Disturbance gaps in forests can stimulate tree regeneration, maintain biodiversity, and promote forest heterogeneity.  In urbanized regions, long term forest sustainability is threatened by many ecological stressors, such as high deer pressure and invasive plant spread, which are more intense than in non-urban landscapes. These pressures can affect regeneration capabilities in disturbance gaps.  This study tested whether forest gaps promoted tree regeneration in comparison to the adjacent intact forests and if gap size was an influential factor in regeneration.  This study was conducted across 54 natural disturbance gaps of different sizes (0.06 – 3.15 ha) in a 590-ha forest tract within an urbanized region in Morris County, northern New Jersey, within the Morristown National Historical Park.  In each gap area, advanced regeneration data and species cover were collected in the understory stratum across three gap locations (gap center, gap edge, and adjacent forest).   Results from 294 plots showed that advanced regeneration was greater in adjacent forest plots than in gap centers.  Small Fraxinus spp. seedling numbers accounted for the difference among locations; when Fraxinus spp. were excluded there was no significant difference among locations.  Gap size had no effect on advance regeneration.  Overall, the mean stocking index was severely deficient and mainly due to excessive deer pressure; numbers of large seedlings and saplings were extremely low, but numbers of all smaller seedlings were sufficiently stocked.  In addition, invasive plants dominated the understory. Stepwise multiple regressions showed that introduced shrubs and the introduced grass, Microstegium vimineum, displaced native tree regeneration.  The only tree species that showed successful regeneration in gap centers was the introduced Robinia pseudoacacia which also had the greatest sapling numbers of all tree species.  Without significant management intervention, natural disturbance gaps in this stressed forest tract will fail to promote native tree regeneration, allow R. pseudoacacia to dominate, and change the future composition and structure of the forest.  This study serves as an example for the many forest tracts that have similar ecological stresses.  Intensive deer control and invasive plant management are required to restore natural regeneration processes and the valuable role of disturbance gaps to promote forest sustainability and heterogeneity. These data offer an additional parameter to discriminate urban forest dynamics from processes in less human-dominated habitats which have dominated discussions of forest ecology.  The fate of urban forest gaps in this study will not reiterate the surrounding mature forest structure.