Help! Suunto Clinometer

[TimberFrank]

I need an idiot's guide to how to use a Suunto optical clinomoeter to measure the height of a tree. I did this years ago at university but haven't used one since and I completely forget. I found a couple of PDF guides on the internet but each says something different and are not necessarily based on the Suunto clinometer commonly used in the UK.

 

The one I have at work (and which I must learn to use asap) is a Suunto and it has 2 scales through the little viewing window and there is also a little card in the box with 4 charts with scale lines. I don't know what that's for to be honest.

 

If someone can tell me how to use the device to measure a tree and what that little chart is for, I would be eternally grateful!

 

[The device at work is like this one but it doesn't have the little black knob.]

[TimberFrank]

Bump! I need to know how to do this for tomorrow! Please, anyone help?!

[treedave]

If its like mine it goes like this.

Stand a known distance from the tree-10 m in this eg.

Then looking through the device so the line hits base of tree, note the number on right scale (-10 in this case). Then sight the top of the tree, ( 100 on scale in this case).

This then gives you a total of 110. This is a % of the distance from the tree ie 110% of 10 m= 11 m

 

It's a bit odd that the -ve number at start is an added to the last reading but it works!

[bunnybasher100]

The two scales are degrees and percent use the percentage scales as its easier to work out. Simple to use, stand a known distance say 20meters away from the tree look through the sunto and take the reading at timber height or what height you want to measure say 80% then take another reading to base at ground level say take this reading say 10%. Add them both 90% so that makes the measurement 18m. This is for level ground.

[TimberFrank]

Thanks so much guys! Much appreciated. :-)

[TimberFrank]

I was wondering about how to use the Suunto clinometer on slopes.

 

There is a little chart inside the box with an incomprehensible Finnish sketch of a stickman looking through the clinometer at a tree from a distance of 20m on a slope.

 

Two of the charts feature a scale with downhill, uphill, and base reading labels in %, and two meter scales with apparent and corrected height.

 

On the other side of the card, there are two similar diagrams, with a stickman looking through the clinometer up a slope towards a tree, and rather than 20m, the distance is marked with a minus symbol. The little scale on the left is Ground slope degrees, and there are two meter scales, corrected height and apparent height.

 

So I now know how to measure a tree height on level ground, it would be most useful to be able to take measurements on sloping ground.

[TimberFrank]

bumpity bump

[morten]

I was wondering about how to use the Suunto clinometer on slopes.

 

...

 

The instructions above does work on (moderate) slopes as well.

 

If you measure the % to the base of the tree, as well as the top of the tree, you should subtract the two, and the result is the tree height in % of your current horisontal distance to the tree.

 

Three examples:

 

1. Level ground

 

Tree top: 80%

Tree base: -7% (downwards)

Distance to tree: 20 m (can be measured along the ground)

 

Tree height: 80% - (-7%) = 87% * 20m = 17,4m

 

2. Slope (up)

 

Tree top: 96%

Tree base: 9% (upwards)

Distance to tree: 20 m (you need to estimate the horisontal distance to the tree)

 

Tree height: 96% - 9% = 87% * 20m = 17,4m

 

3. Slope (down)

 

Tree top: 67%

Tree base: -20% (downwards)

Distance to tree: 20m (you need to estimate the horisontal distance to the tree)

 

Tree height: 67% - (-20%) = 87% * 20m = 17,4m

 

 

 

The most accurate reading is obtained when the top reading is about 100%, i.e. the distance to the tree is similar to the tree height.

 

Does that all make sense?

Edited March 15, 2012 by morten

[TimberFrank]

The instructions above does work on (moderate) slopes as well.

 

If you measure the % to the base of the tree, as well as the top of the tree, you should subtract the two, and the result is the tree height in % of your current horisontal distance to the tree.

 

Three examples:

 

1. Level ground

 

Tree top: 80%

Tree base: -7% (downwards)

Distance to tree: 20 m (can be measured along the ground)

 

Tree height: 80% - (-7%) = 87% * 20m = 17,4m

 

2. Slope (up)

 

Tree top: 96%

Tree base: 9% (upwards)

Distance to tree: 20 m (you need to estimate the horisontal distance to the tree)

 

Tree height: 96% - 9% = 87% * 20m = 17,4m

 

3. Slope (down)

 

Tree top: 67%

Tree base: -20% (downwards)

Distance to tree: 20m (you need to estimate the horisontal distance to the tree)

 

Tree height: 67% - (-20%) = 87% * 20m = 17,4m

 

 

 

The most accurate reading is obtained when the top reading is about 100%, i.e. the distance to the tree is similar to the tree height.

 

Does that all make sense?

 

Yes - thanks very much!

[AlexB]

Save your pennies, but a vertex!