416 FIRE-CONSERVANCY. 



thy, unsound, stunted, croaked and knotty, and become an easy 

 prey to, and serve for the multiplication of, insects and fungi. 

 Fourthly, this deterioration of individuals may, and often does, 

 become permanent and perpetuated in the offspring, resulting in 

 the formation of defective varieties. Fifthly, the production of 

 vegetable mould is effectually prevented, the slight amount of useful 

 mineral matter rendered immediately available in the ash being 

 a very poor compensation for the much larger quantity of other 

 substances dissipated, and being to a great extent blown away by 

 the wind or washed away by the first few heavy showers of rain. 

 Sixthly, the exposure of the soil, consequent on the burning of the 

 weeds and brushwood on it and of the vegetable debris covering it, 

 hardens it, dries it up quickly, produces rapid and wide fluctua- 

 tions of temperature in it, makes it refractory to fertilising influ- 

 ences, and renders it liable to erosion or at least to the washing 

 away of the better portions from the surface. Seventhly, seeds 

 falling on such soil find a most uncongenial bed, and any seed- 

 lings tnat may come up are unable to extend their roots to any 

 depth, remain ill-fed and succumb easily to drought, excessive insola- 

 tion, or frost. Eighthly, the intense heat of the fire bakes the soil, and 

 may vitrify the surface of stones and rocks and delay their disinte- 

 gration and decomposition. Ninthly, owing to the hardening of 

 the surface soil due to the heat and the exposure, rain-water falling 

 on it cannot penetrate it easily, and so rushes over it in a large 

 volume, all the more rapidly because of the absence of any weeds 

 or bushes or covering of dead leaves capable of checking it, the 

 result being inordinately swollen rivers, which fall as suddenly as 

 they rose. Tenthly, another result is that, as the water has no time 

 to sink, in any considerable quantity, into the ground and most of 

 it goes away at once into the rivers, the level of springs falls very 

 low, and springs that would otherwise be abundant or permanaut 

 become exiguous or dry up entirely. Lastly, the heavy floods iu 

 the rivers may cause them to erode and overflow their banks, 

 spread devastation far and wide over the country on each side, 

 and cut out every year a new channel for themselves. Thus fire 

 conservancy is at the very root and foundation of all forest conser- 

 vancy, and is the first object of all to secure before any forestry 

 can be attempted. 



And the necessity for adopting special measures to secure pro- 

 tection from fire is so much the greater on account of the numer- 

 ous wide-spread inducements that exist for the firing of our 

 forests. The first and foremost of these is the interest which 



