San Julian, Santa Cruz de la Sierra, Bolivia - BOL005 Additional Site Information Lidio Lopez, Ricardo Villalba Measurement type: Total ring width Reference: Lidio Lopez, Ricardo Villalba. 2020 submitted. Climate-growth relationships for Aspidosperma tomentosum in South American tropical dry forests. Annals of Forest Science, submitted. Abstract: The precise demarcation and cross-dating of tree rings in Aspidosperma tomentosum, a valuable timber species in the tropical dry forests of South America, were used to develop the first well-replicated chronology covering the period 1843-2015. A. tomentosum tree growth is strongly regulated by soil water availability prior to and during the current growing season. In the context of increased drought severity due to climate change, determining of climate influences on A. tomentosum radial growth is necessary to establish appropriate guidelines for the management, conservation and restoration of this species, currently affected by extreme weather events, extensive fires and deforestation in the Chiquitanía forests, Bolivia. Tropical forest ecosystems play a critical role in the functioning of the Earth, thus a better understanding of the influences of climate on tree growth is needed to estimate changes in forest productivity, and consequently in carbon sink variations at regional and global scales. In the context of global environmental changes, our study aimed at using the growth rings of A. tomentosum to establish the relationships between radial growth and climatic variations. The anatomical characterization of the wood elements facilitated the precise annual band delimitation and the rejection of samples with false rings and growth anomalies. A tree-ring chronology was developed using traditional dendrochronological methods and the relationships with climate determined using correlation functions. The chronology is based on 20 individuals and covers the period 1843-2015. Tree-ring statistics indicate an important common signal in growth variations between trees (R-bar = 0.31, EPS = 0.90). Interannual variations in A. tomentosum are directly related to total annual precipitation (r = 0.76) and inversely to mean annual temperature (r = -0.44). These relationships are similar to those documented for other commercial species (Centrolobium microchaete, Schinopsis brasiliensis) from tropical dry forests in South America, suggesting a consistent climatic influence on tree growth at regional scale. The strong dependence of tree growth on climate variability is a major concern, as climate change scenarios for tropical dry forests in South America predict an increase in the frequency and intensity of droughts, which in turn would reduce the A. tomentosum growth during the 21st century. Notes: Tree-ring width records from tropical dry forests in Bolivia used to estimate rates of tree growth, response of tree growth to climate variations, and reconstruction of past climate variability in tropical South America. Keywords: dendrochronology, tree rings, climate change, climate-growth relationships, tropical dry forests, South America Funding sources: CONICET-Argentina PICT 2018-3691, US National Science Foundation AGS-1501321 COFECHA output: Chronology file name : BOL005.CRN Measurement file name : BOL005.RWL Date checked : 28AUG20 Checked by : B. Bauer Beginning year : 1843 Ending year : 2015 Principal investigators: Lidio Lopez Ricardo Villalba Site name : San Julian Site location : Bolivia Species information : ASTO A.TOMENTOSUM Latitude : -1651 Longitude : -6230 Elevation : 250M Series intercorrelation: 0.555 Avg mean sensitivity : 0.438 Avg standard deviation : 0.612 Avg autocorrelation : 0.290 Number dated series : 24 Segment length tested : 50 Number problem segments: 8 Pct problem segments : 7.41 PART 5: CORRELATION OF SERIES BY SEGMENTS: San Julian ASTO 09:54 Fri 28 Aug 