P. Saikia

Ecological Features of Cultivated Stands of Aquilaria malaccensis Lam. (Thymelaeaceae), a Vulnerable Tropical Tree Species in Assamese Homegardens

Research was conducted in twenty-seven selected villages located in Jorhat and Golaghat districts of upper Assam, northeast India, for population estimation, quantitative ecological analysis, and evaluation of Aquilaria malaccensis (Thymelaeaceae). Vegetation sampling was done by quadrat method and A. malaccensis is the most dominant tree species in all twenty-seven different study sites of upper Assam contributing 10–54% of the total tree density with a mean of . Density of the species varied from 6,236 individuals ha−1 to 429 individuals ha−1 with a mean of 1,609 individuals , whereas frequency of occurrence is very high ranging from 93% to 100% with a mean of in different study sites. Distribution of A. malaccensis is found contagious in all twenty-six study sites on the basis of abundance to frequency ratio except in KBG, Golaghat, where its distribution is random with 0.04 abundance to frequency ratio. The widespread cultivation of A. malaccensis in upper Assam, northeast India, offers a potential ex situ reservoir for the future conservation and management of this threatened tree.

Diversity, Uses and In vitro Propagation of Different Bamboos of Sonitpur District, Assam

Bamboos are the tallest and largest member of the grass family and widely distributed in India and abundantly occur in northeast region. A few species are also found scattered in other parts of the country both in the hills and the plains. Bamboos play an important role in the day to day lives of common people of Assam and become an integral part of the cultural, social and economic traditions of the State. Besides, it is an essential component of forest ecosystem and commonly found in the traditional home gardens of Assam. Study was carried out in 62 randomly selected home gardens of Sonitpur district of Assam. The maintenance of bamboo diversity in home gardens fulfills the household necessity and also contributes to the rural economy. The commonly found bamboos are B. tulda, B. balcooa, B. pallida, B. nutans, B. bambos, Dendrocalamus strictus, D. hamiltonii, Melocanna baccifera etc. Home garden based bamboos have also great demand as a construction materials, fencing, fodder and also as a source of fiber for paper industry. Tissue culture technique is also applied in three selected Bamboos for large scale production of plantation stocks for commercial cultivation. Rural employment can be generated by proper cultivation and management of bamboos in traditional home gardens thereby helps in conservation of bamboo diversity without much care and effort.

Homegardens of upper Assam, northeast India: a typical example of on farm conservation of Agarwood (Aquilaria malaccensis Lam.)

This study has investigated the potential of homegardens in conservation of Agarwood (Aquilaria malaccensis Lam.), a critically endangered tree species of northeast India with great economic value. Agarwood is the most dominant tree species in the studied homegardens of upper Assam as it has the highest frequency (98%) and density (1443 individuals ha−1) and it contributes 34% of the total tree density. It contributes significantly to the economy of the local people and income generation from Agarwood by individual family ranges from ₹ 3000.00 (US

Biodiversity Status and Climate Change Scenario in Northeast India

600.00) to ₹ 9,00,000.00 (US

Tree Species Diversity and Its Population and Regeneration Status in Homegardens of Upper Assam, Northeast India

18,000.00) with an average of ₹ 1,14,393.00 (US

Population status of Aquilaria malaccensis Lam.: A critically endangered tree species of India in Assamese homegardens

2287.86) per year. Besides its economic potential, it is also on the verge of extinction and needs proper conservation and management for further existence. Agarwood shows good regeneration and population status in studied homegardens of upper Assam. Therefore, homegardens can save the species from the risk of extinction and thus can be considered as a tool of on farm conservation of Agarwood.

Floristic composition and plant utilization pattern in homegardens of Upper Assam, India

Conservation of biodiversity and impacts of climate change are perhaps the most critical challenges faced by all sectors of the society. The patterns and processes related to climate change and biodiversity are so complex that corrective measures are often taken with an imperfect scientific knowledge base. This article addresses the biodiversity status and climate change scenario in Northeast India. The normalized difference vegetation index (NDVI) is used to explain the vegetation pattern of Northeast India and majority of area (58 %) are under tropical climatic zone, followed by subtropical (23 %), alpine (10 %), and temperate (9 %) zones. Although the Northeastern India is very susceptible to climate change because of its ecological fragility, the forest cover is reported increasing in the past few years because of the successful implementation of the different plantation and community development schemes. In order to avoid rapid and irreversible change in biodiversity, conservation strategies needed to focus on supporting the species’ natural capacity to adapt to climate change.

