1900. 



AMERICAN FORESTRY ASSOCIATION. 



2 43 



rounded by the ordinary prairie grasses. 

 I observe that where the sod had been 

 cut, as in the removal of the soil for rail- 

 road building, the Pines spring up more 

 abundantly, but I have seen very dense 

 thickets of Pine seedlings where the sod 

 had not been disturbed at all. 



HOW DECIDUOUS TREES SPREAD. 



In the case of the deciduous forests, 

 where they are spreading we observe that 

 there is always a fringe of weeds and 

 shrubs, and that in this fringe the seedling 

 trees appear. The weeds are the common 

 wild weeds of the neighborhood. Thus 

 in regions where sunflowers are abundant 

 these will be found ; also the taller grow- 

 ing goldenrods, asters, ragweeds, etc. 

 Here we have a hint that weeds are not 

 always harmful, as in these cases they cer- 

 tainly do serve to cover the ground in such 

 a way that the more permanent vegetation 

 is able to come in after them. Mingled 

 with the weeds there are always shrubs. 

 At first these are small and inconspicuous, 

 but later they occupy the ground almost 

 to the exclusion of the weeds. In a typ- 

 ical fringe around a forest area the weedy 

 belt is farthest away from the timber, 

 while nearest to the timber is a belt in 

 which the shrubs predominate and where 

 the weeds are of less importance. The 

 shrubs to be found in these fringing belts 

 are Wild Roses, Wild Plum, in some 

 places Dogwood and Wolfberry (Sywphor- 

 icarpos^), Hawthorn, and on lowland, El- 

 derberry, etc. 



THE STRUGGLE FOR EXISTENCE. 



In this fringe of weeds and shrubs the 

 seedling trees start up. Of course a large 

 percentage of these perish. Many of 

 them are smothered by the too rampant 

 growth of weeds and shrubs, but here and 

 there a little tree persists, and finally over- 

 tops the other growth ; and from this time 

 forward the tree predominates. There is 

 a fierce struggle for existence in these 

 fringing belts about the advancing forests, 

 and it is only because of the immense 

 fecundity of the trees that their offspring 

 are able to survive in the struggle. We 

 i-arely think of the large number of seeds 

 produced by even an ordinary sized tree. 



I recently made a calculation as to the 

 number of seeds produced by an Elm upon 

 my place in the city of Lincoln. The 

 tree is about thirty feet in height with 

 spreading, well-balanced, and rounded top 

 of about twenty-five feet in diameter. 

 Every year this tree produces heavy crops 

 of seeds, and my calculations show that a 

 minimum estimate is one million seeds for 

 the tree. I am confident that my estimate 

 is too low rather than too high. Now let 

 us stop for a moment and see what this 

 implies. One million seeds, if scattered 

 over an area in such a way as to have one 

 seed for each square foot, would cover 

 somewhat more than twenty-three acres 

 of ground. If these seeds were all to 

 grow, it would not be long before a great 

 part of them would have to perish on ac- 

 count of their interference with one an- 

 other. I am certain that my Elm tree 

 produces so many seeds that, if they were 

 properly planted and cared for, they would 

 produce a forest of from ten to twelve 

 thousand acres each season. Of course it 

 is never possible for all the seeds to grow 

 into large trees ; and it would not be pos- 

 sible, even if the seeds were properly dis- 

 tributed at the first. What actually hap- 

 pens is this, the seeds are scattered within 

 an area of probably not more than one- 

 sixth of an acre, or say a circle of about 

 fifty feet radius, with the tree in the cen- 

 ter. A million seeds scattered over this 

 small area would equal one to each square 

 inch. Before the end of the first season 

 these little seedlings so closely packed 

 crowd one another so that many of them 

 must die. I suppose that out of a million 

 seeds not more than one-tenth of one per 

 cent, succeeded in growing into young 

 trees under natural conditions; and yet 

 it is in this way, by the lavish use of the 

 seeds which are produced by nature, that 

 the forest areas are extended. These seeds 

 fall upon the loose soil covered with leal 

 mould in the fringing belt of the weeds 

 and shrubs about the timber, and here 

 some of them spring up and eventually 

 become trees. These when grown become 

 centers for the distribution of more seeds 

 and the formation of more seedlings; and 

 so the growth goes on, and in this way the 

 forests are extended. 



