UK plc faces an annual trade deficit of £5bn for timber and wood products. This is despite a forest cover of over 10%. In Scotland this figure rises to 17%. Annual sawlog output in Scotland is set to double over the next 20 years and most of this production will be Sitka spruce which forms almost two-thirds of the commercial forest area in Scotland. Much of this additional timber, however, will only be suitable for non-structural purposes, such as pallets, packaging and fencing, which could lead to oversupply.

Consequently, successful marketing of Scottish sawn timber is largely dependent on gaining an increased market share from imported timber, so a greater penetration of the construction sector will be necessary. In fact, the issue of the quality of future British-grown sawlog supplies has led to the current situation with the construction industry importing the majority of its timber requirements.

Industry impasse

Concerns over the deterioration in timber quality have largely centred on stem straightness and wood density and, as a result, the national timber and construction industries are heading for an economic impasse if an improvement of the breeding population is not rapidly forthcoming.

Conventional tree breeding programmes require long-term commitment with, for example, Sitka spruce screened for quality traits (such as density) at six to nine years. This represents a huge input of resources, with significant levels of labour and capital investment required even before quality assessment occurs. If the trees could be screened earlier, such as three years, via a “smart screen”, there would be significant economic benefits, such as:

  • the level of input in terms of labour, land-use, chemicals, investment, and machinery would be dramatically reduced;

  • the development of a hand-held device (smart screen) for wood properties would create jobs;

  • the time required to improve Scottish timber per se would be significantly shortened.

Ultimately, this would lead to a reduced reliance on timber imports and support an economically sustainable Scottish timber industry.

SCRI funding

My team, based at the Scottish Crop Research Institute (SCRI), has received funding from the Scottish Enterprise Proof of Concept programme to develop such a smart screen. The technique relies upon the fact that chemical bonds absorb infra red light and the wavelength of the absorbed radiation is specific to the type of bond.

This means that, in theory at least, all the components of wood can be determined following a suitable calibration.

In collaboration with Dr Steve Lee (Forest Research Edinburgh), the team has shown the remarkably accurate predictive ability of the technique with regard to wood density (see diagram), with an almost straight line relationship between measured and predicted values over a wide density range and for more than 25 wood species.

In addition, the technique has been shown to determine confidently the amounts of many diverse major and minor wood components such as cellulose and phenol extractives. Significantly all these parameters and more can be determined at the same time from the same infra red scan. Generally the time for a single infra red analysis is 60 seconds! Obviously the savings in time and money from the commercial application of this technique could be enormous, both in the fields of timber breeding and grading.

Discussions are now taking place between Mylnfield Research Services, the SCRI commercial arm, and electronic companies to commercialise this technology and to develop a hand-held prototype.