Trees naturally provide an ability to balance.
When meeting clients to discuss problems or requirements for their trees, I first ask, 'what do you want to achieve?'. I ask this to ensure pruning isn't required to reduce the number of leaves on their driveway or gutters and remove the critical structure from the tree that is essential to maintaining its physiological and structural health. The former is an impossibility while a tree is in the vicinity, and the latter can lead to long-term problems retaining a healthy and safe tree.
Firstly, before touching a tree, it should be remembered that no tree grows anything it doesn't need, secondly the best pruning management for a tree is no pruning and lastly, the primary objective of any plant is to capture light; everything else it uses resource for is in minimal quantities. When removing branches and limbs, the tree must divert critical resources to start compartmentalizing that wound by creating biomass, a 1Llb weight of which can take up to 4000Llb weight of soil solution to make or ten days of entire nutrient flow usually needed by the tree for its whole canopy. So, removing areas that leave large wounds should always be avoided unless necessary, not just for this reason. Most of the larger weighted areas of a tree exist at its lowest point to the ground, and as the tree increases in height, the lower limbs range further out to create stabilization. When these are removed, as is so often seen, weight is automatically transferred to the highest point, creating leverage and a higher possibility of catastrophic failure.
We often face trees that have had large areas removed by a neighbor who doesn't want limbs on their property, resulting in a 'flat' side to the tree. This allows wind into the canopy to exert pressure on joints and structures not designed to withstand these loads. This can cause the loss of a major structure that provides integral parts of a canopy, leaving the remaining areas 'open'. We often meet situations such as this, as seen in the comparison photos shown above, that require a structural reduction to part or all the remaining canopy so that it can be blended back together to form a better wind diffusion unit. Remember, the primary objective of a plant is to capture light, and when the tree loses a portion of its canopy, other areas will take advantage of this new source of direct sunlight and grow into and toward that source. This can lead to over-extended limbs that put massive pressure on their attachments to the main tree column. These areas must be carefully reduced to limit their flexion while other canopy areas catch up to form a better shape and share wind loading more evenly.
If you have any doubts about the correct pruning needs for your tree to make it 'fit' into its urban environment, please consult at least a Certified Arborist, not just someone who calls themselves an arborist who is essentially anyone who chooses to work with trees. Each Certified Arborist will carry an up-to-date certification card with their identification number shown on it that can be referenced against a form of photo ID. No card, no use!