Growth response of four dominant conifer species in moist temperate region of Pakistan (Ayubia National Park)

Abstract

Dendrochronological potential of conifers from Ayubia National Park, Pakistan was determined. A total of four conifer species (Abies pindrow (Royle ex D. Don), Cedrus deodara (Roxb. ex D. Don), Pinus wallichiana A.B. Jacks. and Taxus baccata L.) were studied from different elevations. Comparative analysis of DBH-growth rate and DBH-age were performed among the species with maximum age showed by A. pindrow of 456 years with 0.01 cm/year growth rate. P. wallichiana was found to be fast growing with 0.05 cm/year growth among other species while C. deodara trees were having the strongest correlation between their age and DBH values (R2= 0.9225). Quality of cross dating and accuracy of tree ring measurements was checked by COFECHA. Mean sensitivity of all species ranges from 0.265 to 0.328 with auto-correlations range from 0.562 to 0.712 which specified the dendrochronological significance of these conifers. ARSTAN program was used for autoregressive modeling to remove any possible variance other than climatic disturbance and to standardize the tree ring chronologies. Tree-ring variations were evident among all the cores possessing distinct wide and narrow fluctuations of ring growth with A. pindrow (Avg. mean ring width = 1.46 mm) and T. baccata (Avg. mean ring width = 1.80 mm). All the conifer species showed good climatic signals in their tree ring measurements and are valuable for the dendroclimatic growth response investigations.