20 IMPROVEMENT THINNINGS IN 



region, will be almost exterminated. Of the other trees affected, 

 the cherry and gray birch are weed trees, and so of no importance, 

 and the willow is rather uncommon and quite capable of withstand- 

 ing repeated moth attacks. 



HOW TO THIN. 



The types of forest growth in the cut-over lands of Massachusetts 

 are so many and the conditions are so varied that no hard-and-fast 

 rules in thinning can be laid down. Outside of forest conditions 

 the wishes and purposes of the owner of a specific tract must be 

 one of the main factors to determine the method of its treatment. 



If a stand is almost purely non-resistant, as an oak growth, it is 

 for the owner to decide whether he wants the stand clear cut at 

 once and replanted with pine, or whether he wants to gradually 

 thin out the area, and underplant, keeping all the while some sort 

 of forest cover. The first method is the cheaper, but the woods are 

 gone for a number of years until the pine grows up. If the second 

 method is chosen, practically all white oaks should be cut out any- 

 way, as they are by far the most undesirable trees from the moth 

 standpoint. Of the other species of oaks only those in poor condi- 

 tion, of poor form, or the suppressed, overtopped and intermediate 

 should be removed. One or two of each bunch of sprouts can usually 

 be cut down. An intermediate tree of a resistant species, as pine 

 or maple, should be left, and the oak which is crowding it out 

 removed. 



Where a hardwood stand of good density is to be underplanted, 

 probably 60 per cent, numerically, and from 30 to 50 per cent, in 

 volume, should be removed. Where there is considerable natural 

 pine reproduction under the hardwood, or where it is possible to 

 gain it, not all shade should be taken away, but a heavy thinning 

 should be made. Experience has shown us that, where there is 

 only the choice between leaving the young pine without protecting 

 cover, or leaving white oak as that cover, it is better to remove the 

 white oak if the moth infestation is serious. 



There is one combination method of treatment in nearly pure 

 oak stands where the owner does not wish to lose the wooded effect 

 and yet does not want to go to the expense of taking care of the 

 whole area. 



By this method a thinned strip, which can be sprayed easily, is 

 left along the edge, on the roads or bordering fields, and back of 

 this strip the growth is cut clean and the land replanted. 



