wood strength for climbing

[briscoe]

is there a table or calculation you can use to find the breaking strain/strength of green wood?

[Marc]

is there a table or calculation you can use to find the breaking strain/strength of green wood?

 

In what context do you need to know? I imagine there will also be some variation depending on time of year, growing conditions, amount of sunlight etc etc, so you would need a lot of data to get a good reliable mean figure for each species.

[BenR]

and the direction of load! Pulling sideways or along the strong axis of the wood?

[Marc]

and the direction of load! Pulling sideways or along the strong axis of the wood?

 

Yep that to, although are there not fractometers? Used to ascertain the strength of wood, this is something I know little about. Was hoping someone else would comment on that.

[BenR]

Would be really interested to see some tests and results on this subject. A truly scientific experiment would be cool.

[treewizard]

oak:thumbup1:

 

willow:thumbdown:

 

 

sorted

[BenR]

i guess there are different kinds of "strength" though willow must be pretty strong in some ways to hold big ass pieces on the hinge when you want them to pop off!!!!

[coleman]

Yep that to, although are there not fractometers? Used to ascertain the strength of wood, this is something I know little about. Was hoping someone else would comment on that.

 

Fractometers only measure 2cm bored out samples at a time and is used more for decay detection so it may gie you a rough idea but wont measure how a bigger bit or branch reacts as a whole or take biomechanic features into account. A tirfor linked up to a neuton meter would be loads more fun:thumbup:

[briscoe]

I imagine someone has calculated the average breaking strain for a certain diameter of each species. (for example green oak of x diameter loaded in the middle of a one meter span would require on average x Newtons of force to fail). I seem to remember that there is average data somewhere based on fractometer data

 

I guess we are generally anchoring into the branch collar where I imagine the breaking strain is huge for most healthy trees.

[Pete Bannister]

Hi biscoe,

Good question; but 'No' is the simple answer.

There's a huge amount of information on the mechanical properties of timber (because its such an important construction material for us humans). However, the variations in the properties of living wood are far too great to allow for meaningful simplification. Fractometers are generally used with reference to ‘pole’ structures or the stem of a tree. The data from fractometers is very limited and cant be safely applied to estimate the strength of a limb connection to a stem, for example

cheers Pete