How many conservation volunteers does it take to measure a tree? Part 3

2013/03/13

Aim:

You may recall our seemingly endless quest to measure the height of a sequoiadendron tree in Scone Palace's stately pinetum. To recap, our sadly-missed friend Colin McLean had set us the task of calculating the height and girth of this magnificent specimen plant to mark its 150th birthday. He had chosen this tree because he had recorded the same measurements in 1970 while working at the palace for the Forestry Commission.

While girth was easily checked, our first attempt at height was foiled by Sarah McC measuring the wrong tree. We tried again in the summer - this time our methods gave widely differing results. So could we finally nail the job?

Methodology:

Previously this had involved lying on the ground in the mud, holding various sticks aloft and much pacing, stroking of chins and solemnly striding out with industrial tape measures. But this time we had technology on our side - Greg M had downloaded a clinometer onto his iPad.

This allowed us to note the angle from his eye to the treetop and use trigonometry (remember that?) to measure the tree's height. Twenty minutes later we were done - simple!

Greg at work. (credit: Sarah McConachie )

Greg at work. (credit: Sarah McConachie )

Extract from Greg Milne's detailed field notes. Clinometer or extraordinary trigonometrical-nasal-beam superpowers? (credit: Greg Milne)

Extract from Greg Milne's detailed field notes. Clinometer or extraordinary trigonometrical-nasal-beam superpowers? (credit: Greg Milne)

Results:

Year Girth Height
1970 8m 13cm 35m
2012 10m 29cm 41m - Sarah McC's muddy puddle method
54m - Colin's method, performed by Greg
2013 54.7m - clinometer method, performed by Greg
Mark measures while Tim, Maddy and Greg supervise. (credit: Sarah McConachie)

Mark measures while Tim, Maddy and Greg supervise. (credit: Sarah McConachie)

Conclusions

Since 1970 our tree has increased by approximately 2m 16cm in girth and 19m in height.

It takes eleven conservation volunteers (Greg M, Christine, Keith, Tim, Maddy, Willie, Ken, Sarah H, Mark, Nicola M and Sarah McC), two sticks, one measuring tape, one iPad, lots of concentration, quite a bit of skyward pointing, some bloody-minded perseverance, one calculator and several chocolate biscuits to measure a tree.

This study was limited by Sarah McConachie's questionable abilities as a field researcher. Her grant funding has been duly withdrawn.

Conflicts of interest

None declared