![]() HOLARCTIC ECOLOGY 10:1 (1987) The field layer, which belongs to the Alno-Padion (sensu Westhoff and Den Held 1969), is exposed to full daylight in the first summer after coppicing in winter. Nowadays, large parts are not coppiced any more and the remainder is cut at irregular intervals of 4-15 years. Coppicing was usually done every 6-8 years, but in the course of the 20th century the coppice cycle gradually became shorter. Ash coppice In the region of the river Rhine in the centre of The Netherlands, still a fair amount of the formerly large ash coppice woodlands on clay soils are preserved. palustre in relation to the coppice cycle and the associated environmental changes in two parcels of ash coppice. In this paper we present some data concerning the population dynamics of C. palustre is also common in ash coppice in certain stages of the coppice cycle here it is predominantly biennial (Pons 1983a). The C palustre populations studied by Linkola (1935) and Ballegaard and Warncke (1985) behaved as monocarpic perennials, and the latter authors suggested that this feature is probably typical of the species. Accepted © HOLARCTIC ECOLOGY Entering the flowering stage is related to rosette size (Linkola 1935), as is the case in many 'biennials' with delayed flowering (Gross 1981). Mortality was very high in the seedling stage but was rather low and constant in later stages, except the last: all plants reaching the flowering stage died thereafter. palustre could be classified into five life states, each state usually lasting approximately one year thus, the plants typically flowered in the fourth to fifth year (Ballegaard and Warncke 1985). In a spring area in Denmark, the plants of C. Cirsium palustre (L.) Scop, is a widespread 'biennial', according to Oberdorfer (1970) occurring in a variety of habitats, such as pastures, hay meadows and occasionally also in wet alder woodlands. The tendency to delay flowering to the third year or later depends on the type of habitat in which the population occurs (Gross and Werner 1982, Van Baalen and Prins 1983). ![]() ![]() In fact, nearly all species considered appear to be not strictly biennial they show delayed flowering to a greater or lesser degree and thus belong to the tnonocarpic perennials (Harper 1977, Silvertown 1983). Introduction The age distribution and population dynatnics of biennials (sensu lato) have attracted much attention in recent years since the field study of Werner (1975) and the theoretical paper of Hart (1977). During, Deptof Plant Ecology, Lange Nieuwstraat 106 3512 PN Utrecht, The Netherlands. Rosettes persisting to the third year generally do not flower and ultimately die because shading by the tree canopy has become too severe. It is suggested that the persistence of the species in this system depends on Its ability to form a longhved seed bank and on a nutrient availability high enough to enable some rosettes to exploit the high photosynthetic photon flux density (PPFD) in the first year after coppicing and thus to reach the critical size needed for flowering in the second year. Despite fairly high mortality, the plants flowering in their second year produce enough seeds to replenish the seed bank. In contrast to its behaviour in meadow and spring communities the species typically behaves as a true biennial in this system. In later years the species is nearly absent. ^ In the first years after coppicing, Cirsium palustre is abundant in Dutch ash coppice woodlands and in the second year, it flowers abundantly. 1987, Biennal behaviour of Cirsium palustre in ash coppice. Biennal behaviour of Cirsium palustre in ash coppice Biennal behaviour of Cirsium palustre in ash coppice
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