Explanation of the G-Trees 



M 



R. \V. R. .MATTOON, of the U. S. Forest Ser- 

 vice, who has recently spent several months 

 studying second-growth stands in the southern 



pine belt of longleaf and slash pines, furnishes the follow- 

 ing explanation regarding the peculiar G-shaped trunks 



of pine illustrated on page 



423 of the July number of 



American Forestry. 



" It is not uncommon in 



second-growth longleaf pine 



to come across trees with a 



striking G-form section of 



the main stem. The crook 



usually starts at a point from 



3 to 7 feet above the ground, 



and after more or less of a 



half circular sweep termi- 

 nates in an upv.ard growing 



stem at a point located 



roughly over the initial point 



in the basal portion of the 



tree trunk. The explanation 



lies in the death of the central 



terminal shoot and the sub- 



HOW THE G-TREES FORM 



The contorted branches show the tendency of this permanently deformed 



longleaf pine to develop a vertical growing stem. 



aided by the increasing weight of the growing stem. In 

 perpetuating itself by means of a lateral branch, slash 

 pine {Piiins caribcca), formerly called Cuban pine 

 {Piiiits heterophylla) by the U. S. Forest Service, makes 

 much less of a cur\ing trunk, due undoubtedlv to its very 



much faster growth. One 

 such case is illustrated in an 

 accompanying photograph. 

 " The dying of the central 

 terminal stem may be due to 

 any one of several causes, 

 including fire, insect attack, 

 and wind as the most com- 

 mon agencies. Occasionally 

 large sized groups of saplings 

 nr small pole trees are thus 

 found topped off in the path 

 of a tropical hurricane. The 

 Nantucket tip moth 

 (Rctinia fnisfraiia Scud.), 

 which sometimes does much 

 harm to the young grow- 

 ing stems of shortleaf and 

 loblolly pines, seems to 



G-TREE OF NORTH C.\ROLI.\A 



ONE FOR.M IIP Till-; C-TklCi; 



A WHITE PI-XE G-TREE 



The photograph of this specimen was taken bv By the substitution of a lateral branch for the Harry D. Tiemann. of the Forest Products Labor- 

 P. T. Kneale president of the Woodland Lumber killed central stem, this slash pine, in about 5 years atory. at Madison Wisconsin, sends this photograph 

 Company, oi Philadelphia, near Princeton. North ■ji.-vr c jj- ' '-'*a white pine of G-tree shape on the banks of the 



Carolina, in 1912. There were a number of similarly "as attained a height of 18 teet and a diameter of Wisconsin River near Kilbourn, Wisconsin, 

 deformed trees in the vicinity. 6 inches at breast height. 



sequent effort of the tree to replace it by substituting one 

 of its laterals or side branches. 



" Because of the slow-growing, flexible character of 

 its laterals and their characteristic nearly right-angular 

 forking, sometimes even forming a verv acute angle 

 downward with the main stem, longleaf pine is particu- 

 larly successful in developing well-rounded G-shaped 

 substitute tree trunks. The full curving of the stem is 

 740 



accom])lish very little injury to the large, well-i)rotected 

 " asbestos " bud of longleaf pine. In isolated cases a 

 freak in burning would no doubt act as the initial cause 

 for the peculiar later development of the tree trunk. .\i\ 

 outbreak of some girdling insect working on saplings at 

 about a uniform lieight above the ground or a severe 

 wind storm oft'ers the most likely explanation for the 

 occurrence in the Tulv number of .American Forestry." 



