82 THE MONTHLY BULLETIN. 



stifling process of self-destruction will follow and be the end of thrift 

 in the tree top. 



These stages of imthrift could have been avoided by systematic 

 annual pruning, limb by limb. 



The original branch can long be maintained in vigor by preventing 

 its robbery by upstart shoots, other than short-stemmed growth; if 

 growths, appearing on the main branch, persist in rankness, they must 

 be subdued by the shears before they have reached such dimensions 

 that only the 'saw can separate them from the limb from which they 

 are sapping the vitality. 



Preventive annual pruning of all main branches will surely prolong 

 the life and health of the navel orange tree, better than pruning at 

 longer intervals when the regular formation of the system of growth 

 has been seriously broken up, and vitality has receded toward the main 

 central stems (for the trunk rarely is a single stem). 



When the head of a tree is too poverty stricken to be relied on for 

 profit, and the whole tree becomes decadent, there are still ways of 

 recovery. 



Nature in one of her freaks of temperature which surprised the 

 southland in January, 1913, in many trees, took all the leaves away; 

 then she at once reasserted her powers and clothed the naked trunks, 

 and the parts of the limbs nearest to the trunks with fresh, green leaves. 



Here was a demonstration that the highest recuperative powers of 

 growth have their location where parts are large and undivided. Some 

 time elapsed for leaf renewals, on good branches, even, and on terminal 

 twigs. 



Food storage in starch granules supplied the nutriment for adventi- 

 tious buds, which, under the stimulus of light, sent forth rich leafage 

 in a new region. 



Where openness sufficed the new interior shoots fruited ; later, when 

 the branches renewed their leaves, thus shutting off the light within, 

 the first growth on the trunk ceased to blossom, and, as before, the 

 fruiting region was on, and within the outer area of the tree top. 



The process of leaf development on and near the tree trunk and the 

 retardation of development on the branches (at their terminals) is a 

 lesson the pruner should take to heart ; then he will not be slow to do 

 what he should have done in the first stage of decadence, viz., to cut 

 back the brushy ends of limbs from which little hope of satisfactory 

 renewal of good life and color may be expected. 



Timidity in cutting exhausted ends of limbs to the points where good 

 growth exists, or is promising, and procrastination in so doing, under- 

 mines the health of the tree, for, if the foliage is sickly such will be the 

 state of the unseen root system, for its vitality corresponds to that of 

 the tree top. 



That this may be clearly in the mind of the hearer or reader of this, 

 the following brief statement of root and leaf action is here presented: 

 The root hairs absorb water, holding in solution mineral soil elements 

 needed for growth; the leaves, by respiration of oxygen, which is as 

 necessary for plant life, as breathing the air for its oxygen is to animal 

 life, acquire energy for their functions by this process ; they then take 

 in another constant constituent of the air, carbon dioxide, and combine 

 the carbon and one of its oxygen elements with the water in the leaf, 



