218 



PEUNING AND THINNING. 



PT. IV. 



than to the peculiar attributes of the trees themselves. 

 Such trees, when imported, and planted on the poor 

 soils and exposed situations which are alone planted in 

 cultivated countries, make moderate progress, and 

 never reach any size. 



As long as countries are in a state of nature, trees, 

 being the original possessors, seize on the valleys and 

 best soils, from which they actually exclude man and 

 cultivation. But the case is reversed when man has 

 cleared the best soils for cultivation. Trees are then 

 seldom planted or suffered to grow except on soils so 

 bad as not to pay for cultivation. 



I have received the following marvellous measure- 

 ments of some pinus Lambertianas on the Columbia, 

 from an authority that I cannot doubt. At eight feet 

 from the ground they were fifteen feet in diameter. 

 The stems were branchless to two hundred and fifty 

 feet from the ground, and were there thirteen feet in 

 diameter. If the new annual ring of wood were a 

 quarter of an inch wide, trees would attain this dia- 

 meter in three hundred and sixty years ; and, sup- 

 posing them to have grown a foot a year in height, 

 this would allow them eighty feet of head above the 

 branchless stem. 



These measurements, which I called marvellous in 

 the first edition of this treatise, are (together with the 

 guesses in reference to the age of the trees) rather put 

 in the shade by the following. Adanson measured a 

 baobab tree (Adansonia digitata) to be thirty feet in 



