Max Hooper died back in February.  While you might not have heard of the man, you might just have heard of Hooper’s Rule.  This is the idea that there was a relationship between the number of different woody plant species found in a particular length of hedge, and the age of the hedge.  Hooper formulated this idea in 1965 as he investigated the disappearance of hedges across the country with the growth of intensive agriculture.

As the Times obituary noted:

The Ministry of Agriculture, which was giving farmers grants to make them disappear, claimed that it was no more than 1,000 miles a year. Hooper doubted this. He recalled hearing how the RAF had trained its photo-reconnaissance crews by having them fly over and photograph the English countryside. He tracked these images down and, comparing those taken in the 1940s and 1950s with those in the 1960s, discovered that 10,000 miles of hedgerows were being lost each year. This figure caused a national scandal.”

The rule is:

Age of Hedge (in years) = Number of woody plant species in a 30-yard section x 110

The Times says that this was considered so reliable that it became part of the Hedgerow Regulations (1997), Hooper himself was prone to note that the rule wasn’t much use on hedges more than a thousand years old.

There was more to Hooper than the Rule, however.  He was a writer and head of plant ecology at Wye College, and then head of the College itself.  He was made an honorary fellow of the British Naturalists’ Association in 2007 (along with Sir David Attenborough), and was a recipient of its Peter Scott Memorial Award.

All that said, the rule is not fully reliable.  This is Hedge Britannica:

“It is important to bear in mind that Hooper’s Law is a rule of thumb and can only be used alongside other dating techniques such as local history, old maps, study of the field patterns, other flora in the hedge and so on.”

And Nature.net says that Hooper himself recognised these limitations:

“… as Hooper himself explained at the time, this test is a very rudimentary one and much more information is needed to really report on the condition of hedgerows in the countryside.  To this end, many others have followed Hooper’s lead and developed more complex means of surveying hedgerows.  Now a new edition of an old stalwart publication in this field has been produced: the Hedgerow Survey Handbook, first published in 2002, has been updated.”