RULES FOR PRUNING. 179 



France. Later in 1804 the Baron Des Cars published an 

 able treatise, describing a thorough, practical system of 

 forest-tree pruning, based on the principles laid down by 

 De Courval. The American edition of this work (trans- 

 lated from the seventh French edition) with an introduc- 

 tion by Dr. Chas. S. Sargent, professor of arboriculture in 

 Harvard University, is the most comprehensive work on this 

 subject that has ever appeared in the English language.* 

 The publication of the American edition of this work was 

 made possible by the trustees of the Massachusetts Society 

 for the Promotion of Agriculture, an old and honored asso- 

 ciation, which has done much for the improvement of agri- 

 culture in this Commonwealth. The book should be in the 

 hands of every person who has the care of trees. 



Season for Pruning. — AVriters on horticulture differ as 

 to the best season for pruning. Each urges the advantages 

 of pruning at certain seasons to increase wood growth or 

 the development of fruit. Objections are frequently made 

 to pruning in the winter, on account of real or supposed 

 danger to the tree from exposing large wounds to the extreme 

 cold. Similar objections are sometimes urged to pruning in 

 the early spring and late fall, when the newly cut surfaces 

 are exposed to the influence of sudden and severe frosts. 

 It is frequently said by orchardists that if a tree is pruned 

 in tlie spring, w^hen the sap is flowing copiously, and the 

 crude sap is allowed to flow down from the wound, it will 

 poison the bark below and produce decay of the trunk of 

 the tree. 



Such examinations as we have been able to make of the 

 results of spring pruning indicate that the injury is due to 

 entirely diflerent causes, viz., the crushing of the bark and 

 consequent killing of the cambium layer at the base of the 

 wound or the separation of the bark from the trunk. Such 

 injuries are likely to occur unless great care is used in prun- 

 ing. The danger of a separation of the bark from the trunk 

 below the wound and the consequent running of the crude 

 sap into the cavity thus formed is always greatest during the 



* " A treatise on pruning forest and ornamental trees," by A. Des Cars, translated 

 from the seventh French edition, with an introduction by Dr. Chas. S. Sargent. 

 Boston, 1884. 



