TWIN TREES AND NATURAL GRAFTS 



By E. F. Andrews 



(WITH PHOTOGRAPHS BY THE AUTHOR) 



'T'HE twin oak and elm tree of which a picture was and tuHp tree, and the loblolly and shortleaf pine. 

 - given in the November, 1921, number of AMERICAN Twins of this kind can be produced only when the 

 FORESTRY, attracted a great deal of interest. Such germinating seeds are in such close proximity that the 



Fig. 1. Twin white oak and short-leaf Fig. 2. Rootgraft between elm (Left) and Fig. 3. Root and stem graft, sycamore and 

 pine, near Rome, Georgia. haw (Right) near Rome, Georgia. hackberry, Dayton, Tennessee. 



natural grafts are much more common than 

 supposed. In fact, woody 

 stems of almost any kind, 

 if kept in close and con- 

 t i n u o u s contact while 

 young, will coalesce and 

 form a twin, or composite 

 stem. Altogether, I have 

 observed unions more or 

 less complete between the 

 following species : Willow 

 oak and loblolly pine, white 

 oak and tulip tree, white 

 oak and shortleaf pine, red 

 oak and hickory, red oak 

 and maple, river birch and 

 hackberry, beech and white 

 pine, sweet gum and lob- 

 lolly pine, sycamore and 

 hackberry, hackberry and 

 black locust, elm and haw 

 (C. spathulata) , sweet gum 



is generally stems of the seedlings, as they increase in size, are forced 



by mutual pressure to grow 

 together on their contigu- 

 ous sides. Unions less per- 

 fect, sometimes occur as 

 root grafts, when seeds 

 dropped by birds or by the 

 wind lodge in crevices of 

 the root of a growing tree 

 and germinate there. Haws 

 and pines, the seeds of 

 which furnish so large a 

 part of the food of birds 

 in winter are of frequent 

 occurrence as root grafts. 

 And when we consider the 

 vast number of seeds scat- 

 tered over the ground by 

 trees of all kinds, and 

 tumbled about by wind and 



, ,. , . . , . T- water, buried by rodents, or 



Fig. 4. Stump of twin tuhp tree and white oak, Ashland Farm, , , , . , , , 



Walker county, Georgia. dropped by birds and other 



