116 C. E. Moss , W. M. Rankin and A G. Tansley. 
the species of tree originally dominant. This is often done when 
the ground is completely cleared of trees and shruhs, because, under 
such conditions, natural rejuvenation is sometimes a slow and 
uncertain process, particularly in the case of the hardwoods. This 
kind of wood differs but little ecologically from the second type. 
(4) . Woods planted up, after felling, with a mixture of species, 
consisting partly of the natural trees, partly of other species, 
indigenous or exotic. Unless the planted species markedly differ 
in light-demand from the natural ones, the artificial element does 
not materially alter the character of the ground vegetation. If 
they do so differ, the composition of the ground flora is necessarily 
changed to a certain extent. 
(5) . Woods entirely planted, after felling, with species distinct 
from the original ones, e.g., Larch replacing Oak. Here again the 
change in the flora depends on the character of the planted trees, 
and on the distance apart at which they are planted. The change 
may be very slight or very pronounced, but the relation of the 
ground flora to that of the natural woods on the same type of soil 
is generally quite evident. 
(6) . Plantations on arable land, grassland, or heath. These, 
when recent, are quite easy to distinguish from natural or semi¬ 
natural woodlands, because the ground flora, after the plantation 
has grown up, is floristically poor, and does not consist of typical 
woodland species. How far such woodland species may colonise 
plantations which have been made on open ground, and how long 
it takes to complete colonisation so that a plantation becomes 
indistinguishable from a natural wood, are questions on which 
practically no data, so far as we know, are at present’available. 
Of these types, the second and third are to all intents and 
purposes natural woods, and they are always treated as such in our 
surveys. With regard to the fourth and fifth types, there may, in 
some cases, he a certain amount of doubt and difficulty in assigning 
by inspection a given wood to one of these types ; but the difficulty 
is much less in practice than might be supposed, and for a reason 
that will appear immediately. 
Woods that are completely replanted with species of trees 
different from the natural woodland trees characterising the given 
soil, climate, and geographical position, are distinguishable simply 
because they are composed of trees different from those forming the 
bulk of the woods of the district, so far as they are on the same type of 
soil. When, however, the same association of trees occurs, forming 
