Hydroclimate change in the Garhwal Himalaya, India at 4200 yr BP coincident with the contraction of the Indus civilization

High-resolution analysis of a 3.80 m sediment core recovered from Deoria Tal, a mid-elevation lake located at 2393 m a.s.l. in the Garhwal Himalaya, documents long-term and abrupt hydroclimate fluctuations in northern India during the mid- to late Holocene. The sediment chronology, based on ten 14C dates, indicates the core spans 5200 years. Non-destructive, radiological imaging approaches (X-ray fluorescence (XRF), X-ray imaging, and CT scans) were used to assess the response of the lake system to changing hydroclimatic conditions. Variations in elemental concentrations and sediment density evidenced notable hydroclimate change episodes centered at 4850, 4200, and 3100 cal yr BP. Elevated detrital input, greater sediment density, decreased lake ventilation, and lower autochthonous productivity reflects lake deepening between 4350 and 4200 cal yr BP. An abrupt shift in elemental concentrations and sediment density indicated the onset of lake drawdown at 4200 cal yr BP and a negative hydroclimate anomaly between 4200 and 4050 cal yr BP. Lower detrital flux, decreased sediment density, increased oxygenation, and higher autochthonous productivity, reflects a reduction in lake volume between 3200 and 3100 cal yr BP. The potential link between abrupt climate change at 4200 cal yr BP and the contraction of the Indus civilization is explored.

Extraction of Rhododendron arboreum Smith flowers from the forest for the livelihood and rural income in Garhwal Himalaya, India

Rhododendron arboreum locally known as ‘Burans', that bears magnificent flowers is one of the valuable non timber forest produces (NTFPs) in Garhwal Himalaya. These flowers are good source of income for local populace and help them to their subsistence up to some extent. R. arboreum flower can help local population to improve their livelihoods if potential harvesting is carried out sustainably. An attempt has been made to estimate the flower yield, examine extraction techniques, marketing trends and various uses of flowers. Stratified random sampling method was carried out in eight sites varying in altitudes and geographic locations. Flower yield kg/ha for each site was calculated as standard process. Questionnaire based survey was carried out in selected villages for flower extraction and marketing trends. Projections of potential (probable/-could generate) income were made and cost–benefit analysis was also estimated. Tree density of R. arboreum ranked first and Q. leucotrichophora had second rank while 16–25 cm cbh class tree density for R. arboreum was found highest across the sites. Flower yield was significantly (p < 0.001) higher at Khirsu site with 26–35 and 46–55 cm cbh class. There was positively significant correlation (n = 446, p < 0.001, r = 0.53) between flower yield and actual cbh. Flower yield has a direct relation with size of tree whereas yield has been less impacted by the sites. Average yield of flowers across the sites was about 25.3 ton/ha. On average 30% households are engaged in the extraction and trade activities with the extraction rate of 25–350 kg/household/year. A net household income of Rs. 6000–37,000 (89–545 USD) per year was computed from Rhododendron flower extraction and marketing business. The total monetary benefit was significantly higher than the inputs for all value added items on a per day basis. R. arboreum plays important role in ecological and economic sustainability of poor rural people and unemployed youths in Himalayan region. This can reduce unemployment through development of small cottage industry and entrepreneurship at village level by making different food products i.e. juice, squash, sauce and pickle etc.

STRUCTURAL ATTRIBUTES, DIVERSITY AND MANAGEMENT OF SOME VAN PANCHAYAT FOREST STANDS OF GARHWAL HIMALAYA

Oak (Quercus oblongata) is an important component of mid-altitude ecosystem of the Central Himalaya which are exposed to over-exploitation making conditions favourable for the invasion by light-demanding conifers such as chirpine (Pinus roxburghii). The present study provides information on woody vegetation structure, composition, regeneration and management of four broadleaved forest stands of Garhwal Himalaya managed by Village Panchayat. Quercus oblongata was the most important and dominant species in all the stands. Although dominance was shared by a number of species, no single species was found to complete with this climax species. The presence of Alnus nepalensis (a nitrogen-fixing species) depicts the poor nitrogen status of these forest stands. High density values and low basal cover suggest that these community forest stands are younger than the natural oak reserve forests of the Central Himalaya. The richness index shows that the seedling strata are ecologically richer than the tree, sapling and/or shrub strata. High richness in the seedling strata is attributed to the low magnitude of biotic interferences in these communities based conserved forest stands. The regeneration potential of Quercus oblongata is much higher than the natural oak forests of Central Himalaya managed by the forest department. This supports the view that moderate disturbance regimes are more conducive to satisfactory regeneration of this species. Since the management of these forest stands is looked after by the Village Panchayat, they are introducing some conifers for their vested interests. This may add an additional competition of the broadleaved climax species with conifers as has been witnessed in most of the broadleaved oak forests of this altitudinal range.