334 forestry Quarterly. 



the wind, whose movement is unchecked by the obstacle which 

 might be afforded by the trunks and foliage of trees. In other 

 parts of the forest, the trees are usually so crowded together 

 that many are suppressed to such a point that, if not eventually 

 killed, their growth is very nearly nil, and they serve only to 

 absorb moisture and nutriment from the soil, that had much bet- 

 ter go to the dominant trees standing in the light. By proper 

 spacing it will be possible in future stands to avoid root competi- 

 tion and allow the proper amount of light to reach each plant, 

 for its best growth and development. 



On good, average soils supporting average stands of pure Yel- 

 low pine, containing no large openings, it was found that on ten 

 different sample plots comprising in all 60 acres, there was an 

 average of 33 trees per acre, nearly half being either suppressed 

 or intermediate, as a result of their persistingly growing in groups. 

 The suppression, however, was evidently not primarily due to 

 root competition but to light competition, because no matter how 

 closely together the trees stood, none appeared sickly until they 

 were over-topped by some of their associates, and the light shut 

 off. As soon as this occurred, they rapidly lost ground, and 

 many perished. If the suppressed and intermediate trees occur- 

 ring in these plots had been distributed evenly through the open 

 places in the stand, none would have been suppressed, as each 

 tree large and small over 12" D. B. H. would have been sup- 

 plied with a crown space of 1320 square feet, which is greater 

 than is demanded by any but the very largest of pines, as we 

 later will show. 



By observing single acres, it will be found that more than 33 

 trees can stand within the limits of an acre and thrive, and there 

 should accordingly be no reason why the number of trees over 

 large tracts, where the essential conditions are the same as on 

 the single acre, should not be equally large except as the openings 

 are caused by accident. 



By the suppression of fire and insects, and care to guard 

 against conditions resulting in windfall, forests can be put in a 

 position to return the maximum yields of which they are capable. 

 Fires and windfall are comparatively easy to control. Beetles, 

 it is feared, however, will always prove to be a serious problem. 



It is a characteristic of Yellow pine to fill quickly with repro- 



