Dec. 1895.] RECENT AFFORESTATION WORK IN FRANCE. 



273 



of the currents of tlie rivers not only releases the rich valleys of 

 the low country from the fear of inundation, but permits the 

 extension of cultivation by an easily controlled system of 

 irrigation in parts of the country which have been hitherto 

 unproductive, and by the retention of all sorts of materials 

 brought down by the Garonne, to take one out of many 

 examples, prevents the silting up of the port of Bordeaux by 

 the accumulation of sand-banks, a danger which formerly 

 menaced it. 



The trees found most useful in reafforesting the slopes of 

 mountains are beech, the saplings of two to three years old being 

 brought in bills, w^hich succeed well up to 1,000 or even 1,800 

 metres in height, with oak at the lower altitudes. Above the 

 region of the beech the Pinus sylvestris (which has proved itself 

 more capable of resistance in high latitudes tlsan the black or 

 Austrian pine at first extensively used), the P. iimhra, P. unici- 

 nata, the larch,* and the spruce fir have given satisfactory results. 

 In relatively warm lands the Maritime Pine for the silicious soils, 

 and the pine of Aleppo for the calcareous, conjointly with the 

 oak and the ilex, have been successfully tried. 



Imported trees, such as the Atlas cedar, the Ailanthus, the 

 Robinia (or False Acacia), from which great things were 

 expected, have not proved themselves so hardy as could be 

 desired. Another exam_ple this of the fact which an exceptional 

 winter like the last brought home to ourselves, viz., that, however 

 desirable and instructive it may be to have a variety of foreign 

 species in a pinetum or botanical garden, financial considerations 

 do not admit of the employment oi" any but indigenous trees w hen 

 severe conditions of climate and of temperature have to be faced. 



The cost of the extinction of torrents by plantations is, like that, 

 of the reclamation of the dunes, by no means a small one, and is 

 not to be taken as an operation of a purely financial character 

 per se. " Barrages," which are often costly embankments of solid 

 masonry, are found necessary to prevent the erosion of the 

 river-banks, and there are various auxiliary works which swell 

 the cost. 



The mean price of re-aiforesting 94,730 hectares has been 



found to be — 



282 francs per hectare in the Alps, 

 176 „ „ ,, Cevennes, and 



237 „ „ „ Pyrenees. 



But the mean price of re-afibre sting the same number of 



hectares, including all sorts of supplement ! ry works, barrages,, 



dams, channels, &c., has been found to be — 

 576 francs per hectare in the Alps, 

 263 „ „ „ Cevennes, and 



445 „ „ „ Pyrenees, 



* In making inquiries as to the limit of the forest zone, it was proved that in 1892 

 the 28th Battalion o£ the Alpine Chasseurs, then employed on a strategical road, ble^ 

 up, in a trench they had opened at a height of 2,780 metres, several trunks of larcb, 

 the relics of an ancient forest. 



O 89185. B 



