A study over time provides a unique approach to investigate if landscape-environmental conditions can explain community resistance to invasion by nonnative plants in protected forest patches. This study investigated overall and intra-forest spatial patterns of change in nonnative Lonicera maackii (Amur honeysuckle) after 18 y in a 5.2 ha mature deciduous forest in southwestern Ohio. Changes in height-class abundances were measured in 60 permanent plots and mapped using GIS. Amur honeysuckle density increased from 3361 to 5472 individuals/ha (62.8%), but increases and decreases occurred at different sample plots. Greatest increases were for individuals <1 m (86.3%). A repeated measures MANOVA confirmed the significant effects of time (1992–2010) for total density, density of individuals >1 and <1 m, and mean height, but the decrease in mean height (1.44 to 1.30 m) was not significant in the univariate analysis. Moran's I statistic calculations documented nonsignificant spatial autocorrelations among plots, but landscape-environmental attributes have weak and mostly non-significant relationships with the change in honeysuckle densities among the plots. Management practices can decrease propagule pressure along edges and reduce the establishment of small individuals in the interior, but Amur honeysuckle is likely to remain as a naturalized understory shrub that responds to spatially fluctuating resources in this mature forest fragment.