Limber pines prefer moist, well-drained sites.  You will first want to make sure it is not over or under-watered.  You can check this by inserting a screwdriver near the trunk and around the dripline.  If it goes in easily 6-7 inches, there is no need to add water.  If the soil is soggy, you may need to re-work the soil, dig up the tree and improve the drainage by adding compost, or relocating the tree.  If the soil is bone-dry, give the tree 1-2 inches of water every two weeks.  If these methods do not improve the health of the tree, take a branch sample into the  nearest county extension office to check for insects or fungus.  The CSU Extension Office is located in Castle Rock at the fairgrounds.