It is clear that pruning is the most common intervention in tree maintenance, but we cannot use it as an excuse or justification for all interventions. A precise distinction that a certified arborist can make without any problem and in this way avoid inappropriate work.
With this in mind, mention must be made of the consequences of pruning: proper pruning by and under the supervision of an arborist helps to selectively remove dead or defective parts of the tree, as well as to aid tree structure, therefore contributes to the health and general structure of the tree reducing risks that it may cause to people or properties. On the contrary, inadequate pruning can be detrimental to the health and structure of the tree as well as making trees dangerous, so it is always essential to establish clear and defined objectives before beginning any pruning.
Now, another important aspect to mention is the age of the tree, this factor greatly influences the type, frequency, intensity and objective of the pruning to be carried out. Mature trees provide shade, beauty, and other benefits to the urban environment and require a completely different treatment than young trees; At each stage of growth, the tree is more or less sensitive and susceptible to its environment, likewise vigorousness is key in the response to pruning, so in mature trees it is not recommended to make large cuts as it is physiologically more stressful recovery.
Among the most common types of inappropriate pruning we have the so-called intense thinning (lightening, thinning-out or opening-up in English). The correct term in arboriculture is over-thinning or lion-tailing and occurs when several live branches, particularly in the lower crown, have been removed for whatever reason, removing large foliage from the tree canopy.
It is important to understand that thinning of this type does not necessarily make trees safer and may in fact have the opposite effect. Unfortunately, this type of pruning is very frequent, accepted (often desired by citizens) and tends to change and interrupt the tree's natural load balance, changing its dynamics, usually the stress of when the air blows against the tree. Tree is naturally distributed through the tree effectively from top to bottom (crown to root) in order to minimize breakage, which does not occur when the crown has been modified.
On the other hand, it negatively affects the vitality and resilience of the branches and the general of the individual, affecting the development of the base of the branches, which influences its support and helps to create continuous columns of internal rot making the branches more still weak.
Another common practice within pruning is end-weight reduction, which generally seeks to reduce the longitudinal weight of large branches. Although there is no scientific support that shows that this practice will reduce the risk of rupture, many of these interventions end up turning the branch into a lion's tail, which was previously discussed.