On the earth surface,there is a me-dium latitudinal zone in which the evapo-ration per year is greater than the precipita-tion per year.in China,the northern te
In the description of the characteristic volume of fire behavior,fire intensity I<sub>r</sub>ate of spread R,and flame length L,etc.all have their scientific de
This paper analyses the relationship of forest fires and sunspots in Heilongjiang Province in the past 40 years(1950—1989).The results indicated that each of t
Population increase of Larch casebearer(C. dahurica)were controlled by compre-hensive factors.Spring wind caused 27% of larvae on crown to fa11 down.Early and la
The development and rc research condition about yield table in China were in-troduced in this paper.Several methods of constructing yield table were also descri
This paper describes the researching aim and content of Ergonomics.Some prob-lems existing in modern harvesting system,such as machinery availability,cabin desi
INTRODUCTION In Italy,they have done many bcnefi-cial works in the high yield plantation--the culture and the breeding of Poplar.Forexample,in our country,intro
The poplar bacterial canker caused by Erwinia sp is a serious disease spreading inmost parts of Northeast China,where poplars are cultivalted.The disease seriou