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Push me, pull you

Author:  Keith Sacre
Last Updated:  17/03/2020

Conflicts of supply and demand

Author: Keith Sacre, Barcham Trees

It appears to have become fashionable to focus on the planting of trees. Politicians at both a national and local level are increasingly supporting and implementing policies to encourage more tree planting across the UK.

Ambitious goals are catapulted into the public domain, often without any sound basis. Focus is on increasing canopy cover dramatically and the planting of huge numbers of trees. These goals are often set against ambitious and potentially unachievable timescales plucked from the ether without any evidence to say whether they are achievable or not. The recognition of trees and the benefits they provide and the increased focus on planting more are to be welcomed and are long overdue, but simultaneously there is an increasing awareness about the importance of biosecurity and the threats to our tree populations from imported pests and diseases. The injudicious planting of imported tree stock direct into the indigenous landscape has led to the spread of pests such as oak processionary moth and contributed to the almost universal presence of ash dieback in the UK. There is also an increased awareness of the need to diversify our tree populations to increase resilience, not only in the face of increased threats from imported pests and diseases but also because of the ramifications of climate change, many of which are yet unknown. Coupled with this increased awareness of the importance of biosecurity there is an increased focus on the need for home-grown trees.

From the above scenario a whole series of contradictions arise. Where contradictions arise against a negative background it is easy to be critical but in the current situation, where there is an increased awareness and demand for tree planting, an awareness of the importance of biosecurity and political support for increasing canopy cover, it is more difficult. All three positions are interlinked, essentially positive and to be welcomed. Yet there has to be some degree of realism and pragmatism if ambitious goals are to be met.

Demand, supply and biosecurity

Tree nurseries cannot produce overnight large numbers of additional trees to satisfy the increased demand. It takes between five and seven years for a tree to reach the minimum 10–12cm girth size considered suitable for planting in the urban landscape. The numbers of trees available now and the species mix grown on UK nurseries were calculated five to seven years ago and based on market conditions at the time. Tree nurseries adjust their planting figures annually based on speculative predictive forecasting, anticipating what the market conditions and demands are likely to be at the time the trees in question will be ready for sale. The same analysis applies to the species to be grown, with a focus on a historic knowledge of which trees are likely to sell irrespective of market conditions. This is a very narrow palette. Market conditions five to seven years ago were very different from what they are now – where the focus is on planting more and more trees particularly in urban areas.

It can take nine years for trees raised from seed to reach a saleable size.

It can take nine years for trees raised from seed to reach a saleable size.

The government’s welcome initiative and commitment to plant an additional 100,000 new urban trees over a two-year period, which commences this planting season through the Urban Tree Challenge Fund, coupled with initiatives from many local authorities and other landowners, has resulted in a position where demand is now beginning to exceed supply in terms of what the UK industry can sensibly offer. From this it is obvious that the deficit, if the ambitious planting plans are to be achieved, must be met from somewhere and this inevitably increases the pressure to import trees with a subsequent increased risk of importing pest and/or disease. The European market is equally stressed as the increased demand is not limited to the UK alone. Similar planting initiatives are being implemented across Europe and further afield. The Dutch tree nursery market exported close on 100,000 trees to China in 2019 and for the previous couple of years.

The work of Defra (Department for Environment, Food and Rural Affairs), the Forestry Commission and others in recent years with regard to the biosecurity of the UK’s tree population has been commendable. There is a likelihood of a biosecurity accreditation scheme in the coming months, which should increase awareness, strengthen the position of those who specify trees and make it possible for the judicious to ensure bio-secure pathways into the UK. This will of course not regulate the maverick or the private individual bringing a few plants back from the continent in the boot of their car with the inherent accompanying risk of diseases such as Xylella travelling as well. Essentially, regulation and accreditation are still going to be defined by the action of individuals and their integrity. A shortage in the number of trees available from UK nurseries caused by a sudden increase in demand fuelled by policy decisions, no matter how well meaning and justified, is only likely to increase the likelihood of these scenarios occurring in the future.

The risks of investment

There is also an increasing focus on raising the production of UK tree nurseries with the question being asked ‘How can UK tree nurseries be encouraged to invest and grow more?’ Again, there are contradictions within a wholly positive scenario. The threat from Xylella has been well publicised and the response from Defra has been commendable, but as control measures currently stand, an outbreak within 5km of a major nursery will result in that nursery not being able to ship any Xylella-susceptible trees for a period of five years. Given the range of hosts, this control measure could come close to – and may in fact result in – closing some nurseries down if it is ever implemented. This measure applies irrespective of the biosecurity protocols of the nursery in question and is implemented through circumstances entirely beyond the nursery’s means to control. Such a measure does not create a background scenario conducive to investment.

