one in recent years. There was another in 1815 which is ac- 

 curately documented. There was one in the first half of the 

 17th century, probably in the I630's. We are not sure of the 

 exact date but it was in that fifty-year period. There was 

 another one at the end of the 15th century or the beginning of 

 the I6th. The evidence for these is in materials of various 

 kinds on the forest floor. We have been walking over this for 

 years without knowing what we were seeing. You all know what 

 cradle knolls are. You have walked through old woods and 

 found yourself going over irregularities on the forest floor. 

 These are blowdown mounds. We have now inspected literally 

 hundreds of them and we can find evidence of the early blow- 

 downs in them. 



We have one very good case of the 1815 hurricane. It is a 

 great black birch tree which is about 143 years old. The base 

 of the trunk of the tree is about chest high from the surface of 

 the ground, and everything below this is a great root system. 

 Locked in this root mass are boulders and mineral soil. The 

 whole is now resting on a mound of earth which is perhaps 10 

 or 15 feet long by 5 or 6 feet wide and oval in shape. By dig- 

 ging around in this mound of earth we can find pieces of old 

 pine wood which are still identifiable as the wood of a stump. 

 Looking at the hurricane blowdowns that were formed in 1938 

 we can see black birches germinating on tops of masses of 

 earth that were turned up on the flat root masses of trees. 

 They germinate up there, and if they can get their roots down 

 through the masses before the latter fall away they can keep on 

 growing. These things are quite common. I have seen young 

 trees at least 4 feet high with the base of the trunk at least 8 

 feet above the ground. 



The dating of the earlier hurricanes, those prior to 1815, has 

 been done by other methods. For the one in the first half of 

 the 17th century there is wood in the form of old root systems 

 and the remains of stumps, which by its position and minimum 

 age can be used for making estimates. The date of the still 

 earlier blowdown has been estimated by comparison of maps 

 of the areas of disturbance caused by the blowdowns of various 

 age classes. Most of the work that I am reporting here was 

 done by a graduate student we had recently. Dr. E. P. Stephens, 

 and is as yet unpublished. 



Chapman: When you've got a hurricane of this sort, or when you get a 



break-through of the type that Professor Steers has mentioned, 

 and you get a very big volume of a considerable depth of water 

 on your marsh, very much more than normally, the weight of 

 that water must be very considerable. I just wondered whether 

 the actual level of the marsh is changed in relation to the normal 



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