Soil samples were collected from the genetic horizons of three soil profiles representing three different landtypes. Trace elements in soil and in leaf samples were determined spectrometrically.

It was observed that the vertical distribution of trace elements was related to the amount of clay rather than to the genetic soil horizons. The clay content in these profiles was the attribute ofthe alluvial parent material. Therefore, the redistribution of trace elements was not due to pedogenetic effects.

The clay fraction contains higher amounts of trace elements in all the profiles. It was, therefore, assumed that the topsoil might be depleted of trace elements with the loss of clay by illuviation or by run-off. Trace element/iron oxide ratios of several soil samples show that the vertical distribution of trace elements in the profiles studied were not significant.

It was also observed that in the studied profiles Mn and Cd content was higher but that of other elements waslower than the FAO’s prescribed highest levels of total content of trace elements in soil.

Trace element contents of several leaf samples of tree species were examined and found not related to the trace element contents of soil.

Garjan (Dipterocarpus turbinatus) is one of the most important species growing in the natural forests under Cox’s Bazar, Chittagong and Chittagong Hill Tracts forest divisions. Attempts were made to establish Garjan plantations since 1923 and from the last decade more attention has been directed to raise Garjan plantation on wider areas. The prospects of these plantations have been studied in this paper in order to aid planners in fixing up physical targets for production and management, find an indication of long-run price behaviour of produced timbers and finally assess the rate of economic return of plantations.

The paper indicates the long-run gap between the demand for and supply of Garjan timber. Some major problems of managing Garjan plantation are pointed out and suggestions affecting the cost factors and yield position are made.

Rubber tree (Hevea brasiliensis Mucl. Arg.) is being rajscd commercially by the BFIDC to attain self-sufficiency in natural rubber in Bangladesh. Symptoms of panel-burrs and nodules, cankers, galls, secondary die-back and patch canker have been described. A brief review of their causes has been made. Preventive and/or control measures have been suggested for each of the diseases.

Fibre dimension studies of five Bangladeshi woods, namely, Moluccana koroi (Albizia falcataria), kainjal (Bischofia javanica), jialbhadi (Lannea coromandelica), narikeli (Pterygota alata) and chundul (Tetrameles nudiflora) wets carried out to find out their suitability in paper making. From the data, Runkel ratio, flexibility co-efficient and relative fibre length, which influence certain pulping properties, were deduced. Attempts were made to correlate fibre dimensions to pulping properties of certain species namely, Moluccana koroi and Kainjal. Considering the fibre length and certain anatomical characteristics, the potentiality of narikeli for pulping has bee suggested. It is concluded that fibre dimensions along with pulping properties and the manufacturing processes should be the guiding principles in evaluating the suitability of the species in paper making.

It is an attempt to prepare biomass tables for young trees of the three Eucalyptus species grown in Bangladesh. The paper gives height-diameter at breast height (dbh)-biomass, and dbh-biomass production relationships along with required tables and conversion factors.

Lignin was isolated from Cajanus cajan (Pigeon pea; Bengali : arhar). Lignosulphonic acid resin was prepared from this lignin and characterised by pH titration. This lignosulphonic acid showed titration characteristics resembling those of soluble strong acids. Addition of electrolytes to water increased the ion-exchange capacity. Sorption of moisture by lignosulphonic acid showed a gradual moisture gain upto about 80% relative humiduty which was followed by a sharp increase of moisturegam upto 100% relative humidity.

Rhizome assemblies and clump form and growth of nine arboretum grown bamboo species have been studied. Rhizome stalk has been found to play an important role in determining the form, shape and growth of clumps. This is due to not only the characteristic length of the stalk in some species but also its role in orienting the rhizome in relation to the centre of the clump and the mother culm in general and the line of gravity in particular. In areas where bamboos are worked heavily it is the rhizome stalk that is first affected and may result in congested clumps in species otherwise monopodial or loosely tufted. Rhizomes are commonly attacked by pathogenic soil ganisms, Parts like rhizome stalks, whole bud of the rhizome may be partly or wholly consumed or otherwise become inoperative and although these parts contribute to the development of rhizome assembly they do not contribute towards the growth of clump. This reduces the rate of growth of clumps considerably. Irrespective of species, only 8 percent of the buds develop into normal culms, 77 percent remaining dormant and 15 percent are damaged by pathogenic soil mlcrooganisms. It has been concluded tha- application of antipathogens individually or in combination with fertilizer will ameliorate the conditions of growth and considerably increase the outturn.

The long interval of flowering and seeding has made propagation of bamboos very difficult. Offset plantings are not suitable for large scale plantations. Attemps with branch cutting, layering, etc. for propagation showed low percentage of success. Tissue culture has yet to be tried.

The present study showed that rhizome buds are monoprimordial, represented by the cone of rudimentary sheaths only. The food stored in the rhizome and rhizomatous swelling is utilized by their lateral and terminal buds. The root primordia are borne outside rhizome-buds. The culm and branch-buds are multiprimordial. Each structure is similar to the rhizome consisting of root, rhizome and shoot primordia.

The number of primordial structures and their relationship with the breaking of buds, dormancy and continuous growth in various species of bamboos have been investigated, analysed and discussed.

In tissue culture the entire primordial structure might have to be used as a propagule unlike the use of only callus tissue as in the case of dicots.