LANSING, Mich. (AP) — Michigan's Republican-controlled Senate passed a proposed constitutional amendment to ensure local governments would get a slice of a robust state trust fund for projects such as trails and parks.

State lawmakers voted 26-11 along party lines for a three-bill package to remove the Natural Resources Trust Fund's $500 million funding cap and require the Legislature direct 15 percent of oil and gas revenue toward grants for local public recreation projects. The proposal now heads to the House, where it also needs a two-thirds vote because it revises constitutional law on the trust fund. If the legislation triumphs in the next few weeks, it could be on the August primary ballot.

"I'm very excited to be able to open this funding up for more local investment," bill sponsor Sen. Darwin Booher, R-Evart, said. "Michigan is a regional destination for outdoor tourism and this is one more way that we can provide communities with the resources necessary to improve or create more recreational opportunities."

Projects that would benefit under the potential changes include trails and park infrastructure, as long as local governments or authorities match 25 percent of the total cost. In addition, the proposal potentially increases how much money the Legislature can appropriate toward state parks: up to 55 percent instead of 50 percent of the year's gas and oil royalties.

Senate Democrats opposed the bills because they are suspicious about the state park funding provision. Sen. Rebekah Warren pointed out estimates using numbers from the state Department of Natural Resources indicate state parks would actually lose money for the first two decades under the proposal.

"We need a real, long-term sustainable solution to funding for both our state and local parks and rushing policy like this is not going to get it done," Warren, a Democrat from Ann Arbor said. "We really can't afford to lose tens of millions more dollars a year for the next 20 years."

Michigan's trust fund was created in 1976 for the use of public recreation and protection of natural features. Since then, it has amassed over $1 billion for trails, parks, boat launches and other projects in every county, thanks to revenue from oil and gas companies that use state-owned mineral rights.

When the trust fund hit its $500 million cap in 2011, royalties instead began flowing into the Michigan State Parks Endowment Fund. But interest and earnings from the trust fund's $500 million is still used on land and recreation projects annually at the behest of a Natural Resources Trust Fund board, which has lately frustrated lawmakers in its hesitancy to spend more.

State senators have made past grabs at the trust fund but were halted by state Attorney General Bill Schuette in November. Schuette, a Republican running for governor this year, shut down one of Booher's bills attempting to appropriate extra money from the special state fund and ruled that lawmakers are not authorized to go over the trust fund board without a constitutional amendment.

"This legislation hasn't been updated in sixteen years," said another sponsor of Wednesday's legislation, Republican Sen. Goeff Hansen from Hart. "It's long overdue that we begin to free up these funds for improvement to our communities and natural resources."

DNC director Keith Creagh said he supports the legislation, believing it to be an increase in funding for state parks and in local outdoor recreation. The Nature Conservancy, a pro-environment group that has in the past sparred ideologically with the legislation's Republican sponsors, also endorsed the bills.