Colorado legislative economists on Tuesday predicted that recreational marijuana taxes will bring in only half of what Gov. John Hickenlooper expects they will.

A forecast produced by economists at the nonpartisan Colorado Legislative Council projects taxes on recreational marijuana will generate about $65 million in the fiscal year beginning in July. Hickenlooper’s projection, released last month, expects nearly twice that — $125 million.

The new prediction further adds to the debate over how lucrative first-in-the-nation taxes on recreational marijuana will be for the state’s coffers. In January, tax revenue came in on pace to be far below previous predictions for the last six months of the current fiscal year.

But Legislative Council economist Larson Silbaugh told members of the legislature’s Joint Budget Committee on Tuesday that too many variables — from the low number of stores open, to the high interest in history-making marijuana purchases — make the January numbers unreliable predictors of what’s to come.

“You can basically use that January number to justify any forecast you want,” he said.

Instead, Silbaugh said Legislative Council economists are more pessimistic than the governor’s economists about how many people will stay in the recreational marijuana market long-term. Recreational marijuana costs about 20 percent more than medical marijuana, he said. And that’s before the hefty taxes on recreational marijuana are applied.

Silbaugh said legislative economists believe many people will decide it is more cost-effective to remain medical-marijuana patients. While such patients must pay up front for a doctor’s evaluation and a state registration fee, medical-marijuana purchases are subject only to the state’s general 2.9 percent sales tax.

“We’re not expecting a lot of new marijuana users because of retail marijuana,” Silbaugh said. “And we’re not expecting because of the price differential, many medical marijuana users shifting over to the adult use market.”

For that reason, legislative economists predict Colorado marijuana stores will do more than $750 million in recreational and medical marijuana sales in the coming fiscal year. Hickenlooper’s economists have put that figure at nearly $1 billion.

However much recreational marijuana taxes generate, Hickenlooper has proposed using all of the money to deal with issues related to marijuana legalization — including funding drug treatment and youth drug-use preventions. Lawmakers are considering the proposal.

John Ingold: 303-954-1068, jingold@denverpost.com or twitter.com/john_ingold