56 CLIMATIC CYCLES AND TREE-GROWTH 



grows steeper in the outwash-fan from a small canyon entering the 

 hills. Twelve stumps were selected of different sizes and at various 

 scattered points. Of these, three were high up on the ridge forming the 

 east side of the canyon. Here the cutting had been done some years 

 and the young sprouts of redwood from the stumps formed dense and 

 tangled masses which had to be cut away in order to get at the stumps. 

 In the bottom lands below the cutting had been recent, some of the 

 trees having been felled only a few weeks, so there was no difficulty 

 about getting the final dates. The v-cuts were 4 to 6 inches wide and 

 deep and thus were excellent specimens, well selected and in perfect 

 condition. They were prepared and mounted by Mr. Swan Erickson 

 at Tucson under my direction and cross-compared by him and later 

 by me, but no cross-identification was found. Some of the bottom- 

 land specimens seemed to have perfectly clear records, yet with close 

 study the different trees did not agree. It may be that further study 

 will produce some way of using these good specimens, but so far they 

 are not usable in this study of climate and solar activity. This is 

 unfortunate, since many of them carry records over a thousand years 

 in length. 



DEFICIENCY OF THE COAST REDWOOD 



Though it is true that years ago the theory was entertained that 

 winter snow is important in producing trees that give good climatic 

 records, this failure of the coast redwoods was a surprise. Probably 

 the subsoil water-supply and certain habits of the tree itself increase 

 these nonclimatic variations. The trees get much moisture from the 

 coast fogs, and Mr. W. P. Hoge, of Mount Wilson, tells me that in a 

 fog the trees show some very curious anomalies in their capacity to 

 take moisture from the air. Again, if moisture is in too large a quan- 

 tity, sunshine would be the controlling factor in growth, though this 

 is not at all likely in the southern groves. But a greater difficulty lies 

 in the way these trees reproduce after fire, which is by sprouts from 

 the base of the mother tree. Hence, these trees when near together 

 are apt to be connected underground. This method of reproduction 

 leads to very erratic growth, as observed by Dr. Emanuel Fritz, of 

 Berkeley. In a letter dated May 15, 1923, he says: 



"This section of second-growth redwood is interesting because it 

 shows a large number of rings merging into one and thus on some radii 

 giving an incorrect indication of the age of the tree. In March we cut 

 three-quarters of an acre of second-growth redwood 65 years old and 

 under, and found to our amazement that trees were older at the top 

 than on the stump. Very careful study soon brought to light the fact 

 that we were not counting the rings on corresponding radii. After 

 this discovery we had no further trouble. As you know, redwood 

 sprouts very freely from the stump. As these suckers mature, they 

 crowd out one another and leave but two or three in a clump. Often 



