Tree-Ring Chronologies on the North Rim of the

Item Type Article

Authors Ferguson, C. W.; Black, D. M.

Citation Ferguson, Jr., C.W., Black, D.M. 1952. Tree-ring chronologies on the North Rim of the Grand Canyon. Tree-Ring Bulletin 19(2):12-18.

Publisher Tree-Ring Society

Journal Tree-Ring Bulletin

Rights Copyright © Tree-Ring Society. All rights reserved.

Download date 01/10/2021 11:24:38

Link to Item http://hdl.handle.net/10150/255361 12 TREE-RING BULLETIN Annual Subscription, $2.00 Single Copy, 50c THE TREE-RING BULLETIN THE TREE -RING SOCIETY Editor -in -Chief Dr. A. E. Douglass Managing Editor..Dr. Edmund Schulman President Dr. A. E. Douglass Associate Editors: Secretary Dr. Harry T. Getty Arctic Studies._..Dr. J. L. Giddings, Jr. Tree -Ring Laboratory Botany Dr. Charles J. Lyon University of Arizon Archaeology Mr. W. S. Stallings, Jr. Tucson,

TREE -RING CHRONOLOGIES ON THE NORTH RIM OF THE GRAND CANYON

CHARLES W. FERGUSON, JR. AND DONALD M. BLACK

For a comparative study of chronology differences with respect tospe- cies, area, and age -class on the North Rim of the Grand Canyon,repre- sentative trees were sampled in October and November, 1951, by Black. The set of increment borings was mounted and then sent for analysis to Ferguson at the Tree -Ring Laboratory in Tucson.* Borings were obtained in seven species: Douglas -fir (Pseudotsuga taxifolia), white fir (Abiescon - color), western yellow pine (Pinus ponderosa), scopulorum juniper (Juni- perus scopulorum), pinyon pine (P. edulis), Engelmann spruce (Picea engelmanni), and aspen (Populus tremuloides). Although a number of trees over 400 years of age were sampled, no unusually old ones were found. The oldest in the collection, a pinyon from Cape Royal, had an inner date, as shown by a ring count, of approximately A.D. 1330. Douglas -fir and white fir were found to produce good records and the pines secondary ones; the remaining species were, as in other areas, not usable. This study utilizes Douglas -fir and white fir from three sites on outcrops of : Point Imperial, Bright Angel Point, and Cape Royal. Point Imperial is 7.2 miles northeast of Bright Angel Point; Cape Royal 7.9 miles southeast. These three points form a triangle with 11.3 miles on the third side and offer an opportunity for area comparison.

Douglas -fir and white fir grow on the northeast slopes; some Douglas- fir is found on shaded areas of the west slopes. Pinyon and juniper pre- dominate on the arid west and south slopes. Yellow pine is abundant in the interior forests.Point Imperial (elev. 8801 feet)is less arid than Bright Angel Point (8153) or Cape Royal (7876), owing to its higher ele- vation and exposure to the north and east. These factors encourage the accumulation of winter snows and retention of moisture. In contrast, warm, dry air currents rise from the inner canyon desert and flow over parts of Cape Royal and Bright Angel Point. These desiccating currents seldom reach the Point Imperial area.

*The authors are indebted to Edmund Schulman for guidance in this study and to the Grand Canyon National Park for permission to collect increment borings. TREE -RING BULLETIN 13 In the upper portion of Figure 1 comparative curves of mean growthare plotted, 1800 -1951, for both Douglas -fir and white fir from these three sites. Inspection of this figure shows crossdating to be very good between species and between areas. Variations in chronologyare due primarily to the small number of specimens represented in eachcurve; there are appar- ently no significant differences in chronology. The relatively large number of absent rings in the single Cape Royal white fir and in one of the three Bright Angel white firs seems to be quite unusual for this species. The moister site conditions at Point Imperial are indicated by greater ring- widths. Sufficient material for a study of the effects of ageon chronology was available only in Douglas -fir. The mean curve for each of fourage -classes is plotted in the lower portion of Figure 1. Thesecurves were obtained from a re- grouping of the 15 Douglas -fir specimens represented in the three N orth Rim groups, plus three supplementary specimens. The innermost rings were dated, or counted in the case of the older specimens, and the pith date estimated when the core did not reach the center. Fourage classes were formed on the basis of the estimated pith date plusa mini- mum number of years for height growth to the boring level. Specimens with an estimated age between 150 and 250 yearswere classed as 150 1-; between 250 and 350 as 250+; between 350 and 450 as 350 +; andover 450 as 450+. Inspection of the plotted curves in Figure 1 shows a general agreement among all age classes in major maxima and minima and in most minor details in chronology. The oldest group, which is basedon the records of two very sensitive trees from Bright Angel Point, is noteworthy for the number of rings simultaneously absent in both specimens since 1800, six iir the 152 -year period. This group shows a tendency towards growthre- lease in the recent decades like that in Group 6 below. Eight mean curves of measured ring- widths, unstandardized,are com- pared in Figure 2:

