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