40 



soils shows a very variable growth-rate. On a 20-year old plantation 

 in the crater of a blowout the effect of shading was very pronounced. 

 In the three outside rows, the trees averaged 10 inches D. B. H. and 70 

 feet in height. On a plot taken at least 5 rows (35') inside the margin 

 and representing average interior conditions, the tree average 5 inches 

 D. B. H. and 50 feet in height, with the largest tree 9 inches D. B. H. 

 and 53 feet in height. The plot showed an average growth per acre per 

 year of 69.1 cubic feet as compared with 28.6 cubic feet for oak grown 

 on similar sites. The product of the cottonwood plantation was suitable 

 for fuel, posts, and pulp-wood. Cottonwood planted as a shelter-belt on 

 these sands is a success ; as a forest crop in plantations its value is in 

 doubt. Thus far, experiments with the other broad-leaved species have 

 shown that they will not produce a profitable crop on sands. 



The prospect of growing certain pines on these soils at a profit is 

 better. In general, conifers require about 1/10 the amount of water 

 needed by broad-leaved species, are less exacting as to soil requirements, 

 produce more trees to the acre, and have a faster rate of growth and a 

 higher quality of product. Red, white, jack, and western yellow pines 

 within their respective regions of growth produce valuable wood crops 

 on sand. Plantations of white pine, already established on such soils in 

 Illinois, are generally too immature to show the possibilities of wood pro- 

 duction. However, they do demonstrate that white pine plantations can 

 be established, and that the growth rates during the juvenile period is 

 rapid. The occasional open-grown white pines planted in this region 

 indicate that the excellent growth-rate is carried through to maturity. At 

 40 years such individual pine trees on sand near Amboy, Lee county, 

 produced 38 cubic feet as compared with 4.8 cubic feet produced by black 

 oak at the same age on sand. 



Studies were made in two plantations growing on dune sand and 

 representing 20- and 50-year age classes. The twenty year stand has 

 an average D. B. H. of 4.1 inches and an average height of 27 feet. The 

 largest trees are 7 inches D. B. H. and have a height of 30 feet. The 

 mean annual growth for the twenty-year period is 95 cubic feet per acre. 

 The trees were vigorous; the plantation well managed. (Plate I, Figures 

 1 and 2.) 



The fifty-year plantation has an average D. B. H. of 10 inches and 

 an average height of 55 feet. The largest trees have a D. B. H. of 15 

 inches and a height of 60 feet. The mean annual growth for the fifty- 

 year period is 91 cubic feet per acre. This stand averages 27,364 B. F. 

 per acre for the 50-year period, which is almost exactly the yield given 

 for similar soils in Massachusetts (Hawley and Hawes '13). An in- 

 crease of 318 per cent in the yields for white pine over the native hard- 

 wood stands, and an increase in the quality of product — from cordwood 

 to excellent lumber — is indicated as possible for those in position to make 

 the initial investment of establishing the plantation and carrying the costs 



