Abstract
Habitat fragmentation is one of the most serious threats to plant biodiversity at the within-population level. Growing attention on the genetic effects of habitat fragmentation is reflected in the 2008 publication of several review papers. In general, fragmentation showed a negative effect on the genetic variability of plant populations. However, for forest trees the genetic signal of fragmentation seems less clear. Here I discuss the development of less explored issues that can help to clarify some unresolved questions about tree responses to fragmentation. In particular, the understudied effect of delay in sexual maturity and the need for accurate estimates of gene flow are taken into account. I finally underline the potential role of the Italian peninsula as an open-sky laboratory for forest fragmentation studies.