162 Mississippi Valleu Horticultural Society. 



PROTECTION TO JIEN. 



In tlic western Imlf of Minnesota there is a large tract of very fertile land 

 (10,00(1,0(1) acres), said to be capable of becoming the granary of the North- 

 west, on account of its wonderful adaptation to the wheat crop. This re- 

 gion is estimated to possess but one acre of natural timber to the section (or 

 square mile of 640 acres). Immigration into this region was attempted, but 

 the terrible severity of the winter's winds drove back the distressed settlers, 

 until it was shown, by the successful efforts of Mr. L. B. Hodges, that shelter 

 could be cheaply and quickly furnished by tree planting. This demonstra- 

 tion was followed by a large influx of an industrious population. 



But every gardener understands the great benefits he derives from shelter 

 hedges, even where they arc kei)t trimmed down to a moderate height. This 

 is especially the case when these wind-screens are composed of evergreens. 

 Such lines of living plants not only check the driving winds, and thus ward 

 of! constant accessions of cold air, but they at the same time prevent, to a 

 certain extent, the increased evaporation that would result, and its attendant 

 depression of temperature. Besides this, the hving plants themselves appear 

 to have an amount of specific heat within them, as has been proved by ob- 

 servations made at some of the forest experime: t stations in Germany. A 

 series of observations made in the neighborhood of St. Louis, by Mr. Tice, 

 showed the protecting influence exerted by an evergreen hedge which ex- 

 tended for several rods to the leeward, before the thermometers indicated 

 the same degree of cold as those on the windward side. [Mr. Tice's experi- 

 ments, reported in Ills. Hort. Trans.] 



WOODLANDS RETAIN MOISTURE. 



But another fact in reference to the influence of forests upon climates and 

 its results is too important to be overlookfed. Woodlands are not only re- 

 ceptive of snows and rains, but they are also remarkably retentive of these 

 treasures from the skies. Beneath the trees we usuallj- find the soil loose 

 and open ; the surface is more or less covered by the debris of decaying veg- 

 etable matter, all of which must receive, absorb and temporarily retain the 

 rains and melting snows until the fluid may quietly settle into the soil and 

 subjacent rocks, and thus the forest regions become reservoirs for supplying 

 springs that pour forth the runlets, rivulets and streams which eventually 

 form the rivers of the continents. 



SAND- WASTES — SAND-DUNES. 



While considering the relations of forestry, we should not overlook the 

 immense value of tree plantations upon low, sandy lands. These sometimes 

 occur in the interior of a continent, though they are more frequent in situa- 

 tions exposed to the sea, where the combined influence of the waves and the 

 winds pile up the sands into great dunes that are often mercilessly wafted 



