Calculating DBH of Birch Tree

[mramella]

Hi, I am hoping someone can help me out. I am trying to calculate the DBH for this birch tree. My questions are:
1 - Is this a multi-stemmed Birch tree? Or is this two birch trees that grew together?
2 - Based on 1 , how do I calculate the DBH?

Thanks,
M

 

[ATH]

There are various guidelines to get there. Not to sound elusive, but I'd ask what is your reason for needing DBH - then that will help get the best answer.

For example, I'd probably look at it differently for an appraisal, big tree nomination, timber volume calculation (assume that is not the case here!), and treatment (certain pesticides and growth regulators are applied based on DBH...I'd not only look at actual DNH, but also canopy volume for those...does the diameter make sense for the canopy volume?)

 

[mramella]

There are various guidelines to get there. Not to sound elusive, but I'd ask what is your reason for needing DBH - then that will help get the best answer.

For example, I'd probably look at it differently for an appraisal, big tree nomination, timber volume calculation (assume that is not the case here!), and treatment (certain pesticides and growth regulators are applied based on DBH...I'd not only look at actual DNH, but also canopy volume for those...does the diameter make sense for the canopy volume?)

Thanks,
Trying to identify DBH so that I can determine the tree protection zone needed to identify on survey.

 

[ATH]

I would do DBH of the bigger of the 2 trunks and use that for the tree protection zone. No, that is not "accurate" for the other things I mentioned...but I think that will give you a realistic expectation of the root spread (well, what it would be IF they had room to spread).

 

[Del_]

I agree with ATH for the most part but I'll play the contrarian.

Due to location I bet that was a seedling that came up on its own. Looks like two separate trees fused together. It may be one tree that was cut off at the ground when a small sapling and then two sprouts survived or were selected. Birch in the nursery are often cut at ground level and then several sprouts are selected to make for the multiple stemmed birches we see planted in the landscape.

I'd be temped to measure around both stems to get DBH. It looks like it may be hard to measure a single stem as they look grown together at breast high.

 

[ATH]

Wrapping a tape around both trees would certainly give you a better protection zone. Agree, that you couldn't get a tape around one trunk alone. I would measure just above where they joined together with the diameter tape and then I would use a Biltmore stick to measure DBH on the bigger stem and use those two numbers to come up with my really darn close estimate... rounding up.

 

[Woody912]

I agree with ATH for the most part but I'll play the contrarian.

Due to location I bet that was a seedling that came up on its own. Looks like two separate trees fused together. It may be one tree that was cut off at the ground when a small sapling and then two sprouts survived or were selected. Birch in the nursery are often cut at ground level and then several sprouts are selected to make for the multiple stemmed birches we see planted in the landscape.

I'd be temped to measure around both stems to get DBH. It looks like it may be hard to measure a single stem as they look grown together at breast high.

wrap a tape around both stems, divide by 6.28 and call it good!

 

[jefflovstrom]

wrap a tape around both stems, divide by 6.28 and call it good!

Or buy a DBH tape, I carry one in my truck all the time.
Jeff

 

[ATH]

Or buy a DBH tape, I carry one in my truck all the time.
Jeff

Just one?

 

[jefflovstrom]

Just one?

lol, yeah
Jeff