May 2 1, 







NATURE 



North American forest trees, experimental plantings of 

 which have from time to time been made in Germany. 

 After spending seven months on these researches, and ex- 

 tending his tour through Japan, Java, Ceylon, and Northern 

 Hindustan, Dr. Mayr returned to Germany in 1888, and 

 was shortly afterwards appointed Professor of Forestry 

 and Forest Botany at the College of Agriculture and 

 Forestry at Tokio in Japan. The present writer had the 

 great pleasure of accompanying him in January 1888 for 

 about three weeks through some of the coniferous and 

 oak forests of the North- Western Himalayas and the 

 subtropical forests of the lower hills near Dehra. 



After leaving Germany a second time for Japan, Dr. 

 Mayr bad a further opportunity of visiting North 

 America, and thus has twice traversed the length and 

 breadth of the country between the Dominion of Canada 

 and Mexico. 



Mayr treats of the demands of the most important 

 North American trees as regards climate and soil, with a 

 summary account of their anatomical structure and of the 

 physical and technical qualities of the most important 

 woods, and his book contains numerous illustrations. He 

 also gives lists of destructive fungi and insects observed 

 by him on the different species. 



Brandis has some criticisms to mete out for a few 

 somewhat rash generalizations made by Mayr. These 

 are that evergreen broad-leaved (not coniferous) forest 

 requires a higher winter temperature than deciduous 

 forest, and that deciduous forest vegetation is always 

 absent in tropical countries on account of the uniformity 

 of the climate throughout the year. Brandis shows 

 clearly, from a comparison with the deciduous forests of 

 teak and other species in India, Burma, and Java, that 

 this statement will not hold wherever there is a prolonged 

 dry season, which renders the trees leafless for a certain 

 period of the year. 



Another statement of Mayr's controverted by Brandis 

 is that conifers never grow in tropical countries except 

 where the altitude renders the climate non-tropical, and 

 that in North America they have longer needles, supply 

 heavier timber, and contain the more resin, the nearer 

 they grow to the tropics. The latter statements may be 

 true for Finns anstralis, the pitch pine of the Southern 

 States of North America, but do not hold good in India, 

 where the Pi7i7is longifolia of the Himalayas has the 

 longest needles and probably yields as much resin as 

 the tropical pine {P. Merkensii), which, however, has the 

 heaviest wood of all the Indian pines, and grows in 

 latitude 17' N., in Tenasserim, at about 600 feet above 

 sea-level, in an absolutely tropical climate. 



Mayr's statement that oranges will only grow to perfec- 

 tion in a hot dry climate is also not true for India, as 

 oranges of splendid flavour are grown in enormous 

 quantities in the damp lower hills below Cherapunji, in 

 Assam, where the rainy season lasts for eight months, as 

 well as in the dry regions near Delhi, and the compara- 

 tively dry country near Nagpur, in the Central Provinces 

 of India. 



Apart from these criticisms and an interesting discus- 

 sion on the origin of prairies, we find in Brandis's paper 

 a most complete account of the distribution of North 

 American forest trees. 



Forest vegetation is much richer in North America than 

 in Europe, containing about 412 species, distributed as 

 follows : — 



Atlantic region 



Pacific region 



Common to both 



Central region on and surrounding Rocky Moun- 

 tains 



Tropical species near the coasts of Florida 



as against 158 species in Europe. 

 NO. I 125, VOL. 44] 



176 



106 



10 



46 

 74 



412 



At least six North American species of forest trees, 

 according to Brandis, are also indigenous in Europe, 

 being — 



Cercis canadensis = Siliquastrnm 



Diospyros virginiana — Lotus 



Celtis occidentalis = australis 



Platanus occidentalis = orientalis 



Ostrya virginica = carpinifolia 



Castanea americana = vulgaris. 



All these species now grow naturally in Europe south 

 of the Alps, and since many American forest genera 

 existed in Europe in Tertiary times, whilst only five 

 European forest genera (Ceratonia, Laburnum, Olea, 

 Syringa, Laurus) are not found in America, it is possible 

 that other species formerly common to both countries 

 were destroyed in Europe north of the Alps by the Glacial 

 epoch. 



It would take too long to describe each region in 

 detail, and I must here merely glance at them in the 

 briefest manner. 



A small outlier of the West Indian tropical flora 

 extends into the south of Florida, and is followed by 

 a broad zone of evergreen broad-leaved forest, of which 

 Magnolia f^randiflora is the chief representative. We 

 then get the pitch pine forests on the sandy formations of 

 Florida, Georgia, North and South Carolina, extending 

 westwards to Alabama and Mississippi. The wood of 

 the pitch pine {P. australis) is the best coniferous wood 

 in the world, but the forests are being utterly ruined. They 

 are tapped in the most wasteful manner for turpentine, 

 8,000,000 dollars being the estimated local value of the 

 annual return. More wood is burned than is utilized, 

 and, according to Mayr, already wide belts of white 

 sterile shifting sands border both sides of the railways 

 of the Gulf States, showing what the poorer tracts of the 

 country will come to, if the farmers do not give up their 

 pernicious habit of burning thousands of square miles of 

 forest every year. 



Another tree of the Southern Atlantic zone is the 

 swamp cypress {Taxodium disiichum), growing on an- 

 nually inundated land,' and presumably safe from fire, if 

 not from ill-regulated and wasteful felling. 



The valuable pencil cedar {Juniperus virginiana) also 

 flourishes at its best in the Southern Atlantic region, but 

 grows almost everywhere in the United States and British 

 America, from latitude 54" southwards. To the north 

 and in the prairies it has, however, only a stunted growth. 

 Hardly any sound wood of this species is now procurable, 

 as I learned last year from Messrs. Faber and Co. at 

 Nuremberg. Next to this zone comes the description of 

 the broad-leaved deciduous forest of the temperate region, 

 containing many oaks, walnuts, hickories, and the tulip 

 tree {Liriodendron tulipifera). The heavy seeded trees 

 are found chiefly in the south, and lighter seeded ones, 

 as maples, birches, and elms, more to the north. 



There is along account by Brandis of the prairie region, 

 and the region of thinly-stocked forest bordering on it ; and 

 it appears that here, as cultivation extends, and the fires 

 do not sweep over such vast extents of land as they did 

 formerly, woods of Mesquit bean {Prosopis julijlora), 

 and other trees are spreading by seed or coppice shoots, 

 in Western Texas, and also in Wisconsin, Illinois, Iowa, 

 and other States. Much has been done in the prairie 

 region by plantations, and these succeed admirably 

 wherever the chmate is sufficiently moist ; but in the 

 central and western parts of Kansas all planting has 

 hitherto failed, owing to the extremely dry climate. 



In the northern pine zone of the Atlantic forest region, 

 Pinus Strobus, the Weymouth or white pine is the most 

 important species, and formerly covered enormous tracts 

 from the Gulf of St. Lawrence to North Georgia, and 

 beyond the sources of the Mississippi. At present, the 

 only considerable supply of white pine is in Canada, and 

 in the lake districts of the States of Michigan, Wisconsin, 