It is perfectly reasonable for government through Defra to take decisions which stop the movement of a specific genus when there is a real and proven biosecurity threat, as was the case with ash dieback. Yet such a ban has a huge impact on the nursery industry with huge losses incurred with no compensation available. For example, at Barcham we had to cull 6,000 extra heavy standard and semi-mature ash trees with a wholesale value of £450,000. Ironically this stock had been inspected by Defra (at a cost to Barcham), and passed as clean from infection, a few weeks before it had to be destroyed because of the ban on movement. Again, hardly a background scenario likely to encourage investment and increased production.

Investment in increased production, by definition, implies increased nursery inventories. At Barcham we have over 200,000 trees in production at any one time. Traders and plant brokers create huge biosecurity risks by virtue of how they operate with plants imported and planted, often directly into the UK landscape. This is with little risk to themselves as they hold only small inventories. Again, this is hardly conducive to investment.

All the above, coupled with fluctuating demand, are deterrents to investment at a time when investment by the tree nursery industry is being encouraged. Fluctuating demand is a continuous and ever-present problem. As I have already stated, the lead time from seed/cutting through to saleable tree can be five, seven or even nine years dependent on species. Tree numbers calculated now when demand is high may be totally irrelevant when the trees become available for sale. Investment can be wasted if demand is low.

At this moment in time it would seem that we are entering one of the recurring bubbles of political and social conscience where a course of action is deemed to be the right one and there is a burst of frenetic and spontaneous activity within a defined timescale. Consequently, demand is high.

Nursery production of trees is planned seven to nine years before the trees go to market, by which time market conditions may have totally changed.

Nursery production of trees is planned seven to nine years before the trees go to market, by which time market conditions may have totally changed.

We need long-term, strategic planning

The number of ambitious targets being released into the public domain by politicians of both central and local government, and others spuriously claiming that canopy cover will be increased by a certain percentage within a given number of years, combined with the claims that a certain number of trees will be planted within a two- or three-year period (currently in the millions and going up), are increasing almost daily.

Yet most of these targets – and I am not saying their inspiration is wrong – are ill-considered and often unachievable. Tree population management is strategic and needs to be considered over a longer period: 20, 30, 40 years or even longer. There needs to be a vision. What is the long-term objective of all this accelerated increased planting of trees? There is little evidence that strategic goals have been considered in any of the initiatives which have so far emerged into the public domain. Are trees being planted to increase the level of ecosystem services provided within any given geographical area? Is the intention to improve well-being and physical condition through the provision of more environmentally sound places where people live work and play? Or do the statements just provide a short-term visible political response to the enhanced environmental awareness in the general population?

Yet there is no excuse for spurious goals and targets. The methodology exists to provide the foundation for the emergence of long-term strategic management plans for our urban forests. i-Tree Eco enables the assessment of the urban forest: its condition, composition, value, the benefits it provides, and its vulnerability to attack by any pest or disease can be assessed. Existing tree inventories can be easily converted to yield valuable management information providing an answer to the core question in any management scenario, ‘What have we got?’ This leads to an assessment of ‘where we want to be’ and a management and investment plan as to ‘how we get there’. Inevitably tree planting will be part of any long-term management plan, but such planting can be rational and considered, geared to achieving long-term goals and targets. As a result, it is possible to envisage tree planting being carried out to achieve identified goals over time, resulting in a consistency of demand and a background where nursery investment can be viable. (See www.treeconomics.co.uk for more detailed information.) The eradication of ‘planting bubbles’ through strategic management will also reduce the need for imports and therefore improve the UK’s biosecurity.

How can these apparent contradictions be reconciled?

It is right that biosecurity remains central to both local and political policymakers; it is right that Defra, the Forestry Commission and others continue to advise and where appropriate regulate. An accreditation scheme for nurseries and other players within a complex supply chain is also a positive move and should be supported when it emerges. It is right that individuals recognise and accept personal responsibility for their own actions when purchasing trees. It is right that no imported tree should be planted into the UK landscape without first spending at least one full growing season on a UK nursery where full precautionary biosecurity measures can be implemented.

Alongside this, it is right that the number of trees planted, particularly in our urban environments, continues to increase, and it is right to support national and local policy and funding initiatives which make this possible, but – and this is the big but – if this acceleration in planting is to be sustained and more trees are to be supplied by UK nurseries, either grown in the UK or imported and effectively quarantined for a growing season, there has to be action which reconciles supply with demand.

However, the reconciliation between the need for more planting of trees and the need for improved biosecurity will be encouraged if long-term strategic planning becomes a feature of the way the urban forest is managed. With strategic planning, it is possible that funding streams for new planting, will be continuous rather than subjected to a rollercoaster which rises and falls from plenty to nothing on a continuous basis. With a constant stream of funding, and resource allocation strategically planned, demand streams can be rationalised and therefore long-term consultation with the nursery industry becomes a possibility – to enable supply to be managed to meet demand.

This article was taken form Issue 188 Spring 2020 of the ARB Magazine, which is available to view free to members by simply logging in to the website and viewing your profile area.