone hearth, then fitted around the wooden wheel, shrinking to fit tightly as it cools. Solid rubber tubing is then fitted into the rim (pneumatic tires are generally forbidden). The buggies' gray wooden bodies are handmade. Harnesses are supplied by a taciturn man down the road who, paralyzed from the waist down in a polio outbreak in 1951, tools the leather straps in a makeshift wheelchair.

Nearby, Katie's Variety Shop is an eclectic collection of old and new, ranging from Corningware to handmade quilts. Katie, a spry great-grandmother, recalled that over the last 10 years, her store has attracted "customers from all over the country." Her guileless hospitality seems typical of the Amish--an observation confirmed by a non-Amish area resident whose Old Order neighbors helped, among other things, to deliver a calf and free her mired car. "You couldn't ask for better neighbors," she said.

Amish children occasionally opt to enter the outside society. Sociologist John Hostetler, who left the Amish tradition at age 18, said, "Children have a choice. The Amish emphasize free will . . . . You don't take the vow at 18 if you don't intend to keep it for the rest of your life."