Journal of Forestry Research (2014) 25(3): 511-521 DOI 10.1007/s11676-014-0490-x Phytosociology, structure and dynamics of Pinus roxburghii associations from Northern Pakistan Nasrullah Khan  Kishwar Ali  Shahid Shaukat Received: 2013-04-23; Accepted: 2013-07-09 © Northeast Forestry University and Springer-Verlag Berlin Heidelberg 2014 Abstract: We investigated the phytosociology, structure and dynamics of Pinus roxburghii in 40 stands in northern areas of Pakistan by using cluster analysis (Ward’s agglomerative clustering) and ordination (Non- metric Multidimensional Scaling). Cluster analysis revealed three major groups associated with specific environmental characteristics: (1) P. roxburghii (2) Pinus-Quercus baloot and (3) Pinus-Olea ferruginea community types. NMS-ordination showed the major gradient as an amalgam of elevation (r 2 = 0.441, p <0.01) and slope (r 2 = 0.391, p <0.05) as the two topographic factors correlated with species distribution. The first ordination axis also showed positive correlation with soil variables like pH and electrical conductivity, suggesting that soil chemistry was related to topographic characteristics and probably acted as a secondary gradient. We also examined size class distributions, age structures and growth rates of the three communities in order to describe community development and dynamics. Total tree density was 14700 plants/ha, with P. roxburghii having a relative density of 82% to 100%. Density of juve- nile and total density and basal area of the subordinate tree species were low. The low density of trees in the smallest diameter size-class sug- gested that the recruitment of small P. roxburghii plants into the adult population may be lower than the required replacement rate for the stands. Pooled size-class distributions for the species showed a multimo- dal pattern with some regeneration gaps. Browsing, heavy logging and The online version is available at http://www.springerlink.com Nasrullah Khan ( ) Laboratory of Plant Ecology and Department of Botany University of Malakand Chakdara, Dir Lower 25000, Khyber Pakhtunkhwa, Pakistan. Email: nasrullahdushkheli@yahoo.com. Kishwar Ali Department of Plant Sciences, School of Biological Sciences, University of Reading, RG6 6AS, the United Kingdom. Shahid Shaukat Department of Botany Federal Urdu University, Gulshan-e-Iqbal 75300 Karachi, Pakistan. Corresponding editor: Hu Yanbo other anthropogenic activities were the overriding factors responsible for the poor recruitment of P. roxburghii. We concluded from the age struc- ture that the forests were characterized by the dominance of young trees. Growth rate analysis revealed that P. roxburghii was the fastest growing species among the conifers species in Pakistan. In view of its relatively fast growth and longevity, P. roxburghii seems to be a suitable choice for short-term cultural practices in order to enhance wood production in lesser Himalaya and Hindukush ranges of Pakistan. Keywords: phytosociology, structure, dynamics, multivariate techniques, dendrochronology, Himalayan range Introduction In Pakistan, about 4.8% of the total area is forested which is very low in comparison to 23-70% in other countries of the world (Ahmed et al. 2010; Khan 2012). One-third of the forested area in Pakistan is covered by productive forests and the remaining two-thirds are categorized as protected forests (Sethi 2001). The sub-tropical pine forests located in the lesser Himalayan and Hindukush range of Pakistan are dominated by broad-leaved and coniferous tree species have significant contribution to produc- tive forest types. To date, eight conifer tree species have been reported (Nasir and Ali 1972) of which two species i.e. P. brutia and P. halepensis are not native to Pakistan. Among the native tree species Pinus roxburghii (Chir pine) is considered to be an important species (Gupta and Dass 2007) occurring at elevations from 900 to 1800 m above sea level (Siddiqui et al. 2009). In Pakistan this species is distributed in the lower parts of Khyber Pakhtunkhwa, Azad Jammu and Kashmir in sub-tropical dry and moist temperate areas (Ahmed et al. 2006), while it is also planted in certain areas of Punjab along roadsides and gardens. It is the only pine in the country of the northern forests with a small overlap with Pinus wallichiana (Kail) at the upper elevation limit (Saddozai 1995). P. roxburghii has a wide ecological amplitude and considerable economic importance, providing large stretches of grazing lands due to its typically well-developed grass layer (Wahab 2011) and valuable timber-wood and resin. Hence most of the population in its zone of occurrence depends on these ORIGINAL PAPER