Thinning of Forest Trees. 551 



the most proper distance, making allowances for variation of 

 soil, degrees of latitude, and altitude. From observations and 

 experiments I have made, I will lay down such general rules as 

 shall enable planters to see the impropriety of invariably plant- 

 ing at the same distance in all situations, from the level of the 

 sea up to altitudes of 1800 ft. Trees on- land, at the sea's 

 level, will attain to above 100 ft. in height, in the same time 

 which is required to make them reach 30 ft. at an altitude of 

 1800 ft. This fact is demonstrative of the impropriety of plant- 

 ing trees at the same distance in different soils and climates. 

 The distance ought to be regulated, likewise, by the height 

 which the tree may be supposed to attain. When a plantation 

 is resolved on, it may be necessary, or, at least, profitable, to 

 examine the nearest plantation (if any be near) in an advanced 

 state, and from it to judge of the probable height or heights the 

 intended plantation may ultimately arrive at. Suppose the cal- 

 culations regarding height to be 57 ft., 67 ft., and 85 ft., these 

 three numbers are marked in the fourth division and third 

 column of the accompanying table (p. 553.) ; and on the same 

 lines, to the left hand, in the first column and first division, 2 ft. 

 6 in. is marked as a suitable distance for the first height, 3 ft. for 

 the second, and 4 ft. for the third : and, in the same manner, the 

 table may be consulted to ascertain the distance at which trees 

 of any given height may be planted from each other. 



Trees may be well planted, however, and yet be rendered 

 comparatively valueless from the want of thinning. Many 

 mixed woods and plantations may be seen in which the firs, not 

 exceeding forty years old, have almost died out, and the deci- 

 duous trees are often mere poles. By management such as this 

 displays, the proprietor renounces immense gain, and the coun- 

 try is disgraced. It is no less surprising than true, however, 

 that such imperfect growth occurs in trees under the guidance 

 of men who are reputed to be skilled in the management of 

 woods. The most superficial observer must have remarked the 

 comparative slenderness of all plants or trees crowded together, 

 and the superior strength of those sufficiently distant from each 

 other ; though trees crowded together in plantations suffer more, 

 at first, from the deficiency of carbonic acid and oxygen (both 

 of which are required for respiration) than from a deficiency of 

 nutriment from the roots. Trees, however, as is fully apparent, 

 are a part of the vegetable creation that can only be brought to 

 the greatest perfection by regular and sufficient support from 

 the soil and atmosphere; and, as they advance in height, it is 

 necessary to give them additional support, that they may in- 

 crease proportionally in circumference. This can only be effected 

 by taking part of the trees out ; which operation, at the same 

 time, prevents in a great measure the occurrence of disease, and 