1.Tsegi: 6 Douglas -firs from Navajo National Monument, Arizona; in- ner rings at 1273, 1304, 1358, 1358, 1440, and 1448 (TRB, v. 14, 1948, p. 20). 2. Bryce: 4 Douglas -firs from Bryce and Tropic Canyons, Utah; inner rings at 1114, 1267, 1284, and 1309 (TRB, v. 17, 1950, p. 12). 3. Kaibab, North Rim, Arizona: 2 Douglas -firs, 450+years old. 4. Kaibab, North Rim: 3 Douglas -firs, 350+ years old. 5. Kaibab, North Rim: 15 Douglas -firs, all ages. 6. Kaibab, West: 2 Douglas -firs at 5700 feet elevation, 10 miles.west of Jacob Lake, Arizona.(Data are plotted in Schulman, Bull. Amer. Meteorol. Soc., v. 23, 1942, p. 155. A growth release effect since about 1905 is present in this series, of the type discussed in TRB,v. 18, 1952, p. 17. On comparison with recent collections, the assigned absence at 1798 has been changed to 1810.) 7. Kaibab, Jacob Lake: 4 Douglas -firs at 8500 feet elevation, 6miles south of Jacob Lake (see preceding reference).

8. Kaibab, Jacob Lake: 5 white firs (Schulman, unpublished data). 1800 10 20 30 40 1850 60 70 60 90 , 1900 IO 20 30 ' 40 1950 "NORTH RIM GROUPSPOINT IMPERIAL= WF 3 I ' Ioo-MM. 75 - _ 3 25-50- - BRIGHT ANGEL POINT-WF 2550- - - 25- A- - CAPE_ POINT ROYAL IMPERIAL- - WF DF 25 - o- - BRIGHT ANGEL POINT-DF 5 1041114 25 o - -_ AGECAPE CLASSES,.YEARS. ROYAL- DF 5 410 7525 - - 150+DF 50- 5 25-25- 0- 350250+ + 6 25- - - 450 + 2 _25- o- Fig. 1. Measured ring growth for North Rim groups, A.D. 1800 -1951. The numbercurve. Locally of specimens absent isrings shown are indicatedat the beginning by zeros of below the curves. 40*"111044111.440 O 0 o o O each Isuot;uN uoLfusa aoLfag pus `;uautnuoyz Isuot;sN o[snsN 'nsa;sId quqtex ag; uio.z; sdnoa2 soaazsnotaun .fq ao;pa;sotput g;nwa $utaaas Outa paansualryl ;uasgs SIlsooZ anano toua 2utuut2ag ag; ;s unnous st suaultoads ;o aaqumu agy xaea y 2t3 SZ z b a 52 d SZ £ '1, sz PilliktiPOPRIIIIIIIIIPINkTer $ j0-S39tl lV' HILION '8C81tl) 'S 06 d0- 3Mtl 800C1` 'B09Itl) 'L d0 -1S3M '9tl810) Z oóz061 ...,. ...,,., ' dM-3NCl 803Cf '8V91tlN g w 1v , . 0961 , Ob , 0£ , OZ , OI , 0061 06 OB OL 09 NI 0$BI Ob 00 OZ 01 0 8 O6 OB OG 09 OSLI Ob 0£ Od 01 OOLI 0 iliklitte°00 ' ' AO -193S1 'I ossa:°33 d0 - 30Aö9 b 'Z OSSZ 001SL - - 051S21 000011101101 d0 - SN03A 091, 'WILI HILION '80910) .c- ww QQLI O6 08 OL 09 0991 Ob 0£ 01 0091 £dO=SöA .090 'W18 H180N '80810) 1, 06 08 OL 09 (Dig! 0b O£ OZ 01 0091 06 08 OL 09 0 SbI 16 TREE -RING BULLETIN Table 1A. Mean Ring- Widths of Two Old Douglas -first at Bright Angel Point. Unit .01 mm. A.D. 0 1 2 3 4 5 6 7 8 9 1500 19 130 123 130 161 143 42 114 127 126 1510 87 174 123 113 139 106 124 131 126 127 1520 64 61 52 95 95 77 151 89 58 59 1530 88 117 17 92 84 142 137 132 55 120 1540 87 108 09 99 68 73 89 70 39 103 1550 105 116 114 124 130 98 111 97 63 55 1560 74 66 46 70 101 97 81 100 61 85 1570 85 40 49 59 40 48 53 51 63 51 1580 18 59 57 32 19 02 63 60 50 54 1590 35 33 30 41 69 59 62 40 58 76 1600 07 53 53 59 64 69 57 40 49 64 1610 76 72 45 43 51 61 68 65 66 70 1620 80 74 60 23 32 36 21 42 44 42 1630 41 37 17 39 44 44 42 13 14 26 1640 36 48 41 51 46 51 47 60 39 67 1650 43 54 35 68 17 62 57 50 45 42 1660 42 59 50 54 46 37 26 34 25 27 1670 24 21 25 27 38 46 33 35 56 34 1680 52 61 49 58 52 22 23 60 43 15 1690 46 53 54 55 38 51 41 44 55 55 1700 48 60 47 14 35 60 46 22 26 33 1710 57 42 43 40 44 32 40 41 51 58 1720 61 31 09 60 28 29 33 39 33 13 1730 41 44 44 37 35 08 33 30 39 10 1740 31 42 30 44 34 36 56 58 17 60 1750 42 24 25 29 17 24 32 24 29 35 1760 33 24 36 30 44 29 47 31 37 45 1770 32 47 44 10 30 39 33 23 12 42 1780 30 39 02 36 43 40 44 53 34 33 1790 22 36 45 41 13 40 22 25 22 31 1800 24 17 27 20 30 04 25 28 19 20 1810 05 31 22 08 13 18 32 33 12 25 1820 00 37 04 19 29 31 33 38 39 12 1830 15 37 31 36 24 27 13 29 29 34 1840 44 14 23 18 31 00 24 01 29 28 1850 31 23 36 25 28 39 29 11 39 19 1860 03 12 39 11 07 29 26 35 35 39 1870 21 21 38 09 37 27 18 26 28 00 1880 18 18 06 16 26 24 30 10 31 30 1890 42 39 36 42 21 39 00 30 23 00 1900 23 20 10 19 00 26 25 34 39 45 1910 40 37 43 38 45 59 41 60 34 41 1920 59 36 60 43 38 33 55 51 44 27 1930 42 17 48 16 02 32 26 35 34 26 1940 39 44 40 39 36 31 31 12 13 33 1950 32 21 ......

