Six species, viz., Ailanthus altissima (Mill.) Swingle, Rhamnus triqueter (Wallich) Brandis, Morina longifolia Wallich ex DC., Acroptilon repens (L.) DC., Achyranthes aspera L., Persicaria capitata (Buch.-Ham. ex D. Don) Gross have been recorded from Pin Valley National Park in Lahaul-Spiti, Himachal Pradesh as new additions to the flora of Lahaul-Spiti, a cold desert of N.W. Himalaya. Of these, Acroptilon repens (L.) DC.  is a new record for the state of Himachal Pradesh as well.

Four taxa of flowering plants, viz., Aquilegia nivalis (Baker) Bruehl, Ranunculus palmatifidus H. Riedl (Ranunculaceae); Herniaria incana Lam. (Caryophyllaceae) and Polygonum polystachyum Wallich ex Meissn. var. griffithii Hook.f. (Polygonaceae) have been recorded for the first time from Uttaranchal. Of these, Polygonum polystachyum Wallich ex Meissn. var. griffithii Hook.f. is a new record for North-west Himalaya as well.

Quantitative estimations were made for population built up of soil inhabiting collembola and mites in Hardwickia binata based silvopastures. Temporal distribution pattern showed two peaks of population built up - one major peak during July-September and another peak during December-February. Lower population built up was generally observed during March-June.  Mites constituted 86 per cent of the total population, the major group being cryptostigmata (61%) followed by prostigmata (19%) and astigmata + mesostigmata (6%). The significant positive correlation of mite population with soil moisture and RH and collembolan population with RH in such a system was observed.

Mainly two chemicals, viz., sodium periodate and chromium (VI) trioxide have been used for chemical modification of hardwoods. Aqueous solution of NalO₄ at lower concentrations decreased the dimensional stability (6.97%, 8.37% and 8.93% change in tangential direction for 0.1% concentration and 136 hours water soaking in Bombax ceiba/Red silk cotton tree, Celtis australis/Nettle-tree and Populus deltoides/Eastern poplar, respectively).  Aqueous solution of Cr⁺⁶O₃ (Chromic acid, 5% for 5 minutes) gave maximum dimensional stability (2.78%, 3.56% and 5.46% change in tangential direction after 136 hours water soaking in Bombax ceiba, Celtis australis and Populus deltoides respectively) followed by combined treatment (1.0% NalO₄ for 20 hours followed by 5.0% chromic acid for 5 minutes). Extractive leaching was reduced with the three treatments and was observed minimum in the combined treatment (0.45%, 0.24% and 0.18% after 136 hours water soaking for Bombax ceiba, Celtis australis and Populus deltoides, respectively). Water absorptivity decreased with chromic acid application and was observed minimum in the combined treatment (86.49%, 82.24% and 99.80% after 136 hours water soaking for Bombax ceiba, Celtis australis and Populus deltoides, respectively).

The effect of shifting cultivation on changes in the physico-chemical properties of soils was studied in the jhum and nearby natural forest areas. Various soil properties investigated were bulk density, texture, pH, hydraulic conductivity, organic carbon, total nitrogen, available phosphorus and exchangeable potassium, calcium and magnesium. Soil properties were compared at five different soil depths: 0-5 cm, 5-25 cm, 25-50 cm, 50-100 cm and 100⁺ cm. Lowest and highest soil bulk densities were recorded in land after burning and 1st year fallow, respectively. Natural forest had a moderate soil bulk density. Results indicate that C and N in the soil may be among the most limiting factors for plant growth after a forest is cut and burned. Highest percentage of organic carbon (1.92%) and total nitrogen (0.28%) were found in pre-burning stages of vegetation and it significantly decrease in early fallow periods due to rejuvenation of vegetation. With the progress in the age of fallow, the percentage of organic carbon and total nitrogen increased significantly due to heavy accumulation of litterfall. A large amount of available phosphorus is released just after burning the forest. The lowest value of available phosphorus found in 1st and 5th year fallows indicate that available phosphorus may limit crop production if the fallow periods are too short. Maximum amount of available phosphorus noticed in natural forest is due to heavy accumulation of litterfall. Exchangeable calcium, potassium and magnesium appeared to reach adequate levels in the soil after burning the forest and sharply declined in cropping period and it continuously decreased in early successional fallow. Natural forest exhibited adequate levels of exchangeable calcium, potassium and magnesium, while increase in 15th and 20th years fallow may be due to development of regeneration of tree vegetation. The overall results of this study indicate that the present shifting cultivation cycle of about 5 years is not sufficient to prevent serious soil degradation in the area. A minimum of 10 to 15 years will be required to maintain soil fertility at a reasonable level.

Diseases of Albizia species occurring throughout the distribution zone in planted stands and nurseries have been briefly described, providing information on their distribution, severity and prescribed management measures.

