48 Forestry Quarterly 



districts are studded with conspicuous secondary volcanoes of 

 tufa and ashes, long extinct. 



From the standpoint of dendrological studies all these varied 

 regions are quite accessible ; many of them are within half a day's 

 walk, and the most remote can be reached within a single day. 

 In addition to the automobile roads, plantation roadways, wagon 

 trails, and foot trails, there are two railway lines, a number of 

 stage lines, and a comprehensive motor-car service. There are 

 also available a number of excellent topographic maps, includ- 

 ing trail maps. Food supplies and potable water are obtain- 

 able throughout the island. It is therefore a relatively simple 

 matter to make a dendrological or other scientific expedition 

 to any given region, to transport needed apparatus and equip- 

 ment, and to continue the studies and collecting for as long a 

 period as is essential. 



There is doubtless no other region in all the world — insular or 

 otherwise — similarly blessed with all the conveniences of modern 

 civilized society, where so many diverse types of tropical environ- 

 ment are so easily available within small compass. Within a 

 radius of half a dozen miles of the College campus, for example, 

 there occur the following well-defined ecological districts: 



Manoa Valley: one of the largest of the Oahu valleys, with » 



spacious, well- forested amphitheater of erosion; 



broad, wet-crop floor ; and precipitous ridged 



walls. 

 Waikiki Flats: extensive coastal plain area, artificially flooded, 



and planted with various wet-land crops ; rice, 



taro, lotus, banana, etc. 

 Ka-imu-ki District: elevated, arid, with secondary craters, 



basaltic lava flows, and volcanic debris. 

 Waialae: arid coastal region, penetrating adjacent valleys. 

 Extinct Craters: Diamond Head, Punchbowl, Round-top, Sugar- 

 loaf, Tantalus, Ka-au, etc. 

 Koolau Range: average elevation 2200 feet, summit 3,000 feet; 



dense mantle of indigenous montane rain-forest. 

 Introduced Plantings: Prosopis, Eucalyptus, Acacia, Pithecolo- 



bium, Casuarina, Bambusa, etc. 

 Valleys and Streamways: Moanalua, Kahauiki, Kalihi, Nuuanu, 



Pauoa, Makiki, Manoa, Palolo, Waialae, etc. 

 Foothills and Lower Ridges: eroded remnants of original volcanic 



dome ; chiefly xerophytic. 

 Littoral Zone: including coral, lava, and tufa beaches. 



