B. G. Dabral , S. P. Pant , S. C. Pharasi

Abstract

The paper details the ischolar_main habits of Eucalyptus grown in isolation in pots and in a community In large sized lysimeters and in the plantation. Different ischolar_main habits were observed. In general, ischolar_mains avoid the path taken by existing ischolar_mains. Environment especially bulk density of the soli mass exerts a profound influence upon the ischolar_maining pattern. No interspecific or intraspecific ischolar_main grafting was observed but self-grafting was noticed in Eucalyptus hybrid ischolar_mains. The observations discussed in the paper are not exhaustive but indicative of the ischolar_main habits, this Species is capable of adopting. Considering the vast area, different soli types and agro-climatic zones, where Eucalyptus grows and managed by the differing silvicultural practices, the studies need to be taken up on widespread area. Tbe studies assume an added importance considering the large scale planting of Eucalyptus spp. In agro-forestry and social forestry.

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A. S. Raturi , B. G. Dabral

Abstract

The paper details the water consumption behaviour or Chir-pine, Banj-Oak, Sal and Ipil-Ipil in Juvenile stage conducted in plastic and glazed earthen pots. Amongst Chir-pine, Oak and Sal, lowest transpiration ratio is depicted by Chir-pine and the highest by Oak. Although the transpiration ratio of Ipil-Ipil is lowest, its water consumption is highest. Ipil-Ipil being a rast growing species requires bigger space than that provided here for conducting the experiment. The results indicate that due to the comparatively bigger needs for water consumption by Chir-pine, replacement of degraded Oak forests by this species, on the northern aspects may dry the sites adversely, affecting the water regime of the tract but on southern and western aspects which are comparatively warmer and dryer the water regime may not be significantly affected. Thus it is thought that such degraded Oak areas in the hills, earmarked for Oak regeneration, should not be brought under Chir-pine, lest the already deficit soil moisture regime may further deteriorate. Besides, pines have a tendency to turn alkaline soils acidic, which is detrimental for Oak regeneration. However, studies are required to be done on the watersheds itself for confirmation. The plastic pots seem better indicative of treatment responses compared to the glazed earthen pots.

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B. G. Dabral , S. P. Pant , S. C. Pharasi

Abstract

No Abstract

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J. S. Samra , B. G. Dabral , Kalyan Singh

Abstract

Regeneration of Sal (Shorea robusta) with reference to morphological, physico-chemical, topographical and ischolar_main distribution characteristics of lithosphere have been studied in West Dehra Dun Forest Division of U.P. Soil temperature and moisture at two depths along with air temperature at two heights were also monitored throughout the year. Poor drainage, deficient aeration, dispersed conditions of soil during monsoon due to high Mg, soil moisture stress coupled with hardness during dry periods and topographic location seem to be important edephic factors governing natural regeneration of Sal. Compartively low temperature and high amplitude in diurnal variation in air and soli temperature during winter season possibily due to scanty ground flora, absence of shrub layer and topographical location may be some of micro-climatic factors, affecting natural regeneration.

Keywords

Edaphic Factors, Mioroclimatology, Regeneration

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B. G. Dabral , A. S. Raturi

Abstract

The paper presents the results of water comsumption by Eucaluptus hybrid trees during the last 27 months in 3m × 3m × 3m R.C.C. lyalmeter. Water consuption form 30 to 24.5 cm depth was slightly lower than the rainfall received, although water consuption from the entire soil depth(0-24.5) exceeded the rainfall due to the previously stored soil water. Maximum amount of waater was consumed during rains and the least during summer.

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B. G. Dabral , B. S. Negi

Abstract

no abstract

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B. G. Dabral , S. P. Pant , S. C. Pharasi

Abstract

The paper details the ischolar_maining behaviour in Sal (Shorea robusta) tree at a site having compacted soil and with a hard pan formation. The tap-ischolar_main extended upto 1.2 m only. Lateral ischolar_mains extended upto a length of about 12 m in the direction of a 'nala', thereby sbowing that with shallow tap-ischolar_main, long lateral ischolar_mains running parallel to the soli layers get formed, to meet the water needs of the tree especially in hot dry season.

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B. G. Dabral

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The subject of the elfect of forests upon rainfall has been of a controversial nature for a long time. In this paper, an effort has been made to review the various views expressed on the subject, so far. It appears that forests do not exert any significant influence upon the rainfall of a region.

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R. C. Ghosh , B. G. Dabral

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The experiment details the water consumption of Pinus caribaea in juvenile stage in three high density stockings under three water regimes, in minilysimeters. The experiment aims at judicious utilization of space and irrigation in raising plantations. 63 seedlings per m² with 100-80% available soil moisture gave maximum dry matter as well as highest production ratio.

