Novice guidance on branch clearing wild trees

I would like some practical and ethical guidance on the clearing of living branches from wild sitka spruce as are they only practical climbing option I have so far. I'm speaking specifically of the small branches (~1-2 inches)that sprout from the trunk around larger limbs. Quite often they seem to grow in clusters that form an inpenetrable barrier for my level of experience. My intent is to clear an ascent route to access the higher parts of the tree.

Another characteristic of Sitka's are an abundance dead limbs ranging from small to very large. However, the trees are large enough to have fairly clear ascents in some trees. I've included a picture of "Big Mamma" (160' Sitka)as an illustration.

Any suggestions or guidance offered would be appreciated