Tree Study 



739 



remarkable work in clearing up the mysteries of sap movement. Their 

 results were published in their Bulletins 103 and 105, which are very 

 interesting and instructive. 



The starch which is changed to sugar in the sap of early spring was made 

 the previous season and stored within the tree. If the foliage of the tree is 

 injured by caterpillars one year, very little sugar can be made from that tree 

 the next spring, because it has been unable to store enough starch in its sap- 

 wood and in the outer ray-cells of its smaller branches to make a good 

 supply of sugar. During the latter part of winter, the stored starch dis- 

 appears, being converted into 

 tree-food in the sap, and then 

 begins that wonderful surging 

 up and down of the sap tide 

 During the first part of a 

 typical sugar season, more 

 sap comes from above down 

 than from below up ; toward 

 the end of the season, during 

 poor sap days, there is more 

 sap coming up from below 

 than down from above. The 

 ideal sugar weather consists 

 of warm days and freezing 

 nights. This change of tem- 

 perature between day and 

 night acts as a pump. Dur- 

 ing the day when the branches 

 of the tree are warmed, the 

 pressure forces into the hole 

 bored into the trunk all the 

 sap located in the adjacent 

 cells of the wood. Then the 

 suction which follows a freez- 



ing night drives more sap into s h 



those cells, which is in turn 

 forced out when the top of the tree is again warmed. The tree is usually 

 tapped on the south side, because the action of the sun and the consequent 

 temperature-pump more readily affects that side. 



"Tapping the sugar bush" are magical words to the country boy and 

 girl. Well do we older folk remember those days in March when the south 

 wind settled the snow into hard, marblelike drifts, and the father would 

 say, "We will get the sap-buckets down from the stable loft and wash them, 

 for we shall tap the sugar-bush soon." In those days the buckets were 

 made of staves and were by no means so easily washed as are the metal 

 buckets of to-day. Well do we recall the sickish smell of musty sap that 

 greeted our nostrils, when we poured in the boiling water to clean those old 

 brown buckets. Previously during the winter evenings, we all had helped 

 fashion sap-spiles from stems of sumac. With buckets and spiles ready 

 when the momentous day came, the large, iron caldron kettle was loaded 

 on a stoneboat together with a sap-cask, log-chain, ax and various other 

 utensils, and as many children as could find standing room ; then the oxen 

 were hitched on and the procession started across the rough pasture to the 