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B. G. Dabral

Abstract

Research work on Forest Influences is to evaluate the significance of the effects resulting from the presence of forests upon climate, soil water, run-off, streamflow, soil productivity and to understand their relation to the aspects of succession, natural reproduction, cutting, fire and the management of forest for their climatic and watershed values. The results of research done on regional basis should be applied for appropriate remedial measures for deteoriated and damaged watersheds as well as towards maintenance of the health and hygiene of properly functioning watersheds. The interpretation of forest influences should take into consideration the entire watershed as a living unit and should not be limited to the different components which constitute it.

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B. G. Dabral

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No abstract

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B. G. Dabral , Premnath , Ramswarup

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An attempt has been made to study the interception caused by litter in four forest species. It has been observed that sal and teak litter induced greater interception than done by chir, pine and bamboo species. It was also observed that interception values were higher with lower amounts and intensities of rainfall. The amount of litter present also influenced the interception values.

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J. S. P. Yadav , B. G. Dabral , Premnath

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The paper deals with soil moisture studies made in a bamboo and a grass plot in the Demonstration Area of F.R.I., Dehra Dun. The results revealed that: 1. Soil moisture content generally remained at a higher level under bamboo than under grass, though it was not always the rule. 2. Total soil moisture depletion and accretion values were recorded greater under grass, but the soil moisture balance showed higher negative values under the bamboo cover. 3. Soil moisture depletion decreased with depth excepting 2-3 feet zone where it was less than 3-4 feet layer. Almost similar was the case with accretion values. 4. At no depth soil moisture content exceeded its water holding capacity.

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B. G. Dabral , Sachidanand , Ram Swarup

Abstract

No abstract

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B. G. Dabral , H. K. Bali , H. K. L. Bhalla

Abstract

The studies discussed here reflect upon the trend of dew deposition inside the chirpine, teak and bamboo plantations growing at F.R.I. Reserve forest. It was observed that dew deposition was much retarded under canopy covers. It was also noticed that no frost was recorded inside these plantations.

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I. M. Qureshi , J. S. P. Yadav , B. K. Subba Rao , B. G. Dabral

Abstract

Soil and water constitute by far the two most valuable natural resources and need to be protected from every loss. The various factors like inadequate vegetative cover, indiscriminate deforestation, excessive grazing, faulty cultivation, unsound agronomical practices, burning, defective land use, and neglect of soil conservation in the catchment areas of many rivers cause severe floods and run-off which result in tremendous damage. Excessive run-off whether it results in floods or not is by itself a wasteful phenomenon involving loss of both soil and utilisable water yield. The water balance of a watershed involving the various losses and gains has been explained. The importance of infiltration, percolation and storage capacity of the soil in governing the surface flow, sub-surface flow and base flow of precipitation has been dealt with. An account has been given of the effect of various soil characteristics on infiltration, percolation and storage capacity as well as water movement and hydrology of a given area. The harmful effects of burning, grazing and other faulty practices on the soil properties and hydrological conditions of a tract have been described. Important features of some common soil groups found in India having a bearing on their moisture relations have been mentioned. The value of soil moisture studies in understanding the water balance and in deciding suitable management practices to prevent floods and run-off has been emphasized. The effect of different vegetative covers on the soil properties, water movement and storage, interception, evapotranspiration, water yield, intensity of run-off and floods and such other aspects which are fundamental to the hydrological cycle of watersheds has been elucidated. The importance of the quality of water yield has been emphasized and has been correlated with the vegetative cover and with soil conditions. The beneficial role of the maintenance of a suitable vegetative cover in the control and prevention of floods has been examined. The protective and ameliorative functions of forests on steep slopes and undulating lands which are highly susceptible to quick run-off and easy soil wash have been emphasized. It has been stated that there is scarcity of scientific data on many such aspects in India. In view of the magnitude and complexity of the problem of run-off and floods the urgent necessity for a correct assessment of the exact requirements of each watershed in the light of varying climatic, edaphic and biotic conditions has been stressed so as to evolve most suitable management practices. An integrated approach to the study of hydro-meteorological elements with the cooperation of different research and administrative organisations in the country has been proposed.

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B. G. Dabral , J. S. P. Yadav , D. R. Sharma

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Soil moisture studies made in the sal, teak and chir-pine plantations indicated that the total soil moisture accretion values for 0-4 feet soil depth were nearly the same for teak and sal, the depletion values being slightly lower under teak than under sal. Chir recorded lower accretion and depletion rates as compared to the other two species. Soil nl0isture accretion and depletion rates varied for each foot depth of the soil mass and showed a close relation between themselves, thereby indicating that the available soil moisture is an important factor in governing the loss of water through evapotranspiration. The actual soil moisture content usually remained below the field capacity. In general, the soils of different species studied showed considerable variations in the moisture content. Apart from the effect of species which was of a lower magnitude under the prevalent climatic conditioJ1s of the locality, the differences in mechanical Composition, water holding capacity and organic matter content of the soil appeared to be of greater importance for these observed variations.

