Heading into another season of al fresco dining in Boston, the application process has become cumbersome for many restaurants.

The problems North End restaurant owners have with Mayor Michelle Wu’s plan to charge a hefty fee exclusively in this neighborhood are well documented. But other changes are also affecting businesses across the city.

“What’s frustrating for us is that a lot of time and money was invested over the past year and that investment is now a losing investment,” said David Doyle, owner of Tres Gatos in Jamaica Plain.

He speaks of pallets and planters that many restaurants used to use to protect their terraces. They are no longer allowed.

Restaurants are now required to use more high power equipment such as Jersey barriers.

“So the barriers were a curveball for us,” he said.

“You need concrete or water-filled barriers,” said Ginger Brown, executive director of the Jamaica Plain Centre/South Main Streets organization. “They are impossible to find. If you can find them, they cost anywhere from $200 to $700 and you need at least eight.”

Some restaurant owners continue to oppose Boston Mayor Michelle Wu’s plan to impose fees on al fresco dining in the North End.

Brown sent a letter to the city urging officials to review the new alfresco dining regulations, which she says may be overly bureaucratic and even a source of racial inequality.

“A small business owner who doesn’t have the money, maybe not a native English speaker, will be intimidated by the process and won’t apply,” Brown said. “So they end up losing the opportunity to dine outdoors.”

The city also now needs more insurance, more specific design plans, and some restaurants like Tres Gatos are still awaiting approval to even open their patio with the season starting in just two days.

“That makes it difficult because we have to plan staff,” Doyle said.