Form Class (was -Re: Robinson State Park)
  Nov 29, 2006 07:59 PST 

The tulips sound like they are decent trees.

Do you have any indication of the actual form class of the trees in terms of

For hemlock a form class of 67 is common for some of the ice cream cone
tapered trees of New England but in WV a form class of 78 to 80 is common.

For poplar in these parts young trees are figured in FC 80-82 with high
quality large diameter, tall older trees close to a FC of 84 to 86.

Re: Robinson State Park   Gary A. Beluzo
  Nov 29, 2006 09:42 PST 

Oh, okay, the Form Class is just the diameter inside the bark up at 16 feet
divided by the DBH *100. One problem though, you need to cut the tree down
and strip off the bark to do it! :-) Do you know of a similar ECOLOGICAL
measurement(s) on the live tree? Maybe with the RDL 1000 or similar device
one can get a good estimate of the Diameter at 16 feet (with the bark on of

Re: Robinson State Park
  Nov 29, 2006 15:13 PST 

The US Forest Service developed the volume charts years ago and they are
currently getting reprinted by the USDA.

From the definition of form class in the book this is how it is defined...

"Form class is the percentage ratio between the diameter inside the bark at
the top of the first 16' log and the diameter outside the bark at DBH (4 1/2
feet above the ground) For example, a tree with a first log scaling diameter
16" and a DBH of 20" the tree has a form class of (16/20 X 100) 80

The title of the book is "Tables for Estimating Board-Foot Volume of Timber"

Last I knew it was available through some of the forestry supply companies
and the USFS has a stock number of 001-001-00024-8/Catalog number A 13.2:T

I hope this helps.

Re: Robinson State Park
  Nov 29, 2006 15:38 PST 

Most of the time, I think it is generally assumed that as foresters we are
looking at the actual taper of a standing tree.   For the purposes of ENTS
types of measurements I think it would be appropriate for the measurements at
both points outside the bark.

In certain types of trees with large buttressed bases I think that form
class measurements could prove meaningless.   However, I find it extremely useful
in dealing with forest trees.

The booklet I mention has standing tree volume tables in three forms,
International 1/4" log rule, Doyle Log Rule and Scribner Decimal C Log Rule. The
form classes in all three categories range from 65 to 90.   There is an average
2% increase in overall tree volume for each point increase in form class.   
Form class is pretty much an industry standard and I think it could
eventually become another cog in figuring Rucker indexes.   

Because cubic calculations and volume documentation of extremely large trees
is such an important part of the ENTS mission I would hope that some aspects
of form class could prove useful.

In all cases the volume tables do not cover trees with over 6 15' logs of
100' of merchantable wood.

I have used form class many times in the past as a way to express extremes
in quality or actual height.


Re: Robinson State Park   Gary A. Beluzo
  Nov 29, 2006 16:57 PST 

You got me thinking about tree measurements ("on the hoof") for ecological
purposes and I did some Googling. I discovered some very interesting
articles about folks that are experimenting with the use of a digital
camera, laser rangefinder, calibration stick and photo imaging software for
determining diameter and other metrics remotely. I'll provide a summary
when I finish to this list. about those Whately tulip poplars?

Re: Robinson State Park
  Nov 29, 2006 17:33 PST 

Have you ever used a Relaskop? Many of the timber company foresters that
use tall species like yellow poplar use it because of the gauge that allows you
to estimate diameters high up in the tree. A description of the beast is


I have permission to show them to anyone when I'm in the area. I talked to
the owner of the Whately poplars a few months back and they are still there
and growing.

Maybe we can down there next time I'm in the area.

Re: Hemlocks at MTSF RETICLE???   Gary A. Beluzo
  Nov 30, 2006 05:34 PST 
Hi Will,

I am interested in Jess's program. I am researching methods that utilize a
digital camera this week, there are many that work really well. Also I have
found some equations for approximating above ground and below ground
biomass. Any computer or digitally based analyses that folks have I would
be interested in reviewing. Especially anything that could interface with
ArcGIS potentially.

Is anyone using ArcPad out there in ENTSland?


On 11/29/06, Will Blozan wrote:


Have you measured any Cook Forest hemlocks yet for volume? It would be
great to get some numbers. Jess has developed an interpolator for monocular
measurements that uses only two distance measurements. It is very sweet
and really speeds things up- provided the trunk is straight. I can send you
the program if you want.