MINNESOTA STATE HORTICULTURAL SOCIETY. 13 
tree must have some means of replenishing the supply. These are 
mostly taken away when all of its roots are enveloped in a mass of 
frozen soil. Dry, porous soils freeze deeper and thaw out quicker 
than moist ones. They do this because of the comparative absence 
of water in them which is a poor conductor of heat, and therefore 
serves to render temperature equable. Thus, concerning mulching, 
science explains and enforces what practice has shown to be good. 
But mulching is not equally valuable on all soils, and some attach 
little importance to it. Clay soils need it far less than sandy soils, 
They are more retentive of moisture, and hence do not dry out so 
easily in summer, freeze so deeply in winter, nor thaw out so sud- 
denly in spring. Again, thorough cultivation may in part take the 
place of mulching, since it favors the absorption and retention of 
moisture in the soil. To sum up this matter—mulching preserves 
the moisture of the soil in summer, lessens the depth of frost in 
winter, and renders changes of temperature in the soil less sudden. 
It is most beneficial on sandy soils, and less so on loams and clays. 
It is not so necessary if thorough cultivation be given. 
Prounine.—In looking over the records of the Society, I find sum- 
mer pruning almost always recommended—spring pruning generally 
condemned ; the contrary of that to which I have been accustomed. 
It is not, however, I believe, without a simple explanation. Writers 
on horticulture have long urged spring pruning to promote the vigor 
of the tree, summer pruning to check it. All the evidence I have 
noted indicates that nature in Minnesota needs no assistance in the 
development of trees, but in order that the development shall be a 
healthy one, nature needs rather to be checked and bridled. As to 
the precise effect of spring pruning I am not informed. You per- 
ecive I take it for granted that it produces too luxuriant a growth of 
wood—more than the tree can ripen. 
CuxitivatTion.—On this subject there is legitimate ground for dif- 
ference in practice. Some would be shocked by an advocacy of non- 
cultivation. Others have practiced non-cultivation and are nearly 
or quite ready to declare in favor of it. Now, certainly, if the soil 
can supply both food and moisture for a crop of trees and a crop of 
grass, and the latter does not shade the former, I can see no reason 
why both should not be allowed to grow. ‘That there are such soils 
I have no doubt whatever, and could adduce some instances to 
prove. But I am not going to weave an argument either for or 
against cultivation. Cultivation is much more frequently neglected 
than overdone, and non-cultivation is only too common, in spite of 
constant advice against it. My aim is to arrive at the principle and 
the truth. Poor soils and those only moderately rich, not only can- 
not support two crops at once, but the fruits growing upon them are 
highly benefited by thorough cultivation, at least in the fore part of 
the season, and by manures. On the other hand, very rich soils 
may not only produce grass when set in trees, but the former may 
be a positive benefit to the latter by moderating, not arresting, the 
growth of wood. 
Buieut.—As this is a problem in horticultural practice, I do not 
feel free to close this paper without a word upon it. Still, I ap- 
proach the subject with great diffidence, since I have no new facts to 
