Climatic response of various tree ring parameters of fir (Abies pindrow) from Chandanwadi in Jammu and Kashmir, western Himalaya, India

Total ring width (TRW) and earlywood width (ERW) of fir (Abies pindrow) compared to latewood width (LRW) are strongly correlated with Palmer Drought Severity Index (PDSI) during summer season (March to October). Correlation coefficients for the period 1876-1948 between PDSI and TRW as well as ERW are 0.43 and 0.50 respectively, which is found to be significant at 0.01 level. Thereafter, their relationship weakened as temperature changed over the region, whereas maximum latewood density (MXD) reveals significant negative association with PDSI during summer season. Moreover, monthly mean, maximum and minimum temperatures during August to September of the region indicate significant positive response with MXD. Correlation coefficients of MXD with mean, maximum and minimum temperatures are 0.60, 0.61 and 0.51 respectively, which is significant at 0.01 level. There is also high temporal stability in the relationship between MXD and temperature from 1916 onwards over the region

Growth response of conifer trees from high-altitude region of western himalaya

Tree-ring width index chronologies of some species (Abies pindrow and Picea smithiana) of Western Hima-laya are sensitive to the moisture availability and amount of soil moisture of the region. The first prin-cipal component among the site chronologies explain-ing 61.2 of the common variance is strongly correlated with Palmer Drought Severity Index dur-ing summer season (May-July). Whereas increased temperature of the region had significant adverse effect on tree growth. The moisture availability, espe-cially in the growing season is found more conducive in developing the annual tree-ring width compared to rainfall during the season. Moreover, the increasing temperature and vapour pressure during November and December of the previous year might play an important role for early snow melt over region, which maintains enough soil moisture favouring trees growth during subsequent growing season of the trees as well as in physiological processes

Tree-ring analysis of teak (Tectona grandis L.F.) in central India and its relationship with rainfall and moisture index

Tree-ring-width index chronologies of teak (Tectona grandis L.F.) from three sites in central India have been studied for their dendroclimatic potential. The existence of good correlation among the three site chronologies indicates the in.uence of common forcing factor to the tree growth of the region. Tree growth and climate relationship based on correlation analysis revealed the important contribution of moisture index and rainfall rather than the direct influence of the temperature on tree growth during different seasons. Signi.cant positive relationship of moisture index and rainfall during the monsoon months as well as on the annual scale with tree-ring width variations over the region indicates the important role of moisture availability at the root zone. The results suggest that the teak tree-ring chronologies can be used as high resolution proxy for past precipitation and moisture level in the environment

Treeline dynamics with climate change at the central Nepal Himalaya

Treeline shifting in tandem with climate change has widely been reported from various parts of the world. In Nepal, several impacts of climate change on the physical environment have been observed, but study on the biological impacts is lacking. This dendrochronological study was carried out at the treeline in the high mountain slope of Kalchuman Lake (3750-4003 m a.s.l.) area of Manaslu Conservation Area in the central Nepal Himalaya to explore the impact of climate change on the treeline dynamic. Two belt transect plots (size: 20 m wide, > 250 m long) were laid which included treeline as well as tree species limit. Ecological mapping of all individuals of dominant trees Abies spectabilis and Betula utilis was done and their tree cores were collected. Stand character and age distribution revealed an occurrence of more matured B. utilis (max. age 198 years) compared to A. spectabilis (max. age 160 years). A. spectabilis contained an overwhelmingly high population (89) of younger plants (< 50 years) indicating its high recruitment rate. Population age structure along the elevation gradient revealed an upward shifting of A. spectabilis at the rate of 2.61 m year-1 since AD 1850. The upper distribution limit of B. utilis was found to be stagnant in the past few decades. An increment in plant density as well as upward shifting in the studied treeline ecotones was observed. The temporal growth of A. spectabilis was correlated negatively with the monthly mean and minimum temperature of June to September of the current and previous year. The regeneration of A. spectabilis, on the other hand, was positively correlated with August precipitation and monthly maximum temperature of the month of the current year. The growth and regeneration of A. spectabilis was more sensitive to maximum and minimum temperature rather than average temperature. The growth of the B. utilis was mainly limited by moisture stress during the pre-monsoon season. As these two species presented species-specific responses to climate change with differential pattern in regeneration condition, much wider differences are anticipated in their population status as climate continues to change throughout the century

