Under growth

Does anybody know how much under growth and brush can affect sap yield. Here's my problem, my sugarbush is on a slope facing almost straight north. Some of the area is fairly clear but the rest is growing up with beech and other small saplings. I'm wondering if I should spend the time clearing these out or will they not make much difference. My thought is to clear them out, save some of the better maple seedlings but get rid of the rest. Could these be helping to keep the lines froze in the mornings? Do any of you have some tricks to getting better sap yield from North facing slopes? Any advice is apprieciated. Thanks

I have some areas like this as well. In my situation, in areas where there are mature beech, most are suffering from beech bark scale disease and are slowly dying. Therefore they are sending up root sprout thickets. Generally I clear them only if making a trail for a mainline or other purpose as they will keep sprouting. In the understory, they won't compete with any maples in the canopy so I don't worry too much about it.

In other areas I have good regeneration from past thinning, and in those areas I may try to encourage the maple saplings by removing other species, especially invasives, but generally I don't do much there either.

I would say that unless they are really in your way, you should leave the saplings there and try to encourage the maples by thinning if they are competing with the beech or others. Generally a good understory is a good thing as it means you have the next generation of trees waiting for a gap to open up. The beech thickets can be problematic though as they may outcompete others species in the near term as they are shade tolerant. Addiitonally, those sprouts will likely never become mature as they will soon die from the nectria fungus.