Growth-rates of Hippophae rhamnoides L.

Six populations of the sea buckthorn, Hippopha rhamnoides Lare sampled systematically and graphs of age against stem diameterplotted. Regression analyses are used to derive the mean girthincrease per annum for the whole of a population and for thepopulation divided according to the stem age, i e 0–10years and 11–40 years The six populations represent fivemajor edaphic types of the Spurn Peninsula (I) stable dunes,sheltered, sand depth > 1 m, (II) unstable dunes, sheltered,sand depth > 1 m; (III) unstable, exposed dunes, sand depth> 1 m; (IV) stable dunes, sheltered, sand depth < 1 mover coarse gravel and mud, (v) stable dunes, sheltered, sanddepth < 0.5 m over coarse shingle/sand mixture The annualgrowth increment for the whole population is shown to be greatestin the sheltered areas on deep sand, the highest figure recordedbeing 4.5 mm per annum The rate of growth for the plants upto 10 years old in the three populations on deep sand vanesbetween 3 88 and 4 5 mm per annum, whilst in shallow sand areasthe range is between 2 0 and 2.8 mm per annum Girth increasein plants over 10 years slows down to 2 92 mm per annum in shelteredareas on deep sand, is considerably retarded in exposed areason deep sand (1.53 mm per annum), and is least on shallow dunes(1 34 mm per annum).