{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,15]],"date-time":"2026-06-15T03:18:19Z","timestamp":1781493499958,"version":"3.54.1"},"reference-count":34,"publisher":"American Association for the Advancement of Science (AAAS)","issue":"5470","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Science"],"published-print":{"date-parts":[[2000,5,26]]},"abstract":"<jats:p>Fully mapped tree census plots of large area, 25 to 52 hectares, have now been completed at six different sites in tropical forests, including dry deciduous to wet evergreen forest on two continents. One of the main goals of these plots has been to evaluate spatial patterns in tropical tree populations. Here the degree of aggregation in the distribution of 1768 tree species is examined based on the average density of conspecific trees in circular neighborhoods around each tree. When all individuals larger than 1 centimeter in stem diameter were included, nearly every species was more aggregated than a random distribution. Considering only larger trees (\u2265 10 centimeters in diameter), the pattern persisted, with most species being more aggregated than random. Rare species were more aggregated than common species. All six forests were very similar in all the particulars of these results.<\/jats:p>","DOI":"10.1126\/science.288.5470.1414","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T09:40:50Z","timestamp":1027762850000},"page":"1414-1418","source":"Crossref","is-referenced-by-count":922,"title":["Spatial Patterns in the Distribution of Tropical Tree Species"],"prefix":"10.1126","volume":"288","author":[{"given":"Richard","family":"Condit","sequence":"first","affiliation":[{"name":"Center for Tropical Forest Science, Smithsonian Tropical Research Institute, Unit 0948, APO AA 34002\u20130948, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter S.","family":"Ashton","sequence":"additional","affiliation":[{"name":"Center for Tropical Forest Science, Harvard Institute for International Development and Harvard University, Cambridge, MA 02138, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patrick","family":"Baker","sequence":"additional","affiliation":[{"name":"Silviculture Laboratory, College of Forest Resources, University of Washington, Seattle, WA 98195\u20132100, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarayudh","family":"Bunyavejchewin","sequence":"additional","affiliation":[{"name":"Royal Thai Forest Department, Chatuchak, Bangkok 10900, Thailand."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Savithri","family":"Gunatilleke","sequence":"additional","affiliation":[{"name":"Department of Botany, University of Peradeniya, Peradeniya, Sri Lanka."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nimal","family":"Gunatilleke","sequence":"additional","affiliation":[{"name":"Department of Botany, University of Peradeniya, Peradeniya, Sri Lanka."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephen P.","family":"Hubbell","sequence":"additional","affiliation":[{"name":"Center for Tropical Forest Science, University of Georgia, Athens, GA 30602, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robin B.","family":"Foster","sequence":"additional","affiliation":[{"name":"Center for Tropical Forest Science, Field Museum of Natural History, Chicago, IL 60605\u20132496, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Akira","family":"Itoh","sequence":"additional","affiliation":[{"name":"Osaka City University, Osaka 558-8585, Japan."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James V.","family":"LaFrankie","sequence":"additional","affiliation":[{"name":"Center for Tropical Forest Science, National Institute of Education, Singapore 1025."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hua Seng","family":"Lee","sequence":"additional","affiliation":[{"name":"Sarawak Forest Department, Kuching, Sarawak 93660, Malaysia."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elizabeth","family":"Losos","sequence":"additional","affiliation":[{"name":"Center for Tropical Forest Science, Smithsonian Tropical Research Institute, Unit 0948, APO AA 34002\u20130948, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"N.","family":"Manokaran","sequence":"additional","affiliation":[{"name":"Forest Research Institute of Malaysia, Kepong 52109, Kuala Lumpar, Malaysia."