scholarly journals Analyzing environmental determinants of tree species distributions and regeneration pattern in Western Himalaya, India

2020 ◽  
Author(s):  
Arun Kumar Thakur ◽  
Rajesh Kumar ◽  
Raj Kumar Verma ◽  
Pankaj Kumar

Abstract Proper documentation of tree distribution across the globe has been considered crucial to assess the relationships between species occurrence and changing climate, and accordingly in designing the conservation action plans. Himalaya is one of the regions in the world where the temperature is gradually increasing at a rate higher than the global average. Therefore, it becomes imperative to understand the most influential parameters for major tree species distribution and its regeneration pattern across their habitat in Western Himalaya (WH) via direct gradient analysis. We used National Forest Inventory (NFI) data which has a robust statistical design with data collected in a consistent manner across the timeline in systematic order. This allowed us carrying out detail analysis to reveal the aforesaid relationship and pattern. Three topographical factors (altitude, aspect, slope), four major climatic variables (temperature, temperature seasonality, precipitation and its seasonality) and four edaphic factors (soil depth, soil humus, soil consistency and soil coarse fragments) were considered as defining variables. The results indicated that the altitude and temperature were the most determinant factors followed by precipitation in shaping the distribution of major tree species in WH. The analysis also indicated the upward shift of regenerating individuals of these tree species towards higher altitude. These relevant information about the extent of current tree distribution and their regeneration pattern over the last one and half decade might help in systematic conservation planning and monitoring range dynamics under future climate change conditions.

2015 ◽  
Vol 166 (6) ◽  
pp. 408-419 ◽  
Author(s):  
Nicolas Bircher ◽  
Maxime Cailleret ◽  
Markus Huber ◽  
Harald Bugmann

Sensitivity of typical Swiss forest stands to climate change In Switzerland, first climate-induced changes of forest ecosystems can be observed. However, it is widely unknown how and to what extent the typical (widespread) forest stands will respond to future climate change. With the data of the third National forest inventory and the forest succession model ForClim we examined the development 71 typical stands under current and future climatic conditions (A2 emission scenario) with and without management, respectively. The simulations show a weak response until the middle of the century. In contrast, an increased sensitivity towards the end of the century becomes apparent, expressed by declines of basal area at lower elevations, respectively increases at higher elevations. The responses of forest stands are depending on site-specific characteristics. For example, Norway spruce is expected to decline up to higher elevations. Our results show an increase of deciduous tree species in higher elevation zones, particularly if management is applied. The impacts of climate change on important forest ecosystems services vary along a bioclimatic elevation gradient. Thereby, current forest management shows approaches how to at least partly counteract adverse effects of climate change. However, target- and site-specific strategies are needed and, particularly with regard to lower elevations, more knowledge on the potential of tree species to adapt is required.


2020 ◽  
Vol 12 (2) ◽  
pp. 341-355
Author(s):  
Arun K. THAKUR ◽  
Rajesh KUMAR ◽  
Raj K. VERMA

The forest in India have a long history of human induced modifications through intensive forest management that began in the colonial period but continued afterwards to meet the wood-based demand until the forestry goals shifted towards conservation efforts. All this greatly influenced the plant community structure. We attempt to describe the abundance and distribution pattern of trees in recorded forestland of Western Himalaya using the National Forest Inventory database. A total of 3549 sample plots laid across different forest types were analyzed to reveal the abundance, frequency and distribution pattern of 226 tree species/genus using various indices i.e. abundance by frequency ratio, Morisita index and variance mean ratio. Twelve tree species and Eucalyptus genus were found to be most abundantly found tree species in recorded forest area of Western Himalaya. Ten tree species were found to have regular distribution pattern, one hundred ninety-two were contagiously distributed while twenty-five were randomly distributed. Results derived from huge datasets helps in establishing firm statements with quoted significance value. Myrica esculenta and Aegle marmelos were found among the most abundantly occurring tree species whereas Myrica esculenta, Syzygium cumini and Pyrus pashia, were among the most relatively frequently occurring wild fruit yielding tree species. These species (apart from fodder tree species) can be considered in social forest and joint forest management programs in forest fringe villages/areas to enhance and sustain the provisional ecosystem services in Western Himalaya.


