TRANSACTIONS OF NORTHERN II. I,. HORTICULTURAL SOCIKTV. '285 



The last year has developed phenomena in our orchards, both new 

 and startling, yet which may be traced to obvious causes. Mf we recall 

 the situation of orchards, and the forms of trees which have suffered most 

 from the extremes of temperature combined with the extreme drought, 

 we will discover that, as a general rule, other things being equal, the 

 greatest fatality has been among trees standing upon ground exposed to 

 the extremes of drought and deep freezing. 



Low-head trees, by shading the ground beneath them, have prevented 

 the extreme heating and drying of the soil in summer, and thus the ex- 

 treme depth of the frost last winter did not affect them as seriously as 

 those whose roots were imbedded in a dryer soil J for we all know that 

 severe freezing of an orchard soil, if it contains about the right amount of 

 moisture to promote healthy tree growth, will not injure the trees, when 

 the same degree of frost in a soil almost destitute of moisture would de- 

 stroy them. 



This fact gives us a clue to the explanation of some other facts which 

 have been used with great confidence as evidences — proofs in fact — that 

 protection by groves or belts are injurious to, and that northern slopes 

 are advantageous to, orchards. It has been found that in the same , 

 orchard, which extended over a ridge or hill, to the north and south of 

 it, the trees upon the northern slope have survived the terrible ordeal of 

 the past year better than those on the southern slope ; yet we can readil) 

 see, from the light of the generally observed and admitted facts above 

 named, that the exposure really had nothing to do with these results, further 

 than that the soil upon the southern slope, exjjosed to the almost vertical 

 rays of the sun, became very much dryer than that upon the northern 

 slope; and hence when the roots of the trees were imi)risoned by the frost 

 of the last winter, in this "powder-dry" soil they were inevitably de- 

 stroyed. While upon the other slope, the soil being in a better condition, 

 the trees suffered far less. While it is doubtful if, in the life of the 

 youngest orchardist, a succession of three year's extreme drought, followed 

 by a season of enormous fruitfulness, and this by nearly sixty degrees of 

 frost, may ever recur again ; yet the fact that such a combination is 

 jjossible should lead us to consider M-ell the subject of keeping the soil in 

 a damp state by mulching or otherwise, and also lead us to select orchard 

 sites not having an abrupt southern slope, j 



TJiird — Protection b)' groves, or belts of trees. Upon this head 1 

 shall say but little; and this little will be to simply reiterate the opinion.^, 

 founded upon extensive observations, which I have so often given during 

 the last fifteen years, viz. : that a due or proportionate mixture of woods 

 and cultivated lands is more advantageous for orchards iIkiii an open 

 prairie country on the one hand, or a closely walled in field on the other. 

 I am not disposed to quarrel with the Darwinian theory that to produce 

 a race of animals or stock of trees fitted to endure certain hardshij)s we 

 must select our individuals for such stock or race from those whose pro- 

 genitors were exposed to, and yet not fully able to withstand, such hard- 

 ships ; or, in other words, the theory that the offspring are better fitted to 

 endure hardshi[)s to which their jirogenitors were exposed, than the)' 



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