Fir Tree Problems

This appears to be a fir tree, but without a close-up of the needles, we can’t be sure. Firs have needles that are flat and flexible, and not overly sharp. Spruces look much the same, but their needles are square and painfully sharp.
Your tree’s failure to thrive could be due to a number of factors. What’s under the gravel? If there’s plastic, it could be blocking air and water from the soil. Both firs and spruces appreciate a cool spot and extra irrigation at lower elevations. The reflected heat from the rocks could pose a problem. The roots should extend at least twice the distance past the edge of the foliage as from the trunk to the edge of the tree. Do you irrigate in that area? Has the soil been improved, and do you ever feed the tree?