Supervisors:
Prof. S.C. Tiwari Department of Botany, HNB Garhwal University, Srinagar (Garhwal)
Dr.
K.S. Rao GBPIHED, Kosi-Katarmal, Almora
Summary: 1. The present study has been conducted in the buffer zone of ‘Nanda Devi Biosphere Reserve’ (District Chamoli). The area is completely protected and one of the most reputed in terms of cultural heritage, religious faith, biological wealth, climate and soil types etc. It is situated in Himalayan highlands biogeographic province-2B in India. The area was declared as a ‘Biosphere Reserve’ on 18th January, 1988 under ‘United Nations Education Scientific and Cultural Organization’ (UNESCO) ‘Man and Biosphere’ (MAB) programme. Its area increased from 2,236.74 km2 (624.62 km2 core & 1,612.12 km2 buffer zone) to 5,860.69 km2 (712.12 km2 core & 5,148.57 km2 buffer zone) recently due to addition of ‘Valley of Flowers’ and other adjoining areas of the reserve. The area of ‘NDBR’ extends into three districts viz., Chamoli, Bageshwar and Pithoragarh of recently segregated Uttaranchal state. Presently, the Biosphere Reserve covers 47 villages out of them, 34 villages falls in Chamoli, 10 villages in Pithoragarh and remaining 3 villages in Bageshwar district. Out of the 47 villages, 2 villages viz., Dwali and Phurkia in Bageshwar district are uninhabited.
2.
Geologically, the study area
falls between Dhauliganga and Rishiganga valleys of Garhwal Himalaya and
lie in the Joshimath formation. Which constitutes north-west to south-east
(NW-SE) trending belt and occurs in a high grade of metamorphism
represented by mica-gneiss, kyanite-silliminate and leuco-gneisses. The
central crystallines in the Dhauliganga valley divisible into three
litho-units viz. (i) Pandukeshwar
(ii) Joshimath and Tapovan formations. All
the litho-units represent fairly regular and lateral extensions. The
parent material mainly represents crystalline rocks and comprises of
garnetiferous mica, schists, garnet mica and mica-quartzite. The soil in
broad-leaved forests is usually dark black and deep due to the
decomposition of a large amount of organic matter, while in coniferous
forests it is generally light and shallow due to the presence of hard
rocks in soils and less amount of organic matter.
3.
The
area represents montane dry monsonic type climate due its undulating
topography and unique vegetation features. The whole year is divided into
three seasons viz., Rainy from
June to Mid-September; Prolonged-winter from Mid-October to April last and
Short summer i.e., May. The winter season represents harsh climate
and heavy snowfall, most of the rainfall is received during monsoon period
from June to Mid-September, while the winter snowfall frequently occurs
from November to March.
(i) The mid-June to mid-July was the hottest month of the year observed during study period i.e., March, 1998 to February, 1999 having an average temperature of 25.87 ºC to 29.10 ºC (maximum) and 13.19 ºC to 15.31 ºC (minimum). Average maximum temperature was 29.10 ºC and minimum -1.29 ºC recorded in the month of July, 1998 and January, 1999 respectively.
(ii) The
study area has an average annual rainfall 649.39 mm. The area is chiefly
influenced by the South-Western monsoon. The rainfall starts from Mid-June
and continuously takes place till Mid-September. The first half of the
June, prior to onset of the monsoon, occasional rainfall occurs. The
snowfall is frequently occurs in winter months. It was recorded 10.97 cm
and 0.32 cm in the month of March, 1998 and February, 1999 respectively.
(iii) The
maximum humidity 91.81 (at morning time) and minimum 66.36 (at morning
time) was recorded in the months of August, 1998 and April, 1998
respectively.
4.
The area represents one of the
most fascinating and characteristics vegetation all over the Garhwal
Himalaya not in terms of diversity but also in terms of density. The
vegetation of ‘NDBR’
comprises montane, sub-alpine and alpine types. The forests of the study
area are chiefly dominated by coniferous and broad-leaved species viz.,
Abies pindrow, Cedrus deodara, Pinus wallichiana, Mixed Abies & Pinus,
Betula utilis and Quercus
semecarpifolia.
5.
