Interact with the tree in your landscape through the rhizosphere.

It was to be expected that with the weather patterns in the UK so far this winter, and the resulting damage, that there would be many calls for felling trees near to homes to avoid ‘possible’ future damage to persons or property.

A knee jerk reaction against trees in the immediate vicinity of your home is to be expected when confronted with the images of damage when a tree does fall in an urban or suburban area. And there can be no blame attributed to anybody, no failings by local authorities or their arboricultural teams or contractors when a tree that would pass the most vigorous of assessments falls due to extreme winds.

We always have to accept that not all people love the trees in their landscape, but it is rare to see communities polarised due to trees. And in most urban or suburban landscapes most people, virtually all, will believe that any trees outwith their property and certainly on public land are not their responsibility, (many people with trees on their property do not accept that the health of that tree is their responsibility), not surprising given the significant costs of surveying and maintaining large mature trees.

It is sad that whilst trees remain an important, indeed vital, landscape feature in the urban and suburban areas of Britain the people who benefit from that tree in their place and the tree itself have no interaction until disaster strikes or the tree or the person are gone.

The work of Christopher Neilan and some others who have been able to break down this stand off through encouraging the celebration of trees is a huge step in the right direction and I personally believe as with others that this is bridge required for a new value on all trees. But maybe there is something more we should be encouraging the more interested tree lovers to be doing to interact with the trees in their landscape, using the rhizosphere?

Britain, as is being so well proven by the increased flooding, suffers from a massive problem that is rarely discussed. Soils in virtually all areas suffer from compaction. The UK has a landscape, that possibly more than any other country in the world with a significant remaining proportion of rural land left, that is the result of human activity. In urban and suburban areas soils now exist which are unique and even enviable due to how they have continued to be ‘alive’ despite centuries of human activity. I would argue though that the skills and knowledge to work with these soils is severely depleted. Some good work continues and there are some exemplary, internationally lauded case studies of good practice with regards soil in the UK, but on the whole far too many are ignoring soil and therefore the rhizosphere is also ignored.

It is all too easy to explain the uprooting of a tree by way of a simple chain of events: Excessive rain saturates the soil – this weakens the soil in the rhizosphere – the roots can no longer anchor themselves against strong wind. There are many omissions from this chain of events, omissions where some mitigation work can be carried out by non professionals concerned about the trees in their landscape.

Sub surface soils in the urban and suburban landscapes and further are immensely complex. The interface between roots and subsurface infrastructure as well as in relation to smear surfaces by various causes cannot be tackled by standardised methodology. The means of surveying these major issues with regards urban, suburban and garden trees is impractical in terms of cost for younger trees, things are often too late by the time the tree is mature – if the tree even survives that long.

By simple maintenance to the soil surrounding the tree – the future extent of a tree’s rhizosphere is suitable for it then we can help ensure the longevity of that tree and insure, in part, against that tree as being a threat to persons and property in the future.

For the vast majority of younger trees, we can sadly assume that they have not been planted as well as they could have been. Many will be sitting in ‘pots’ created by smearing the clay soils when the tree pit was dug, thus creating a shear zone which in turn allows the tree to fall far too easily when it is older and heavier.

Simply spiking the ground at 0.2m intervals or digging small holes at 0.5m intervals (diameter <30cm, depth >40cm), backfilling with small stones mixed with composted material or even just good quality soil is incredibly effective at encouraging root development into anchor positions.

If mulching then ensure by way of using a fork or spike that the mulch enters into sub surface layers of soil. Mulching of trees in urban and garden soils has to be done with discretion, too many trees in these locations sit in soils far too rich in nitrogen.

Better still, use a more benign medium; 80% sand mixed with well rotted horse manure or compost.

In many places it is still common practice to use a dead branch from the tree in question, whittled to a point and then hammered into the ground within the dripline of the same tree.

These are all quick and easy things that will help that tree by way of giving something to its roots, helping you engage with that tree and form a relationship with it.



Leave a comment

Filed under Trees and Woodlands

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s