{'fraction_non_alphanumeric': 0.0352543177636655, 'fraction_numerical': 0.027954181257047895, 'mean_word_length': 4.682967959527825, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
SIGNIFICANCE OF INTRA ANNUAL FLUCTUATIONS IN SOME SELECTED CONIFERS FROM A DRY TEMPERATE AREA (KALAM FOREST DIVISION), KHYBER PAKHTUNKHWA, PAKISTAN: A DENDROCHRONOLOGICAL ASSESSMENT

Dendrochronological potential of some gymnosperms was determined by dividing a study site into 9 stands. 76 samples of Abies pindrow with maximum age of 698 years having 149.3 cm diameter, 23 samples of Taxus baccata with maximum age of 479 years having 137.2 cm diameter, 4 samples of Pinus roxburghii with maximum age of 218 years having 19.2 inches diameter and 2 samples of Cedrus deodara were obtained. All species were crossdated successfully by Skeleton Plot Model. Among them, mean growth of A. pindrow was 0.05-0.27 cm per year while for T. baccata it was 0.15-0.24 cm per year. Moreover, regression analysis between age and dbh was (y = 0.0847x + 4.0756), (R = 0.921) in 3 stand and (y = 11.108x-41.174), (R = 0.8424) in 2 stand of A. pindrow and T. baccata respectively. The maximum value observed was in the 3 stand of T. baccata species which showed better correlation as compared to the rest of the stands. Strong correlation was also observed between TRW and difference of earlywood and latewood cell mass in all species. A. pindrow showed maximum value as (y = 1.1397x + 0.1873), (R = 0.9972).


Introduction
Dendrochronology, "the study of tree time," is a multidisciplinary science that dates annual tree rings to their exact year formation to investigate prehistorical, historical and modern events Cook and Kairiukstis, 2010). It is applied in various subfields like climatology, ecology, forestry, fire history, geology, hydrology, volcanology and many other disciplines (Nash, 2002). Trees are intimately bound to environment as they record natural (temperature and precipitation) or unnatural (human induced) events or processes which can be seen in varying patterns of tree ring widths (Ali et al., 2021).
Year to year climate variation induces variability in volume of wood that the tree produces in most geographic regions. When environmental conditions become favorable, trees respond by creating large volume of wood and produce less volume of wood in other years when conditions are unfavorable for growth (Sun et al., 2016;Panyushkina, 2011). Coniferous forests are important natural resources to sustain life in tropical, subtropical and temperate regions throughout the globe as they have economic and ecological importance. Among them, Kalam Forest Division (dry temperate area) is also geographically vulnerable to climate change due to environmental and some anthropogenic activities. The study was conducted in Kalam Forest division with objective to determine dendrochronological potential (age and growth rate studies) and to develop tree ring chronologies of conifers by SPM (Skeleton Plot Model) Method (Speer, 2010) (Fig. 1).

Chronology development by skeleton plot model
Skeleton Plot Model is one of most appropriate and extensively used method by dendrochronologists to crossdate the tree samples which is the "procedure of matching ring width variations." Skeleton Plot, "Plot of vertical bars in which bar length is inversely related to tree ring width, is used to identify the double or false rings which occurs if seasonal growth is interrupted by severe climatic conditions, diseases or other agents and is later resumed a second growth layer, visible and added in during one growth season (Copenheaver et al., 2006). Such additional layer is false ring, which is simply a band of latewood cells between latewood part of previous ring and early wood part of next ring (Nash, 2002). As temperate trees (conifers) develop rings yearly so, patterns of tree ring widths are matched and compared in similar and dissimilar geologic regions (Vasconcellos et al., 2019;Speer, 2010).
Pakistan is more vulnerable to climate change due to environmental factors changing forest types (Bajwa et al., 2015) inducing health problems (Gosling et al., 2009), as well as reducing the oxygen levels in the sea (Shaffer et al., 2009). These changes are not uniform throughout globe and vary with change in regional temperature and precipitation so, dendrochronology helps to examine the past climate as well as to predict future climate by annual rings of trees (Shah et al., 2019 (2) to determine relationships, if any, between diameter/age, diameter/growth rate and between seasonal parts of annual rings of trees; (3) to determine correlation between different parameters to model meaningful relationships in form of regression analysis; (4) to develop Skeleton Plot Model of all samples, composite skeleton plot of climatically sensitive trees and their matching with master skeleton plots and raising their master chronologies.

Study site
Kalam Forest Division is geographically known as Swat Kohistan (Fig. 2), an independent Forest Division from last 5 decades as it was a part of Swat Forest Division in previous times. It consists of two tehsils known as Kalam and Behrain and covers an area about 3182.9272 km 2 . The site is climatically very sensitive as it lies in dry temperate zone, too much cold at high elevations causes migration of people to bottom of valley to fulfil their needs and survival. Here temperature and precipitation varies with altitude and appears in form of rain and snow. Rain falls from December to May as its average record is 492 mm and annual record is 423.56 cm (Iqbal, 2014).