2020 Page 5 ----------------------------------------------------------------------------------------------------------------------------------- Correlations of 50-year dated segments, lagged 25 years Flags: A = correlation under .3281 but highest as dated; B = correlation higher at other than dated position Seq Series Time_span 1850 1875 1900 1925 1950 1975 1899 1924 1949 1974 1999 2024 --- -------- --------- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 1 jic28b 1933 2015 .54 .59 .57 2 jic50a 1898 2015 .60 .56 .63 .69 .78 3 jic50b 1898 2015 .58 .57 .65 .68 .77 4 jic42 1872 2015 .54 .56 .48 .42 .40 .40 5 jic12 1873 2015 .73 .69 .58 .36 .40 .45 6 jic36 1902 2015 .47 .54 .47 .47B 7 jic16 1928 2015 .65 .67 .62 8 jic33 1877 2014 .26A .42 .74 .61 .63 9 jic56 1876 2015 .58 .71 .64 .46 .56 10 jic55 1900 2015 .75 .77 .78 .80 11 jic51 1902 2015 .31A .44 .33 .42 12 jic44 1910 2015 .40 .30B .28B .35 13 jic14 1929 2015 .31A .35 .47 14 jic22 1933 2015 .36 .47 .41 15 jic15 1898 2015 .60 .56 .63 .69 .78 16 jic11 1888 1954 .72 .72 .75 17 jic05a 1880 2014 .67 .72 .68 .69 .72 18 jic05b 1905 2014 .70 .70 .68 .60 19 jic04 1843 2014 .53 .50 .51 .58 .47 .54 20 jic16a 1871 2014 .83 .83 .80 .73 .71 .69 21 jic16b 1875 1978 .63 .70 .69 .69 22 jic03b 1895 2014 .85 .82 .63 .57 .49 23 jic03a 1885 2014 .40 .41 .54 .40 .33 24 jic07a 1884 2014 .26A .27A .34 .37 .56 Av segment correlation .66 .58 .57 .57 .54 .56 PART 7: DESCRIPTIVE STATISTICS: San Julian ASTO 09:54 Fri 28 Aug 2020 Page 8 ----------------------------------------------------------------------------------------------------------------------------------- Corr //-------- Unfiltered --------\\ //---- Filtered -----\\ No. No. No. with Mean Max Std Auto Mean Max Std Auto AR Seq Series Interval Years Segmt Flags Master msmt msmt dev corr sens value dev corr () --- -------- --------- ----- ----- ----- ------ ----- ----- ----- ----- ----- ----- ----- ----- -- 1 jic28b 1933 2015 83 3 0 .530 1.96 3.77 .763 .385 .396 2.48 .527 -.035 1 2 jic50a 1898 2015 118 5 0 .640 1.20 2.81 .502 .242 .399 2.88 .592 -.018 1 3 jic50b 1898 2015 118 5 0 .638 1.20 2.78 .496 .277 .382 2.87 .537 -.012 1 4 jic42 1872 2015 144 6 0 .463 1.06 2.35 .425 .424 .337 2.58 .419 -.040 1 5 jic12 1873 2015 143 6 0 .519 1.11 3.33 .477 .427 .348 2.83 .497 -.012 3 6 jic36 1902 2015 114 4 1 .505 1.80 4.35 .749 .305 .350 2.89 .517 -.012 1 7 jic16 1928 2015 88 3 0 .612 1.90 4.19 .738 .212 .394 2.71 .476 -.056 1 8 jic33 1877 2014 138 5 1 .525 1.12 3.32 .524 .414 .398 2.78 .501 -.017 1 9 jic56 1876 2015 140 5 0 .570 1.42 3.39 .618 .303 .412 2.69 .504 -.003 3 10 jic55 1900 2015 116 4 0 .765 1.18 2.76 .462 .219 .398 2.87 .535 .014 1 11 jic51 1902 2015 114 4 1 .386 1.03 2.65 .530 .613 .364 2.83 .662 .049 2 12 jic44 1910 2015 106 4 2 .373 1.65 3.53 .644 .068 .426 2.83 .453 .052 1 13 jic14 1929 2015 87 3 1 .406 2.13 5.16 .957 .421 .401 2.62 .442 -.008 1 14 jic22 1933 2015 83 3 0 .366 1.95 5.39 .816 .370 .385 2.68 .474 -.011 1 15 jic15 1898 2015 118 5 0 .640 1.20 2.81 .502 .242 .399 2.88 .592 -.018 1 16 jic11 1888 1954 67 3 0 .705 .92 1.86 .464 .007 .579 2.76 .668 -.022 1 17 jic05a 1880 2014 135 5 0 .686 .93 3.17 .533 .006 .659 2.80 .484 -.021 1 18 jic05b 1905 2014 110 4 0 .671 1.08 2.96 .579 .043 .612 2.77 .578 .028 1 19 jic04 1843 2014 172 6 0 .533 1.40 6.03 1.194 .597 .510 2.86 .418 .008 1 20 jic16a 1871 2014 144 6 0 .741 1.19 3.13 .581 .272 .486 2.72 .593 -.020 2 21 jic16b 1875 1978 104 4 0 .665 1.11 2.73 .522 -.028 .515 2.73 .517 .002 1 22 jic03b 1895 2014 120 5 0 .623 .97 3.29 .514 .263 .469 2.89 .518 .010 1 23 jic03a 1885 2014 130 5 0 .394 1.30 3.47 .655 .269 .492 2.72 .526 -.039 1 24 jic07a 1884 2014 131 5 2 .342 .98 2.48 .456 .298 .409 2.70 .450 -.047 1 --- -------- --------- ----- ----- ----- ------ ----- ----- ----- ----- ----- ----- ----- ----- -- Total or mean: 2823 108 8 .555 1.29 6.03 .612 .290 .438 2.89 .516 -.009