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THE AGRICULTURAL NEWS. 



MAErn 11, 1916. 



THE EFFECT OP LIGHTNING ON 

 COCONUT PALMS. 



^h: T. Tetch contributes an interesting article to the 

 Tropical Agr-icii'turut (October 191o), on the subject of the 

 ■effect of lit;htniiig on coco-nut palms. 



That roco-n""ut palms may be killed by lightning is well 

 known to all coco-nut planters. (.)n the other hand, it i.s 

 necessary to exercise caution in accepting that as an explan- 

 ation of "the death of trees in any particular case. It appears 

 that in the East, the native as a general rule assigns the 

 death of a palm to lightning always, whereas the cause 

 very frequently is bud rot or red beetle [Rhi/ncojihorvs nigna- 

 tica'/ia). 



The damage intiicted on coco-nut palms by lightning 

 may take any one or any combination of the following three 

 forms: (1) The crown may be set on fire: (2) the tree may 

 be mechanically injured, either by splitting of the stems 

 or by defoliation; (3) the tree may exude liqui<l which dries 

 in red-brown streaks and patches-! on the stem. 



The lust is by far the commonest eflect of lightning on 

 coco-nut palms. As a rule, there is no sign of injury to the 

 stem or scorching of the crown, but the stem exudes at 

 numerous points a liquid which dries in red-brown streaks 

 and patches on its surface. In a case examined by Mr. Fetch, 

 the stem was not split or marked by the lightning in any 

 way. Owing to the collapse of the inner tissues of the 

 bud, the central spike had fallen over, but it was still 

 green and not charred. The outer leaves, namely those 

 which bent over towards the ground, were charred 

 along the midrib; and round the tree, at distances 

 of 8 or 10 feet from the trunk, the grass and weeds 

 were burnt in small patches, each patch being situated below 

 the point of the leaf. But the most striking phenomenon 

 observed by Mr. Fetch was the exudation of sap from the 

 stem. Liquid was oozing out from the innumerable cracks 

 which are always to be found in the rind of the coco- nut 

 •stem, forming white frothy masses and then running down 

 in long red streaks. The appearance gave one the impres- 

 sion that the whole of the internal tissues were undergoing 

 rapid fermentation. On cutting into the stem the internal 

 tissues were found to be slightly pale brown, uniformally 

 coloured, and full of sap. It is to be regretted that, as the 

 tree was situated in a district at least three days' journey from 

 a laboratory, no further investigation could be made. It is 

 hoped, however, that the facts placed on record above may lie 

 taken up under favourable conditions for detailed investi- 

 gation. 



Another case was examined by ^Mr. Fetch about 

 a month after the occurrence. A breadfruit tree was said to 

 have been actually struck, and this was dead and leafless 

 though its trunk was not split. Close to it was a coco- 

 nut palm about 12 feet shorter. This was not quite dead; 

 it showed long red streaks of .sapj particularly in the lower 

 half of the stem, and had two short vertical wounds, one at 

 12 feet and the other at 18 feet from the grcund, from which 

 the vascular bundles were protruding in Ioo.se masses. West- 

 ward from these two, th(' palms only 1.5 feet away showed no 

 sign of injury, but to the east, twenty trees, which were 

 taller than the breadfruit tree were eflfected. Their trunks 

 bore red bleeding spots and their crowns were scorched, the 

 outer leaves being generally withered and drooping, though 

 the youngest leaves were still erect ivnd green. None of these 

 showed any injury to the stem, except the exudation of sap 

 Two palms had been felled, as being beyond recovery; four 

 other appeared to be dying. The tree with the worst crown 

 Vfas about 20 yards from the breadfruit tree, and the effected 



area formed, roughly,^ an eclipse with the breadfruit tree at 

 one focus. 



No explanation of this fermentation effect can at present 

 be offered. It may, however, be pointed out that the same 

 effect may be produced on a small scale by making a fire near 

 the base of a coco nut palm, but not near enough to char the 

 stem. The reil-brown patches subsequently appear on the 

 parts which have been heated. The number of red-brown 

 spots and streaks at the base of the tree, usually on 

 on one side only, indicates that it had been injured by tire. 

 As a rule on trees .which have been injured by fire, the 

 bleeding occurs immediately afterwards, and the spots do not 

 subsequently increas^ in number or size. Only the cortex 

 is affected, and the amount of sap which exudes is small. But 

 when trees are severely struck by lightning, the exuding sap 

 is derived from the whole of the inner tissues, and issues in 

 such quantity that it runs down the stem in long streaks. 



In conclusion Mr. Fetch summarizes the effect of light- 

 ning on coco-nut palms as follows: 'A group of trees not 

 differing in any obvious respect from the surrounding trees, 

 is affected; sap exudes from the trunks of all these trees; 

 their crowns are sliglitly scorched; one tree is more severely 

 affected than the others, and this is regarded as the tree 

 actually struck. In some cases longitudinal wounds are 

 made in the stem; and if the crown is surrounded by dead 

 leaves these may be set on fire. But apparently these last 

 two affects are rare. The occurrence of injured trees in 

 groups is especially remarkable." 



The general opinion seems to be that coco-nut palms 

 which have been struck by lightning may recover if properly 

 treated. The treatment adopted by the native is to cut 

 a hole in the stem in * order to let out the excess of sap. 

 There appears to be some reason to support this apparently 

 crude procedure. 



THE STATE OF SCHOOL GARDENING 

 IN JAMAICA AND BARBADOS. 



Two educatinual reports, one on .lamaica (1914-1-5), and 

 the other on Barbados (1914), contain interesting information 

 with regard to the standard and progress of school gardening 

 work in those colonies. 



As regards .Jamaica, extracts are published from the 

 Agricultural Instructors' reports on their visits of inspection 

 during the year. Each district contains from twenty to forty 

 gardens, and the general condition of these appears to be 

 satisfactor}-. In some places ojjcrations have been rendered 

 difiicult on account of drought. For its successful working, 

 a school garden must have access to a supply of water. 

 Another factor militiiiting against the successful working of 

 these gardens in Jamaica is the provision of fences, which is 

 very inatlequate. These are necessary to prevent theft, but 

 more e.specially to prevent small live-stock from gettin" in 

 and doing damage. In the case of one or two of the Jamaica 

 districts, the In.structors urge that more time should be 

 devoted tf> btidding and grafting, and that whatever work is 

 dcme th(! educational value should be well kept in view by 

 the teachers. The corn-growing competition provided for by 

 the Jamaica Agricidtural Society has aroused a good deal of 

 interest amongst the schools in C(mnexion with this 

 important industry. The competition is much appreciated 

 and serves a very useful purpose; similarly the prizes offered 

 by the educational department for the best gardens. It is 

 stated that if more money could be devoted to tliispurpo.se, it 

 would be money well spent. 



