Weight reduction pruning (also known as crown thinnning) is a type of tree pruning that involves removing larger branches to reduce the weight of the tree's canopy. This helps to make the tree more stable and less likely to break or fall during strong winds or heavy snow/ice. The goal of weight reduction pruning is to balance the weight of the tree's canopy with its root system, reducing the risk of structural damage or failure. 

Height reduction pruning (also known as crown reduction) is a type of tree pruning that involves reducing the height of a tree to control its size and shape. This is typically done for safety reasons, to improve visibility, or to maintain the tree's overall health by removing weak, crossing, or diseased branches. The pruning process involves making strategic cuts to remove specific branches, taking care to maintain the natural shape and balance of the tree and to avoid over-pruning or creating large stubs.

Dead wooding is the process of removing dead or decaying branches from a tree. This type of pruning helps to maintain the tree's health, prevent the spread of disease, and reduce the risk of falling branches, which can pose a hazard. The process involves removing dead, dying, or diseased branches back to a healthy growth point, avoiding damage to the live tissue of the tree. 

Clearance pruning is a type of tree pruning that involves removing branches or growth that are in the way of buildings, structures, roads, sidewalks, power lines, or other obstacles. The goal of clearance pruning is to provide safe and unobstructed access or visibility, while preserving the overall health and stability of the tree. The process involves making precise cuts to remove only the necessary growth, while avoiding damage to the tree's structure or health.