10 YELLOW POPLAR IN TENNESSEE. 



straight undivided stems to the very top of the crown. Since the branch- 

 es on them are small, logs which lie within the crowns of young trees are 

 suitable on account of their straightness both for sawlogs and for pulp- 

 wood. This character which permits the close utilization of young trees, 

 adds to their value. 



The seedling yellow poplar has a long, straight taproot, which bears only 

 a few fleshy rootlets. The taproot interferes with transplanting. Seedlings 

 when transplanted do not readily establish themselves on account of the 

 few rootlets. 



Old trees have a very deep-seated and strong root system which renders 

 them windfirm. 



SILVICAL CHARACTERISTICS. 



Soil and moisture requirements. Yellow poplar requires for its best 

 growth a deep, fertile and moist, but well drained, soil. It has a strong 

 preference for soils which are derived from limestone, although it is com- 

 mon on other fertile soils which are rich in humus. It makes very slow 

 growth and reaches only a small size, however, on either wet or extreme- 

 ly dry soils. The most congenial sites for it are the lower slopes and hol- 

 lows of the mountains, and the soils of the rolling limestone valleys which 

 are well drained through the underlying fissured rock. The soils occu- 

 pied by yellow poplar are usually of high agricultural value for the grow- 

 ing of grain and grass, and, consequently when not too steep have been 

 largely cleared and placed in cultivation. The chief remaining areas of 

 considerable size which contain merchantable yellow poplar and which 

 are best suited for its growth are the hollows along the Cumberland 

 Mountain, the lower slopes and coves of the Smoky and Unaka range, 

 and the hollows of the intervening ridges. The small tracts of forest 

 which yet remain on the farms of the limestone valleys frequently con- 

 tain considerable old poplar, and on many tracts a large amount of young 

 timber, and are well suited for its growth. 



Temperature and light. In spite of its exacting requirements respect- 

 ing soil moisture, yellow poplar demands considerable warmth. It grows 

 well from the lowest elevations in Tennessee up to altitudes of 3,000 feet 

 on the north slopes of the Unaka and Smoky mountains, but it becomes 

 sporadic on north aspects above this altitude. It demands a large amount 

 of direct sunlight for its best growth, at all ages after it is thoroughly 

 established. 



The seedling and young tree will endure considerable side shade, more 

 on moist than on dry soils, but if the overhead shade is too dense or is 

 prolonged, the tree dies. A very light overhead shade or a side shade 

 is beneficial to seedlings until they are two years old, by which time they 



