THE DECIDUOUS FOREST CLIMAX. 201 



"The Spfiagnum is a superficial layer supported upon the sedge mat, and 

 contributes Uttle toward peat formation. It begins growth some distance 

 within the bog margin and spreads both ways, slowly toward the margin, faster 

 centerward. The area between the Sphagnum and the upland commonly 

 forms a marginal trench. In some places the moss by recent invasion has 

 obliterated the marginal trench, and occasionally it transgresses the bog 

 margin, spreading up the forest floor for several meters. 



"The Sphagnum spreads margiiMlly, svu-roimding and smothering such 

 plants as can not keep pace with its growth. Certain species by upward 

 elongation are able to survive for some time, especially Andromeda and 

 Chamaedaphne, the latter persisting longest. 



"Ledum almost invariably follows the Sphagnum, and its root system is 

 usually strictly confined to the masses of it. It forms a very dense growth, and 

 through its shading power and the great amoimt of waste that falls from it 

 finally eliminates the lower shrubs and stops the upward growth of the moss. 



""Hie bog trees, Larix, Thuja, Picea mariana, usually follow the Sphagnum 

 when it is present. When it is lacking they start upon the sedge mat with the 

 shrubs. The climax trees enter very soon after or often actually with the bog 

 trees, so that pure bog forest is practically absent. The bog trees die out 

 because they are intolerant of shading, and the climax forest results. 



"Telescoping of stages is prominent throughout the late history of the 

 succession. 



"The reason for the early establishment of the climax forest is found in the 

 likeness between the bog soils and those of the forested uplands, the latter 

 being almost as peaty as those of the bogs. It follows that whatever trees can 

 grow upon one soil may also exist upon the other. 



"THE DELTA SWAMP STJCCESSION. 



"Delta deposits are foimd in most of the sheltered bays where streams enter 

 from the upland. 



"The succession of vegetation upon these deposits passes through the 

 following stages: (1) aquatics; (2) sedges; (3) grasses {CaJamagrostis canadensis 

 most important), which form broad meadow-like growths and produce a 

 limited amount of peat; (4) shrubs, among which Myrica gale and Alnu^ incana 

 are most important; (5) swamp forest, made up of Thuja ocddentdlis, Larix 

 laridna, and Fraxinus nigra, the first being dominant; (6) climax forest of 

 Abies hoLsamea, Betula alba var. papyrifera, and Picea canadensis. 



"There is a general likeness to the bog succession; among other points, in the 

 early establishment of the climax forest after the coming in of the swamp trees. 



" The important points of difference from the bog succession are : the firmly 

 groimded sedge mat; interpolation of the grass stage; absence of Sphagnum- 

 hog shrubs, aiid Picea mariana; dominance of Thuja in the swamp forest. 



"Intermediate conditions between the two successions occur, and actual 

 transition from delta swamp to bog succession occasionally takes place." 



Johnson and York (1912 : 234) have recognized the following groups in the 

 tide-levels of Cold Spring Harbor: 



(1) Plankton, of Diatoms and Peridinese; (2) bottom vegetation, at 0.5 to 1.5 

 feet, (a) soft, muddy bottom, with Zostera, Ruppia, ZJlva, Enteromorpha, 

 (b) pebbly bottom, with various brown and red algse; (3) mid-littoral belt at 

 1.5 to 6.5 feet, dominated by Spartina cynosuroides; (4) upper littoral belt, at 

 6.5 to 8 feet, with alternating dominants, Spartina patens, Juneus gerardi, 

 Salicomia europaea, S.Jtmbigua, Seirpus americanus, S. robustus, Suaeda mari- 

 tima, and Distvchlis spicata; (5) suprahttoral belt, dominated on the sand by 

 Ammophila, with Solidago, CakUe, Lathyrus, Salsola, and in the marsh, in the 



