Search Results (4)

Abies pindrow is a keystone tree species of temperate forests in the Himalayan range with immense ecological significance. The current study was designed to investigate the spatial distribution, population structure, associated flora, and sustainability of Abies pindrow in the temperate forests of Azad Jammu and Kashmir (AJK), Pakistan. Vegetation data were collected from 48 forest sites distributed in six districts of AJK with respect to the geography, microclimates, and vegetation structure by employing a systematic quadrate-based methodology. Abies pindrow populations were characterized by an average stem density of 183.9 trees/ha with an average basal area cover of 789 cm. A. pindrow populations showed a regeneration value of 555.6 seedlings/ha. A digital elevation model revealed that A. pindrow exhibited a large extent of distribution in an altitudinal range of 1800–3400 m. GIS analysis identified that north-facing slopes with a moderate degree of slope steepness constitutes the preferred habitat of the species in the Kashmir mountains. A floristic analysis revealed that a total of 282 species from 74 plant families comprised the associated flora of A. pindrow-dominated forests with Pinus wallichiana, Picea smithiana, Aesculus indica, and Viburnum grandiflorum as codominant companion species. A. pindrow forests exhibited significant levels of species diversity and richness with average values of Simpson’s diversity as 0.94, Shannon’s diversity as 3.09, species richness as 1.45, and maturity index value as 45.9%. The A. pindrow populations in the study area were found to be subjected to significant deforestation pressure along with overgrazing and erosion impacts. Results provide valuable scientific information for the conservation management of A. pindrow populations, ensuring the sustainability of temperate forest ecosystems in the Western Himalayan region of Kashmir. Full article

A changing climate and global warming have adversely affected Pakistan’s moist and dry temperate vegetation. Abies pindrow (fir) (Royle ex D.Don) Royle and Picea smithiana (spruce) Wall.) Boiss are the two major representative species of the moist and dry temperate forests in Northern Pakistan. The dendroclimatic study of both species is crucial for the assessment of climate variability at various spatial and temporal scales. This study examined the dendroclimatology of fir and spruce, and analyzed the growth–climate relationship along the latitudinal gradient. Two hundred and nineteen samples (ring cores) of the two species were collected from five different sites (Shogran (SHG), Upper Dir (UDS), Bahrain Swat (BSG), Astore Gilgit (NPKA), and Sharan Kaghan (SHA)) in Northern Pakistan. The cores were cross-dated, and chronologies were generated for the species and climatic data (precipitation, temperature, and Palmer Drought Severity Index (PDSI)) correlated with radial growth. The interspecies correlations for fir were calculated as 0.54, 0.49, 0.52, 0.60, and 0.48 for SHG, UDS, BSG, NPKA, and SHA, respectively, whereas in the case of spruce, the interspecies correlations were 0.44 for SHG, 0.55 for UDS, and 0.49 for BSG. Climate variability was observed in the samples of both species, which showed significant drought and humid years at specific intervals. With respect to the correlation between tree-ring width and climatic factors, a positive correlation was observed between fir growth and summer season precipitation, mean temperature, and PDSI in the spring, summer, and autumn seasons. Similarly, the growth of spruce was positively correlated with precipitation (in February, September, and May) and PDSI (in the summer and autumn seasons); however, no correlation was observed between monthly temperature and spruce growth. The relationship of fir and spruce growth with seasonal precipitation and PDSI showed a change from a negative to a positive correlation after 1980, following rapid warming. During the winter and spring, the correlation coefficient between fir radial growth and seasonal temperature showed an initial upward trend followed by a progressive decrease along with increasing latitude. Seasonal variations were observed regarding the correlation coefficient between spruce radial growth and increasing latitude (increasing in winter; a decreasing trend in spring and summer; an initial increase and then a decrease in autumn). In the same way, the correlation of seasonal temperature and PDSI with the radial growth of both species showed increasing trends with increasing latitude, except in the autumn season. Full article

Multivariate analysis was conducted to explore the moist temperate forests of the Shangla district, Khyber Pakhtunkhwa. The prime objective was to quantitatively describe and differentiate the vegetation groups and the factors that determine the boundaries and composition of plant communities in the Shangla district. This was achieved by sampling all common species in a complex vegetation mosaic coinciding with local gradients in topography and soil distribution. Ward’s clustering dendrogram demonstrated four significant vegetation clusters with respect to environmental effects. These four major groups of the tree vegetation were superimposed on the ordination plane: 1. Pinus wallichiana, the dominant group associated with Abies pindrow; 2. Abies pindrow and the Picea smithiana group; 3. Dominant Cedrus deodara associated with the Pinus wallichiana, Abies pindrow, Picea smithiana, and Quercus baloot group; 4. Pinus roxberghii pure group. The key controlling factors for each group were the environmental characteristics (i.e., edaphic factors, topographic factors, soil physical properties, and soil nutrients). The results revealed elevation (p <0.001) to be the prominent factor in the composition of plant communities. Furthermore, pH, soil moisture, maximum water holding capacity, and soil physical properties (sand, silt, and clay) also showed a significant (p < 0.05) relationship with vegetation. The other environmental factor did not show a significant relationship with vegetation. Ward’s cluster dendrogram of understory species also demonstrated four groups. Group 1 comprises two subgroups, a and b, with the highest number of species, i.e., Digeteria sanguinalis, Fragaria nubicola, Verbascum Thapsus, Pinus wallichiana seedlings, and Polygonatum multiflorium, respectively. The second large group contains twenty-five species out of eight stands, and the dominant species was Tagetis minuta. Eighteen species out of six stands were found in group 3, which was considered the smallest group. Group 4 consisted of seven stands containing twenty-four species of ground flora, with Anaphalis scopulosa followed by Adiantum venustum as the dominant species. The environmental characteristics of the understory vegetation showed a resemblance with the tree communities. With the exception of elevation, the other factors did not show a significant correlation. Full article

We investigated changes in soil chemistry and foliar metabolism of Himalayan cedar [Cedrus deodara (Roxb. Ex Lamb.) G.Don] and Himalayan spruce [Picea smithiana (Wall.) Boiss] trees along a steep elevational gradient in the lower Himalayan Mountains at Kufri, Himachal Pradesh (HP), India. The foliar and soil samples were collected from four locations along a 300 m elevational gradient at ridge, high-, mid-, and low-elevation sites within the forested Shimla Water Catchment Wildlife Sanctuary that provides water for the city of Shimla, HP,. Observations at the time of sampling revealed that the high-elevation site was being heavily grazed. Soils collected at the four sites showed differences in soil chemistry along the gradient. Surface soils (top 10 cm) at the high-elevation site had the highest concentrations of carbon, nitrogen, calcium, magnesium, phosphorus, organic matter, and effective cation exchange capacity, possibly caused by grazing. Mineral soils were slightly acidic at all sites except the mid-elevation site, which was extremely acidic in the upper mineral soil. Similar to surface soil chemistry, foliar metabolism was also comparatively unique for high elevation. In Himalayan cedar foliage, higher concentrations of soluble proteins, polyamines, amino acids, and potassium were observed at the high-elevation site as compared to the ridge, mid and low elevations. No major differences were observed in the metabolic profiles of cedar between the ridge and low elevation ranges. Spruce foliage was sampled only from the ridge and low elevations and its metabolic profiles suggested healthier conditions at the low elevation. The results of the study demonstrate the impact of the interplay between local and regional drivers of forest health on cedar and spruce trees in a forested catchment that acts as a water source for downstream communities. Full article