The United States and Japan Wednesday reached agreement in principle on removing Japanese import restrictions on processed wood products.

The deal for wood products, which should lead to an increase in U.S. exports of roughly $1 billion a year, means that the United States and Japan have resolved the three issues of market restrictions for which Japan was cited last year under the Super 301 provision of the Trade Act of 1988."We believe this agreement will provide major benefits to U.S. exporters. Not only will it result in millions of dollars of U.S. exports, but it will offer lower cost and high quality wood housing to Japanese consumers," said Carla Hills, U.S. Trade Representative.

Under the agreement, Japan will reform its system of tariffs and certification and its standards procedures. They have been effective non- tariff barriers to the import of finished wood products like planks or laminated goods.

Laminated wood products - such as veneer lumber - will be shifted to a lower Japanese tariff classification effective June 1. That will cut duties

from 20 percent to 3.9 percent.

Moreover, Japanese officials pledged to streamline the process through which the quality of goods is certified. Methods used by U.S. companies in testing for quality and soundness of such products have been deemed acceptable by Tokyo for imported wood products.

Regulations that discriminate against U.S. products, such as standards based on design rather than performance, will be eliminated. Certification that had previously been granted only to specific individuals for specific applications will be opened to include most new products and business systems.

Several Japanese standards involving nails, fire retardant materials, machine-stress-related lumber and oriented strand board were also resolved.

Moreover, the government of Japan assured U.S. negotiators that tariffs on wood products would be dealt with in the context of the ongoing Uruguay Round of multilateral trade talks under the General Agreement on Tariffs and Trade. GATT is the Geneva-based body that governs most world trade in goods.

The forest products barriers were listed along with Japanese government restrictions in procuring foreign-made satellites and supercomputers, as Super 301 cases in 1988. By statute, the administration had until June 16 to negotiate successful accords in these areas. With all three now concluded, Japan faces no threat of retaliation by that deadline.

Industry officials expressed satisfaction with the outcome, as did two senators with close association to the forest products industry, Sen. Max Baucus, D-Mont., and Sen. Bob Packwood, R-Ore.

''The agreement that has been reached did not eliminate all of these

barriers. But it does address all of the major problems identified by the U.S. industry, including tariffs, tariff misclassification, standards and building codes," Sen. Baucus said. "After consultation with industry, I believe the agreement brings us about halfway to our goal of an open Japanese forest products market. It is a major, major step forward."