In the past few years,the digitizing regression method has been introduced into forest inventory work,in its application,different sampling methods have been suggested.The chief advantages of the method applied are possibilities to fully utilize the aerial photographs and reduction of field work on the ground,which results in an increase of efficiency.This report deals with a sampling model method,designed by us and tried in our forest inventory project,together with some formulas for its error estimation.In derivation of the formulas,properties and sources of error are also examined and analyzed. It is attempted that our results may be used by those who will apply this method to design their inventory plan in forest inventory work.

A cytoplasmic-polyhedrosis virus causing a spectacular epizootic disease has been isolated from the body of pine caterpillar(Dendrolimus tabulaeformis Tsai et Liu)in Sept.1977 in Liaoning Province. This virus infringes Cylindrate cells of mid-gut(chylific),forming polygonal bodies in the cytoplasm. The image of the polygonal body is shaped like a dodecahedron in stereoscopic view and like a regular hexagon in surface view. The image of virion is also shaped like a hexagon in plance with a diameter of 57—63 mμ. According to the international classification system,it should belong to Reoviridae.It is one of the species of Cytoplasmic-polyhedrosis viruses(CPV).Based on the investigation and information available,it is considered to be a promising biologicalcontrol agent to control pine caterpillar in China.

The cotton locust,Chondracris rosea rosea DeGeer,is one of the most destructive insect pest of beef wood(Casuarina equisetifolia L.)in Kwangtung Province.In Dong-hai Forest Farm it damages about 150—200 ha.of trees every year.It has one generation per year and over winter in egg stage in the sandy soil.At the end of April and in the beginning of May next year,the hoppers or nymphs appear,emerge as adults usually from mid-June to late July,and die in the period from July to September. The most practicable control of this pest is,if the young hoppers appear from the soil,to spray with 6% BHC dust,if the old hoppers and adults climb up the tree,apply smoke "DDVP".

Permanent sample plots were laid under fir forest in the 31°36′ latitude north and 102°67′ longitude east,between 3,400—3,700 metres above sea leval,in Miaro region western Szechwan. Four forest types were chosen for the sample plots:1. Abietum-sinarundinariosum,2. Abietum-hylocemicso,3. Abietum quercosum and 4. Abietum rhododendrosum. Observation began in 1960 and ended in 1964.changes in soil water,soil temperature,soil gas exchange(CO₂ in the soil air),organic matter,leaching water(composition lysimetric water)and soluble substances(available nitrogen,phosphorus,potassium,soluble ferric oxide and ferrous oxide)and soil acidity were recorded.Their diagnostic velue for classification of the fir forest soils are discussed.

This paper deals with the selection of fast-growing Clones of Pond baldcypress (Taxodium ascendens)at an early stage in the nursery.The selection began in 1975 in Wuhan,Hubei Province.The rate of selection was about 1:8400,89% of which developed from seed of normal mother trees and 11% from seed of open pollinated of plus trees.An advantage of selection at seedling stage in the nursery is that a large number,of plants can be examined in a short time.In the first two years 才clonal test of the selected super seedlings was made with cuttings from the stem and shoots.In the third and fourth year clonal test was made grafting.Grafts made from scions of superseedling or plus trees were compared with these made from scions of common seedling 1-year old(control).Analysis of variance and T-test showed that there were significant differeces between clones from the super seedling and the clones from plus trees,the form grew bether than the later.This gives the hint that early selection in the nursery may be possible to become an efficient method to obtain fast-growing ortets as may be desired.

18 local hardwoods of Kwangtung province were chosen for pulping experiment to evaluate their possibility for paper production.Two fast-growing species Paulownia fortunei and Albizzia falcata were recommended on account of their advantages in high fibre percentage,high coefficient of flexbility in fibres,high cellulose content,ease in pulping,high purity and whiteness in pulp and stronger tensile strength in paper.