1919] WILSON. PHYTOGEOGRAPHICAL SKETCH OF KOREA 39 



of the north and Is not found elsewhere. This Larch with the two 

 Spruces, the Nut Pine, and the Mountain Fir cither grow together or 

 form more or less pure forests and the wood of one and all is of good 

 quality. The other Fir {Abies holophijUa Maxim.) is of little value as a 

 timber tree but for garden purposes it ranks with the Japanese A. homo- 

 lepis S. & Z. as the best of the xVsiatic species. The branches are moder- 

 ately stout, spreading or ascending-spreading and crow^ded with dark 

 green leaves. Trees 100 ft. tall with trunks 15 ft. in girth are not un- 

 common in fairly open country where the soil is rich and moist. 



Of Taxaceae only Cephalotaxus drupacea S. & Z. and Taxii^ cuspidata 

 S. & Z. grow on the mainland of Korea. The Cephalotaxus as a small shrub 

 of no particular shape is scattered here and there from the vicinity of 

 Keijyo, the cai)ital, southward; the Yew is much more widely spread, 

 growing as far north as the upper waters of the Yalu River. It is not a 

 common tree, though on the Nemonrei, in the Diamond ]Mts., it is more 

 plentiful and of greater size than I have seen it anywhere else in the Japan- 

 ese empire. 



At this point it seems opportune to say a little about the natural rotation 

 of forests, or, the succession of forest growth as it may be termed — a sub- 

 ject little understood but clearly demonstrated in and by the virgin forests 

 of north Korea, To appreciate this succession and to properly understand 

 what follows, it is necessary to state that in the temperate regions of north- 

 east Asia (and probably everj'where in the world) there are aggressive 

 northern and southern types that are ever extending their geographical 

 range at the exi)ense of (a) types already in occupation of intervening re- 

 gions, (b) those that flourish under peculiar conditions only, (c) themselves 

 finally. Of these aggressive northern tyj^es in Korea may be mentioned 

 Aspen {Populus tremula var, Davidiana Schneid), Alder {Alnus hirsuta 

 Turcz.)> Birches {Betnla davurica Pall., B, Ermanii Cham., B, japonica 

 Sieb.), Creeping Pine (Pinus pnmila Regel), Fir {Abies nephrolepis Maxim.), 

 two Spruces {Picea jezoensis Carr., P. Koyamai Shiras.). Of southern 

 aggressive trees Red Pine {Piniis densiflora S. & Z.), Oaks {Quercus 

 mongolica Fisch., Q. dentata Thunb., Q. glanduUfera Bl.), Hornbeam {Car- 

 pinus laxiflora Bl., C cordata Bl.), Ash {Fraxinus rhyncophylla Hancc, F, 

 mandshurica Rupr.) may be instanced; of types in possession, that is 

 species endemic or nearly so, Fir {Abies holopJnjlla Maxim.), Nut Pine 

 [Pinus koraiensis S. & Z.) Birch {Betula Schnidtii Regel), Maple {Acer 

 pseudo-sieboldianum Kom.), Box-elder {Acer triflorum Kom., A . vian- 

 shuricum Maxim.), Wild Pear {Pyrus ussuriensis Maxim.), Apricot {Pru- 

 nus raandschurica Kooline) may serve as exam])les. 



After forest fires or deforestation by man Birch, usually Betnla davurica 

 Pall, or B, Ermanii Cham, less commonly B, japonica Sicb., is the first tree to 

 a])pear in almost any part of Korea. In the south and at low altitudes and to 

 a less degree in central Korea the Birch may be forestalled by coarse grasses 

 {Miscayiihus SYt\). and allies) and natural reafforestation long retarded, but 

 normally. Birch is soon joined by other broad-leafed deciduous trees and 