Out of the six studied
coniferous and broad-leaved forests (viz.,
Abies pindrow, Cedrus deodara, Pinus wallichiana, Mixed Abies & Pinus,
Betula utilis and Quercus semecarpifolia dominated stands), 16 species of top-canopy,
24 species of sub-canopy and 56 species of understorey layer vegetation
have been recorded during the study period (March, 1998 to March, 2002). The
highest number (52) of plant species (trees, shrubs & herbs) is
recorded under Quercus
semecarpifolia dominated and least (37) under Cedrus
deodara dominated forests.
6. The total density of top-canopy species ranged from 335 to 1415 individuals ha-1 under Quercus semecarpifolia and Betula utilis dominated forests respectively. Whereas, the total density of sub-canopy species ranged from 1118 to 2449 individuals ha-1 and the total density of understorey species ranged from 2526 to 7875 individuals ha-1. The basal area of top-canopy (trees) species ranged from 10.02 to 84.87 m2 ha-1.
7. The regular pattern of distribution was 0% under all the strata of all the six forest types. Whereas, the random pattern of distribution of top-canopy species ranged from 0 to 66.60%; for sub-canopy species it ranged from 0 to 18.75% and for understory species it varies from 2.12 to 27.72%. The contagious pattern of distribution for top-canopy, sub-canopy and understorey layer species varies from 33.40 to 100%, 60 to 100% and 72.72 to 95.13% respectively.
8. The highest (3.226) and lowest (0.014) diversity index (H¯) was found under Pinus wallichiana and Quercus semecarpifolia dominated forests respectively for understory species. The diversity index (H¯) of top-canopy species ranged from 0.043 to 2.286. Whereas, it was ranged from 1.193 to 2.158 and 0.014 to 3.227 for sub-canopy and understorey species respectively.
9. The concentration of dominance (cd) was highest (0.985) and lowest (0.032) observed under Cedrus deodara and Quercus semecarpifolia dominated forests for top-canopy and understorey species respectively. Under top-canopy it ranged from 0.157 to 0.985, under sub-canopy layer it ranged from 0.171 to 0.377. Whereas, the concentration of dominance for understorey species ranged from 0.032 to 0.768.
10. The community coefficient among six studied forests of the ‘NDBR’ ranged from 5.16% to 100%. The least value of community coefficient was observed between Cedrus deodara and Quercus semecarpifolia dominated forests.
11. Out of the six studied forests (Abies pindrow, Cedrus deodara, Pinus wallichiana, Mixed Abies & Pinus, Betula utilis and Quercus semecarpifolia), the highest amount (7.19 t ha –1 yr-1) of annual litter is under Betula utilis and lowest (5.19 t ha –1 yr-1) under Cedrus deodara dominated forest. The annual litter was sorted into five categories viz., leaves, twigs, barks, reproductive parts and miscellaneous. Tree leaves contributed the highest amount in total litter production, which varied from 45.60 to 70.22 % yr-1.
12. The contribution of dominant species in total production of forest litter was highest (81.14%) and lowest (38.72% by Abies) was found under Quercus semecarpifolia and Mixed (Abies & Pinus) forests respectively. The annual trend of litter production (t ha –1 yr-1) under four coniferous and two broad-leaved forests of the ‘NDBR’ was observed in order of Betula utilis (7.19) > Quercus semecarpifolia (7.17) > Pinus wallichiana (6.62) > Mixed Abies & Pinus (6.25) > Abies pindrow (6.16) > Cedrus deodara (5.19).
13. Published information on forests of the world indicates that the annual leaf litter production is almost equal to annual productivity of warm & cool montane forests. In the present study the productivity of litter was generally higher in broad-leaved forests viz., Betula utilis dominated and Quercus semecarpifolia dominated forests in comparision to conifer (Abies pindrow, Cedrus deodara, Pinus wallichiana) dominated forests. This is in contrast to observations made from other regions. Similarly, the non-leaf component of total litter is also higher when compared with other regions of the world.
14. The moisture content among senescenced leaf litter of 9 prominent top-canopy species viz., Abies pindrow, Cedrus deodara, Pinus wallichiana, Taxus baccata, Populus ciliata, Acer caesium, Juglans regia Betula utilis & Quercus semecarpifolia and composite leaf litter of Abies pindrow & Pinus wallichiana species was maximum (19.733 ±0.951%) observed in composite leaf litter than followed by Quercus semecarpifolia (19.300±1.441%) and least (8.207±2.953%) by Cedrus deodara in their dominated forests.
