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Calling all volunteers: updating the Arboretum’s 2014 Tree Survey

  • by JW

“We will be carrying out a repeat survey next year to assess how the treescape has changed. Would you like to be one of our volunteers tree counters?” [Sidmouth Arboretum]


The Sidmouth Arboretum embarked on a huge project a decade ago – and would like to update it:

In 2014, the Arboretum volunteers teamed up with iTree and Treeconomics to carry out a survey of the valley’s trees. Using a computer generated sample of 200 circular plots, volunteers collected data on all the trees within the 7m circles, including which tree species were present and how big the trees were, girth and height.  The sample data was then sent off to the US Forestry Department for analysis.

It turned out that our valley was home to just over 400,000 trees in 2014, with nearly a quarter of the valley under tree canopy.  The three main species were the commercial plantations of Douglas Fir and Larch with Ash as the most common native broadleaf tree.  It was noted that, even in 2014, the Larch and Ash trees were under threat from two new diseases, Phytophthora and Ash Dieback.  In 2023, most of the Larch plantations have been removed and significant numbers of the Ash trees have been felled.

We plan to repeat the survey in 2024.  If you would like to be involved, please get in touch via

A summary report on the survey can be seen if you click Tree Report v6

Back in 2014, the Arboretum found a host of volunteers to help in the survey – including Sidmouth students trained to ID trees for the survey.

The survey was clearly very impressive – to the extent that it has been referenced in a report on urban forests from London, as well as the wider forestry community, with a handy summary of the 2014 report available.

Now the Arboretum is looking to update the research – and is looking for volunteers to help in that work:


Sidmouth Arboretum carried out a survey of the valley’s treescape in 2014, you can see a copy of the report on our website. In 2014 there were about 400,000 trees in the valley but there have been major events in the world of trees over the last ten years and we will be carrying out a repeat survey next year to assess how the treescape has changed. Would you like to be one of our volunteers tree counters?

We didn’t count all 400,000 trees, the survey involves a sample of 200 computer selected plots around the valley, each an eleven metre circle. Groups of volunteers visit the plots and record any trees they find, some plots have no trees but they are still recorded. All the collected data is then analysed for us by iTree and Treeconomics to tell the story of our treescape in numbers.

The volunteers get plenty of help to identify and measure the trees. If you would like to be part of this interesting and important project, or even just interested to find out about it, then come along to the Amyatt Room in Kennaway House on Wednesday morning 4th October at 10.30. If you can’t make the meeting but are still interested please contact us on