416 ON THE ELIGIBILITY OF DECORTICATING TREES. 
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be, by far the thickest parts of the trunks. This shows that even forest 
trees may be benefited by judicious discortication, or slitting the bark 
of the stems. We have often seen plantations of stunted, starveling 
oaks, which we are convinced would be the better for some kind of 
manipulation of this description ; and we earnestly recommend the 
matter to those of our readers who may have faith in the expedient, 
and opportunity to put it to the test, as there is no reason why stunted 
trees should be allowed to remain unassisted, any more than that we 
should remain satisfied with our present acquirements of knowledge 
concerning them. 
In proceeding to the practice of this arboricultural tact, there are 
two or three other matters to be attended to, viz. the kinds of trees 
on which it is practicable, and the best time of the year for its 
performance. 
The best time for the performance is certainly at or just before the 
time the vital membrane (called cambium by botanists) begins to swell; 
that is, in the grafting season, for all trees having an aqueous or watery 
sap, and in the month of May, or later, for all trees bearing stone fruit, 
or which have a gummy sap : and for these reasons—if a stone-fruit 
tree be wounded when not in a state of growth, its sap exudes, and in 
the air thickens into gum, which contaminates by shutting up the pores 
of the parts in contact; but if cut or wounded when the vital mem¬ 
brane has gained considerable consistence, the incision is quickly 
closed by this, which prevents the flow of sap, and no running sore is 
caused. It is these circumstances which have fixed the proper time for 
budding. Here the reader must not fail to observe that the sap, and 
what has been called the cambium of a tree, are two very different 
constituents, and are always so considered in these observations. 
Apple and pear trees, having a watery sap, are those which have 
been mostly subjected to disbarking, and, if the trees have been other¬ 
wise sound, with the best effects. The growth, before feeble and lan¬ 
guid, in consequence of the indurated state of the outer layers of bark, 
has been renovated, the vital membrane allowed freedom to swell, and 
the vascular structure rendered capacious and healthy. Old orchard- 
trees are often seen to require this manoeuvre; for, if from over¬ 
bearing, a cold subsoil, or from some ungenial season, they become once 
debilitated, so as to allow the outer bark to become inflexible, they can 
never recover while such constriction continues. Another thine in 
favour of divesting such trees of all their old scabrous bark is, the 
certainty of clearing away all the moss, lichens, eggs and larvae of 
insects which nestle in the crevices, besides obtaining a smooth surface, 
which is much less inviting to insects afterwards. 
