The amount paid by the Federal Government to any State-certified institutions eligible for assistance under this subchapter shall not exceed during any fiscal year the amount available to and budgeted for expenditure by such college or university during the same fiscal year for forestry research from non-Federal sources, except that for the fiscal years ending June 30, 1971, and June 30, 1972, the matching funds requirement hereof shall not be applicable to the Virgin Islands and Guam, and sums authorized for such years for the Virgin Islands and Guam may be used to pay the total cost of programs for forestry research. The Secretary is authorized to make such expenditures on the certificate of the appropriate official of the college or university having charge of the forestry research for which the expenditures as herein provided are to be made. If any or all of the colleges or universities certified for receipt of funds under this subchapter fails to make available and budget for expenditure for forestry research in any fiscal year sums at least as much as the amount for which it would be eligible for such year under this subchapter, the difference between the Federal funds available and the funds made available and budgeted for expenditure by the college or university shall be reapportioned by the Secretary to other eligible colleges or universities of the same State if there be any which qualify therefor and, if there be none, the Secretary shall reapportion such differences to the qualifying colleges and universities of other States participating in the forestry research program. If in any year the amount made available by a State from its own funds (including any revenue-sharing funds) to a State-certified institution eligible for assistance under this subchapter is reduced because of an increase in the allotment made available under this subchapter, the allotment of such State-certified institution from the next succeeding appropriation shall be reduced in an equivalent amount. The Secretary shall reapportion the amount of such reduction to other eligible colleges and universities of the same State if there be any that qualify therefor and, if there be none, the Secretary shall reapportion such amount to the qualifying colleges and universities of other States participating in the forestry research program.