TREE SELECTION 11 



grows close to or in the pine belt. Its rings are apt to be complacent, 

 with considerable difference in mean size due to locality. From the 

 average rate of growth of junipers measured near Cibecue, 500 to 700 

 years would seem to be the usual maximum age of this tree. 



This species has one idiosyncrasy which often rules out an attractive 

 tree. A vertical half may die and the other half live. This may happen 

 to the trunk and follow up some of the larger branches nearly to the 

 top of the tree. Close to Elden Spring at Flagstaff is a juniper of this 

 sort which is 4 feet through east and west and is still growing actively 

 in those directions, but north and south it is only a foot through and 

 completely dead. The alligator-bark juniper is more promising than 

 the other species and may become a valuable tree on more complete 

 investigation. 



The cedars are somewhat like the last-mentioned juniper. They 

 are rather complacent, but do show some variations. The west 

 coast cedars take a good deal of water-supply. Some extremely large 

 ones are occasionally found, but they have not seemed promising. 

 The rings are generally larger than the sequoia rings and for the same 

 size the trees are not so old. Many cedars growing in the vicinity 

 of the sequoias have been examined and the ring record is considered 

 below the big tree record in quality. 



Oak and other hardwoods — The oak is less generally distributed 

 in the Southwest than the yellow pine, but there are large and im- 

 portant areas over which it is the available tree. Various samples col- 

 lected seem very promising, but it has not been available extensively 

 in the form of stumps and it is too hard to bore, so no final tests can 

 be reported here. Kapteyn's first work in the Rhine Valley was on 

 oaks, and in the last few years (1921) Professor William J. Robbins, 

 of Columbia, Missouri, has traced a fine relationship between oaks and 

 spring rainfall. This tree was used in the Swiss lake dwellings, and 

 fossil oaks are very common, showing some of the best ring records 

 to be found in museum specimens. Undoubtedly it is a valuable tree. 



Beech rings in northwestern Pennsylvania show good variations 

 and seem very promising. This is well to keep in mind, because there 

 are great beech forests in South America whose rings may contain 

 important climatic information. 



Tropical hardwoods have been examined in museums in large 

 numbers. The annual rings are mostly very hard to make out and 

 naturally that is what we would expect where the trees have over- 

 abundant rain and sun. Yet there are pines from tropical areas 

 whose rings look very attractive and well worth a careful test for 

 climatic effects. They grow mostly at higher levels. Two Araucanian 

 pines from southern Brazil, showing 500 years of age, were measured 

 in the Commercial Museum at Philadelphia. Their variations looked 

 very attractive, but there was no success in finding cross-identity. 