15. Among the conifer species Cedrus deodara showed least and Pinus wallichiana showed highest mass loss in 360 days of leaf litter decomposition. Similarly, among the broad-leaved species Populus ciliata and Acer caesium showed highest mass loss in 360 days of decomposition. Whereas, the composite leaf litter showed about 50% of initial mass loss in 360 days of decomposition.
16. The concentration of nitrogen in initial mass was least in Pinus wallichiana and highest in Abies pindrow. Similarly, for exchangeable phosphorous concentrations in initial mass of litter the values is least for Acer caesium and highest for Abies pindrow. The concentration of potassium was highest in Acer caesium and least in Taxus baccata leaf litter and exchangeable calcium concentration is highest in Quercus semecarpifolia and least in Juglans regia leaf litter mass.
17. The composite leaf litter of Mixed (Abies & Pinus) forest showed highest release in 360 days of decomposition. Among the species studied Juglans regia showed maximum release and Populus ciliata least release of nitrogen after 360 days of decomposition. While Abies pindrow and Taxus baccata showed least nitrogen release among the conifers the other two remaining conifers considered in the present study (Cedrus deodara & Pinus wallichiana) showed release of about 50% nitrogen of initial mass. Barring the Juglans regia all the broad-leaved species considered in the present study showed release of less than 22% nitrogen of initial mass.
18. The release pattern of total phosphorous from decomposing leaf litters of studied species was generally more than 47% of initial mass in all species studied and maximum in Abies pindrow (81.30%) and Juglans regia (80.34%). Betula utilis is a prominent species of cool montane forest communities showed least release of total phosphorous during the 360 days of decomposition. The release is prominent for Abies pindrow, Pinus wallichiana and composite leaf litter of Mixed (Abies & Pinus) forest stand during the first 90 days of decomposition.
19. The release pattern of potassium from decomposing leaf litter of studied species was highest in Juglans regia followed by composite leaf litters of Mixed (Abies & Pinus) forest stand showed highest release in 360 days of decomposition. It was observed to be least in Populus ciliata leaf litter. Among the conifers both Abies pindrow and Taxas baccata showed less than 20% release of initial mass while the other two species among those studied (Cedrus deodara and Pinus wallichiana) showed release of about 40-55% of initial mass during the 360 days of decomposition. Among the broad-leaved species studied, Betula utilis, Quercus semecarpifolia and Populus ciliata showed release of less than 24% of initial mass while the other two species among those studied (Acer caesium and Juglans regia) showed about 43% and 66% of initial mass respectively.
20. The release pattern of calcium during 360 days of decomposition was highest in Juglans regia and least in Populus ciliata. The release patterns of this element for other studied species do not showed any pattern of variation between conifers and broad- leaved species.
21. The studied species showed annual decay constant (k) between 0.61 to 0.74 indicating that all species required more than one year for complete disappearance of litter mass. Among the species studied, three broad-leaved species viz., Acer caesium, Juglans regia and Quercus semecarpifolia showed least turnover rates (1.35) and highest by Cedrus deodara (1.64), Taxus baccata (1.52) and Abies pindrow (1.47). The composite leaf litters of Mixed (Abies & Pinus) forest showed a turnover time of 1.41 years.
22. The decomposition of dominant species contributing maximum biomass of litter influences the quantity of nutrients returned to the soil. Though the removal of leaf litters from the forest floors for supporting annual food crop production is a major threat to forest health, understanding the decomposition rates of dominant tree species in their natural environment is required to understand the natural mechanisms existing in the region. The broad-leaved species and most commonly used conifer species (Pinus wallichiana) of the region showed similar decomposition rate (k) and time (t). These litters generally disappeared faster in comparision to those of Abies pindrow, Cedrus deodara, and Taxus baccata. Barring Populus ciliata all other species showed strong correlation between remains mass and its nutrient concentration.
