45 



and then deep roots take these materials to tlie leaves for elaboration 

 by sun chemistry. 



Trees ma}- be grown wherever crops of annual plants ma}^ be grown 

 and where annual plants may not be grown profitably. They do not 

 require the service of high cost labor for annual tillage of the soil. 

 For example, four large pecan trees or black walnut trees on an acre 

 of ground without tillage or fertilizer may average a thousand pounds 

 of nut meats annually for a century. How often is the market value 

 and food value of a thousand pounds of nut meats per acre equalled 

 by crops from annual plants which would require from, 100 to 200 

 plowings and harrowings during a hundred years of continuous culti- 

 vation, leaving out the question of expensive fertilizers and labor. 

 Large populations live upon dates, olives and figs. For trouble they 

 have to look to religion. 



Several centuries were required for the British farmers to raise the 

 wheat croj) from six bushels to thirty bushels per acre. Things move 

 faster nowadays. It will not require so long a time to carry tree 

 crops fromi the seedling phase to the phase of grafted kinds with 

 greater productivity and quality. In the past the successful tree 

 grafter was a specially skilled man. Now almost anybody may graft 

 almost any sort of tree at almost any time of the year. 



Aside from grafting the hybridizing of nut trees, like that of 

 cereal grain plants, has become a scientific sport appealing to the play 

 instinct of man. When work becomes play in any field of human 

 activity progress goes by leaps and bounds. The recent advance in 

 tree grafting has amounted almost to a revolution rather than an 

 evolution process. Application of a few new grafting principles of 

 great consequence is now the order of the day. Old established graft- 

 ing methods frequently ran into failures when dealing with all but a 

 few trees like the common fruit bearing kinds. 



The two chief obstacles to successful grafting were desiccation of 

 the graft and fungous or bacterial parasites which entered the land 

 of milk and honey where sap collected in graft wounds. Both of 

 these dangers have now been practically eliminated and it remains 

 "or us to extend the season of grafting, carrying it away from a hur- 

 ried procedure in busy spring weeks. 



The chief obstacle to this extension of the grafting season has been 

 the difficulty in finding the right sort of grafting wax or protective 

 material for covering the graft, buds and all, as well as the wound of 

 the stock. For covering the entire graft in order to avoid desiccation 



