transported, \vitli the soil in -wliicli they 
grew, from Scandinavia." Nor is this con- 
jectui'e at all unreasonable, from "what we 
know of the nature of the processes of growth 
in these plants ; but we have no means, in 
cryptogamic plants, of accui'ately ascertain- 
ing the length of tune they have been m 
growing. Nor is this possible in endogen- 
ous plants, or even in all exogens ; but, in 
the latter, the stem presents, very generally', 
a series of zones, and each zone has been 
found to corresi^oncl with one period of ve- 
getation. This period mostly represents a 
year, hence, by counting the number of zones 
in the trmik of an exogenous tree, we may 
form an estimate of the years it has existed. 
It is in this way that the age of many very 
old ti'ees have been arrived at. The fol- 
lowmg list of old trees has been published 
by Moquin-Tandon, in his Teratohyie J^ec/c- 
tale, and is reproduced in the English trans- 
lation of Schleideu's Principles of Scientific 
Botany. There are loiown. 
Years. 
1 
1 
'iiiiil 
f 1; 
:fil titllii 
Sections of a Stkm as it appears in May and Jtjjte op the Fifth 
Year. The wMte spaces show the swelling- cambium. 
^^^^^ 
Sj^ctions of a Stem at the E^D of the Fjfih Tear. The en"\e- 
lopes and layers of liber are too thin to be shown by the pencil. 
Palms of 
200 
300 
Cercis 
300 
Cherodeudron . 
327 
Uhnus (Elm) . 
355 
Cupressus (Cyj^ress) 
388 
Hedera (Ivy) 
448 
Acer (Maple) . 
616 
Lai-ix (Larch) . 
263 
576 
Years. 
360, 626 
,800, 
Years. 
860, 1000 
Quercus(Oak) 600, 
1600 
Olea (Ohve) 700, 1000, 2000 
Taxus(Ye-iv) 1214,1466,2588,2880 
Schubertia (Taxodium) 3000, 4000 
Leguminosae . . 2052, 4104 
Adansonia (Baobab) . 6000 
Dracaena (Dragon Tree) . 6000 
Castanea (Chestnut) 
Citrus (Lemon, Orange, 
&c.) . . 400, 509, 640 
Platanus (Plane) . . 720 
Cedrus (Cedai-) . 200, 800 
Juglans (Wahmt) . . 900 
Tiha (Lune) 364,530,800,825,1076 
Abies (Spruce) . . 1200 
We might add considerably to this list, but it already supplies a sufficient number of illustrations 
of oui' general remarks. 
The means, by which the age of these trees has been ascertained, are two — first, fr'om historical data, 
and second, fi-om counting the zones. Thus, the colossal Dragon-tree of Oratava is known to have 
existed, in almost its present condition, in 1402 ; and, comparing it with the younger trees in its neigli- 
bom-hood, its vast age is inferred. The Yew trees at Fountahi's Abbey, in Yorkshire, are known to 
have sheltered the monks whilst the abbey was building. The abbey is now in ruins, but the trees re- 
tain theii' vigour ; the lowest age that can be assigned them is twelve centuries ; they are probably 
much more. But where trees have been cut down, the method of counting the zones has been had 
recourse to. There is no difficulty in this, where the tree is sound ; but, in many instances, the older 
trees ai'e, the more Ulcely they are to be decayed in thefr centre. The plan then adopted is, to take a 
square inch, count the zones in it, multiply this number by the number of mches from the bark to the 
pith, which will then give the whole number of zones, and the age of the tree. This was the plan 
adopted by Adanson in calculating the age of the Baobabs of Africa, and which has also been employed 
in calculating the age of other gigantic trees. The numbers, however, thus obtained, can only be 
looked upon as approximations to the truth, seeing that the zones of wood vary very much in thickness, 
not only one with the other, but in parts of the same ring. 
Size is no indication of the age of a tree, as various species grow at very different rates, and the 
same species, under different ch-cumstauces. The following table shows the different rates at which 
some common trees grow. 
First Year. 
Ft. In. 
Second Year. 
Ft. In. 
Tliird Tear. 
Ft. In. 
Oak, circiuuference, IO5 
Larch „ 1 0| 
lU 
1 3" 
1 Oi 
1 i 
Lombardy ) 
Poplar j 
Ebn „ 2 n 
2 9 
2 11 
Lime 
First Year. 
Second Year. 
Third Year 
Ft. In. 
Ft. In. 
Ft. In. 
, 8 
cu'Ciim., 1 
2 
2 H 
„ 1 8* 
1 lOJ 
2 
Some trees attain an enormous size by their rapid growth. Species of Eucalyptus have 
measured that reached a height of 250 feet, and measm'ed 70 feet round their trank. 
