Narrow Results

Taking 1 year-old Elaeocarpus sylvestris seedlings as test materials, density effect on physiological characteristics of the seedlings was studied using pot experiment. The seedlings were planted with four different densities: 1, 2, 4 and 8 seedlings of each bag (density I, density II, density III and density IV). Physiological indexes of the different density seedlings were determined. The results showed that with increasing density, changes in contents of chlorophyll, soluble sugar and MDA in the leaves of the seedlings were not significant, soluble protein content and SOD activity increased followed by a decrease, whereas proline content decreased.

It is estimated that there are 70 million hectares of forest requiring rehabilitation in the Asia-Pacific region. Heavily disturbed and abandoned shifting cultivation areas need to be replanted, which consequently will require huge amounts of seedlings. Production of dipterocarp planting stock has been considered somewhat difficult. Seed availability and storage are continuous problems in mass production of dipterocarp seedlings. There is a lack of reliable knowledge of basic nursery operations because of the large number of species, the recalcitrant seed and contradictory information from different areas. Planting stock of dipterocarps can be produced from seed, wildlings and vegetatively by cuttings. Containerized seedlings or wildlings grown in mixtures of peat and ricehusk or topsoil provide the most reliable solutions at the moment. Vegetative propagation has had promising results recently and it is increasingly used on a practical scale. Reliable mycorrhizae inoculation is one of the key issues in successful seedling production. Pest and disease problems have to be considered more carefully if dipterocarps are used in large-scale plantations. Strict quality control of the planting stock is necessary. Production of dipterocarp seedlings is more expensive than seedling production of fast-growing trees, but investment in proper nursery practices is necessary. For large-scale plantation programmes, seedling production by combining all of the available methods (seeds, wildlings, cuttings) seems to be the most appropriate strategy. A strong emphasis on continued research and development activities is recommended. More knowledge is needed, but this fact should not prevent anyone from starting to plant dipterocarps.

With Elaeocarpus Sylvestris seedlings as the experimental materials, the density effect on nutrient distribution of the seedlings was studied. The results showed that nitrogen concentration decreased in the order of leaves > branches > roots > stem, phosphorus concentration varied without regular patterns, whereas potassium concentration was leaves > branches > stem > roots in E. Sylvestris seedlings. Accumulation of nitrogen, phosphorus and potassium increased with increasing density. Generally, the nutrient accumulation was great in roots and small in branches.