One of the best known arboricultural statements is Right tree, Right place – often used to explain the species choice or planting site for new trees. Unfortunately, this phrase has become a bit hackneyed and is really too simplistic for useful application in urban planting schemes, where there are so many factors involved.
Alan Simson, Professor of Landscape Architecture + Urban Forestry at Leeds Becket University helpfully updated the phrase, adding;
“for the Right reason and in the Right Way.”
This makes the statement a lot more valuable and meaningful.
So let’s take this phrase apart and analyse it, starting with Right Tree. What size of the canopy do we want to achieve long term? Do we want spring blossom? Autumn colour? Does it matter if the tree produces allergenic pollen or has poisonous fruits? The shape of the canopy? Often trees are chosen purely on their aesthetics rather than environmental performance, but new research is allowing us to intelligently select a tree on the basis of the attributes and benefits that we are seeking to gain by planting the tree – including carbon sequestration over the lifetime of the tree. So we can get the Right Tree choice.
So where is the Right Place? At GreenBlue Urban we believe that trees can be planted nearly anywhere, but it is sensible to take account of some important factors. Is there space for the tree to grow to maturity without conflict with other infrastructure or buildings? Will the tree be subjected to vehicular damage? Will leaf drop block up drainage? Will the tree cause problems with shading on nearby properties? Can appropriate soil volume be achieved below ground without conflict with adjacent utilities? If these questions can be answered acceptably, then a tree can be planted. It is wise to consult with nearby residents, as working collabohttps://greenblue.com/products/rootspace/ratively always brings better results and often the residents take some of the responsibility for maintaining and caring for the newly planted trees.
And what is the right reason? Why are we considering planting the tree in the first place? At GreenBlue Urban we have a belief that street tree planting should focus on quality rather than quantity. The current push for increased numbers of new trees in streets is, on the surface great – but will they survive long enough to repay us for the cost of growing and planting the tree? If we are serious about using trees to help mitigate climate change and to bring biodiversity to our urban areas, to assist with stormwater management and to enhance health and well-being then we need to articulate that, and that then justifies the investment needed. Too often, tree planting, both on new builds and retrofit planting is done to meet planning requirements or arbitrary planting schedules hoisted on the street tree team by the higher echelons in the local authority – known as cynical tokenism. The use of tree numbers as political weaponry is unhelpful – what matters is how many trees actually attain maturity.
And finally, what is the right way? This depends on where the tree is to be planted, but essentially every tree needs access to an adequate volume uncompacted soil volume, water, air and support to keep it upright until it establishes its own rooting system, protection against damage and maintenance. In reality, recreating the natural environment in which the tree would normally grow in the wild: in planting in soft areas, is usually a simple procedure. Where we are planting in hard paved areas, where there are high levels of compaction below the surface and where impermeable surfacing prevents water ingress into the rooting zone, a more specialised engineered solution is required. The GreenBlue Urban RootSpace soil cell system supports the paving or roadway above and keeps the soil aerobic and uncompacted and in optimum condition for root establishment. Root management solutions such as ReRoot/RootStop barriers, Root Directors and RootForm encourage roots to go deeper, moving them away from sensitive surfacing areas. RootRain irrigation and aeration products ensure that water and air are delivered directly to the emerging fibrous roots, saving water from evaporation, and encouraging deeper rooting and better drought tolerance. Arborguy underground guying systems keep the tree upright whilst allowing stem movement; this stem movement releases a root growth hormone, kick-starting faster establishment and earlier independence in the landscape. Finally, consideration of potential sources of damage to the tree will lead to the correct choice of above-ground protection; which tree grilles/grates and guards would be appropriate, or whether some sacrificial bollards should be installed.
When we take the planting proposal through these four stages successfully, we stand a far better chance of a healthy long term tree canopy, and this should be the main reason for planting. If the tree is unlikely to grow in a certain situation, don’t plant it there, find somewhere else where it will have a better chance of survival. Canopies for centuries.
Want to discover more? Our latest webinar on Friday 14th May discusses just this – with current speakers from City of Trees and Portsmouth City Council, highlighting hybrid engineered tree pits and a host of successful projects with underground constraints.