For each of the plantation-and natural-grown Korean Pines(Pinus koraiensis Sieb. Et Zucc.)four sample trees had been selected in this study.In first place,results for comparison of the anatomical features and physico-mechanical properties of the fast- (plantation-)(a)and slow-grown(natural-grown)(b)Korean Pine timbers have been shown.Secondly,with the plantation-grown material the writers have proven the Turn- bull's hypothesis that the increase in density of coniferous wood from the pith outwards is determined solely by age from the pith and has nothing to do with ring-width.These conclusions may be indicated as follows: 1.In diameter growth,(a)grows 4 times faster more than(b);in length growth, about 3 times,(a)vs.(b).Tracheids in(a)are longer(ca.31%)and larger(early- wood,11%;latewood,28%)than in(b).Latewood percentage and density of(a)are 28% and 2% lower respectively than(b);but strength properties have been shown about the same.In case of comparison on their corresponding rings,(a)is generally heavier and stronger than(b).Thus the fact that the rapid growth,high yields and good qualities of Korean Pine timbers could be reached by a proper silvicultural treatment has been proven. 2.From pith outwards,tracheid length and growth ring width decrease more ap- parently;except the first few years,the variations of the diameter of tracheids,per- centage of both latewood and cell wall are small and fluctuate irregularly.The density and strength of(a)reach the maximum value at 9th to 18th growth rings;in(b),at 30th to 70th growth rings. 3.Upwards from height at 1.3—11.3 meters within a growth ring or scope of growth rings,tracheid length increases,but latewood percentage,density and so forth decrease.The strength properties except(b)the maximum value of which occurs at height of 5.3—7.3 meters and tends to increase outwards before 50 rings from pith,de- crease upwards. 4.The number of resin canals is in direct proportion to the width of growth rings. They are mostly distributed in the summerwood bands or(and)the transitional regions of early-and summerwood.

The Chinese fir is an important forest tree of South China,it has been under cul- tivation for a long time.With the object to increase its growth rate and cut short rotation period,we made inter-generic crosses reciprocally between Cunninghamia and Cryptomeria since 1955.Inspite of their morphological differences,they were cross- compatible and fertile with each other.The F_1 hybrids showed different degrees of heterosis as compared with their parent species and material inheritance,whether they will segregate or not needs further investigation.In the fall of 1959,we found one of the cryptomeria hybrids set forth a shoot with comparatively flat needles,which were quite different from the rest,they were linear-lanceolate,rather than awl-shaped,with two resin ducts. At the same time we also made intra-specific crosses between trees from different localities.The hybrids also showed certain degrees of hybrid vigour.It suggests to make systematic crosses within the species by selecting elite trees from different regions for propagation and breeding materials.The best trees should be selected to establish seed orchard to produce seeds for planting. The whole report deals with technic of crossing,growth rate of hybrids,and the inheritance of the character of viridis of the race of cryptomeria.