Tree growth and climate change

ADAS' principal consultant, Jon Abbatt, led the study into tree growth and climate change and believes the results confirm the prediction that warmer temperatures and increased rainfall - climatic changes associated with global warming effects the UK - would speed up growth rates.

Climate change is causing tree growth to speed up across the UK. And Utility companies with overhead power lines are looking to adopt new management strategies to prevent faster growing trees causing power cuts for consumers.

This is the key finding from early data collected during a collaborative large-scale study led by environmental consultancy ADAS and five major utility companies.

The study, which began in 2008, is the first of its kind to investigate the effect of climate change on vegetation growth patterns for UK utilities.

The project used forecast climate change data from 2020 and 2050 and current growth rates to predict future growth rates right across the UK. This showed a potentially strong relationship between growth rates and climate with some areas showing a 30 per cent increase in growth rates by 2020.

Ultimately, if climate change predictions materialise as expected, energy utility companies will have to cope with trees growing much faster.

They will need to change their vegetation management strategies to continue to ensure the safety of their networks and the security of electricity supply to consumers.

With this project ADAS is currently providing utilities with vegetation growth rate data for each management area.

The next step is to work with the utilities so they are able to extract this data in a format suitable for their systems, extrapolate the most valuable datasets and trends so they can start to plan their vegetation management programmes for future years.

The study, which involved the National Grid, Central Networks, Electricity North West ltd, Scottish Power and EDF Energy Networks, analysed vegetation growth data collected periodically from 1,665 sites from the South East to the North West of the UK since 2008.

This baseline data was cross referenced against 40 years’ of weather information and climate change forecasts to project growth rates in 2020 and 2050.

Each site had been allocated to one of 21 bioclimatic areas which accounted for variables like sunlight levels, rainfall and soil qualities, meaning the dataset was very robust.

As expected there is a correlation between growth rate and bioclimatic areas.

Sidebar: how the study was carried out

To accurately forecast growth rate, the ADAS research team developed 21 bioclimatic conditions based on an analysis of soil type, temperature and rainfall levels across the UK.

These zones were based on GIS soil information and 40 years’ of meteorological data. By accounting for these factors which remained relatively constant, ADAS was able to isolate temperature and rainfall as the key variables likely to be affected by changes in global temperatures.

Each year at more than 1,600 selected sites on the participating utilities’ networks, the researchers measured the shrinkage of the Utility Space, the area around the overhead line required for safe operation.

This gave a reliable measure of how fast vegetation grew each year. This data, combined with forecast data from the highly regarded United Kingdom Climate Impact Programme was used to predict future growth rates for different bioclimatic regions of the UK in 2020 and 2050.

It’s been a long term, large scale study and we’re incredibly pleased with the dataset. We’ve still got one measurement phase to carry out in October 2010, but the general trend of the results is already firmly established.

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