Candace Byrum, her complexion weathered and lined at age 29, pedals her bicycle through this hapless but hopeful town because she can afford neither gasoline nor car payments. She has been without a job since last July.

Byrum has given up her telephone, her television set, vacations to Opryland and nights on the town. Her hopes now are focused on someday being able to scrape up enough money to leave this small industrial community nestled in a carpet of corn and soybeans.

"If I wasn't so strong I'd be suicidal or in the funny farm," said Byrum, a divorcee with an 11-year-old daughter and an 8-year-old son. "I've been pretty lucky. I worked just enough time to draw unemployment in this state. I just barely made it this time."

Byrum, who used to take home $265 a week making accessories for Ford and Chrysler cars, hasonly worked off and on for several months. Now she juggles $103 a week in unemployment to cover $150 a month in rent, $105 for her three-year-old car, $70 for utilities and $200 for groceries. It doesn't work. She said she should get child support from her ex-husband, but it's too expensive to keep going to court to force him to pay.

Since Union City is largely dependent on other declining auto-related industries, there is no other work for Byrum here. Her 11 years of seniority on the job mean little now. She wants to move to Texas, where most of her friends have gone to find work, but she can't afford the plane fares, moving expenses or storage of her furniture.

Byrum and hundreds of other laid-off workers here believe they are victims of an important new trend affecting employment--international trade. Byrum is one of more than half a million auto-components workers across the country who that industry says lost their jobs as a result of an influx of Japanese automobiles.

"There can be no doubt that trade has become a more important influence on U.S. employment," a Labor Department report says. Figures on actual job losses from foreign trade are not available, according to the Labor Department. But between 1964 and 1975, 422,000 job opportunities were lost in the top 20 industries hurt by such trade, while 315,000 were gained by the 20 most aided by trade, the Labor Department said. Although exports and some imports have created some new jobs, the net effect has been a decrease in low-level jobs..

The profile of a typical worker laid off because of imports is a woman or minority with few skills, little education and low income. Economists say the jobs lost to imports over the past 15 years probably won't be replaced, but even if they are, these same economists predict, the new positions probably will be white-collar jobs.

The United States has gained an edge in areas requiring high technological skill and has a disadvantage in those requiring high concentrations of labor. Manufacturing jobs have remained static at about 20 million over the last decade, while the civilian, nonfarm labor force has grown from 77 million to 90 million.

Added to that are low labor costs in developing countries such as Taiwan, Korea and Singapore where they already have a competitive advantage in products such as textiles. Many American firms build plants overseas to get close to new, burgeoning markets. They also ship all or part of their production overseas to avoid paying some of the highest manufacturing wages in the world. But many of those countries, with inefficient agricultural production and shortages of raw materials, subsidize their firms to help them compete internationally. For many nations, exporting manufactured goods to American markets is the only way to survive.

This all leads to a political situation pitting the social needs of the unemployed against the government's desire for less welfare and a balanced budget, the consumer's desire for a variety of low-cost goods versus the protection ofjobs.

The Reagan administration, in a trade policy White Paper, advocates survival of the fittest in the trade-affected industries. Protecting inefficient domestic industries aggravates inflation, the administration says.

"We should recognize that any form of trade restraint to help a specific industry really is an internal transfer of income and wealth to that industry from U.S. consumers, and from American workers and owners of our export industries," said Murray Weidenbaum, chairman of the Council of Economic Advisers. "The emphasis in trade adjustment policies should be just that, adjustment, not preservation of an uncompetitive industrial structure."

Weidenbaum, testifying before a Senate Finance subcommittee, said workers laid off because of an influx of foreign goods shouldn't be treated differently from workers who lost their jobs for other reasons, such as the government canceling a defense contract.

As communications and transportation developed and the less-developed countries acquired foreign aid and assistance, their textiles, automobile, steel and electronics industries grew.

While the United States retains technological superiority to other nations in many industries, "it has no across-the-board advantage," according to a report of the Office of Technology Assessment. Part of the steel industry's problems stemmed from old capital equipment and plants, some dating back to before World War II, while countries destroyed by the war ironically were able to build new, efficient plants.

American industries facing stagnant or slowly growing markets "may have to choose between maintaining competitiveness at the sacrifice of employment opportunities or maintaining employment at the sacrifice of competitiveness," the OTA report said. The Reagan administration appears to have chosen the former.

Maintaining the conventional industrial jobs has been a rallying point for the nation's labor unions. United Auto Workers President Douglas Fraser earlier this year blamed imports for everything from higher levels of tooth decay to increases in alcoholism and suicides of laid-off auto workers.

"Many people aren't aware of the extent of some of the losses," said Elizabeth Jager, an economist with the AFL-CIO. For example, the auto industry claimed it lost 300,000 jobs because of imports, but Jager said 1 million people in related industries such as machinists, dealers, and employes of glass, rubber and steel firms also have lost jobs in the last two years. Since World War II the United States has dropped from the largest and strongest producer to a net importer of steel, textiles and automobiles, Jager said.

"Practically every type of consumer product is imported," says Jager. For example, 50 percent of industrial nuts, bolts and screws are imported, she said, as are one-third of the toy balloons sold here. In the late 1950s, 2 percent of shoes were imported; now 53 percent are. In 1958, four of 100 women's garments were imported. That number has risen to 40 of 100, she said.

