292 JOURNAL OF FORESTRY 



do we know what effect the opening up of the crown cover in the 

 various degrees from shght disturbance to complete removal has ; what 

 effect these disturbances have upon the regeneration and growth of the 

 commercial species, determined by actual measurement of conditions? 



There is probably little doubt that at least one-half of our commer- 

 cial forest area has been burned. Some of it was burned a hundred 

 years ago and not since ; some has been burned only once in more re- 

 cent years. Unfortunately, a great deal has been burned twice and 

 three times or more. One-half of our future supply, on the basis of 

 area, must come from these burned lands ; and yet do we know by 

 actual surveys what proportion of these areas can be depended upon 

 for a second crop, at what periods and how much we can cut? 



Considerable areas of forest still continue to be burned. Some of 

 the fires occur in the spring, some in midsummer, and others in the fall. 

 By actual investigation of the subject do we know what relationship, 

 if any, exists between the time of year a fire occurs and the amount of 

 regeneration which follows it? Do we know what the relationship of 

 fire intensity is to the killing of the seed buried in the duff", seed upon 

 which the future crop must dei:)end ? 



I have suggested a few problems which seem to me fundamental. 

 They must be solved before we can formulate any intelligent plans or 

 establish any silviculture systems to insure the continuous productivity 

 of our forests. There are two methods by which these problems may 

 be approached — the one extensive and the other intensive. The exten- 

 sive is in the nature of a reconnaissance survey. It consists of a rela- 

 tively rapid tabulation of conditions by means of strip surveys and 

 then by exploration the determination of the extent of such conditions. 

 While this method has its uses, its chief weakness lies in the difficulty 

 of determining the past history of the area investigated with accuracy, 

 and hence generalizations from the data contain so many suppositions 

 and modifications that they lose their force. 



By the intensive method I mean the establishment of sample plots 

 and making a record of what happens from the very beginning of the 

 conditions which we wish to investigate or on areas whose historv is 

 definitely known. Sample plots should be established within a given 

 forest type on areas which have been severely, moderately, slightly 

 culled by actual logging operations and records made of the consequent 

 regeneration and rate of growth through a series of years. It would 

 probably be necessary to extend them at least twenty years, perhaps 

 longer. Sample plots should be established where slash disposal has 



