Lush growth in the mountains has raised the risk of wildfires.
The number of bighorn sheep in the range now totals 42.
Another release of 16 is scheduled for today amid criticism from opponents.
The sheep were released in the foothills north of Tucson Thursday morning.
State agency rebuilding herd in mountains north of Tucson.
New group will be released near existing herd.
Twelve of the original 31 sheep transplanted are still alive.
Not enough is being done to save Mexican gray wolves, lawsuit contends.