Forest Research scientists visit the OneOak tree

posted on September 9, 2009
Forest Research scientists measure the OneOak tree

Forest Research scientists measure the OneOak tree

Matt and Ian from Forest Research visited the tree today. They work with the government research agency as scientists specialising in tree measuring or ‘mensuration’.

Matt brought along a hemispherical camera – basically a normal camera fitted with a fisheye lens. A fisheye produces a picture that takes in an amazing 180 degrees field of view. We will be posting some the images that were taken with the fisheye on the website soon. Images taken looking up at the canopy will be analysed with special software that will calculate the leaf area index – effectively a measure of how much sky is visible between the leaves. This will be used to calculate the biomass of the tree.

Ian used some other equipment to measure tree height, timber height, crown width and stem diameter. Below is a picture of Ian using a hypsometer – this uses pythagoras to calculate (from a known distance from the tree + the the angle to the top of the tree) the total height of the tree. Look carefully at the photograph and you can see the distance to the tree is 36.3m. The tree measurements below it are the three different angle readings to the top of the tree. These will average at about 22.6m. However, after more readings from all directions, the final height of the tree has been estimated to be 23.9m.

We had estimated that the tree was 17.5m. We now know that we were quite inaccurate (or it grew 5+ metres in one year!). We look forward to receiving the detailed results from our friends at Forest Research, and will post them here in the OneOak blog, and on the web pages when available. You can read more on our Tree Facts & Figures page.

A hypsometer is use to measure tree height

A hypsometer being used to measure tree height

Our thanks to Ian and Matt and to Forest Research.


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