Table 1B. Mean Ring- Widths of 15 Douglas -firs on the North Rim. Unit .01 mm. A.D. 0 1 2 3 4 5 6 7 8 9 1800 30 24 37 30 36 21 40 32 37 27 1810 17 38 39 16 28 33 43 42 23 37 1820 15 40 16 32 37 38 48 42 48 22 1830 31 47 38 45 39 45 31 46 53 49 1840 57 31 29 36 42 12 32 11 40 43 1850 43 38 45 42 36 49 38 28 48 32 1860 23 21 47 27 21 33 45 46 48 52 1870 37 41 50 24 36 30 22 30 27 07 1880 20 25 17 21 25 26 31 15 33 33 1890 42 41 39 34 25 38 06 32 34 06 1900 26 22 17 23 06 29 30 41 41 40 1910 39 37 41 35 41 54 41 50 31 38 1920 50 34 47 39 34 29 39 39 36 24 1930 33 23 35 24 14 32 20 27 25 24 1940 32 32 31 34 25 21 22 12 18 23 1950 22 14 ...... _ -. TREE -RING BULLETIN 17 The Kaibab groups show good crossdating not only with each other but with the Bryce group, about 100 miles north, and with the Tsegigroup, about 95 miles east -northeast. A quick quantitative estimate of the degree of crossdating in Figure 2 is given by the trend coefficient (TRB, v. 17, 1950, p. 9). The average 50 -year coefficient for the oldest North Rim group was .70 vs Bryce and .72vs Tsegi; for the 350 -year group it was .72 vs Bryce and .75 vs Tsegi; for the 15 -tree group it was .72 in both cases. These results show only slightly better agreement in crossdating of the North Rim chronologies with Tsegi than with Bryce and might be changed by the addition of more material or by use of the more exact correlation coefficient method (e.g., TRB, v. 17, 1950, p. 5). Unmodified growth averages for the two very sensitive old trees at Bright Angel Point, 1500 -1951, and for the region as a whole for 1800- 1951 are given in Table 1.

