82 ORGANOGRAPHY. 



by him to be more than 5000 years of age, we cannot but be- 

 lieve with Dr. Lindley, that such calculations give an exagge- 

 rated result. However erroneous they may have been, still 

 there can be no doubt but that exogenous trees do live to 

 a great age; in fact, when we consider that the new zones of 

 Avood are developed out of the cambium cells which are 

 placed on the outside of the previous zones, and that it is in 

 these new layers that all the active functions of the plant are 

 carried on, there can be, under ordinary circumstances, no real 

 limit to their age. Mohl believes that there is a Umit to the age 

 of all trees, arising from the increasing difficulty of conveying 

 the proper amount of nourishment to the growing point, as 

 the stem elongates from year to year. Thus, in some Coniferae 

 as Phius Lambertii, and Abies Douglasii, which reach the height 

 of more than 200 feet, he believes the maximum height which 

 the sap was capable of rising to nourish the upper part of the 

 plant was attained, and the terminal shoot being then less per- 

 fectly nourished, became every year more or less stunted, and 

 the tree ultimately died from want of a proper supply of nourish- 

 ment. We cannot however attach much importance to this 

 opinion, because it is now known that a tree exists in California 

 ( Wellinytonia gigantea), which has reached the height of 450 

 feet, and is still in full vigour. This tree is supposed to be 

 at least 3000 years old. 



The following table is given by Lindley of the age of some 

 trees, all of which, he states, can be proved historically : — 



An Ivy near Montpelier .... 433 years. 

 Lime trees near Friburg .... 1230 

 „ „ Neustadt . . . .800 



Larch 576 



Cedars, on Mount Lebanon . . . 6 — 800 

 Oaks at least 1000 



There can be no doubt, therefore, but that such trees will live 

 beyond the above periods. Other trees, such as the Yew and 

 Olive, may be added to the above list; thus, the Yew will cer- 

 tainly attain the age of 1200 years, and the Ohve at least 800 

 years. 



Size of Trees. — As there is no assignable limit to the age of 

 exogenous trees in consequence of their mode of growth, so in 

 like manner the same circumstance leads, in many cases, to 

 their attaining great size. Thus the Wellingtonia gigantea has 

 been UK-asurcd 116 feet in circumference at the base. The 

 Chestnut {Castanea vescd) of Mount Etna is 180 feet in cir- 

 cumference. A Plane tree (Platanus orientalis) near Con- 

 stantinople is 150 feet in circumference. The Ceiba tree 

 {Bombux pentandrwn) is said to be sometimes so large that it 