Moisture index during the last two centuries inferred from tree growth in the western Himalaya, India

In the present study, a regional tree-ring chronology prepared from two species (Picea smithiana and Cedrus deodara) over the western Himalaya has been used in relation to climate fluctuations. This analysis shows that moisture index and rainfall during February to May have significant positive relationship, whereas temperature and heat index show a negative relationship with tree growth. However, moisture and heat indices show greater impact on tree growth than rainfall and temperature. The strong association of tree-ring chronology with moisture demonstrates that tree rings are much more sensitive to the availability of moisture at the root zone, which enabled us to extend our analysis back to AD 1789; in the present reconstruction, moisture deficiency for two consecutive years was noticed during 1846–1847, 1908–1909, 1921–1922, 1931–1932, 1947–1948 and 1966–1967

Dendroclimatic analysis of teak (Tectona grandis L. f.) annual rings from two locations of peninsular India

Climate-related tree-growth variability in teak (Tectona grandis L. f.) has been studied based on response function analysis from dry deciduous forests of Mundagod (Karnataka) and Chandrapur (Maharashtra), peninsular India, representing two ecological zones. Rainfall during the monsoon months of the current year was found to be positively associated with radial growth of teak at both sites, whereas premonsoon April rainfall was found to be negatively associated. Rainfall and temperature of the current year during March have positive influence on the growth of teak at Chandrapur and Mundagod respectively. Furthermore, rainfall during October of the preceding year showed negative influence on tree growth at Mundagod and positive influence at Chandrapur, which might be due to the difference in relative humidity and soil type at both the locations, apart from soil moisture

Effect of growth rate and latewood content on basic density of wood from 120-to 154-Year-old natural-grown Teak (Tectona grandis L. f.)

The relationship between the radial variations of growth ring features and basic density were investigated in juvenile and mature wood for five 120-to150-year-old trees of Tectona grandis L. grown naturally in moist deciduous forest of Thane,Maharashtra. The study showed that the mean basic density of growth rings in juvenile wood was 0.665 (0.602-0.702) g cm-3 and 0.613 (0.562-0.665) g cm-3 in mature wood. The annual growth in juvenile period was high with a ring width mean of 4.03 mm and the latewood content represented 76.36 % of the annual growth, while in mature period was low with a ring width mean of 1.24 mm and the latewood content represented 59.41% of the annual growth. The patterns of radial variation of ring width, latewood content and basic density were more inherent in the juvenile wood than mature wood of all trees due to cambial ageing. The basic density of five individual trees showed an insignificant correlation between ring-width and latewood content in juvenile wood, whereas a significant positive correlation was found in mature wood of most of individual trees. The mean ring width value of all trees showed a highly significant positive correlation with basic density in both types of wood but mean latewood content showed a non-significant or low significant correlatio

Estimation of past atmospheric carbon dioxide levels using tree-ring cellulose Delta 13 C

We study the applicability of the Farquhar model for carbon isotopic discrimination (change in carbon isotopic composition from air CO2 to tree-ring cellulose) in C3 plants to trees growing in the field. Two new carbon isotope datasets from Himalayan conifers with published data from another eight sites across the world show disparate trends in the plot of carbon isotope discrimination versus atmospheric carbon dioxide concentration, in contrast to the model prediction of absence of any trend. This is because the model assumes that the tree adjusts its stomatal conductance for water-use efficiency to maintain a constant ratio of carbon dioxide concentrations inside and outside the leaf and treats the diffusive and biochemical fractionation factors as constants. By introducing a simple linear dependence of these fractionation factors with ambient temperature and humidity, we have enhanced the applicability of the model to naturally growing trees. Further, despite the disparate trends exhibited by the 10 trees, we show using the inverse modelling that it is possible to derive a unique record of past atmospheric CO2 concentrations using tree cellulose 13C data. The reconstructions also replicate the summer pCO2 gradient from tropics to mid-latitudes. We also discuss the merits and demerits of the model, and compare the model-derived pCO2 with that of the ice core-based records from Law Dome