For a more detailed analysis of age -class and other effectson chronology, the coefficients of mean sensitivity and of crossdating are used (TRB,v. 18, 1952, p. 11). Data for the major groups, 1840 -1940, are presented in Table 2.

Table 2. Coefficients of Mean Sensitivity and Crossdating, 1840 -1940. Aver. No. Tree Tree Group Areal Species2 Trees M.S. M.S. M.S. R Jacob Lake WF 5 .255, .195, .196, .246 .2023 .82 .240, .342 Jacob Lake DF 4 .328, .363, .325, .319 .282 .88 .260 Kaibab West DF 2 .405, .389 .397 .386 North Rim: .97 Point Imperial DF 5 .374, .306, .262, .310 .272 .88 .292, .318 Bright Angel Point DF 5 .529, .364, .419, .433 .394 .91 .403, .451 Cape Royal DF 5 .520, .346, .451, .389 .319 .82 .248, .382 All DF 15 .378 .288 .76 Bryce DF 4 .163, .382, .394, .336 .268 .80 .403

Tsegi DF 6 .400, .284, .468, .417 .344 .82 .410, .519, .421 `Specimen numbers are: Jacob Lake (WF) : KBB 3106, 3107, 3108, 3109, 3110 Jacob Lake: KBB 646, 647, 648, 649 Kaibab West: KBB 657, 658 North Rim Point Imperial: PI 209, 212, 214, 216, 217 Bright Angel Point: BAP 8, 11, 12, 16, 27 Cape Royal: CR 94, 95, 96, 99, 101 Bryce: BRY 3178, 1161, 1189, 3145 Tsegi: BTA 2411, 2450, 2412, 2456, 2458, 2460 3WF- -white fir; DF- Douglas -fir. 3M.S. of the standardized group is .210. 18 TREE -RING BULLETIN Individual mean sensitivities vary greatly, from.25 to .53 in the three North Rim groups, .16 to .40 in the Bryce group,and .28 to .52 in the Tsegi group. By first deriving the M.S. of samplesfrom a large collection, specimens with the highest M.S. could be selectedobjectively and then averaged to produce the most sensitive group average.This, within limits, is done subjectively in the field by experiencedcollectors; i.e., they attempt to judge by site conditions the approximate treeM.S. and, in general, sample only the probably most sensitive trees. The coefficient of crossdating is substantiallyhigher for each locality on the North Rim thanit is for the area as a whole; this suggests that there are systematic local differences inchronology. Of the three North Rim groups, the Bright Angel Point collectionshows the best crossdating. The relatively low average tree M.S. of thePoint Imperial group is prob- ably due to the relatively wet site. In addition to the 100 -year coefficientslisted in Table 2, 20 -year coeffi- cients were derived for the first three areas.The mean coefficient for five 20 -year intervals was the same, to twoplaces, as the 100 -year coefficient for each of the two unstandardizedJacob Lake series. The 20 -year mean coefficient of the standardized white fir set was.21, the same as for the 100 -year interval. For the unstandardizedKaibab West group, it was .03 above that of the 100 -year coefficient.It thus appears that the over -all mean sensitivity coefficientis not greatly affected by such subdivision of the interval. Mean sensitivities of the oldest groups for three100 -year periods, 1600- 1900, are presented in Table 3. Table 3. Mean Sensitivity in Old Trees. North Rim, Bryce, Tsegi, North Rim' 6 -500+ Interval 3-350+ 2- 450+ 4 -600+ .294 1600 -1700 .252 .244 .236 .306 .413 .234 .344 1700-1800 .349 1800 -19002 .313 .555 .272 Means' .290 .404 .247 .329 'Specimen numbers are: North Rim, 3- 350+: CR 94, 95, PI 216 North Rim, 2 -450 +: BAP 8, 27 'For the interval 1840 -1940 the coefficients are .296,.450, .268, .344. 'By 50 -year intervals the means are .290, .406, .247,.328. The average M.S. of the North Rim groupsfor the period 1600 -1900 is a reflection of theindividual M.S. from the different localities and sug- gests that sites such as that atBright Angel Point may provide source material for longer chronologies of highersensitivity. Analysis, year by year, of the plotted growth curvesin Figures 1 and 2 shows a general agreement in chronology amongall groups. Minor dif- ferences, such as the occurrence of anabsolute minimum in one year or another of a general growth minimum, areapparently real but seem to be of no special importance in chronology. As in other areas of the Southwest, growth hasevidently been below normal during much of the last two decades, though thedeficiency does not approach that near 1900. On the basis ofclimatic analyses which have been made on similar material (TRB, v.18, 1952, p. 17), these results are very suggestive interms of rainfall.