The effectiveness of the preparation with borax, boric acid and copper sulphate salt (BBC) as a water borne wood preservative was studied in the laboratory soil-block test. Blocks of civit (Swintonia floribunda) and chapalish (Artocarpus chaplasha) wood were dip-treated with the preservative solution and exposed to a common white rot fungus (Polyporous versicolor) and a brown rot fungus (Poria nionticola). The loss in weight of the wood blocks due to the fungal decay was recorded to be in the range 0-1.4%. This showed that the preservative was very effective. The field test of the preservative is being carried out with chapalish and garjan (Dipterocarpus spp.) wood stakes along with untreated ones. All the untreated stakes deteriorated due to fungi or other wood destroying agents within two years, but the treated stakes remained uneffected even after five years of exposure.

The physical characteristics, physical and mechanical properties of Calamus ereclus have been studied at three height positions. The variation of physical properties due to node and internode have also been investigated. The moisture content and shrinkage increase, whereas the specific gravity decreases with the height of the stem. The specific gravity is higher at the node than that at the internode. The bottom portion is stronger in respect of compressive strength, bending strength, nail withdrawal and side hardness.

The forest soils of Bangladesh have been discussed under the four generalized dendro- ecological regions e. g. (i) Floodplain region, (ii) Plio-Pleistocene Terrace region, (iii) Mio-Pliocene Hill region and (iv) Anthropogenetic landtypes region. The dominant soil forming factors and their attributes on physico-chemical, mineralogical properties and the natural soil fertility in each region have been briefly narrated. In addition, major tree species of the dendro-ecological regions and the opportunity for forest production have been discussed. The limitations for tree growth on different dendro-ecological regions have been mentioned. Emphasis has been given on the role of soil moisture regime, acidity, fertility and soil depth on site specific species selection.

Seven different bamboo species have been growing naturally in the forests of Sylhet, Chittagong Hill Tracts, Chittagong and Cox’s Bazar of Bangladesh. Bamboo does not grow naturally in the mangrove and sal (Shorea robusta) forests. The distribution and ecological conditions of species have been described. The overexploitation, fire and other biotic interferences are reducing the area of natural bamboo forests on an average by two per cent annually. Lack of scientific management, especially large scale death after gregarious flowering is also considered to be an important factor for shrinking the bamboo area in the forests. Among the naturally grown forest bamboos the occurrence of Dendrocalamus hamiltonii, Melocalamus compactiflorus and Neohouzeaua dullooa is reducing alarmingly due to the destruction of their habitat. Therefore, these three species have been considered as threatened bamboo species of Bangladesh.

The physical and mechanical properties of Bambusa arundinacea, B. longispiculata, B. vulgaris and Dendrocalamus giganteus have been studied at three height levels. The moisture content and shrinkage decrease, whereas specific gravity increases as the height of the culm increases. B. longispiculata exhibits the highest specific gravity among the four species. The diameter shrinkage is found much lower than the shrinkage in wall thickness. The compressive strength, fibre stress at elastic limit and modulus of elasticity increase with the culm height. Among the four species, B. arundinacea shows the highest strength in almost all cases.

Two provenance trials of Pinus caribaea var. hondurensis were established in randomised complete block design in 1983 and later in 1984 at Keochia Silviculture Research Station, Chittagong, Bangladesh. It was observed that there was no significant difference among the provenances in respect of survival percentage, height and diameter growth and volume yield till December, 1989. All the provenances are doing well in the area. The mean height, diameter at breast height and volume yield per plot of 148.84 m² ranged from 9.5-10.4 m, 12.5-13.8 cm and 1.242-1.663 m³ respectively for the 1982 trial at the age of 7.5 years. The corresponding data for the 1984 trial at the age of 5.5 years were 4.2-5.4 m, 6.0-7.7 cm and 0.102-0.300 m³ respectively.

The growth and distribution of root systems of an annual crop (French dwarf bean) and a young tree species (poplar) in large soil columns at three different soil water supply regimes were studied in a simulated agroforestry under a greenhouse condition at the University of Edinburgh, UK. The root biomass production of bean plants was found unaffected under the limited soil water supply whether grown in a monoculture or in mixed stands in contrast to that of poplar plants. The root system of bean explored only top 36 cm of soil column whereas poplar root system explored beyond the depth of 36 cm . These differential responses of an annual crop and a young tree species may be used as a basis for selecting complementary agroforestry components in a dry area.