Tropical Timber Tree Research Articles

Tree biology, forestry and agriculture, especially in the tropics. A personal viewpoint

Summary This is a review of some problems posed by research on tree biology. First, phase change and in vitro culture are discussed as they affect vegetative propagation of woody plants. Then the breeding of timber trees, with an evident and important trend to clonal propagation is considered. Tropical timber tree breeding has enormous potential but has only just started (on very few species). The trend to making tropical woodlands into planted pure stands, of converting production forestry into, ‘tree farming’, an aspect of agriculture, so to speak, is apparent. ‘Ideotypes’ have fallen out of favour but some important ideas as to biomass and its allocation remain and well-defined economic objectives must become paramount. A broad review of the tropical agricultural context with regard to trees, suggests an acute need for far better understanding of them and for much introduction and breeding to generate new woody food-crops.

Seasonal Pattern of Cell Division in the Vascular Cambium of Some Tropical Timber Trees.

Seasonal pattern of cell division in a year in four deciduous (Albizzia lebbeck, Dalbergia sissoo, Tectona grandis and Terminalia crenulata) and three evergreen (Calophyllum inophyllum, Mangifera indica and Morinda tinctoria) plants is described in detail. The anticlinal division of fusiform initials were predominantly pseudotransverse although a few radial divisions in Dalbergia and lateral (or tangential) divisions in Albizzia were noticed. There was often a difference in the orientation of the anticlinal division spindles even in the adjacent fusiform initials in the different plants. The timing of both the periclinal and anticlinal and initial location of division were studied and recorded for all plants studied.

Organisation of vascular cambium during different seasons in some tropical timber trees

The vascular cambium of Albizzia, Tectona, Terminalia, Calophyllum, Mangifera and Morinda was non‐storied while that of Dalbergia was semi‐storied. The ray initials were uniseriate in Terminalia and Calophyllum, both uniseriate and biseriate in Albizzia, Dalbergia, Mangifera and Morinda and were also multiseriate in Tectona. They were homogeneous in Albizzia and heterogeneous in the other species. The radial walls of cambial cells were always beaded, although beads were more prominent and closer to one another during periods of cambial dormancy than during activity. The fusiform initials were comparatively less vacuolated during dormancy/ least activity. When active, the fusiform and ray initials of all species, except Calophyllum, also showed multinucleate condition (2–10 depending on species). The proportion of ray initials to fusiform initials was almost constant throughout the year in all species.

Shoot regeneration fromAgrobacterium tumefaciens-induced tumors of a tropical timber tree,Fagraea fragrans

Agrobacterium tumefaciens A208 with nopaline plasmid pTiT37 was used to obtain stem tumors on plantlets ofFagraea fragrans grown in vitro. Bacterial elimination and tissue proliferation were simultaneously achieved by growing tumors on cefatoxime medium. After some tissue growth the shoots regenerated. An examination of these showed the presence of nopaline, indicating genetic transformation by T-DNA.

Seasonal Production of Secondary Phloem in the Twigs of Certain Tropical Timber Trees

Seasonal Production of Secondary Phloem in the Twigs of Certain Tropical Timber Trees

Some Photosynthetic Characteristics of Tropical Timber Trees as Affected by the Light Regime During Growth

Some Photosynthetic Characteristics of Tropical Timber Trees as Affected by the Light Regime During Growth

Boundary layer conductance of the leaves of some tropical timber trees

Abstract The boundary layer conductance of brass models of leaves exposed in a wind tunnel was determined from their cooling characteristics. Conductances were generally very low, as expected from large leaves. Nusselt numbers were calculated from the rates of heat loss, so that the results could be compared with established theory. There was generally good agreement between observed and calculated values. Leaves with veins displayed an apparent transition from a laminar to a turbulent boundary layer, and so did leaves inclined at an angle from the horizontal. In still air the observed rates of heat loss by natural convection were substantially higher than those calculated.

Boundary layer conductance of the leaves of some tropical timber trees

Boundary layer conductance of the leaves of some tropical timber trees