626 SECTIONAL TRANSACTIONS.— K. 



Experiments now under way (June 6) are already indicating that the time of 

 sowing plays an important part in determining the efiect of the initial presence or 

 absence of phosphate upon growth, and the results of this current work will be 

 available for presentation at the meeting. 



Mr. J. Parkin. — The two Laburnums : a Problem in Water Loss. 



The leaves of the common Laburnum {Laburnum, vulgare) wilt and dry up con- 

 siderably more rapidly than those of the so-called Scotch Laburnum (Laburnum 

 alpinum). This behaviour is contrary to what might have been expected from 

 structural characters. The leaves of Laburnum vulgare are pubescent, while those 

 of Laburnum alpinum are glabrous. Anatomically the leaf of Laburnum alpinum is 

 on the whole more mesophytic, e.g. it has wavy epidermal walls and a less pronounced 

 palisade tissue. The difference in rate of water-loss appears then difficult to explain 

 on structural grounds, and stomatal behaviour does not seem to ofier a solution. 

 The explanation is probably more deep-seated and of a biochemical rather than of a 

 morphological nature. The difference is, however, in harmony with habitat. 

 Laburnum alpinum occupies a higher level in the mountains of Central Europe than 

 Laburnum vulgare, and so presumably is exposed to drier conditions. 



Sir John Stirling-Maxwell, Bt. — Lecture (semi-popular) on Forestry in 

 Scotlaiid, Past, Present, and Future. 



Department of Forestry. 

 Dr. R. C. Fisher. — Recent Work on Insects Injurious to Timber. 



The Forest Products Research Laboratory, Princes Risborough, has been con- 

 ducting since December 1925 an investigation into the losses caused by insects to 

 timber in store. During the past 2^ years attention has been paid particularly to 

 Lyctus Powder-post beetles (family Lyctidoe), which are causing serious losses to the 

 furniture trade and other industries using quantities of oak, ash, walnut and 

 other hardwood timbers with large pores. It has been shown that three species of 

 Lyctus have been, and still are being, brought into this country in American oak 

 and ash of low grade. A successful means of sterilising infested timber has been 

 demonstrated, and a study has been made of the conditions in timber which render 

 it liable to Lyctus attack. 



The work of the Entomology Section of this laboratory also comprises a study of 

 two well-known insects injurious to timber — the Death-Watch beetle, Xestobium 

 rufo-villosum, attacking structural timbers, and the Common Furniture beetle, 

 Anobium punctatum, which causes damage to old furniture (family AnobiidcB). In 

 the past more attention has been given to methods of control and eradication of these 

 wood-destroying insects by means of insecticides than to their biology, life-cycle, 

 habits and rate of development under varying conditions, of which very little is 

 known. Work is now in progress at the Forest Products Research Laboratory to 

 study the bionomici of Xestobium rufo-villosum and of Anobium punctatum, to ascertain 

 the effect of varying temperatures and humidities on the length of the life-cycle of 

 both species, and to determine whether there exists any relationship between fungal 

 infection of timber and progress of Anobiid attacks. The settling of these points 

 may have high practical value and a very important bearing on the planning and 

 ventilation of houses and other buildings. 



Dr. E. J. Salisbury. — Principles of Ecology with special reference to Soil. 



Afternoon. 



Joint Discussion with Section M on The Economic Balance of Agriculture 

 and Forestry. (Dr. J. D. Sutherland, C.B.E.) 



Dr. J. D. Sutherland. — The disproportion disclosed between the areas assigned 

 to agriculture and those utilised for sylviculture within the United Kingdom. The 