23. The soil fertility status of these forests indicated that though the parent material has greater influences in determining the nutrient availability, the vegetation development influences the status when the parent material is similar. In the present study the soil available phosphorus showed strong correlation with total nitrogen than organic carbon. The immobilization of phosphorus in soils from Himalayan region in particular and montane regions in general is a major point of discussion for the people concerned with forest health and nutrition. The relatively lower concentrations of phosphorus in tree leaves as reported by other workers might be an adoptive mechanism of plants growing in the region.
24. The soil colour of six forest stands was studied and it was observed that the soil chroma was found lighter with increased depth except in Cedrus deodara and Pinus wallichiana dominated forests. The soil depth in the studied forests greatly varied. With increased depth, the gravel particles (> 4.75 mm size) increased generally except in Mixed (Abies & Pinus) forest stand. However, the finer particles (< 75 mic size) showed marked variation among the communities. While they were found to be higher in Abies pindrow dominated forest, least in Pinus wallichiana dominated stand in top layer of soil (0-15 cm depth). Similarly, the finer particles (< 75 mic size) were higher in Quercus semecarpifolia dominated and Mixed (Abies & Pinus) forest types and least in Betula utilis dominated forest in top-layer of soil (0-15 cm depth).
25. The bulk density (gm cm-3) of forest soils varied between 1.14 to 1.94 g cm-3 in from 0-45 cm depth. No variation was observed between coniferous and broad-leaved stands. A little variation observed even between two conifer dominated forest or two broad-leaved forest stands.
26. The canopy density of forests generally determines the amount of sunlight reaching the ground level. As the canopy regimes of studied forests varied greatly due to composition and due to periodicity within a community, the soil moisture values varied greatly between forest communities and between seasons within a forest community. Though these differences are due to soil texture and inherent capacity of soil, seasonal variations within community are related to the phenophases of the plant community.
27. The soils of the region are generally acidic in nature. The pH values of studied communities is significant variation was observed between conifer and broad-leaved forest types. The seasonal variation of organic carbon concentrations (%) is prominent across the soil depth in all forest types. Generally September or December sampling periods showed least values. While the organic carbon concentrations in soils varied greatly between each of the forest community studied, no pattern was observed to differentiate between conifers and broad-leaved forest types.
28. The concentration of total nitrogen in the soils of studied forest communities decreased with increasing soil depth. The values are maximum either during September or December sampling periods in the study area.
29. The plant available phosphorus concentrations were lowest in the soil of all studied forests during the sampling of June, 1998. Though the concentration was observed to be decreasing with increasing soil depth no significant variation was observed.
30. The exchangeable potassium concentrations in the soils of studied forest communities generally decreased with increased soil depth. While the concentrations were lowest during June, 1998 in all the stands. No significant pattern between conifer and broad-leaved forest communities could be observed.
31.
The exchangeable
calcium concentration in the soils of studied forest communities increased
with increase in soil depth. Generally the concentration was least during
June, 1998 observation in most instances.
32.
The soil C: N: P ratio
from 0–45 cm depth was studied. The ratios of C & N varied
consistently with respect to P. Barring few exceptions on sampling dates,
the C:P ratios are generally high in Mixed (Abies & Pinus)
forest soils and least in Betula utilis dominated forest soils.
However, C:N ratios didn’t showed any specific pattern.
33. The three studied villages are situated between 2100 to 2500 m elevation. Only Lata village had some community forest managed by a local council. The other two villages do not have any such forest. All these villages like others in the buffer zone depended for all their requirements on forests existing in their vicinity. Lata is the biggest village with 77 households and Peng is the smallest one with 31 households. Households with 5-8 members are predominant in all villages and households with more than 8 members are few. Agriculture is the main occupation of more that 45% of households. Than livestock rearing followed by Government jobs, forest resource extraction and woollen handloom are other occupations where households of studied villages depend for their livelihoods.
34. The diversity of resources used as fuel and fodder is great compared to other uses. Food supplements and medicinals are the major uses for which these resources are harvested. Most of these resources are collected mainly during summer and rainy seasons, as they are available during these periods. The number of resources collected during the winters is least, as the availability is least due to harsh climatic conditions.
35.
The most preferred
fuelwood species are Quercus
semecarpifolia, Abies pindrow, Cedrus deodara, Populus ciliata etc.
