SHADE TREES. 17 



and, as the trees grow larger, care should be taken to loosen and 

 enlarge the guards as the trees require. Neglect in this matter 

 has occasioned the death of quite a number of shade trees. 



Grills are designed to prevent the trampling of the soil about 

 the base of the tree and are especially desirable on street corners 

 and other places where many people pass. On paved sidewalks 

 where the traffic is large and the amount of exposed earth at a 

 minimum, some such means of keeping the soil light and porous 

 may be considered a necessity. Grills also afford an excellent 

 means of watering trees during periods of drought. The con- 



DESCRIPTION OF PLATE. 



PIRATE IV. Some Fungi which attack Shade Trees. The Trees mentioned 

 are living, unless the contrary is stated. 



A. White Oak on the campus of Cornell University attacked by Poly- 

 POTUS applanatus. 



B. Polyporus hispidus on Sycamore at Wiesbaden, Germany. 



C. Polyporus on black locust, Falls Church, Virginia. 



D. Silver maple in Washington which has been headed back, seriously 

 attacked by Polyporus obtusus. 



E. Polvporus sulphureus on black oak, Palisades Park, New Jersey. 



F. Polyporus squamosus on English field elm, Tower of London. 



G. Upper surface of same. 



H. Daedalea quercina on white oak, Palisades Park, New Jersey. 



/. Fruit bodies of Pleurotus ulmarius appearing on the roots of a dying 

 sugar maple which had been uncovered in the process of lowering 

 the street. Eddy Street near Cascadilla Place, Ithaca. 



J. Pholiota adiposa on red maple, Palisades Park, New Jersey. 



K. Polyporus Beatiei found at the base of a large black oak tree near 

 Blacksburg, Virginia. Related to Polyporus frondosus. 



struction of the grill may be readily determined by examining 

 the accompanying illustrations. It is made of sections of iron 

 grating which fit together about the tree in a circular, rectan- 

 gular, or hexagonal form and are supported on wooden pegs 

 driven into the ground. A special form of grill is sometimes 

 used on very busy streets, which extends outward beneath the 

 sidewalk leaving considerable space about the tree, while, being 

 covered with pavement, it permits free use of the sidewalk up to 

 within a foot of the tree trunk. Grills are regularly used with 

 the iron guards in Paris, Berlin, and London in places where they 



