Bob Loy, director of environmental programs for the Outdoor Circle, said the group would oppose removing many of those monkeypod and kamani trees.

"The Outdoor Circle will do everything in its power to prevent the monkeypod trees on Kapi'olani from being removed and we will do everything we can to prevent the kamani trees on Dillingham from being removed," he said. "They are significant resources of this city that cannot be replaced.

"We're not going to let that happen easy."

There also could be a disturbance of Abutilon menziesii, a native endangered shrub, near Saratoga Avenue and North South Road.

The guideway also could have shadow impacts along Kamehameha Highway at the Waiau Stream taro patch and Sumida Watercress Farm, according to Parsons Brinckerhoff.

Randy Ching, chairman of The Sierra Club O'ahu Group, said it's unlikely mature monkeypod trees can be relocated.

"If it came down to several million for right of way (to avoid a tree), or a couple thousand (for tree removal), I hate to say it, but I think I know what way that decision is going to go," he said. "I think we should do what we can to save those, but I don't think there's going to be much of an option. It's going to pretty much be chop."

Both the Outdoor Circle and Sierra Club said they hope to learn more about the environmental impact of the project once a draft environmental impact statement is released this summer.