Nurseries and planting strategies: a reciprocal relationship

CURRENTLY in wide circulation is the DEFRA England Tree Strategy consultation document published in June 2020, with a closing date of September 11th, 2020. It is not intended to offer a detailed critique of the document here other than to say it is heavily weighted towards forestry and woodland creation and very lightly weighted towards trees in the urban environment. To be expected, I suppose, but disappointing all the same. It has been questioned as to whether the document itself is fit for purpose, but, again, that is for others to decide and beyond the scope or intention of this article.

The document, in reference to street trees, mentions a government commitment ‘that all new streets should be lined with trees’ and that the Building Better, Building Beautiful Commission recommended ‘the planting of more street trees, the creation of urban orchards and the planting of fruit trees for homes’.

Ulmus davidiana var japonica ‘Morton’, a Dutch elm disease-resistant elm.

At this moment in time, tree planting is very fashionable with politicians, both national and local, rather belatedly but commendably recognising that trees provide many benefits and are an essential part of urban infrastructure. However, planting targets are often reduced to promises and commitments based on numbers or percentages such as: “Across the country we will plant 22,000 large trees and 28,000 small trees from Thanet to Middlesbrough and Merseyside to Bristol” (first round of the government’s tree planting challenge 2020), or, “We will increase the capital’s tree canopy cover by 10 per cent by 2050” (Sadiq Khan, London Assembly).

Such initiatives are to be welcomed but it is questionable as to whether successful outcomes will be achieved by numbers and percentages alone. In many instances, the strategic element of tree planting is ignored. Often such targets as those mentioned above, and there are many more of them in the public domain, have no strategic foundation, no vision for the future and are often presented with no clear understanding of what the position is now with regard to the tree population as a whole.

Returning to the consultation document, there is to be welcomed references to biosecurity and the need to source more UK-grown trees. There are several references in the document to building the capacity of the UK nursery industry. The document states: “The UK’s nurseries currently produce over 100 million trees each year for forestry. This seems a lot but the market for planting stock operates across the UK and demand over recent years has usually outstripped supply. A significant capacity is required to meet increasing demands for new woodland creation.” As with much of the document, the emphasis and focus are on woodland creation and forestry. There is no attempt to quantify the size of the market or the demand for the larger trees used on major developments or conventional street tree planting.There is also no quantification as to the number of large trees imported into the UK each year. However, the ambition is implicit, more trees to be UK grown with tree nurseries encouraged to expand their production to meet a growing demand.

Carya illinoinensis, another underused species.

As with planting initiatives, the focus on UK-grown tree stock is to be welcomed and the attention being given to biosecurity commendable, but there are problems associated with this approach.

The consultation does reflect on the inconsistency of annual budgets for tree planting and the fluctuations in demand for tree stock which makes it very difficult for the tree nursery to plan ahead with any certainty. Again, there is a sense that the focus is on forestry and woodland creation where the trees to be planted are at most two years old and not trees for the urban environment, which are invariably 7–10 or more years old when they are planted into the landscape. This means the forward planning necessary for tree nurseries producing large trees is significantly longer, yet the identified problems with fluctuating demand are the same and the range of species that will be available in the market constrained because of similar uncertainties as to likely demand.

Such a background is not conducive to nursery investment in increased production. This barrier to investment is exacerbated by penal biosecurity regulations, particularly those associated with Xylella fastidiosa where an identified outbreak in the locality of the nursery could result in a ban of the shipment of any Xylella-vulnerable material for a period of five years. In many instances, this could lead to nursery closure. This is a regulatory problem.

It is also true that because of the increased demand for large trees stimulated by the current focus on the benefits of trees, mentioned above, there is a real possibility that demand will outstrip current supply capacity in the UK with the result that less UK-grown stock will be used and more imported material will be needed to fill the supply gap. The production plans for trees in the ground and ready for despatch now were drawn up five or more years ago when demand conditions were entirely different.

So, how can this supply and demand be mitigated against and the use of more UK-grown large tree stock be achieved?

One possibility is the production of long-term strategic planting programmes and a reduction in the number of well-meaning and to be welcomed planting initiatives based on numbers and percentage canopy cover increases.

The production of long-term tree planting strategies offers several advantages and the process can be divided into several interrelated and co-dependent elements. These are:

Create a vision: what is wanted based on a thorough understanding of what is there now.

Set targets and goals which are achievable and deliverable.

Create an action plan comprising where to plant, what to plant, how to plant, management and maintenance necessary.

Monitor and review.

It can be argued that such strategising would offer several advantages:

• Allow uniformity and planning.
• A clear vision to be articulated.
• Realistic and achievable goals and targets to be set.
• Suitable and appropriate species to be selected.
• Informed planting techniques to be specified and adhered to.
• Programming of appropriate management and maintenance.
• Progress to be monitored and reviewed.

Such long-term planning could allow sensible and useful dialogue to result between the tree nursery and the tree manager. Both parties would be able to plan ahead, with production geared to meeting both current and future demand. Because of the known planting strategy, contract growing becomes a real possibility. This has the added benefit of perhaps widening the rather narrow species choice available because of the risk involved to the nursery of producing species for which there is no current demand. There is an added benefit in that diversity, considered an important factor in the resilience of the urban tree population to invasive pests and diseases, can be considered and acted upon.

New York City, as part of its MillionTreesNYC initiative, committed to planting 20,000 urban trees every year for 10 years. They achieved this goal. An integral part of this was a comprehensive and prioritised tree planting strategy coupled with extensive dialogue with tree nurseries, agreed specifications and contract growing.

The above is a rather simplistic and sketchy summation of the situation. It does not do justice to the debate and simplifies the nursery position and does not explore fully the advantages of tree planting strategies.

If you would like to know more about evidence-based tree planting strategies, please contact Kenton Rogers at treeconomics kenton@treeconomics.co.uk who has been working with the London Borough of Islington and other authorities on the production of such tree planting strategies. If you would like to discuss nursery production or understand more about contract growing, please contact me at keith@barchamtrees.co.uk.

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