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S. K. HYUN 



Fig. 5. Pinus koraiensis-Pinus 

 densiflora Sieb. $ Zucc. forest type 

 on a dry west facing slope (Elev. 

 1,500 m, Mt. Chii, 35°N lat.). 



^n 



SILVICULTURAL CHARACTERS 



P. koraiensis is typically a pyramidal straight tree around 40 m 

 high and 1.50 m d.b.h. at 300 to 500 years. It is known as the finest 

 tree of Korea for timber quality. Leaves are dark green, straight, and 

 6 to 12 cm long. Cones are short-stalked and 9 to 14 cm long. The bark 

 is thin, except on old trees, reddish grey, and smooth or dividing into 

 scaly plates (Fig. 6) . 



Natural stands of P. koraiensis have served as a very important 

 timber source of north Korea and Manchuria. This species also produces 

 nuts and in many instances pine nuts are a good source of income. 



It is a shade-tolerant tree when it is young, but gradually becomes 

 intolerant as it grows. 



P. koraiensis starts to bear cones at about 15 years but does not 

 become a good producer until about 30 years of age. Although some cones 

 are produced almost every year, abundant seed crops are produced only at 

 intervals of 2 to 3 years. The seeds are large (1,080/1 or 950/lb) and 

 heavy with no wings; consequently, they are not carried great distances 

 by wind. But seeds are often buried by rodents and birds at considerable 

 distances from seed trees. The seeds exhibit embryo dormancy which can 

 be broken by cold stratification. Although the rate of germination of 

 stratified seed is as high as 64%, natural regeneration is difficult due 

 to the destruction of seed by rodents and birds (Uyeki, 1925). 



Artificial planting, however, is very successful anywhere in Korea 

 except the coastal low land. Planting stock is obtained by sowing seed 

 at the rate of 0.59 1/m 2 , preventing rodent and bird damage, shading with 



