SECTIONAL TRANSACTIONS.— K*. 415 



7. Prof. Augustine Henry. — The Swamp Cypresses of China and North 



America. 



A recent paper by Prof. A. Henry and Mrs. M. Mclntyre (Proc. B. Irish Acad., 

 vol. 37, pp. 90-116) describes in great detail the swamp cypresses, Olyptostrobua of 

 China and Taxodium of North America. These two genera were widely spread over 

 the northern hemisphere throughout the Tertiary era, their fossil remains having 

 been found as far north as Spitzbergen, Greenland, and Alaska. Their distribution 

 at the present time is much restricted in area and practically confined to marshy 

 sites, where the roots of the trees develop peculiar woody growths called ' knees,' 

 which project above the soil and enable the roots to breathe when the ground is 

 inundated. The Chinese species, Olyptostrobus pensilis, has died out in the wild 

 state, and is known only in cultivation in two limited areas, around Canton and 

 Foochow. Like Ginkoo, it has been preserved from extinction for superstitious 

 reasons. The CTiinese peasants plant it beside villages to bring luck to the family 

 home, and amongst rice-fields to increase the crop. 



The wood of both genera is valuable on account of its strength, fine grain, and 

 remarkable durabilitj' under trying conditions of moisture. The trees, when grown 

 in swampy ground liable to inundation by fresh water, yield a considerable volume 

 of timber. The object of this paper is to point out the desirability of making 

 plantations of Taxodium and Olyptottrobus in the warm temperate zone, on marshy 

 land which has hitherto been unproductive. 



8. Mr. R. Maclagan Qq-kki^.— Irrigated Plantations of the Punjab. 



Recent canal developments in the Punjab have brought huge tracts of land 

 under cultivation, and, as these were previously semi-desert waste, the increase in 

 population is enormous. The economic needs of these new colonies demand a supply 

 of wood for fuel and timber, and this is being met by the establishment of artificial 

 forests dependent upon canal irrigation. 



The type of work required in these irrigated plantations is very highly specialised, 

 and the methods now in use are the result of nearlj' sixty years' experiment in Changa 

 Manga, the oldest plantation of this type. The experience gained by the Punjab 

 foresters should be of the greatest interest to all who are connected with the canal- 

 development schemes now afoot in many of our colonies and other countries such as 

 U.S.A., Soudan, Australia, and Mesopotamia, where the economic needs of new canal 

 colonies will have to be faced. 



Choice of site. Water requirements for forest plantations are different from those 

 of cotton and farm crops, thus site should be adjoining a main canal, not on a small 

 distributary channel. All parts of a plantation should be within economic radius for 

 extraction by some form of tramway to railhead. 



Irrigation. Area is divided into compartments, each forming a wait for watering. 

 Standard method of work has been evolved in Changa Manga since 1866 by trenching 

 at 10- ft. intervals along contour. Water is led into trenches through a series of parallel 

 distributary channels. Usual supply of water is 10 cubic feet per second for each 

 thousand acres during six summer months, equivalent to a depth of 3 feet of water on 

 whole area. 



Methods of stocking : 



(a) Sowing. Seed of shisham (Dalbergia sissoo) is sown along lip of trench, and 



germinates on soil kept damp by water in trench. 

 (6) Root and shoot cuttings. Two-year-old plants are transplanted after being 

 pruned down to a stumpy length of main root and stem. Shisham responds 

 to this treatment with greatly increased growth. 



(c) Saltpetre soils. These form a serious problem in the Punjab, and can be 

 cured by stocking with root and shoot cuttings of shisham. 



(d) Alternatives to trenching. Success has recently been attained by stocking 

 with root and shoot cuttings land which had previously been levelled 

 under a temporary cultivation lease. Area is divided off by ridges to form 

 acre plots, each of which is flooded separately. 



(e) Restocking felled areas. Clear felling on a 20-year rotation leaves ground 

 full of stumps, but acidity of humus makes trenching necessary. 



Dangers, (a) Drought damage due to failure of canal-water is serious and takes 

 years to obliterate. It can be met by undertaking only such an area as can be irrigated 



