Land managers and owners across Scotland should put in place management strategies to tackle a virulent tree disease which could significantly reduce timber yield and cause serious physical and economic damage to their conifer forests, says land agency firm Strutt & Parker.
Dothistroma (red band) needle blight (DNB) is a serious disease spreading through the UK’s pine woodlands causing premature needle loss, reduction in timber yield and, in severe cases, tree death.
Cases have increased dramatically in the past 10 years, particularly amongst Corsican pine, lodgepole pine and, more recently, Scots pine. It is particularly prevalent in Moray, Aberdeenshire and the North Highlands.
It is present in all 10 Forestry Commission Districts in Scotland and 46% of infections on the national forest estate in 2011 affected Scots pine.
Alastair Macmillan, forestry specialist in Strutt & Parker’s Inverness office, said: “Forestry Commission Scotland (FCS) has indicated that DNB is now endemic in Scotland and although we can never get rid of it, careful management of the disease can help lessen its negative impact on the health of our forests - and the quality and quantity of our timber.
“High levels of spring and summer rainfall, and the availability of suitable host tree species, are factors which have helped the disease to spread – and infected plants may also have initially arrived through the plant trade. Infected needles on footwear, clothing, machinery and timber can also potentially spread the disease but the risk is low.”
He added: “The Forestry Commission no longer plants Corsican pine - and currently there is also a moratorium on planting lodgepole pine on the national forest estate in Scotland until the relative susceptibility of various ‘origins’ is better understood. Scots pine now also appears to be more susceptible than first anticipated and the FCS has placed some restrictions on where it plants Scots pine.
“Sitka spruce, Norway spruce and Douglas fir can also become infected but these, and other non-pine conifers, currently appear to have low susceptibility.”
Needle blight cannot be eradicated from the UK so the challenge lies in working out how to live with it, said Mr Macmillan. “It is very important to put in place strategies which will reduce the impact of needle blight - and the FCS is very clear that now is the time for action if we are to prevent significant damage to our native pinewoods, support the future of Scottish forestry and minimise the economic impact of needle blight.”
Those working in Scotland’s forests need to look out for the signs of infection - typically yellow and tan spots and bands on needles, which soon turn red. The needle ends turn reddish-brown while the needle base remains green. It is most obvious in June and July, after which the infected needles are lost and trees develop a typical ‘lion’s tail’ appearance.
Mr Macmillan said: “FCS interim guidance is to be vigilant, take precautionary measures and act soon and widely to counter the disease. There is no quick fix for this. It is a long-term problem but the good news is that there are actions we can take to lessen the impact of this disease and help make our future forests stronger and more resilient.”
The FCS has established a forest tree nursery transition scheme which provides support for forest tree nurseries infected with DNB in 2011/12 and, subject to circumstances, 2012/13. Support will be conditional on their setting out and implementing a robust DNB resilience action plan.