Hknkv and Flood — The Dougbts Firs. 81 



portion (loriis), ou tlio nipnilirane of the limdcicd pits, between the tiacheids, 

 is placed in a central position, dividing equally the pit cavity. In tlie 

 Colorado species the torus is usually pressed to one side, against the opening 

 of the pit cavity, completely closing it. In consequence, the wood of the 

 Oregon species is readily permeated by creosote, the reverse being the case 

 in the other species. 



7. Reproduction. The Oregon Douglas Fir bears seed freely and at an 

 early age in the British Isles, and reproduces itself naturally in many 

 districts, self-sown seedlings being especially numerous on sandy soil in the 

 New Forest and other parts of Hampshire. They are 40 feet high on poor 

 gravelly soil at Dunster, Somerset, where the parent trees are only thirty- 

 eight years old. In Ireland natural seedlings have been noticed at Derreen 

 in Kerry, and at CooUattiu and Powerscourt in Wieklow. The seeds have, 

 however, a poor gei-minating capacity as a rule, and are liable to be destroyed 

 by the larva of an insect, Megastigtmis sjxrmotroj^hvs, which has been 

 accidentally introduced into Europe from Oregon. Eafn^ has made numerous 

 tests of imported American seed, and finds a remarl;able difference in the 

 germination of the two species. The seed of the Colorado Douglas Fir 

 germinates much sooner and in considerably larger percentage than that of 

 the Oregon species. 



8. Resistance to Frost. The Colorado Douglas Fir is much hardier than the 

 Oregon species, and is never injured by autumn or winter frosts in this 

 country. It is, however, occasionally damaged by late frosts in spring, as on 

 23rd May, 1911, when young trees at Ampton, Suffolk, were just as badly 

 cut as the Oregon Dougjas Firs beside them. At Balmoral it begins to make 

 new growth later in the season than the other species, and is said ou that 

 account never to suffer there from frost. 



The Oregon Douglas Fir does not withstand extreme cold in winter, and 

 for this reason cannot be cultivated at high altitudes or in northern climates. 

 It is unharmed by ordinary winter temperatures in all parts of the British 

 Isles below tree limit. The great frost of February, 1895, when the tempera- 

 ture fell to - 17"' F., did not hurt the Oregon Douglas Fir at Balmoral, where 

 it is planted up to 1,200 feet elevation. It is, however, liable to be injured 

 in low-lying damp localities by both late frosts in spring and early frosts in 

 autumn. Injury by frost is more likely to occur in the nursery tiian in the 

 forest. In Bavaria the leaves turn red when the winter is severe, and 

 drop off in the following spring. The Colorado Douglas Fir is never 

 injured in this way, possibly owing in part to the protection of the thin 

 layer of wax which gives the leaves their glaucous tint. 



' Testing o/ Forent Seeds, 18S7-191-2, p. 40. 



