14 



southern California. It prefers rich, moist soil, and reaches its best 

 development in the river bottoms of Washington and Oregon. The 

 census of 1900 reports a very small production (126 gallons of sirup) 

 from Columbia County, Wash* 



SUGAR GROVES. 

 GENERAL. CONSIDERATIONS. 



The ideal sugar grove should contain that number of trees which 

 will give a maximum yield of sap per acre ; whence it follows that the 

 formation of a grove must consider the yield per given area rather 

 than the yield per tree. To determine the exact number of trees that 

 should occupy an area would take many years of experiment, but 

 directly and indirectly there has been much information collected on 

 the subject of sap production through a study of individual trees, 

 and from this a number of safe deductions can be made. An equal 

 amount of sunlight being given, the sap and sugar production is pro- 

 portionate to the leaf area of the tree. This statement is corroborated 

 in a recent bulletin of the Vermont Agricultural Experiment Station, 

 where it is also asserted that the sugar production of the tree depends 

 more on the actual leaf area than on the amount of light which it 

 receives. In other words, if a small-crowned mature tree be set free 

 to light on all sides, the sap production will be stimulated only to a 

 very slight extent. From this it follows that the number of trees 

 per acre must be consistent with the greatest possible crown develop- 

 ment of each tree in the grove. At the same time it is not to be 

 forgotten that the maple is inherently a forest species. The large 

 crown of foliage has an extensive leaf area for evaporation, and 

 demands a protected soil which can keep it well supplied with water. 

 Such soil is best found in the forest, where the ground is kept heavily 

 matted with leaves and humus, so that the sun and drying winds will 

 have little access to it, and a comparatively uniform degree of mois- 

 ture and coolness may be maintained under all conditions. Commer- 

 cial sugar making is confined to a small part of the botanical distribu- 

 tion of the sugar maple, because of a peculiar climatic requirement. 

 It is the gradual northern spring, with the slow yielding of the frost by 

 the ground, which makes the sap flow long and continuously enough 

 to give a paying production of sugar. A sudden thaw affects both the 

 quality and the duration of the sap flow. On this account it is always 

 desirable to maintain forest conditions in a sugar grove, for if the 

 ground has a heavy carpet of leaves and humus, it will be less sensitive 

 to changes in temperature. 



a Bui. No. 103, Vermont Agricultural Experiment Station, Dec., 1903, pp. 117, 118. 

 252 