A study has been conducted to know the relative salt tolerance of Acacia nilotica (Linn.) Willd., Azadirachta indica A. Juss., Dalbergia sissoo Roxb., Dalbergia latifolia Roxb., Gmelina arborea Linn., Leucaena leucocephala (Lam.) de Wit., Prosopis cineraria Druce and Prosopis juliflora DC. tree species. Four different salt levels, viz., 0, 2.5, 3.5 and 6.5 dS/m were artificially created in the clayey soil by employing NaCl, CaCl₂ and MgSO₄ in the ratio of 5:3:2. Azadirachta indica and Dalbergia latifolia tolerated salts up to 6.5 dS/m at germination stage whereas Leucaena leucocephala and Gmelina arborea appeared sensitive even at 3.5 dS/m level. Their order of performance was A. indica> D. latifolia> Prosopis cineraria> P. juliflora. The maximum number of leaves and root length was observed in Prosopis juliflora whereas Leucaena leucocephala registered maximum shoot length. Dalbergia latifolia registered minimum number of leaves and shoot length whereas Gmelina arborea registered minimum root length. The reduction in the number of leaves/plant and shoot and root length under 2.5, 3.5 and 6.5 dS/m salinity levels as compared to control condition was 19.01, 47.17 and 63.66 per cent, 27.37, 52.15 and 70.71 per cent and 18.65, 42.43 and 62.86 per cent respectively.

An experiment was taken up to study the effect of VA mycorrhizal inoculation on the growth and development of Garcinia indica at the nursery stage. The plant height, No. of leaves per plant and plant biomass was significantly higher in the seedlings inoculated with VA mycorrhiza compared to uninoculated control. VA mycorrhizal inoculation also improved the phosphorus nutrition and in turn the root growth of the seedlings considerably over the uninoculated control. Among the VA mycorrhizal inoculated seedlings, the overall plant growth was better in the seedlings inoculated with Scutellospora calospora and Acaulospora laevis.

An experiment on silvipastoral system was conducted for three consecutive years (1996 to 1998) in slightly slopy, red lateritic culturable wasteland. Six popular tree species (viz. Eucalyptus tereticornis, Acacia auriculiformis, Acacia nilotica, Dalbergia sissoo, Samanea saman, and Albizia lebbeck) differed significantly on growth of plant height (PH), and Girth at shoulder height (GSH). Eucalyptus tereticornis showed maximum growth of PH and GSH followed by Acacia auriculiformis. Fodder yield of Dinanath grass in two cuts was highest under the tree canopy of Dalbergia sissoo followed by Samanea saman and lowest in the interspaces of Eucalyptus tereticornis.

The paper describes the statistical procedure in a case study of Silver fir (Abies pindrow Spach.) forests of Western Himalayas in India to assess the breast height diameter and crown diameter of trees from stump diameter with the help of regression and correlation analysis. A series of regression equations have been developed using the stump diameter (DSH) as independent variable while crown diameter (CD) and breast height diameter (DBH) as dependent variables. With the incorporation of DSH in the equation, the DBH and CD of the felled and removed trees can be accurately predicted. The method is simple and easily applicable. The results will provide clues to detect the undersize recordings and excessive felling of trees. For each diameter class the crown area, number of trees per ha and the number of trees per ha after thinning can be calculated and a table constructed. This will provide an aid in thinning of even-aged crop and thinning can be done for any stage of the crop quantitatively, using this table.

Among the two host plants of Hyblaea puera Cramer (Lepidoptera: Hyblaeidae), field observations revealed that teak, Tectona grandis L.f., preferred first then Vitex negundo L. Weight gained by larvae, pre-pupae and pupae of teak leaf-fed larvae were significantly (P<0.001) greater. Teak leaves showed significantly (P<0.01) more moisture and protein contents whereas V. negundo contained significantly (P<0.001) high titre of phenols. The ratio of proteins to phenols was relatively high in teak, which possibly influenced the growth of the insect.

Elaeocarpus lanceifolius Roxb. (Elaeocarpaceae) is earlier known to Andhra Pradesh, Assam, Karnataka, Kerala, Meghalaya, Sikkim and West Bengal.  It is added recently to the flora of Tamil Nadu from the Courtallum hills, Tirunelveli.

Possibility of artificial regeneration through vegetative propagation of Aegiceras corniculatum (Myrsinaceae) was studied. Rooting in air-layer was induced with the aid of root promoting substances like IAA, IBA and NAA. Maximum rooting ability (in terms of percentage of rooting and root number) was recorded in the air-layers treated with IBA 2500 +NAA 5000 ppm with a promising rate of survivability. Untreated air-layers, however, did not produce any root. Anatomical and biochemical changes were investigated during rooting. Exogenously applied auxins hastened rooting by stimulating cambial activity resulting in the formation of root primordia from phloem parenchyma and eventual root emergence after 27 days of treatment. The rooting response in the air-layers might be determined by higher level of carbohydrate and lower level of nitrogen (a high C/N ratio) especially at the root initiation stage which was confirmed by the activity of amylase, a hydrolysing enzyme. The metabolism of auxins during rooting might be due to enhanced activity of peroxidases and polyphenol oxidase, which had a protective and preparatory role on auxins. Present study revealed a high possibility of scaling up propagation of Aegiceras corniculatum, an economically important tree mangrove through air-layering for use in afforestation programmes.