Sample collection, processing and measurement
Four conifer species were targeted for sample collection namely A. pindrow, T. baccata, P. roxburghii and C. deodara (Fig. 3). Subjective sampling was performed in the field and those individual trees were selected that were present on high and low elevation sites, steep slopes and well drained soils because they could possess the tree rings significantly sensitive to regional climate and cross dating could be performed successfully (Ahmed, 2014). Cores were obtained from healthy, rigid and unbranched trees by Swedish increment borers at height as 1.3 m or 4.3 ft. A total of 105 cores were obtained from 51 different trees in 2019. The cores were preserved in plastic straws to maintain alignment of cores. The ends of straws were covered with paper tape and holes created in trees were refilled by wax to protect them from any fungal or pathogen disease . The diameter at breast height (dbh) of each tree was measured by dbh measuring tape (Hart and Grissino-Mayer, 2008). Later on, cores were mounted on wooden frames with glue and were allowed to dry. Sander machine fitted with different grades of sand papers (80, 100, 120, 150, 180, 320 and 400 grit, depending upon particular species) was used to make smooth and fine surface of cores. It was proceeded until suitable polished surface was achieved after varnish coat (Phipps, Muhammad et  ). Velmex measuring system (TA4021H1) having connection with computer installed with J2X software was used. All samples were measured one by one with respect to earlywood, latewood and total ring width (Volney and Mallet, 1992;Yamaguchi, 1991). All samples were crossdated successfully by skeleton plot method and further statistical analysis was performed.

Results
Dendrochronological potential of above-mentioned species was determined by dividing study site into different stands and their relationships were determined by different parameters.

Age and growth rate determination
Age of all trees was estimated from nine stands of study site as shown in Table 1. The oldest tree was A. pindrow with 698 years age and 149.3 cm diameter. The youngest tree was 63 years of age with 73.15 cm diameter. An age of 479 years with 137.2 cm diameter was recorded in T. baccata as maximum age in this particular species while youngest was 113 years old having 45.72 cm diameter. In case of P. roxburghii, the maximum and minimum age was estimated as 218 years and 68 years with 48.76 cm, 67.05 cm diameter respectively. C. deodara was found to be minimal as regional climate and other topographic features of site were found to be unfavorable for this particular species.
Growth rate of all trees was also determined from this dry temperate area as shown in respective table. The maximum and minimum growth rate of A. pindrow was 0.48 cm/year and 0.05 cm/year. It was maximum as 0.06 cm/year in case of T. baccata while minimum was 0.12 cm/year. P. roxburghii also showed maximum and minimum growth rate as 0.15 cm/year and 0.10 cm/year respectively. Overall, T. baccata was found to be denser in study site and its growth rate was also recorded as maximum as 0.66 cm/year.

Seasonal dynamics
Tree ring width (TRW) and its parts (earlywood and latewood) were also measured ( Fig. 1). The maximum TRW measurement was 4.86 mm and 0.69 mm as minimum in case of A. pindrow. The early and latewood part was 4.70 mm, 0.53 mm and 0.53 mm, 0.13 mm respectively. In case of T. baccata, TRW was 6.64 mm and 1.37 mm as maximum and minimum. The early and latewood part was 6.5 mm, 1.2 mm and 0.71 mm, 0.41 mm respectively P. roxburghii showed TRW value as 1.66 mm and 1.11 mm and early latewood parts were 1.45 mm, 1.00 mm and 0.24 mm, 0.14 mm wide respectively.

Correlations between dbh/age, dbh/growth rate, TRW and difference of earlywood, latewood cell mass
Correlations of all species were determined ( Table 2). Diameter at breast height (dbh) of A. pindrow showed positive significant correlation with age ( Fig. 4a) while it was positive/negative correlated with growth rate (Fig. 4b). T. baccata showed positive correlation between dbh and age ( Fig. 5a) and negative between dbh and growth rate ( Fig. 5b) and it was found to be highly negative in P. roxburghii trees (Fig. 6a, b). Moreover, the correlation was also observed between tree ring width and difference of early, latewood cell mass. It was observed highly positive in all selected species gymnosperms (Figs. 4c, 5c, 6c). The maximum value was observed in 5 th stand of A. pindrow (Fig. 4c).

Discussion
Conifers population increases with increase in forest resources and particular species have wide range of distribution. The nature of any forest is determined by interaction of many physical and biological factors resulted in species distribution in particular geographical region depending upon resource requirements in tolerant sites where it makes necessity for survival (Glatzel, 2009;Shaheen et al., 2015). Thus, present study focuses on age and growth rate determination and intra annual fluctuations between different species by graphical representation. In this way, chronology was prepared by Skeleton Plot Model after identification of climate sensitive years in selected species (Sheppard, 2002).
Environmental factors are very important in determining species dominancy at site such as sufficient light, nutrition, moisture and other edapho climate features. So, A. pindrow was found to be in large number as edapho climate features favored its growth Muhammad et  while T. baccata, P. roxburghii, C. deodara was found to be minimal which may due to some anthropogenic activities like cutting, logging, fire and overgrazing.

