MIXED CROP OF UNirOKM AGE. 45 



a great advantage over such of their companions as are more shade- 

 avoiding, the crowns of which would in consequence be generally 

 more open. Whereas young individuals of the former class could 

 always ultimately get up into the leaf-canopy above, a result that 

 would be rather facilitated than otherwise by the more open over- 

 hanging trees of the other class acting as nurses, the young of 

 these latter would not only be subject to suppression by the leaf- 

 canopy above, but would also be elbowed out by their more shade- 

 enduring companions in the undergrowth. Thus where sal and 

 Pinus long/folia meet, although pine seedings are produced in a- 

 bundauce, they are very soon choked up and overtopped by young 

 sal, w-hich gives them no chance of existence except where the soil 

 is too poor and dry for it. Similarly, although deodar and the 

 silver fir are both pre-eminently shade-enduring species, still the 

 superiority which the latter possesses in this respect, gives it a 

 complete mastery over the other in those localities where the two 

 species are equally at home. 



Some trees there are, which, although after a certain age they 

 cannot flourish except with their crowns free on every side, yet, 

 during their early years, are able to stand a great deal of shade. 

 A very remarkable example of this is the Hardwickia binata, seed- 

 lings of which will persist under dense and even low cover for ten 

 years and upwards. Again, young Pinus lonyifolia seedlings 

 are not unfrequeutly to be found, if not absolutely vigorous, still 

 full of vitality, under low, bushy Quercus incana. Nay teak itself 

 will live for years as undergrowth in forests of medium density, 

 consisting of bamboos, Pterocarpus Marsupium, Terminal/a tomen- 

 tosa, Cochlos])ermum Gossyp/um, Boswellia thurifera, Hardwickia 

 Ithiata, Anogeissus latlfoliu, <fcc. In this way a young plant that is 

 overtopped by a larger individual of another and more shade- 

 enduring species may survive long enough to see the latter disap- 

 pear from one cause or another, and then be able to push on un- 

 checked. 



Again, a tree standing in immediate contact with, and on the 

 same level as, another belonging to a more shade-enduring species 

 may, if it is still in the phase of active lateral development while 

 the other has passed it, be able to elbow it out of the crop or at 

 least maintain an equal struggle with it. 



Since every species can stand more shade, the brighter the sun 

 is, or the longer the season of vegetation, or, within certain limits, 

 the higher the elevation, it naturally follows that the vigour with 

 which it can struggle with other associated species will vary with 



