HFDGEROVV SURVEY
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1750 and 1850. In east Suffolk and north Essex, however, enclosure seems to have taken place at a much earlier period and most of the existing field boundaries to date from the 17th Century or earlier. Work done by Dr. M . D . Hooper indicates that the number of kinds of shrub in a hedge depends in part on the management of the hedge, in part upon the type of soil in which the hedge is growing and to a very large extent upon the time during which the hedge has been in existence. In general a hedge 100 years old has only one or two species of shrub in a 30 yard Stretch, one 200 years old two or three species, until a hedge 1,000 years old has ten or twelve species. Hedges, moreover, support a large proportion of our lowland wild life: in particular, since hedges are very similar to that most rieh of woodland habitats the woodland edge, it is to hedges we owe the fact that our woodland birds can survive so well in agricultural land. T h e number and variety of birds' nests in a hedge depend in part upon the management of the hedge and in part upon the number of species of shrubs present in the hedge and the same is true of other creatures and herbaeeous plants. A survey of the hedges of a farm or of a parish can therefore be of great interest both to the naturalist and to the historian, while hedges in general are of the greatest importance so far as the preservation of our wild life is concerned. T h e N a t u r e Conservancy is accordingly undertaking an investigation of hedgerow ecology and as a beginning is trying to survey the distribution of different types of hedgerow, their management and the different kinds of shrub in them, throughout the country. T h e information required is set out on the 'tear off' pro-forma printed on page 121, and members are asked to help by selecting a hedge and recording on the pro-forma all the features present in a 30-yard length of that hedge. It is hoped that any interested person will examine as many hedges as possible, sending in a pro-forma for each one. At the present stage of the investigation even incomplete information is useful and no one should be deterred because they cannot, e.g. determine the age of the hedge or define the soil type. Further copies of the pro-forma may be obtained from and should be returned to:
Dr. Max Hooper, The Nature Conservancy, Monks Wood Experimental Station, Abbots Ripton, Huntingdon.