>If the effect was negligible but measurable by close inspection, it would
>explain why general observation show no effect. A loss of 10% will not be
>noticible by general observation but would if scientifically measured.

Hello Bill,

I would not call 10% a minor loss. Given the cost and return structure
of beekeeping for a living, 10% off crop is a huge great whack off
profit. Our costs run at about 60% of average yield, so 10% off crop
would equate to 25% of our average net income, so it is serious.

We keep rudimentary location records going back over 20 years, as we
cannot afford to persist with regular underachieving yards.

This particular location (the one in the base of the large pylon) shows
a significant positive anomaly, not a negative one, and yards as little
as 800 metres away do not do as well. Again, I attribute this to forage
and aspect. If there was a negative anomaly caused by power lines it
would show up in our records averaged over a long period. We will use at
least 15 (out of around 150) locations over the course of a season which
will be within 50 metres of high voltage systems, so a pattern would be
easily discernable, and there appears to be no positive or negative
effect.

Not perhaps the scientifically robust type of evidence perhaps required
by some, but evidence enough for me to continue using these places.

A good scare about them could prove helpful though, as it could make
more places available to those of us who are not fussed.
--
Murray McGregor