The Quercus semecarpifolia have
high moisture content while Betula
utilis and Viburnum cotinifolium have low moisture contents. The average
fuelwood consumption in Reni village is least while Peng village showed
highest value and the total village requirements are highest (458.88 t yr-1)
at Lata and least (225.59 t yr-1) at Peng.
36.
The crop by products
contribute 58 to 63% of total fodder used for stall-feeding and rest of
the fodder is collected from forest (21 to 25%) and grasses from forest
floor and community lands (16%). The total fodder consumed for
stall-feeding in these three villages is not significantly different and
also the estimated total fodder requirements. The estimated fodder
consumption through open grazing by the bovines and equines based on
average feed requirements works out to be 58 to 59% of total requirements
in these villages.
37.
The non-timber forest
products and other food supplements such as wild- edible fruits,
vegetables etc., constitute a major part of harvested resources
followed by medicinal plants. Such harvested resources are significantly
higher in village Peng compared to villages Lata and Reni.
38. The ‘Protected Areas’ are legally established chiefly for the conservation of biodiversity and ecological balance in nature. In ecosystems of the ‘Protected Areas’ such as Sanctuaries, National Parks and Biosphere Reserve, the sole objective of forest ecosystem is to provide ‘in situ’ conservation of biota. Out of a variety of resources, the forest is one of the most significant biological units for the existence of humanbeing and other creatures having a vast social organization at functioning stage. Thus the forest ecosystem is a complex entity having a variety of trophic organization like food chain, food web made up of various biological units that have come into being as a result of combined action, co-action and many reactions of organisms with complex factors of habitat.
39. The warm & cool montane forests surrounding the human habitations in the buffer zone of ‘NDBR’ have classified into six types. They are Abies pindrow, Cedrus deodara dominated, Pinus wallichiana, Mixed conifers, Betula utilis and Quercus semecarpifolia dominated forests. The density (ha-1) of stems and IVI values of these forests were found to be within the ranges observed for montane forests in the region and elsewhere, except those of Quercus semecarpifolia dominated forest. The lower values for this forest stand may be due to excessive anthropogenic pressures on the community by the local population in the region.
40. The regeneration potential information of forest communities studies indicates this may be true as the number of trees existing both as mature and regenerations individuals is highest in these communities. The highest number of species also indicates threats to the existing biodiversity of this community without any regenerating individuals in this community.
41. The anthropogenic pressures on surrounding forests near to habitations indicate, they are significantly large. This may be a major reason for gradual degradation of forests near to habitations. The ecodevelopment plans of ‘NDBR’ management needs to give special emphasis on providing alternate source of fuel, fodder and biomass for manure preparation to reduce the impact of human use on forests near to habitation.
42. The central Himalaya, with its dramatic differences in altitude and climate,
supports
a great variety of forest ecosystems. The moist temperate evergreen
broad-leaved and mixed coniferous forests are found between 1500 to 3500 m
elevation zones. Major ‘Protected Areas’ such as ‘Nanda Devi
Biosphere Reserve’ is situated in this zone and they contain even the
sub-alpine and timberline forests, alpine graging lands and perpetual snow
zones. Three basic farming systems are supported by vast forest resources
of central Himalaya. These are: livestock farming, mixed livestock-crop
farming and mixed crop-livestock farming. Though the first two types used
to be the predominant farming systems of ‘Nanda Devi Biosphere
Reserve’ area, the last one is becoming more prominent during the lest
20 years or so. Such changes impose drastic changes in natural resource
use patterns and change the dependency of local inhabitants on forests
near to their habitations. Majority of the rural people in Himalaya use
multipurpose trees for their domestic needs (fuelwood, fodder and minor
timber) and such resource utilization in the region existed for many
centuries. The dead, dying, diseased trees and branches are quite
sufficient for the domestic needs through the year.
Understanding this dependency of villagers on adjoining forests is
a complementary aspect of interdisciplinary study, which helps in
identifying the various economic groups of any region and their biomass
energy requirements. Thus the present study aims at assessing the fuel,
fodder and minor forest produce extraction patterns from adjoining forests
of villages.
Shankar Datt Tiwari
Subject : Botany
Ph. D - Botany H.N.B.Garhwal University, Srinagar (Garhwal)
Work Title
Studies on forest ecosystem in a protected area of Garhwal Himalaya