148 The Plant World. 



BOOKS AND CURRENT I.ITERATURE. 



Whitford has contributed to the Philippine Journal of 

 Science a paper entitled "The Composition and Volume of the 

 Dipterocarp Forests of the Philippines." He has made valuation 

 surveys in six of the largest islands and states that of the 49,000 

 square mJles of virgin forest in the archipelago 30,000 are made 

 up predominantly of members of the Dipterocarpaceae, which 

 occur in stands simple enough to admit of their being utilized 

 by modern steam logging methods, and comprise both hard and 

 soft woods ca':able of a diversitv of uses. 



Whitford 's earlier work on the forests of the Lamao Reserve 

 in Luzon showed them to have a complex composition in which 

 the Dipterocarps formed 30% to 40%. In those surveys all 

 trees over 4 m. in height were enumerated, while in his more re- 

 cent work only trees of merchantable size — over 30 cm. in trunk 

 diameter — have been taken into account. In one of the Lamao 

 tracts the merchantable trees were 71% of the total enumeration, 

 and of them 50% were Dipterocarps. The nine sets of data 

 given in the present paper show the Dipterocarps ranging from 

 33%) to 89%o of the stand and from 46% to 95% of the volume. 

 Some grouping of the 35 Philippine species of this family is found 

 to be predominant "in all classes of habitats from sea level to 

 an altitude of approximately 900 metres." The author states 

 that the forests of Bataan are subjected to a pronounced dry 

 season and those of the delta plain of Mindoro are periodically 

 flooded, in each of which cases the forest is less in volume and 

 more complex in composition than in such locations as the 

 plains of Negros, w^here "it is believed that a combination of 

 edaphic, climatic and biotic factors has reached the optimum 

 necessary to the establishment of the most successful growth in 

 the Philippines." All situations which are unfavorable through 

 the character of the soil, steepness of slope, etc., are poorer in 

 Dipterocarps, and such situations as the Negros plains much 

 richer in them. The author therefore regards the forests with 

 the highest percentages of Dipterocarps as the most successful 

 in the islands, and those which are poorer in them as some stage 

 in succession toward that type. 



Whitford's studies are the first of their kind and extent 

 which have been carried on in tropical forests and they indicate 



