The federal Bureau of Land Management may permanently close a popular climbing site in southeastern Idaho, over opposition from local rock climbers who argue the plan is too restrictive.  Agency officials say they hope make a decision this month, with plans to close climbing routes sometime this summer.  The 400-acre area known as Castle Rocks has been closed off and on to climbers since 2003. Both the Shoshone-Bannock and Shoshone-Paiute tribes consider the land sacred, and BLM surveys have found the region contains important archaeological resources and artifacts.  Citing those and other reasons, the BLM on April 12 proposed closing the Cassia County area to climbers for good — hikers and hunters would still have access.  But climbers say for years they've offered less restrictive alternatives that still protect wildlife.