In addition, many goods that bear American labels are made from imported parts, Jager said.

The Citizens Band radio industry is an example. In the late 1950s and early 1960s, CB radios were used mostly by farmers, hobbyists and truck drivers. But when truckers and other motorists were faced with gas shortages in 1973 the CBs became popular for finding gas stations, calling for help and avoiding "Smokey" when driving over the new 55-mph speed limit..

Domestic CB production rose from 82,000 CBs in 1972 to 1.15 million in 1976. But at the same time, imports rose from 75,000 to 15 million, valued at $800 million..

Ever since World War II, leather apparel has been popular among Americans. But during the last decade nearly all leather clothinghas been imported from Korea, Taiwan, Argentina, Uraguay and Hong Kong. Some of the garments have been made from hides that came from the United States. Some U.S. leather producers stopped making leather coats and jackets here and began importing them for sale under their own labels because it was cheaper that way. Some of the garments were imported as shells and finished in the United States.

Even as American cowboy leather and suede styles became popular between 1975 and 1978, the foreign share of the U.S. leather coats and jackets market rose from 62 percent to 82 percent. By 1977, U.S. workers, mostly unskilled, with little education and low incomes, began losing their jobs.

Between 1964 and 1975 the largest employment loss was in the textile industry, which lost more than 103,000 jobs.

As a result of tariff reductions alone in the Multilateral Trade Negotiations agreement, 167,000 new job opportunities will be created and 137,000 opportunities will be lost. But the new job opportunities will be in semiconductors and electronic components, aircraft and equipment in aircraft, electrical, construction and mining fields as well as other technical areas..

So far, U.S. industry winners in the trade war, according to the Labor Department, are aircraft equipment, computing machines, electrical and nonelectrical machinery. Most of the job gains were in the high-technology areas. Agricultural exports have also made great gains.

Even the auto industry had its winners. The American International Automobile Dealers Association says it represents 4,500 dealers with 140,000 employes who service and sell imported automobiles. More than 1 million people working directly or indirectly with the nation's ports have prospered, mostly from imports, which have grown from 61.4 percent of export-import activity through ports in 1975 to 66.4 percent last year. It is projected to remain at about 65 percent through 1985, according to figures supplied by the American Association of Port Authorities.

"Although the secular increase in both imports and exports as a percentage of Gross National Product is generally regarded as beneficial to the economy and increased exports have generated additional employment opportunities, these changes have been accompanied by reduced employment opportunities and adjustment burdens for workers in import-competing industries," according to the Labor Department report. "The adaptation of workers in the import-competing industries to these new and changing demand conditions can involve extended periods of job search, retraining and relocation and is likely to be costly."

The burden of adjustment, the report continues, often falls on women, minorities, the less educated and the lower-paid "groups least able to afford it."

Of the workers hurt by imports, 41.1 percent were women, while in industries helped by trade only 21.1 percent were women, the Labor Department says. Nonwhite workers constituted 11.5 percent of employes in industries hit hard by imports, compared with 7.4 percent who were in businesses helped by trade..

The net effect of the changes is small, the report continues. Although there are no large drops in overall employment figures, the impact on workers is great. The greatest problem is fitting the unemployed worker, generally with poor skills and education, into the new job-producing industries.

"Some people in the shoe industry cannot get reemployed making integrated circuits," said Robert Hormats, assistant secretary of state for economic and business affairs. "It's a major adjustment problem. It's very hard to solve. If you're a 55-year-old shoemaker you're not going to spend the next few years learning to make integrated circuits."

Studies have shown that the United States has a comparative advantage in making goods intensely, using skilled labor, and a disadvantage in making goods using unskilled workers.

"Over time, with the strengthening of the other major industrial countries and most recently the rapid growth of the upper-tier developing countries, the United States has met increased competition in more traditional industries which employ proportionately more unskilled labor," the Labor Department said. "Alternatively, U.S. production and export of advanced technology products such as aircraft and computers which employ relatively more skilled labor has historically led other nations."

Have jobs like Byrum's gone the way of the $2 minimum wage?

"Some people do conjure up that specter but I think that's wrong," said C. Fred Bergsten, a former assistant Treasury secretary now with the Institute of International Economics. "In the 1950s and 1960s the swing of the composition of the labor force was into service." But in the last decade, he said, there has been no great change in the share of the labor force used by agriculture, service and manufacturing. He also said some jobs will be lost in certain sectors within an industry but gained in another..

Job loss and import competition have severely hurt the smaller firms that specialize in narrow product lines and those companies making inexpensive goods in one location, according to a study by the National Planning Association..

Even if the government wanted to impose quotas, tariffs or laws restricting imports to protect jobs, those measures would impose inflationary costs on the public. For example, a study for Consumers for World Trade found it cost Americans $114,000 a year for each job saved in the footwear business when that industry was protected from imports from Taiwan and Korea..

"The challenge to America is not to protect our weaknesses by perpetuating yesterday's industries, but to build up our strengths by shifting capital and labor into tomorrow's industries," the consumer group said.