Nguyen Xuan Quat Ngo Que INTRODUCTION In order to find soil mixtures to be used as a medium for raising P.merkusii seedlings for large-scale production, in the years 1972- 1975, the research subject concentrated on the determination of figures in components and best properties of soil media, on the selection of available materials and on the determination of mixture formulas meeting requirements relating to the medium which can easily be used in practice. METHOD Surveys were … [Read more...]

Nguyen Sy Giao Nguyen Thi Nham INTRODUCTION Pines are species having growth depending on fungi (Mycotrophe). Research on adding suitable symbiotic fungi into soil media used for sowing pines in order to produce seedlings having many mycorrhiza for their good growth was and is of interest to many researchers in many countries. The aim of our research subject is to use some pure symbiotic fungus species to make Mycorrhiza. METHODS AND RESEARCH CONTENT Fungus species used in … [Read more...]

Truong Thi Thao INTRODUCTION Serious failures commonly found in sowing Pinus merkusii in the last few years have resulted in a need for research on NPK mineral nutrient requirement of the species at different stages in the first year , which can serve as a basis for finding the most reasonable fertilizing techniques. RESULTS Based on analysis of NPK components in leaf and ecological features of Pinus merkusii planted with different NPK treatments at different stages in … [Read more...]

Nguyen Ngoc Tan Nguyen Luong Ngoc Nguyen Sy Huong INTRODUCTION It was realised that there are some abnormal phenomena in sowing P.merkusii in practice: white leaves, yellow leaves, weak growth, quite high mortality, and carcospora needle blight are commonly found. Micro-elements proved to be important for crops. Therefore, trying to use micro-elements to increase the tolerance of P.merkusii to adverse conditions (fungus diseases, drought) and assimilation ability of trees is … [Read more...]

Nguyen Sy Giao Nguyen Thi Nham Than Van Dua INTRODUCTION Cercospora needle blight is a most serious disease for many pine species in the seedling stage in the nursery or at 1-3 years after planting in the field. This is a very important reason why planting pines have met considerable difficulties in recent years, especially P.merkusii. Therefore, many production organizations have concluded that Cercospora needle blight is the main reason for the success or failure of pine planting … [Read more...]

Le Dinh Kha Pham Anh Tuan INTRODUCTION Pines are the main species for planting on bare hill soils of our country at present. To find some pine species with fast growth and adaptability to certain soil and climatic conditions is an important step in increasing the effectiveness of a planting programme. This research subject investigates the growth situation of P.kesiya and P.merkusii with various provenances, P.caribaea and P.massoniana. Pines were sown in bags having the same … [Read more...]

Vu Dinh Phuong INTRODUCTION P. kesiya is found naturally in Lamdong province and is an important forest product in this region, however, so far the species has been exploited without a scientific basis. To serve as a basis for more reasonable forest management, a study on the increment rule of P.kesiya trees and stand was carried out. Ten temporary plots were placed with 4 sub-plots of younger age. Some trees were taken from plots for analysis by diameter levels. The locations … [Read more...]

Doan Chuong, Vu Ngoc Toan Luu Vinh Quan, Le Quang Lien INTRODUCTION Many damaging factors have a considerable in influence on the quality of Dendrocalamus forest, of which pest and disease are the most serious , especially worms which cause damage to young shoots. In some areas, 30-40% of young shoots have been destroyed so that the forest was degraded, depleted and lost. Therefore, study on the biological characteristics of this worm species is necessary and on that basis, … [Read more...]

Bui Nganh Vu Van Me INTRODUCTION Due to the characteristics of the species and structure of Styrax tonkinensis plantation forest, there are some problems as follows, 1. Can erosion of soils under Styrax tonkinensis forest reduce the soil fertility, so that long-term management of Styrax forest can not be applied? 2. If in fact there is erosion at a severe level, can we take measures to control it in order to ensure adequate production of Styrax tonkinensis forest to meet the … [Read more...]

Nguyen Cong Doi INTRODUCTION The questions is after exploiting the first rotation Styrax tonkinensis forests, can new Styrax forests be established? and by what techniques? Research was carried out at Yen Bai province from 1971. Ten -twelve year old Styrax tonkinensis plantation forests having average heights of 18-22m, average diameter of 17-18cm (D1.3) total production of 50-100m3 were selected for study. There was vegetation including shrubs, Saccharum arundinaceum, Miscanthus … [Read more...]