In the sub-alpine, natural mono-specific Abies densa forests in Chamgang-Helela region, Thimphu (Western Bhutan), almost all trees in the upper ridges were killed by drought triggered massive fir dieback in the late 1970s and early 80s. There is lack of information regarding the regeneration and vegetation dynamics of these affected fir stands. We investigated tree regeneration in 20 20x20m randomly established permanent plots spread across the study area with a distance of 50m between each plot. Inside each plot 5 1x1m mini-plots were nested. The working hypothesis was that ultimately die-back affected stands would be replaced again by mono-specific Abies densa stands, because fir, with the exception of Juniperus recurva, is the only dominant, long lived tree species at this elevation. Some advanced tree regeneration was present in the vicinity of the mini-plots but not inside the mini-plots. Since the dieback Abies seeds have been deposited and germinated, although recruitment during the initial years after the dieback was discontinuous. At present an average density of 0.6 seedlings of fir per m exists. The fact that only 26 percent of the mini-plots showed regeneration indicates patchiness of the regeneration which will result in a mosaic of dense and open forest. Different site factors and other factors like micro-site (moss, leaf litter, mineral soil and organic matter), grazing, shade, slope, altitude, competing ground vegetation have influence on Abies densa germination and survival. The mortality of Abies densa germinants could not be observed. The seedling density of other tree and shrub species like Juniperus recurva (0.1 m-), Acer sp. (0.18 m-), Rhododendron arboreum (0.13 m-), R. cinnabarinum (0.11 m-), R. lepidotum (0.18 m-), R barbatum (0.02 m-), Viburnum nervosum (0.01 m-) and Rosa sericea (0.29 m-), were much lower compared to Abies densa (0.6 m-). Seedlings of pioneer trees such as These low numbers indicate that it is unlikely that a closed pioneer, Juniper or Acer stand will be formed, displacing the previous fir stands. For some time, the forest stands will be a mosaic of dense and wide spaced fir trees. We anticipate that over time, mono-specific Abies densa forest will eventually once again replace the present stand composition of the dieback affected fir stands.