Population structure and regeneration of Zanthoxylum armatum DC. in Salyan, Nepal

Background: Zanthoxylum armatum is one of the 30 prioritized medicinal plants for economic development of Nepal with a high trade value.Understanding the ecology of individual species is important for conservation and cultivation purposes.However, relation of ecological factors on the distribution and populations of Z. armatum in Nepal remain unknown.To address this knowledge gap, an attempt has been made to study the population structure, distribution, and regeneration potentiality of Z. armatum.Vegetation sampling was conducted at six different localities of Salyan district along the elevation range of 1,000 m to 2,000 m.Results: Altogether 50 plant species belonging to 44 genera under 34 families were found to be associated with Z. armatum.Significantly higher species richness was found at Rim (1,400-1,700 m) and Chhatreshwori (1,800-2,000 m) and lower at Kupinde (1,600-1,800 m).The highest population density of Z. armatum was at Kupinde (1,600-1,800 m) with a total of 1,100 individuals/ha.and the lowest at Chhatreshwori (1,800-2,000 m) with 740 individuals/ha.Based on the A/F value (Whitford index), it can be said that Z. armatum has random distribution in the study area.The plants were categorized into seedlings, saplings and adults based on plant height and the status of natural regeneration category determined.The regeneration potentiality of Z. armatum in the study area was fair with the average seedlings and saplings densities of 150 and 100 individuals/ha.Respectively.A Shannon-Weinner index mean value of 2.8 was obtained suggesting high species diversity in the study area. Conclusions:The natural distribution and regeneration of Z. armatum is being affected in the recent years due to anthropogenic disturbances.Increasing market demand and unsustainable harvesting procedures are posing serious threat to Z. armatum.Thus, effective conservation and management initiatives are most important for conserving the natural population of Z. armatum in the study area.