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I. M. Qureshi , B. K. Subba Rao , B. G. Dabral

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A study towards establishing the rdationship of frost deposition and the prevailing metrorological phenomena in open and sal cover conditions (2 to 600 cm height) during the cold spell of 1963-64, was made at NoW Forest. In the open it was observed that lower minimum temperatures and vapour pressure followed the frosty nights. Mulches were conducive in inducing frost depcsiticn. No frost deposition occurred under sal cover. Although frost caused damage to the standing vegetation, the established shrubs, poles and trees got reclothed with foliage on the return of favourable weather. As frost occurence is a microclimatic phenomenon, it is suggested that the microclimatic effects produced by the forestry operations in vogue be studied in detail and factual scientific data be collected.

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B. G. Dabral , B. K. Subba Rao

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The paper presents the results of studies made on stemflow, throughfall and interception losses in a chir and teak plantation at Forest Research Institute Reserve Forest. It was seen that chir pine conducted 3.6, 74.3 and 22.1 per cent of gross rainfall as stemflow, throughfall and interception losses respectively for rainfall groups up to 2". The corresponding figures for all rainfall groups considered together were 8.8,69.7 and 27.0 per cent of gross rainfall. In teak 6.0, 73.2 and 20.8 per cent and 7.1, 64.1 and 28.8 per cent of rainfall were conducted as stemflow, throughfall and interception losses in respect of all rainfall groups combined together and for 0"-2" rainfall groups respectively. Since maximum number of trees in chir plantation fell within the diameter range 7.6 mm to 22.9 mm (3" to 9") it may be assumed that stemflow and interception losses ranged between 2 to 3.9 and 22-24% respectively of the total rainfall. The corresponding figures in respect of the teak plantation, where maximum. Number of trees were within diameter range of 15.2 mm to 30.5 mm (6" to 12") were 2.5 to 7.9 and 18:9 to 24.4 per cent of the total rainfall

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B. G. Dabral , B. K. Subba Rao

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The paper presents results of interception studies conducted in sal and khair plantations raised at this Institute. It is seen that sal conducted 7.2, 54.6 and 88.2 percent of rainfall and khair 4.2, 67.8 and 28.5 percent of rainfall as stemflow, through-fall and interception, respectively Maximum number of trees ranged between 17.8 cm to 30.5 cm diameter class in sal and the stemflow, through-fall and interception ranged between 5-10%, 48-58% and 35-40% of rainfall respectively. In khair masimum number of trees were in 10.2 to 20.8 cm diameter range and the corresponding values of stemflow, through-fall and interception were between 2.5-7.0, 64-67 and 27-82% of rainfall respectively. The results are applicable to a dense canopied stand in which maximum interception may take place.

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B. G. Dabral , B. K. Subba Rao , I. M. Qureshi

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A preliminary study of the extremes of weather elements, (temperature and humidity) inside the forest plantations of chir (Pinus roxburghii) and bamboo (Dendrocalamus strictus) has been made, observations being made at different heights from ground surface to five feet. It was observed that both the air temperature and humidity were modified by the sheltering as well as the blanketing effects of vegetation cover. It was also observed that fair weather conditions induced the maximum differences in the temperature behaviour.

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B. G. Dabral

Abstract

Preliminary studies were made to determine the potential evapotranspiration using different forest species in juvenile stage. It was observed that Eucalyptus citriodora, Dalbergia latifolia, Pinus roxburghii and Populus casale in between 6-16, 6-16, 12-22 and 5-17 months of age consumed 16579/5526, 4570/1143, 1872/936 and 8112/2704 mm of water. The trend of water consumed for unit gram of dry matter production was least for Eucalyptus, and maximum for chirpine (Pinus roxburghii). Further work is necessary for conclusive results.

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B. K. Subba Rao , B. G. Dabral , B. C. Ramola

Abstract

Regular hydrological studies are in progress since 1967 in the two experimental watersheds in the hill sal coppice forest of Rajpur Forest Block in the Debra Dun Forest Division. This paper presents the preliminary observations on runoff, sediment discharge and guality of water, made in one of the experimental watersheds (watershed No. 1) during 1967-70. It has been observed that the water flowing out is of high purity, pH was 7, tending to be slightly acidic. Among the dissolved chemicals CaO ranged highest. The total silt washed out during the monsoon months varied from 49 to 153 tonnes/km².

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