Tree Height to Crown Diameter Ratio

[10 Bears]

Its been a while since I have been on here due to a significant workload ATM, but I'm here asking for help from my fellow AT'ers.

 

I've had no luck finding a suitable reference for a tree height to crown diameter ratio. I know this exists as I recall reading it in the distant past, but I just cannot track it down.

 

Even a rule of thumb example can be worked with, something like:

 

Given the measured height of (h), crown diameter (cd) will be n or h:cd = n

 

Does anyone in AT land recall such a ratio, and could be a great help and direct me to a citation/paper/book?

 

Many thanks.

[kevinjohnsonmbe]

Wouldn't that be entirely species dependant or am I misunderstanding the question??

[10 Bears]

Hello Kevin,

 

Yes, there would be inter-species differences, but as I recall there was a general ratio that could be applied to broadleaf as a general rule of thumb - I just can't find the citation...

 

I should have clarified earlier, it is a broadleaf ratio I was looking for.

[sloth]

And open grown trees presumably, not that I have ever come across such a rule of thumb ratio.

Why do you need to know, out of interest? Or tell me to wind my neck in!

[10 Bears]

No neck winding needed.

 

The position of the tree would be a factor in the real world, but when dealing with a model, or ratio like this, then some assumptions are always made such as having idealised maiden tree growth.

 

Well, Sloth, I am working on some research (hence not being on here too regularly ATM as I cant spare the distraction) where I am modelling tree locations from an observed (measured) position, and where my model would predict them to be as another dataset. Understanding the probable crown size, given a certain height, would help me use the predicted crown size as a filter, hopefully leading to a good match between the measured data and the predicted data.

 

I'm sure that paragraph doesn't make a lot of sense, but in a nutshell, that's what this ratio is for!

[Mark Bolam]

The crown diameter v. height ratio increases dramatically as you approach areas where Joe Newton and Stephen Blair have been working.

 

 

Sent from my iPhone using Arbtalk

[Cedar84]

It's used a lot in continuous cover forestry in regards to stability etc- try looking for some FC information notes or the continuous cover forestry group for further information.

[sloth]

Ah, I see, that does make sense (I think). Could you not take some site/species specific ratios as a benchmark to estimate the remainder?

[daltontrees]

No neck winding needed.

 

The position of the tree would be a factor in the real world, but when dealing with a model, or ratio like this, then some assumptions are always made such as having idealised maiden tree growth.

 

Well, Sloth, I am working on some research (hence not being on here too regularly ATM as I cant spare the distraction) where I am modelling tree locations from an observed (measured) position, and where my model would predict them to be as another dataset. Understanding the probable crown size, given a certain height, would help me use the predicted crown size as a filter, hopefully leading to a good match between the measured data and the predicted data.

 

I'm sure that paragraph doesn't make a lot of sense, but in a nutshell, that's what this ratio is for!

 

How about you take all your survey data ever in spreadsheet form, and calculate the average ratio from that? Oddly I would have no bother doing this as I have never cleared out survey data from my handheld, it would take me about 5 minutes to come up with a figure in Excel. Or use your own data more selectively, from surveys that you know were mainly maiden open grown mature trees?

 

It's gopt to be impossible to generalise. The ratio for any tree is partly a manifestation of apical dominance, but there will be factors of maturity, species, variety, competition, exposure.

 

For example during the week I took down a Norway Spruce, in a windy, alluvial coastal situation. 42 years old from the ring count, spread at the base 12 metres, and conical from there, height 12 metres. The week before another Norway, sheltered by other giants in a garden, on clays, 28 years old spread 14 metres most of the way up, height 24 metres.

 

Or is there something in this that might point you in the right direction? https://www.sorbus-intl.co.uk/hi-tech/survey-equipment/traditional-survey-equipment/iml-multi-tool

[mdvaden]

It seems inconsequential.