Age and growth rate studies
Maximum and minimum age and growth rate of all selected conifers is presented in Table 1. Age and growth rate varies with elevation variation, from species to species and even among the similar species of similar sites. Many researchers have been engaged and are investigating dendrochronological potential from Pakistan and around the globe. Ahmed et al. (1990) Youngblood et al. (2004). In the present study, we determined age of A. pindrow, T. baccata and P. roxburghii, 698 years with 149.3 cm dbh, 479 years with 137.16 cm and 218 years with 48.76 cm dbh respectively. C. deodara was found in minimum quantity due to reduced competition among trees and illegal cutting and burning of trees. So, significant positive correlation was observed in age and dbh among different species. Age may increase or decrease with increase of diameter as species lie in different geographical positions. Moreover, it was not observed an effective parameter for age variation as regional climate also favors the growth of conifers after Scipioni et al. Maximum and minimum growth rate of all species is presented in Table 1. Growth rate of conifers is also affected by availability of forest resources such as moisture content, favorable temperature and precipitation, adequate nutrients and prevention from natural or unnatural disasters after Ahmed et al. (2012). Among selected species T. baccata was found to be with maximum growth rate as environmental factors favored its growth and development. However, growth rate of rest species was also observed reasonable but not responded like T. baccata. Siddiqui et al. (2013) observed slow growth rate of A. pindrow from moist temperate area. Ahmed and Sarangzai (1992) determined growth rate of P. wallichiana, 2.5 cm/years from Murree. Ahmed et al.
(2009) also determined as 1.7 cm/years in P. wallichiana from Dir. A. pindrow and C. deodara was observed with faster growth rate from Dir and Naran areas. In present study, T. baccata was observed with maximum growth rate, 0.66 cm/year while it was 0.05 and 0.10 cm/year as maximum in A. pindrow and P. roxburghii respectively.

Correlations study
Many researchers observed significant positive correlation between age and diameter from different sites of world. Ahmed and Sarangzai (1991) 2009) did not find such correlation four species i.e., A. pindrow, P. wallichiana, C. deodara and Picea smithiana but they observed positive relation in P. roxburghii. In the present study, A. pindrow, T. baccata and C. deodara showed positive correlation while P. roxburghii showed highly negative correlation between age and diameter.
Growth rate was also observed non-significant by various researches. Muhammad et al. (2021) did not observe significant correlation between dbh and growth rate in C. deodara from Murree, Pakistan. Wahab et al. (2008) also observed negative relationship between dbh and growth rate in P. smithiana from conifers of Afghanistan Forest. A. pindrow, P. wallichiana and C. deodara also showed highly significant negative correlation between dbh and growth rate by Siddiqui et al., 2013. Ahmed et al. (2012 observed strongest response by rainfall. All selected species showed highly negative correlation between dbh and growth rate in present findings as shown in Figures 4b, 5b, 6b.

Conclusion
Kalam Valley, located at the junction of three mountains (Hindukush, Himalaya, and Karakoram), has a special topography, according to the researchers. The alpine peaks in the area vary in elevation from 1900 to 4600 m. Conifers grow taller as a result of edaphoclimate factors such as harsh winters, acidic soil, altitude variation, salts, sand, silt, and organic matter. Briefly to conclude, the study site was densely covered with A. pindrow as huge number of this species was observed while C. deodara was observed as minimal due to some anthropogenic disturbances. Significant positive correlation was observed between age and diameter in all species except P. roxburghii after Ahmed and Sarangzai (1991) while no such significant relationship was observed between diameter and growth rate after Wahab et al. (2008). Moreover, environmental factors mainly temperature, precipitation and rainfall also favored age and growth rate of these conifers and T. baccata responded well to these climatic variations as maximum growth rate was recorded in this species after Ahmed et al. (2012). A lot of reasons (deforestation, burning of wood as to fulfil needs of coal, overgrazing, town planning, and frequent forest fires) have placed the study site under biological stress due to C. deodara was observed a few in number. The chronology presented in results clearly depicted highly sensitive tree rings which were distinct indications of growth rate variations during development of trees. The developed chronologies signify the sensitivity of conifers of dry temperate study region towards diverse climatic factors and could be analyzed to predict future seasonal climate variations. Some highly recommended steps can be followed to conserve species habitat (natural biodiversity) through traditional practices such as: • Need of awareness and management of forests to regain their valuable potential regarding to scientific research projects. • Implementation of Forest rules to avoid from illegal cutting, burning and chopping by providing alternative fuel resources. • Old age trees of study site such as A. pindrow, T. baccata, particularly C. deodara (national tree of Pakistan) etc. must be declared as cultural heritage of country. • Ecotourism must be developed to promote cultural and economic significance by working with international counterparts, to acquire global exposure.