An Electronic Version of the Relascope? 

First, it is not a “Relascope” (or “Relaskop”), which is a trademark of the Relascope company in Austria.  The Laser Tech Company has more recently been calling it a “basal area scope” or some version of that wording.  The Criterion 1000 is an attempt to put the Relascope into an electronic form.  I think it falls well short of the mark.

The Criterion is larger, and weighs a bit more than the traditional Relascope, but not greatly so.  Costs are roughly equivalent.  Criterion kept their cost down by not including a range finder, which is a major disadvantage.  Hooking it up to a data logger or range finder with wires is certainly a poor option in brushy conditions.  To get the range finding advantage would greatly increase the cost, weight and bulk.  Even when they do that, it is not clear that the accuracy will be sufficient. 

It is probably not hard to get around the patent on the Relascope (which has been done before), the problem is to produce the fine precision of the machining.  Relascopes are durable, don’t use batteries, and you can work on them a bit yourself to mend minor damage.  They have a pretty good track record, and have earned their place as the standard. 

I tried the Criterion myself, and also asked three experienced timber cruisers for their reaction.  This is what we have observed so far. 

The data ports are exposed, but I hear that Criterion products have been pretty good in the past with weather resistance, so that’s probably not critical. 

You can view the BAF as either a solid “bar” or a “gap” between lines.  The first thing I did with the Criterion was put it on a tripod to see if I got the same reading with the “solid” and “gap” displays when I viewed a target.  They were very different.  They are supposed to be the same as I understand it, although the manual suggests the solid bar for “in/out” determination.  For approximately a 15 foot horizontal distance to a “borderline” 11 inch tree I got about 14 feet with one method and 16 feet with the other.  The display uses small lighted bars, and if you wait a moment I noted that extra lines pop up for some reason, further changing the size.  Perhaps my instrument was faulty, so try it yourself on a tripod with a sheet of paper on the wall if you already have one of these machines. 

The BAF did not calibrate correctly either, which was a major concern.  My 40 BAF (about 9 metric) was off by about 5 when I tested it.  You might use the Star_Bar spreadsheet available at this website to calibrate your instrument (use section 5, column I to enter data).  Let me know what you find.  I tested a new Metric Relascope at the same time, and it was very precisely calibrated, but certainly all instruments should be tested in some way, including prisms.

The manual is difficult to read, and is not clear about where the tape should be placed at the instrument when you measure horizontal distance.  Setting the “modes” for making different kinds of measurements is slow and awkward, and the tiny font on the side display is a real irritant if your eyesight is not perfect or the light is low. 

There seem to be a lot of compromises based on solving engineering problems rather than accommodating field needs.  It’s a real hassle to enter numbers into the machine by pushing “up or down” buttons to change each number. 

While the Relascope shows you all the scales and bars as you look through it, the Criterion 1000 shows you just a minimum of information, and I found that I needed to alternate looking at the side of the instrument and the viewfinder quite a bit (really a hassle on a tripod).  All this would be quicker after you were familiar with it, but it strikes me as a poor design. 

It would have been a great improvement if readings and instructions had been available through the viewfinder as you were using the instrument.  The fact that it allows Metric or Imperial is a marketing advantage, rather than a field issue, but is a minor benefit.

The Criterion corrects for slope like the Relascope, but in a jerky pattern rather than a smooth transition (because of the lighted bars used).  I found nothing in the manual indicating how accurate this might be, and I have not tested it enough to know.

The upper limit in BAF is restricted to 127 (Imperial) or 29.1 (Metric) which is a bit less than Relascopes.  That is too restrictive if you were doing “Big BAF” cruising, and needs to be a larger range for use on the West Coast.  It might be an acceptable range on the East Coast or Southern parts of North America. 

The BAF can only be adjusted to even BAFs for Imperial measurements (ft²/acre), but has a decimal for Metric BAFs.  Their suggestion of switching to metric to get a fractional BAF in Imperial seems a bit silly.  Also, it is easier to remember dividing by 4.356 (many cruisers remember that there are 43,560 ft² in an acre) rather than multiplying by 0.22957 to convert from Imperial to Metric.

The calculation for in/out is based on the face of the tree, although that is not easily found in the manual (it is a big mistake not to make this quite clear).  It would be better if either method could be used.  The Laser Tech Company thinks this way automatically because they assume that their laser will be used to measure the distance to the tree face.

Their claimed diameter accuracy of ¼ inch seems very optimistic (even if the calibration was right).  I suspect that it is no better than the Relascope, and probably not as good, but I have not yet tested it enough to know for sure.  This is particularly the case if they are using distance to the face of the tree and not accounting for it mathematically.  The manual gives no hint about this, and makes me wonder if it is computed correctly. 

The American scale Relascope gives you height (above or below horizontal) in feet, and diameter in inches from fixed distances.  The new Criterion improves on this, but it seems slower than using a Relascope and a calculator.  The Criterion allows a variable distance to the tree for reading heights and diameter.  It lets you fix the base of the tree as zero and see the height from that base displayed as you go up the stem.  That would be useful for training, and is an advantage. 

One of the large consulting firms will give you a break on the purchase price of a Criterion if you send them a used Relascope.  This may be a way to acquire Relascopes for their own use, or maybe it is a way to get competing Relascopes off the market – hard to tell. 

My past experience with requesting simple changes to the older Criterion models has not been very positive.  Their technical staff were resistant to simple improvements.  This instrument has a long way to go before it is a polished product. 

Even though we live in an electronics obsessed world, I don’t think it will be a replacement for the real Relascope, and my cruising colleagues all felt the same way. 

Kim Iles