REPORT ON FORESTS. 37 



While the data for pitch pine are not very full, it is interesting 

 to note that its growth in height approximates to, and after 50 

 years of age exceeds that of the best deciduous forest. 



In comparing the growth of white cedar we must bear in mind 

 the density. The above measurements were made in timber 

 numbering upwards of 1,000 trees per acre, or at least five times 

 as many as the deciduous forest and twelve times as many as in 

 the pine forests. Mr. Pinchot also remarks that where some 

 cedars stood on the edge of a clearing uncrowded they showed 

 a rate of growth in diameter just double the average shown in 

 the foregoing table, which would be well above the rate for the 

 short-leaf pine of the Southern States and nearly as great as the 

 rate shown for deciduous timber on the best soil. 



INFLUENCE OF MOISTURE. 



The large yield and rapid growth of white cedar, which 

 grows in very wet swamps and the more rapid growth of short- 

 leaf pine in the South, where the rain-fall is more abundant 

 than in New Jersey leads us to inquire how far this more-rapid 

 growth may be attributed to moisture. It would be interesting 

 to have figures for short-leaf pine in moist localities in southern 

 New Jersey for comparison, although it does not favor wet soils. 

 Water is a most important factor in the growth of the ordinary 

 forest tree, as it is in all plant-growth. From data given in the 

 " Strasburger Botany," I estimate that a thrifty oak forest will, 

 in one growing season, take up into the trees a quantity of water 

 equal to 16 inches of rain-fall, and other independent data 

 enable me to compute that a mixed deciduous forest will take 

 up 19 inches of rain-fall in a season, and a coniferous forest of 

 an equal volume will require even more water. 



Some species are not adapted to grow with their roots in 

 standing water, as the white cedar, larch, willow, etc., do, and 

 it may be observed that the presence or absence of free ground- 

 water is sufficient to determine the species in many cases. The 

 chestnut thrives best on the ridges of the Highlands or upon 

 gravelly, well-drained soils in the valleys. It is abundant and 

 reaches its maximum size on the glacial sands and gravels of 

 Bergen county, but is almost unknown on the southwestern red 



