Tickled Squirrel May 2015 | Page 32

Mediterranean Gardens Roald Goorman The art of pruning trees: Tree pruning is as the headline says an art, a craft, a skill, that has to be learned. One needs to understand the physiology and the phenology of each tree (and believe me, there are many types of trees!) in order to apply proper pruning practices. There is actually an official specialisation on tree care; arboriculturist, in some countries it is taken up to university level to obtain a degree as one. Fortunately we need not to go so far as to have a university degree before tackling our trees, however some basic understanding of your tree before the actual pruning starts is definitely a must. If I discuss all different pruning styles and practices, I could write two bibles full of text, so even in the basics I shall select further still to prevent information overload! For the sake of simplicity let’s assume that there are 5 pruning styles, I will discuss these in further detail below and give some examples in images. Pruning techniques, left to right, from most severe to lightest removal of tree biomass. Coppicing/Pollarding: This practice in which all branches are removed , by just leaving the main trunk or several main branches is called pollarding or topping, coppicing is the same but removes practically all aboveground biomass. This practice is seen much in the Netherlands and rural UK. In the Netherlands both coppicing and pollarding is done with Willows and Elms, an old tradition to be able to harvest the new shoots in consecutive years, these shoots were used to build fences. In the UK hawthorn hedges were coppiced to create natural fences for livestock. Nowadays in both countries practices are maintained mostly for aesthetic/ historic purposes, as well as preserving niches for certain animals that have become 32 dependent on them (like hedgehogs!). In Spain pollarding has been done for centuries with mulberry trees, to keep them a manageable size, otherwise they can become enormous. Mulberry trees withstand this practice very well and produce new growth quickly. Unfortunately, due to improper training of garden/park maintenance personnel quite a few other trees undergo the same treatment, with horrible results as a consequence. Examples are Rosewood trees (Tipuana tipu), Jacaranda trees and Silk trees (Albizia). All three species perform best when left undisturbed or receiving a light prune (removing max 20% of the canopy), allowing them to produce their attractive architecture. If their mature size outgrows your garden, simply do not consider them. Select smaller species instead as the aesthetical result of keeping them in check would not please you anyway. A big downside on this pruning method is that it is very labour intensive, once done, it will need to be done every year, as new shoots are much weaker than any normally formed branch ever would be (so called water shoots), and if left to grow large will cause a serious risk by falling over in high winds, causing damage or injury to buildings or people.