722 XLVI. VERBENACEAE 



and that without this early exposure it may fail altogether during the first 

 year, even in the open ; (2) that the best results are obtained by burning the 

 soil-covering, hoeing up the soil, and lightly covering the seed ; (3) that the 

 worst results are obtained in the case of seed lying uncovered on ground 

 neither burnt nor loosened. 



In this experiment it was noticeable that the seedlings made the best 

 start and the weed-growth was retarded most on ground burnt and hoed, 

 while on ground not burnt but hoed up conditions were nearly as good. Weed- 

 growth was most plentiful on the plots which were neither burnt nor hoed up ; 

 on these a tall growth of grass and weeds sprang up early, and by July had 

 begun to kill out the seedlings. 



(3) Factors influencing the survival and development of seedlings. So far 

 as is known the chief factors influencing the establishment of natural repro- 

 duction are (i) light, (ii) soil-aeration, (iii) soil-moisture, (iv) weed-growth, 

 (v) grazing, and (vi) fire. 



(i) Light is one of the most important factors in the establishment of 

 natural reproduction, the teak being a strong light -demander from its earliest 

 youth. Although saplings may persist for a time under the light shade of 

 bamboos and other overhead cover, their development is slow and they become 

 readily suppressed. Experiments carried out within recent jesbis in Pyinmana 

 and Prome have shown that a sudden influx of light to badly suppressed 

 teak saplings, far from causing their recovery, may cause their death. The 

 admission of light by the opening of the overhead cover is the main object 

 of so-called improvement fellings for the benefit of the young crop in natural 

 forest. In Burma, where bamboos play such a prominent part in the com- 

 position of the forests, excellent teak reproduction is often seen in areas where 

 elephants have been herded for some time in connexion with timber extraction ; 

 these animals perform a useful service in breaking down the bamboos and 

 admitting light and warmth to the ground, with the result that teak seedlings 

 sometimes spring up and establish themselves in a manner suggesting a well- 

 stocked plantation. At the same time elephants, if kept longer than is necessary 

 in such areas, may undo the good they have done owing to their propensity 

 for damaging young teak poles. Intensive bamboo exploitation has a similar 

 effect in stimulating teak reproduction. Again, along the sides of dragging- 

 patfis, on fire-lines and in other openings through the forest, natural reproduc- 

 tion tends to spring up freely (see Fig. 274). Along the sides of dragging-paths 

 and where exploitation has been in progress the breaking up of the soil no 

 doubt also acts favourably, apart from the admission of light. IVIr. R. Bourne 

 has noted an interesting case of the adverse effect of side shade in one of the 

 Nilambur plantations. Part of the Aravillicava plantation was clear -felled 

 in 1917, and natural reproduction sprang up in quantity in July ; in places 

 the seedlings were so dense that it was hardly possible to step without treading 

 on them. This clear-felled area had already been planted up the previous 

 month and the new plantation was weeded without damaging the natural 

 seedlings. In this clearing were two areas on which shade was cast for a con- 

 siderable period in the morning by the adjoining plantations, which were 90 to 

 110 ft. high. Here not only did no natural seedlings spring up within the 

 area shaded after 8 to 9 a.m., owing to the temperature necessary for germina- 



