Small-scale spatial pattern and size structure of Rubus hirtus in a canopygap

The response of a Rubus hirtus population to the creation of a new forest g ap was analysed. All individuals in two 30-m(2) plots-one in a gap and one with full canopy cover-were mapped and the length of Rubus shoots measured. This was done 1, 2, 3, 4, and 7 yr after creation of the gap. Spatial patt erns were analysed using Ripley's K-method. Although the density of Rubus i n the gap increased from 3 to 24 rooting goints/m(2), the change in spatial pattern of individuals over 7 yr was very limited. During the first four y ears a clumped pattern appeared at distances of >0.5 m. After seven years t he pattern was random at all distances. Young shoots spread in all directio ns with equal probability. The expansion was achieved by establishment of n ew ramets, increase in the number of shoots per rooting point playing a min or role. Individual plants contributed to gap filling very unequally; few o f them produced many rooting points. The average size of canes and the prop ortion of tip-rooting canes were highest in the second year after the gap f ormation.