234 SYLVICULTURE IN THE TROPICS pt. m 



they overtop, as e.g. rubber vines, such as certain 

 species of Landolphia or Clitandra, or certain kinds of 

 canes such as Calamus. Such climbers are necessarily 

 left untouched, or they are trained in such a manner as 

 to give the best return possible ; others, which are of 

 relatively small value, should be grubbed out, if possible, 

 or if the area to be covered is too large to permit such 

 thorough extirpation, they should be cut back, the stool 

 being shattered by blows of the axe, first with the edge 

 and then with the back, if it is of sufficient size to be 

 able to be dealt with in this manner. It is also advis- 

 able to cut the climber a second time as high up as the 

 arm will reach, as otherwise any shoots given out by 

 the stool will soon obtain a support by means of which 

 they will draw themselves up the tree once more. 



Certain herbaceous or semi-herbaceous climbers will 

 do a lot of damage to the young crop, and even to larger 

 trees, by covering their crowns as with a web. Such are 

 numerous species of Convolvulaceae, particularly of 

 Tpomaea and Merremia, many Cucurbitaceae, such as 

 Cucumis, Momordica, Luffa, Ade?iopus, etc., and repre- 

 sentatives of several other natural orders, such as 

 Leguminosae, Rubiaceae, Asclepiadeae, Acanthaceae, 

 Ampelideae, and others. Such climbers should be 

 pulled up, or if too strong they should be stubbed out. 

 Where the climbers have a certain commercial value, as 

 e.g. for their fibre, the operation may be farmed out 

 under supervision and may even become remunerative. 



Of parasites, those belonging to the natural order of 

 the Loranthaceae, such as Viscum and Loranthus, are 

 the most abundant. In the mountains of southern 

 India and Ceylon a large number of introduced Austra- 

 lian wattles, especially Acacia Melanccj/lon, have been 

 killed by Loranthus. If such are found on small trees 

 they should be cut out, and it may even be necessary to 

 cut down entire trees whose crowns have been invaded 

 by them in order that they may not become centres of 

 distribution. 



When cleanings have to be executed within a crop 



