IMPORTANT FOREST SPECIES 399 



Habitat. — Silver fir does not extend beyond the limits of Europe except to the East, 

 where it penetrates for some distance (beyond the Sea of Marmora) into Anatolia. 

 Its somewhat restricted area is in the shape of an irregular elUpse, whose main axis 

 rests east and west, reaching from the western Pyrenees, in the neighborhood of the 

 Gulf of Gascony, to beyond Constantinople, over a length of about 32° of longitude; 

 the smaller north and south axis, from Cologne to Mt. Etna, extends over 14° of lati- 

 tude. Ireland, England, Belgium, Holland, Northern Germany, Sweden, and Norway, 

 and the whole of Russia are beyond the northern and eastern natural limits of this 

 species . . . also Spain, exclusive of the Pyrenean slopes, Sardinia, southern 

 Sicily, and Greece. There is a possibility that silver fir may be found in the Caucasus. 

 In France, it is found only east and south of a zigzag line, which starts from fipinal, 

 and passes by Bourg, Clermont, Aurillac, Careassone (to reach along the Pyrenees) 

 and down to Bayonne. 



The distribution of fir within its habitat area is most irregular; eastwards it is scattered 

 amongst beech and spruce, but, as one goes westward, it becomes more plentiful so that 

 it reaches its maximum development about the western hmite of the area and forms 

 pure stands or is the most important species. It may be seen piire (in France) in the 

 Pyrenees, Upper Corsieres, C^vennes, the Auvergne, Forez and Loire Mountains, the 

 Dauphine Alps, and principally the Jura and Vosges; (Germany) in the Schwarzwald 

 (Black Forest) and the Franconian Hills. 



Situation. — Silver fir (Frigoris comes et causa, as Linmeus put it) is essentially a 

 species of the mountains . . . above the vine and oak but below the spruce. 

 Coming almost into the plains at northern latitudes ... it reaches between 1,300 

 and 4,250 feet altitude in the Vosges; 1,500 to 1,960 feet in the Jura; up to 4,900 feet 

 in the Monts-Dore, 5,590 feet in Corsica, 6,390 feet on Mt. Etna group, and 6,397 

 feet in the French Pyrenees on northern exposures. 



Soil. — It seeks deep, cool, fertile soils, avoiding compact, marshy or peaty ground. 



The mineral nature of the soil is of minor importance, provided its physical require- 

 ments are met. In the Jura, on Umestone soil, the fir forests are equal if not ■superior 

 to the best grown in the Vosges on silica or granite. 



Conditions of Vegetation. — There must be a mean August temperature of at 

 least 15° C. (59° F.), with a maximum of not over 39° C. (102.2° F.); mean January 

 temperature not below 5° C. (41° F.), nor above 27° C. (80.6° F.), with a vegetative 

 rest of at least 3 months, and plenty of moisture. 



Silvicultural Characteristics. — The fir, like other indigenous conifers, should be 

 treated as high forest. It forms very dense stands. A fir forest, left to itself, is always 

 many-storied. ... A thick cover results in retaining the fertihty of the soil, as 

 well as its freshness. ... In addition the fir can be treated in selection stands. 

 Moreover, in all forests which have been injured by grazing or by excessive exploitation, 

 the natural regeneration is never lacking, even under a complete canopy. Unless local 

 climatic conditions prevent it, the fir forms a regular high forest. . . . When it 

 has stopped its height growth its crown becomes open, exposed, and thin, so the soil, 

 insufficiently protected by the cover . . . runs wild. . . . This makes natural 

 regeneration often difficult and sometimes even impossible. . . . The fir forms 

 excellent pure stands, but it is preferable to mix it with other species, notably beech 

 or spruce. The mixture depends on the conditions of the altitude. . . . The fir 

 makes an excellent mixture with broadleaved trees or shrubs which protect the ground. 



