Dendritic or fractal islands occur naturally during epitaxial growth i
n systems where island edge diffusion is restricted. Here we use a lat
tice-gas model to characterize the evolution of island structure in su
ch systems, from the low coverage to the coalescence regime, and to co
nsider the ramifications for multilayer growth. Island densification a
nd slowing of radial growth prior to coalescence is observed in the si
mulations, as in Au/Ru(0001). We also elucidate the relationship of th
e real-space island structure to the width and shape of the correspond
ing kinematic diffraction profile. Our multilayer growth studies incor
porate disruption of and downward funneling from island edges upon imp
act of depositing atoms, in the presence of a large Schwoebel barrier.
Using the geometry and length scales appropriate for Pt/Pt(111), the
calculated kinematic Bragg intensities for a two-layer model show that
even limited disruption can produce the observed low-temperature ''re
entrant'' oscillations.