2020 ◽  
Vol 14 (1) ◽  
pp. 34
Author(s):  
Faezah Pardi

This study was conducted at Pulau Jerejak, Penang to determine the floristic variation of its tree communities. A 0.5-hectare study plot was established and divided into 11 subplots. A total of 587 trees with diameter at breast height (DBH) of 5 cm and above were measured, identified and recorded. The tree communities comprised of 84 species, 63 genera and 32 families. The Myrtaceae was the most speciose family with 10 recorded species while Syzgium glaucum (Myrtaceae) was the most frequent species. The Myrtaceae recorded the highest density of 306 individuals while Syzgium glaucum (Myrtaceae) had the highest species density of 182 individuals. Total tree basal area (BA) was 21.47 m2/ha and family with the highest BA was Myrtaceae with 5.81 m2/ha while at species level, Syzgium glaucum (Myrtaceae) was the species with the highest total BA in the plot with value of 4.95 m2/ha. The Shannon˗Weiner Diversity Index of tree communities showed a value of 3.60 (H'max = 4.43) and Evenness Index of 0.81 which indicates high uniformity of tree species. The Margalef Richness Index (R') revealed that the tree species richness was 13.02. Myrtaceae had the highest Importance Value of 20.4%. The Canonical Correspondence Analysis (CCA) showed that Diospyros buxifolia (Ebenaceae) and Pouteria malaccensis (Sapotaceae) were strongly correlated to low pH. Dysoxylum cauliflorum (Meliaceae) and Eriobotrya bengalensis (Rosaceae) were correlated to phosphorus (P) and calcium ion (Ca2+), respectively. Therefore, the trees species composition at Pulau Jerejak showed that the biodiversity is high and conservation action should be implemented to protect endangered tree species. Keywords: Floristic variation; Tree communities; Trees composition; Pulau Jerejak; Species diversity


Author(s):  
Johannes Breidenbach ◽  
Lars T. Waser ◽  
Misganu Debella-Gilo ◽  
Johannes Schumacher ◽  
Johannes Rahlf ◽  
...  

Nation-wide Sentinel-2 mosaics were used with National Forest Inventory (NFI) plot data for modelling and subsequent mapping of spruce-, pine- and deciduous-dominated forest in Norway at a 16m×16m resolution. The accuracies of the best model ranged between 74% for spruce and 87% for deciduous forest. An overall accuracy of 90% was found on stand level using independent data from more than 42,000 stands. Errors mostly resulting from a forest mask reduced the model accuracies by approximately 10%. The produced map was subsequently used to generate model-assisted (MA) and post stratified (PS) estimates of species-specific forest area. At the national level, efficiencies of the estimates increased by 20% to 50% for MA and up to 90% for PS. Greater minimum numbers of observations constrained the use of PS. For MA estimates of municipalities, efficiencies improved by up to a factor of 8 but were sometimes also less than 1. PS estimates were always equally as or more precise than direct and MA estimates but were applicable in fewer municipalities. The tree species prediction map is part of the Norwegian forest resource map and is used, among others, to improve maps of other variables of interest such as timber volume and biomass.


2012 ◽  
Vol 16 (7) ◽  
pp. 2193-2217 ◽  
Author(s):  
H. Wulf ◽  
B. Bookhagen ◽  
D. Scherler

Abstract. The sediment flux through Himalayan rivers directly impacts water quality and is important for sustaining agriculture as well as maintaining drinking-water and hydropower generation. Despite the recent increase in demand for these resources, little is known about the triggers and sources of extreme sediment flux events, which lower water quality and account for extensive hydropower reservoir filling and turbine abrasion. Here, we present a comprehensive analysis of the spatiotemporal trends in suspended sediment flux based on daily data during the past decade (2001–2009) from four sites along the Sutlej River and from four of its main tributaries. In conjunction with satellite data depicting rainfall and snow cover, air temperature and earthquake records, and field observations, we infer climatic and geologic controls of peak suspended sediment concentration (SSC) events. Our study identifies three key findings: First, peak SSC events (≥ 99th SSC percentile) coincide frequently (57–80%) with heavy rainstorms and account for about 30% of the suspended sediment flux in the semi-arid to arid interior of the orogen. Second, we observe an increase of suspended sediment flux from the Tibetan Plateau to the Himalayan Front at mean annual timescales. This sediment-flux gradient suggests that averaged, modern erosion in the western Himalaya is most pronounced at frontal regions, which are characterized by high monsoonal rainfall and thick soil cover. Third, in seven of eight catchments, we find an anticlockwise hysteresis loop of annual sediment flux variations with respect to river discharge, which appears to be related to enhanced glacial sediment evacuation during late summer. Our analysis emphasizes the importance of unconsolidated sediments in the high-elevation sector that can easily be mobilized by hydrometeorological events and higher glacial-meltwater contributions. In future climate change scenarios, including continuous glacial retreat and more frequent monsoonal rainstorms across the Himalaya, we expect an increase in peak SSC events, which will decrease the water quality and impact hydropower generation.


Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1227
Author(s):  
Moein Farahnak ◽  
Keiji Mitsuyasu ◽  
Takuo Hishi ◽  
Ayumi Katayama ◽  
Masaaki Chiwa ◽  
...  

Tree root system development alters forest soil properties, and differences in root diameter frequency and root length per soil volume reflect differences in root system function. In this study, the relationship between vertical distribution of very fine root and soil water content was investigated in intact tree and cut tree areas. The vertical distribution of root density with different diameter classes (very fine <0.5 mm and fine 0.5–2.0 mm) and soil water content were examined along a slope with two coniferous tree species, Cryptomeria japonica (L.f.) D. Don and Chamaecyparis obtusa (Siebold et Zucc.) Endl. The root biomass and length density of very fine roots at soil depth of 0–5 cm were higher in the Ch. obtusa intact tree plot than in the Cr. japonica intact plot. Tree cutting caused a reduction in the biomass and length of very fine roots at 0–5 cm soil depth, and an increment in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot one year after cutting. However, very fine root density of the Cr. japonica intact tree plot was quite low and the soil water content in post-harvest areas did not change. The increase in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot could be caused by the decrease in very fine roots at 0–5 cm soil depth. These results suggest that the distribution of soil water content was changed after tree cutting of Ch. obtusa by the channels generated by the decay of very fine roots. It was also shown that differences in root system characteristics among different tree species affect soil water properties after cutting.


2016 ◽  
Vol 32 (6) ◽  
pp. 498-509 ◽  
Author(s):  
Carlos L. O. Cordeiro ◽  
Dilce F. Rossetti ◽  
Rogério Gribel ◽  
Hanna Tuomisto ◽  
Hiran Zani ◽  
...  

Abstract:Amazonian white-sand vegetation has unique tree communities tolerant to nutrient-poor soils of interest for interpreting processes of adaptation in neotropical forests. Part of this phytophysionomy is confined to Late Quaternary megafan palaeo-landforms, thus we posit that sedimentary disturbance is the main ecological factor controlling tree distribution and structuring in this environment. In this study, we characterize the topographic trend of one megafan palaeo-landform using a digital elevation model and verify its relationship to the forest by modelling the canopy height with remote sensing data. We also compare the composition and structure (i.e. canopy height and diameter at breast height) of tree groups from the outer and inner megafan environments based on the integration of remote sensing and floristic data. The latter consist of field inventories of trees ≥ 10 cm dbh using six (500 × 20 m) plots in várzea, terra firme and igapó from the outer megafan and 20 (50 × 20 m) plots in woodlands and forests from the inner megafan. The unweighted pair group method with arithmetic mean (UPGMA) and the non-metric multidimensional scaling (NMDS) were applied for clustering and dissimilarity analyses, respectively. The megafan is a sand-dominated triangular wetland with a topographic gradient of < 15 cm km−1, being more elevated along its axis. The outer megafan has a higher number of tree species (367), taller canopy height (mean of 14.1 m) and higher diameter at breast height (mean of 18.2 cm) than the white-sand forest. The latter records 89 tree species, mean canopy height of 8.4 cm and mean diameter at breast height of 15.3 cm. Trees increase in frequency closer to channels and toward the megafan's axis. The flooded and nutrient-poor sandy megafan substrate favoured the establishment of white-sand vegetation according to the overall megafan topography and morphological heterogeneities inherent to megafan sub-environments.


1981 ◽  
Vol 61 (1) ◽  
pp. 173-175 ◽  
Author(s):  
M. R. CARTER

In Chernozemic soils, active CaCO3, an estimate of the CaCO3 in the clay and fine silt particles, proved to be a more effective site index for several tree species than total CaCO3. In general, active CaCO3 exceeding 7–9% caused incidences of stunted growth and chlorosis. High levels of active CaCO3 within the 0–30 cm soil depth were related to enrichment of CaCO3 in the clay fraction.


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