Comparative Study on Homegardens of Assam and Arunachal Pradesh in Terms of Species Diversity and Plant Utilization Pattern

Study was conducted to investigate tree diversity and its population and regeneration status in homegardens of upper Assam, Northeast India through field study by quadrat method. A total of 154 tree species have been recorded from 135 studied homegardens under 109 genera 53 families. Most of these species (79%) are indigenous to our country, while the rest (21%) arealiens (naturalized and cultivated exotics) by origin. Tree species richness per homegarden varies greatly in different homegardens and is ranged from 5 to 52 tree species with a mean of 22 (). A. malaccensis is the most dominant tree species in the studied homegardens contributed 34% of the total tree density of the documented trees. The tree density is much higher with 4,259 individuals but, basal area () is very less. Based on the number of individuals present, very rare species is accounted for 10%, rare species 39%, common species 19%, dominants 14% and predominant species 18% in the present study. The population density of 154 tree species is 4,259 (individuals ) for adults (>3.18 cm DBH), 5,902 (individuals ) for saplings and 38,164 (individuals ) for seedlings. The density of seedlings>saplings>adults represents good regeneration status of tree species in studied homegardens. The population structure study showed that about 8% tree species have good regeneration status, 9% have fair regeneration status, 48% have poor regeneration status and 34% tree species have no regeneration. Study suggests that research and development action is needed to stimulate regeneration of those tree species which having high importance value indices but showing poor or no regeneration. Based on present observation, it can be conclude that homegarden can emerge as an effective means for both economic well-being and biodiversity conservation in upper Assam, Northeast India.

Agar ( Aquilaria malaccensis Lam.): a promising crop in the homegardens of Upper Assam, northeastern India

N ribosomal internal transcribed spacer (ITS) and chloroplast matk DNA sequences variation was analyzed to understand the inter-specific relationships of the genus Cucumis with focus on Indian representative species. 16 taxa, belonging to 11 species and 5 varieties of Cucumis were studied. The aligned ITS sequences were 688 bp in length, while that of matk sequences were 1364 bp. Both the regions showed variability with respect to sequence lengths, G+C content, nucleotide substitution, insertion/ deletion, transition/ transversion. Phylogeny reconstructions were conducted separately for these two data sets using maximum likelihood criteria and Bayesian inference. The genomic diversity and phylogenetic interrelations of the genus Cucumis will be discussed in detail.P observations were taken for 20 woody species for three years in the four tropical dry evergreen forests namely Kothattai, Sendhirakillai, Palvathunnan and Vada Agaram on the coromandel (east) coast of peninsular India. In total four forest sites were selected, of which Vada Agaram was located 28 km north of Pondicherry (11°56′ N and 79°53′ E) town, and three other sites are around Cuddalore (11°43′ N and 79°49′ E). The sample size ranged between 5 to 10 individuals per species and 20 species with 251 individuals. The flowering and fruiting pattern was almost similar during the study period. During the study period, the flowering and fruiting phenology has two peaks, one major peak was observed during the dry month (Feb to Apr) and another small peak was observed in the monsoon (Aug to Oct). In tree individuals it was found that 78 % flowering and 67 % fruiting was recorded in 2011 followed by 76 % flowering and 62 % fruiting was in 2010 and 74 % flowering and 64% fruiting was recorded in 2009. There is no much annual variation in flowering and fruiting phenology of tropical dry evergreen forest. Out of 20 species 4 species were found to produce flowers and fruit twice in a year remaining all the species produce flowers and fruit only once in a year. Flowering and fruiting phenology of TDEF clearly shows the seasonality pattern.T number of mushrooms on the earth was estimated around 140,000 of which only 10% are known (Wasser, 2002; Lindequist et al., 2005). Tropics are considered as rich repositories of mushroom diversity and most of the new mushrooms reported in recent years are from tropics, especially those species forming ectomycorrhizas with native trees (Hawksworth, 2001). In various tropical areas, 22–55% of mushroom species have proved to be undescribed (Hawksworth, 2001; Wasser, 2002). India is one such tropical country with diverse ecological characteristics for species richness. Considering the large area of the country and different vegetation types, this species number is accountable. Further, a large agaric flora from different parts of the country is yet to be described.