Twelve year old, six broad-leaved agroforestry tree species, growing at the same site, have revealed significant intergeneric diurnal variations in photosynthetic rate, amount of water transpired, leaf water potential (Y) and canopy temperature during the months of May and June. Significant mid-noon (13.30 hour) drop and substantial afternoon recovery up to 17.30 hour for all the physiological attributes were observed in all the six investigated tree species, namely, Grewia optiva, Morus alba, Celtis australis, Bauhinia variegata, Dalbergia sissoo and Toona ciliata.

Life forms of the vegetation and biological spectrum of the flora of sand bars (islands) of Brahmaputra River have been determined. Results show that the percentage of therophytes and cryptophytes in the newly developed sand bars is nearly three times higher than those of the same life forms in the normal biological spectrum of Raunkiaer (1934). Gradual sedimentation with annual recurrence of flood may be attributed for higher percentage value of therophytes. There is a general progression of plant species resulting from modification of the micro-environment by developing forest vegetation and changes in the soil characteristics with time, which resulted invasion of more phanerophytic plant species in the mature sand bars.

A new nematode Steinernema carpocapsae L. was recorded from Hypsipyla robusta larvae from Jamnipur, Dehra Dun. This nematode can be easily mass produced and is now available commercially in Canada. Laboratory tests have shown that wide range of forest insects are susceptible to them. This nematode is a promising pathogen for microbial control of toon shoot borer.

The community structure, tree diversity and physicochemical properties of soil of the West Gangetic Moist Mixed Deciduous Forest have been studied on four different slope aspects, viz., North-East, North-West, South-East and South-West in the foothill region of Garhwal Himalaya. The northern aspects were species rich, well stocked and dense as compared to southern aspects. However, Garuga pinnata (TBC = 19.27 m²/ha and tree volume = 2034.7 m³/ha) and Lagerstroemia parviflora (TBC = 14.34 m²/ha and tree volume = 1298.5 m³/ha) were the single dominant species on the SE and SW aspects respectively. The lowest concentration of dominance value (0.2517) was observed on the NW aspect, where maximum diversity (2.1239) persisted, on the other hand highest cd value (0.3646) was recorded on the SE aspect, where minimum diversity (1.5164) existed. The soil was almost neutral (pH ranged from 6.5 to 7.3) in these forests with maximum organic carbon (average 1.19±0.56%) and available nitrogen (average 0.576±0.868%) contents prevalent on SE aspect.

Rainfall distribution index defined by earlier workers, was used for weekly rainfall analysis from June 18 to October 14 on the basis of 38 years data from 1958 to 2000 at Chandigarh. The index was considered to be more realistic for crop planning, since the same included number of rainy days. Linear relationships established between the weekly rainfall distribution index (RDI) and weekly rainfall, were found to hold good at 1 per cent level of significance and the regression equations explained more than eighty per cent variation in RDI values. Expected weekly RDI values showed zero values, thirty fifth week (Aug. 27 – Sep. 2) and thereafter at eighty per cent chances, suggesting the necessity of short duration crop varieties for the kharif season.

Fissidens griffithii, a moss, earlier known to occur only in Bhutan, is recorded for India from the southern Western Ghats of Tamil Nadu. A detailed description and an illustration are provided.

Changes as brought about in diversity of floral species and in chemical properties of soil under pure plantations of Robinia pseud-acacia and mixed plantation raised over the mine overburden areas of Paonta Sahib in Sirmour District of Himachal Pradesh were studied during August, 2000. The number of ground flora species under Robinia pseud-acacia and mixed plantation was 25 m-2 and 31 m-2 respectively. On the basis of importance value index (IVI), Peristrophe bicalyculata and Ageratum conyzoides were the dominant herbs under Robinia pseud-acacia and mixed plantation respectively. Distribution pattern reflected that most of ground flora species were contiguous. Index of dominance was found to be lower and diversity index was recorded higher for ground flora under plantations while compared with exposed mine overburden area. The ground flora under mixed plantation however, showed the highest diversity index (4.168). Index of dissimilarity between plantations and exposed mine overburden area was high thereby indicating remarkable degree of dissimilarity in ground flora species.  Plenty of similarity between two plantations was however observed as far as ground flora growing under them was concerned. The chemical properties of soils as assessed under plantations showed improvement in fertility status while compared to exposed mine overburden areas.