164 THINNING. 



in soil so saturated with water that no air can pene- 

 trate it and reach the rootlets — hence the lingering 

 and sickly state the trees remain in for years after 

 being planted ; and it is only after they grow to such 

 a height, when the action of the wind shakes and loosens 

 the soil, that they begin to grow freely. 



Having thus laid down some general rules and 

 principles for thinning pine and fir plantations, and 

 indicated how the work generally should be performed, 

 I shall now make some observations upon the serious 

 injuries inflicted by improper thinning, how these are 

 produced, and how to avoid them. 



Thinning, admittedly, should be done gradually, 

 cautiously, and gently; but what, in the opinion of 

 one man, constitutes gradual, cautious, and gentle 

 thinning, is a very different thing in the opinion of 

 another. 



Gradual thinning, as generally understood, is the 

 practice of thinning by degrees, according as the 

 plantation advances in growth and requires it; cau- 

 tious thinning means the practice of cutting few in- 

 stead of many trees at one operation ; gentle thinning 

 signifies a little exposure at one time of each individ- 

 ual tree thus influenced, hence gentle exposure of the 

 whole crop. 



Words and phrases are, however, as yet but an 

 imperfect medium of conveying what is meant re- 

 garding thinning, and must not therefore be too 

 implicitly relied upon where such important conse- 

 quences are involved. 



The first most important case of injurious thinning 

 that came under our own observation was in the 

 Highlands of Scotland. The plantation was an ex- 

 tensive one, comprising about 1600 acres, and com- 



