THE MANURING OF FOREST TREES 



BY ARTHUR SMITH 



OURING the past quarter of a cen- suitable for this country as some of the 



tury the question of manuring clovers, such as the White Clover, 



forest trees has been given con- Trifolium repens and Alsyke, Trifolium 



siderable attention in Europe, and, hybridum. An ideal method would be 



among other experiments, that of using to plow in a crop of clover the season 



sewage effluent has been tried. previous to planting, then sow clover 



Near Berlin irrigating a forest of again and plant the trees in the young 



trees having considerable size by a clover. Failing, this clover could be 



monthly application of sewage water broadcasted over he ground in the 



during two growing seasons was a de- spring. To obtain a stand of clover 



cided failure and it caused the death of upon the more sandy soils the applica- 



rnany of the trees. A similar irrigation tion of some form of line would be ob- 



at Gerlitz gave better results. In this viously necessary. 



case, however, the growth was consid- It is of course well known that the 



erably younger. The city of Berlin has amount of mineral matter retained in 



obtained encouraging results by top lumber is comparatively small, and, by 



dressing the soil of coniferous woods the fall of their leaves, trees during 



with city refuse. their growth return to the soil the 



In view of the long period between greater part of the mineral matter taken 



the planting and the cutting of a forest from it; this applies, however, more to 



the direct application of manure in any deciduous species than to conifers. But 



form is not likely in a general way to the main point to be considered is that 



prove remunerative. At the same time of giving young newly planted trees a 



the question of helping along a planta- good start and helping them along dur- 



tion of young trees, especially conifers, ing the first few years of their life, 



is worth considering and in the earlier when they have the greatest struggle for 



stages in the life of forest trees growing existence. It is in this connection that 



in poor soil the value of some form of the value of giving the soil some 



manuring may possibly become an previous preparation upon the lines sug- 



acknowledged fact in practical forestry, gested above comes in of course where 



For instance on poor sandy soils it is practicable as not only is plant 



where the nitrogen content is very small food added to the soil in a slowly avail- 



the problem of supplying this neces- able form but, what is of the greatest 



sary plant food in a slowly available importance, the early growth is ac- 



form is worthy of consideration. The celerated, being measured by feet in- 



idea of applying nitrates or other com- stead of inches. 



mercial forms of nitrogenous fertilizers Another means which works to the 



may be put aside as impracticable both same end and which is more applicable 



on account of cost and because they are to the heavier classes of soils is that of 



too rapid in action, besides causing an keeping the ground in clean cultivation 



excessive growth of weeds. Making during the first two or three years of 



use, however, of atmospheric nitrogen the trees' growth. During the past sea- 



by growing on the land some form of son the writer has kept about 8,000 two- 



the Leguminosse appears to be feasible year-old conifers under clean cultiva- 



an dworthy of trial. Upon some sandy tion and another block of 5,000 has 



soils in Europe lupins have been used only had the weeds out and left lying, 



for this purpose and good results are The soil of the latter is, if anything, 



reported. Lupins would scarcely be so better than the former, but the growth 



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