| | | C. SACRAMENTO RAINFALL AND GROWTH OF 80 SEQUOIAS IN MOIST | | LOCATIONS, 1861-1910 | | | | 10 years of rainfall +0.605 +-0.062 9.8 | | | | D. ANNUAL SEQUOIA GROWTH AND RAINFALL OF PRECEDING 5 YEARS | | AT STATIONS ON SOUTHERN PACIFIC RAILROAD | | | | 1 = _Years_ | | 2 = _Altitude_ (_feet_) | | 3 = _Rainfall_ (_inches_) | | 4 = _Approximate distance from sequoias_ (_miles_) | | | | 1 2 3 4 (_r_) (_e_) (_r_/_e_) | | --------- ---- ----- --- ------ ------ --------- | | Sacramento, 1861-1910 70 19.40 200 +0.398 +-0.081 4.9 | | Colfax, 1871-1909 2400 48.94 200 +0.122 +-0.113 1.1 | | Summit, 1871-1909 7000 48.07 200 +0.148 +-0.113 1.3 | | Truckee, 1871-1909 5800 27.12 200 +0.300 +-0.105 2.9 | | Boca, 1871-1909 5500 20.34 200 +0.604 +-0.076 8.0 | | Winnemucca, 1871-1909 4300 8.65 300 +0.492 +-0.089 5.5 | | | +-------------------------------------------------------------------+ In the first line of Section A a correlation coefficient of only -0.056, which is scarcely six-tenths of the probable error, means that there is no appreciable relation between the rainfall of a given season and the growth during the following spring and summer. The roots of the sequoias probably penetrate so deeply that the rain and melted snow of the spring months do not sink down rapidly enough to influence the trees before the growing season comes to an end. The precipitation of two preceding seasons, however, has some effect on the trees, as appears in the second line of Section A, where the correlation coefficient is +0.288, or 3.2 times the probable error. When the rainfall of three seasons is taken into account the coefficient rises to +0.570, or 8.7 times the probable error, while with four years of rainfall the coefficient begins to fall off. Thus the growth of these eighteen sequoias on relatively dry slopes appears to have depended chiefly on the rainfall of the second and third preceding rainy seasons. The growth in 1900, for example, depended largely on the rainfall in the rainy seasons of 1897-1898 and 1898-1899.