REVIEWS 111 



a whole coupe is open to question. But the averages for the different 

 coupes check each other, and on the whole they yield an approximate 

 estimate of the outturn under present conditions. 



(c) Sample plots established and maintained by the silviculturist. 

 The first plots were laid out in 1910-11 and their remeasurement was 

 carried out in 191 5-16. Fresh plots have been formed annually since 

 1910-11 and remeasurements are to be made at intervals of five years, 

 so that every year certain plots will fall due. 



(d) Miscellaneous investigations by officers acting independently. 

 The publication of the statistics is to show the rate of growth and 



yield under present conditions. They should be useful in showing the 

 need of change of species and change of treatment. They should also 

 be useful to working-plans officers in framing estimates. As the figures 

 are in most cases very incomplete and apply only to definite localities, 

 the direct application of the statistics is, however, out of the question. 

 As yet they are little more than suggestive. A series of graphs showing 

 the growth of teak in three different types of forest are of particular 

 interest. From these graphs it is possible to determine at a glance the 

 time required for the yield of timber of various forms and sizes. These 

 statistics should be of special interest to silviculturists in the United 

 States who are now studying growth and yield by means of permanent 

 sample plots. They should emphasize in this country the need of uni- 

 formity. It is hoped that through the Committee on Forestry of the 

 National Research Council we will be able to secure greater uniformity 

 in the studies on growth and yield in this country, thus making it pos- 

 sible to compare results derived from the work of dift'erent investi- 

 gators. 



H. N. W. 



Commercial IVoods of the Philippines: Their Preparation and Uses. 

 By E. E. Schneider. Bulletin No. 14, Bureau of Forestry, Philippine 

 Islands. Pp. 274. Figs. 12. Plates X. Manila, 1916. 



Not since the publication of Gamble's Manual of Indian Timbers has 

 there appeared so complete a treatment of the woods of a tropical re- 

 gion as Schneider's Commercial Woods of the Philippines. Two things 

 are combined to make this a successful piece of work. The first is that 

 for fifteen years the officials of the Bureau of Forestry of the Philip- 

 pines have co-operated witli the botanist of the Bureau of Science in 

 the collection of wood specimens combined with botanical material. 

 'i'his insui-cs ihc |)r()|)cr (k'tcrniination of tlic woods. The second is 



