TimberFrank

Guys, just looking for opinions on this.

Does 50 cu m sound about right for approx. 60 Sycamore trees? They are fairly mature. I measured all the DBHs and a sample of heights. I'm not sure if that is acceptable, but it might be alright. I worked out the volumes using DBH, heights, and then got the tariff numbers and read off the tables.

Yes, you're right. Must remember that!

 

I'm pretty sure that as a general rule you would round down, fairly certain this applies to log measurements. All of a sudden what I learned at college seems a long time ago.

 

The best rule would seem to be, if in doubt - check the blue book.

Yeah me too - I forget the basics I learned in college too! If it isn't used, it is forgotten.

Thanks for your help.

Pretty sure the usual rule is round down for everything to do with timber measurement, so your 50.7 would be 50. Even on the cusp of 50 and 51 the rule would be round down to 50.

Ah right, thanks. So would that make my previous calculations inaccurate?

(FC Timber Measurement book says, 'In cases where the zero point [of the DBH measuring tape] falls on the dividing line between two diameter classes, the higher diameter class should be used.') But that is for a tape which is marked in rounded down 1cm diameter classes...

So it seems the diameter class is what is actually recorded from the dbh field measurement? That's news to me! I didn't realise that you rounded down.

Is a rounded down 1cm diameter class tape the same as a standard dbh tape except it hasn't got the divisions?

When measuring dbh and when consulting FC charts to work out volume etc..., do you use whole numbers for dbh or do you use decimal places? How precise are you supposed to be or does it not matter? What's the usual way of measuring it and using it for calculations?

The reason I ask is cos I was recording it with decimal places (like say 50.7cm) and then consulting various charts, for example the tariff number alignment chart in the blue book, and instead of setting the ruler at 50, I placed it at what I estimated was 50.7. I now think that might have been erroneous?

Oh right, thanks.

Here's the context:

Wet woodland occurs on poorly drained and waterlogged soils, and is widespread across Northern Ireland. The habitat occurs on a range of substrates, from acid to base-rich and from peaty to mineral soils. It is found on the margins of water bodies along lowland and upland streams, on hill-side flushes and as successional habitat on fens and bogs.

I got a copy of the new edition of TIMBER MEASUREMENT.

It offers a simple procedure to estimate the volume of a stand from basal area and form height. It says that '[T]his method should be sued when an estimate of total volume alone is sufficient, when doing an inventory, or for stands of low value.'

Would this be good enough for measuring a stand of fairly crappy sycamore and ash, or would an abbreviated tariff be much more accurate?

An abbreviated tariff may be beyond my competence. I feel confident about doing the volume estimation using basal area and form height.

Do you think the basal area/form height method would be pretty satisfactory for an estimate of standing timber for sale as firewood?

no not really.........do u know how to work ut the volume of a standing tree.......hectare 2.5 acres .....measure all the trees to fell.......why u worrying about the trees not to fell?

Not really. I have the blue book here but it wreaks my head.

Folks, this is my basic problem:

Having looked at the blue book, I am even more confused about timber measurement than I was at university over 4 years ago. I've been asked to measure a small compartment of broadleaves with a view to offering the standing timber for sale as firewood. The compartment is about a hectare or so, and is comprised mostly of low quality sycamore, with some ash, oak, and holly scattered throughout. They want to sell the sycamore (and a couple of beech and horse chestnut) for timber, but retain the native broadleaves... They need an idea of the volume of timber for sale. Now I just don't know how this can be done, and in such a variable, low grade stand, and not only that, but a stand where some of the trees are to be retained. It seems to me like a mensurational nightmare!

I had a look at the blue book and I am now ready to tear my hair out.

Is it the case that it is not reasonable to expect anybody to be able to work out a standing volume of timber in this sort of case?

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!

bumpity bump

The problem is, not all the trees are eligible to be cut. Most are. All the sycamore is to be removed, but oak and ash are to be retained. So I am at a loss as to how to measure the stand so that a volume can be provided for potential buyers.

What will be left is a fairly open area with some scattered trees.

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.

I was wondering what is the best way to measure a broadleaved compartment? The wood is fairly low quality and is to be used as firewood. The idea is that the compartment is measured (accurately) and then the standing timber is offered for sale.

I am not sure what the best way to measure it would be. I haven't access to the blue book so I can't refer to that right now, but there is one slight complication: the standing wood to be sold is sycamore, but within it there are some native broadleaved trees like ash and oak which are to be retained. I guess that means that an inventory or tariff would not be accurate.

Also, if anyone can give any insights into the issues surrounding firewood and harvesting and the factors which affect whether or not a parcel of timber would be sell-able (for firewood for example), and how you might decide if timber is worth harvesting or not.

We need to come up with some basic guidelines to help folks decide if an area of timber is viable to be sold for standing timber and also how you would measure it as accurately and simply as possible.

Thanks so much guys! Much appreciated. :-)

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

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.]