SAVING AN OLD ELM 



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THE accompanying illustration shows a method re- 

 cently employed by the Bronx Parkway Commission 

 to save from destruction a large elm tree which 

 stands just inside the boundary line of the parkway 

 reservation. 



The thoroughfare to the left of the picture is Gun Hill 

 Road where it crosses the Bronx River, in the Borough 

 of the Bronx, New York City. In connection with the 

 raising and widening of this road it was necessary to 

 build a large 

 retaining wall, 

 the base of 

 which is shown 

 in the middle 

 f o r e g round. 

 Many of the 

 main roots of 

 the large elm 

 tree in the pic- 

 ture lay direct- 

 ly across the 

 foundation ex- 

 cavation for 

 the new wall. 

 To have sever- 

 ed these roots 

 would have 

 meant the 

 death of the 

 tree. 



The Park- 

 way Commis- 

 sion naturally 

 follows a poli- 

 cy of saving 

 trees wherever 

 possible, and it 

 was recognized 

 that this par- 

 t i c u 1 a r tree 

 would be es- 

 pecially valua- 

 ble for screen- 

 ing the propos- 

 ed reta i n i n g 

 wall and an 

 elevated struc- 

 ture. The sav- 

 ing of it in- 

 volved the problem of providing adequate foundation 

 support for a heavy wall having a base 12 feet wide, and 

 at the same time providing adequate spaces to prevent 

 pressure or constriction of the tree roots. 



When the foundation excavation was approaching the 

 tree, care was taken to remove the earth carefully and 

 with minimum possible injury to the roots. Some 

 of this work had to be done with trowels, As the roots 



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Courtesy the Davey Tree Expert Company 



A MAGNIFICENT BLACK MAPLE 

 It is almost impossible to compute the value of such a tree for far and above its commercial valuation 

 lies its esthetic contribution to the joy and pride of its owner, varying with the individual in every case. 



became exposed they were firmly wrapped with a jacket 

 of straw and kept moist. Thin wooden sheeting was 

 driven vertically so as to completely enclose the main 

 roots in channels or compartments. Adjacent smaller 

 roots were deflected without injury, to make them also 

 occupy these channels, the idea being to divide the avail- 

 able space equally between tree roots and wall sup- 

 porting piers. The channels were then filled with soil 

 well tamped and compacted. Concrete was placed in all 



of the founda- 

 tion spaces not 

 occupied by the 

 root channels. 

 Above the 

 channels o 1 d 

 steel rails were 

 laid in the con- 

 crete, thus 

 forming a 

 heavily rein- 

 forced slab, 

 s u p p orted by 

 irregular shap- 

 ed piers out- 

 side of the 

 root channels. 

 These channels 

 are, of course, 

 open on the 

 bottom and 

 give the roots 

 perfectly free 

 access to 

 ground water, 

 and as the chan- 

 nels pass en- 

 tirely through 

 the wall there 

 is free access 

 to good soil be- 

 yond the wall. 

 On this foun- 

 dation which 

 bridges over, 

 and relieves 

 the tree roots 

 of pressure, a 

 heavy, dry wall 

 about 30 feet 

 high has been built. The work was done early in the 

 spring, and the appearance of the tree in late summer in- 

 dicates that it has not suffered. It is a large old elm and 

 well worth the effort made to save it. The method used 

 was devised by Mr. Hermann W. Merkel, Consulting 

 Landscape Architect and Forester of the Bronx Park- 

 way Commission. 





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