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R.","family":"Sukumar","sequence":"additional","affiliation":[{"name":"Indian Institute of Science, Bangalore 560012, India."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takuo","family":"Yamakura","sequence":"additional","affiliation":[{"name":"Osaka City University, Osaka 558-8585, Japan."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"221","reference":[{"key":"e_1_3_1_2_2","doi-asserted-by":"crossref","unstructured":"M. R. T. Dale Spatial Patterns Analysis in Plant Ecology (Cambridge Univ. Press Cambridge 1999).","DOI":"10.1017\/CBO9780511612589"},{"key":"e_1_3_1_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0169-5347(99)01616-X"},{"key":"e_1_3_1_4_2","unstructured":"A. R. Wallace A Narrative of Travels on the Amazon and Rio Negro (Haskell House New York 1853)."},{"key":"e_1_3_1_5_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.203.4387.1299"},{"key":"e_1_3_1_6_2","doi-asserted-by":"publisher","DOI":"10.1086\/282687"},{"key":"e_1_3_1_7_2","unstructured":"J. H. Connell in Dynamics of Populations P. J. den Boer and G. R. Gradwell Eds. (PUDOC Waneningen Netherlands 1971) pp. 298\u2013312."},{"key":"e_1_3_1_8_2","unstructured":"M. Lieberman and D. Lieberman in La Selva: Ecology and Natural History of a Neotropical Rain Forest L. A. McDade et al. Eds. (Univ. of Chicago Press Chicago 1994) pp. 106\u2013119."},{"key":"e_1_3_1_9_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0169-5347(00)88955-7"},{"key":"e_1_3_1_10_2","unstructured":"P. S. Ashton in Forest Biodiversity Research Monitoring and Modeling: Conceptual Background and Old World Case Studies F. Dallmeier and J. A. Comiskey Eds. (UNESCO and Parthenon Publishing Paris 1998) pp. 47\u201362."},{"key":"e_1_3_1_11_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.284.5413.445"},{"key":"e_1_3_1_12_2","doi-asserted-by":"publisher","DOI":"10.2307\/3236356"},{"key":"e_1_3_1_13_2","doi-asserted-by":"publisher","DOI":"10.2307\/1938452"},{"key":"e_1_3_1_14_2","first-page":"806","volume":"38","author":"Penttinen A.","year":"1992","unstructured":"Penttinen A., et al., For. Sci. 38, 806 (1992).","journal-title":"For. Sci."},{"key":"e_1_3_1_15_2","unstructured":"We proved sample-size independence by randomly selecting 100 individuals without replacement from all populations and observing no change in \u03a9 x even for species with as many as 40 000 individuals. There is proof of sample-size independence of this statistic (29). To estimate confidence limits for \u03a9 x a sample of exactly half the population of each species was drawn at random 15 times without replacement and for each \u03a9 x was calculated in all 10-m distance intervals. A variance and 95% confidence limits\u2014based on a t statistic\u2014were calculated from this sample; because the sample was halved the limits were divided by (2) 1\/2 before being applied to the entire sample. We judged statistical significance of aggregation or overdispersion by checking whether confidence limits included 1 and to compare two different estimates we checked whether confidence limits overlapped."},{"key":"e_1_3_1_16_2","unstructured":"Even under complete spatial randomness the probability that \u03a9 0\u201310 = 0 is high when N < 50 in 50 ha. Across all plots no species with N \u2265 100 had \u03a9 0\u201310 = 0 whereas a few species with 50 to 100 individuals had \u03a9 0\u201310 = 0. With N < 10 \u03a9 0\u201310 = 0 in most species. For this reason most of our analyses refer to all species with \u226550 individuals in the 50-ha plots (to standardize density the cutoff was set at 1 per hectare or 25 individuals in the Sinharaja plot and 52 in the Lambir plot)."},{"key":"e_1_3_1_17_2","unstructured":"Supplementary material is available at www.sciencemag.org\/feature\/data\/1048222.shl."},{"key":"e_1_3_1_18_2","unstructured":"When all stems of \u22651 cm diameter were analyzed a Spearman rank correlation between \u03a9 0\u201310 and a species' abundance was significant and negative at all plots but Mudumalai and HKK for species with N \u2265 50."},{"key":"e_1_3_1_19_2","doi-asserted-by":"publisher","DOI":"10.2307\/3237248"},{"key":"e_1_3_1_20_2","doi-asserted-by":"publisher","DOI":"10.1023\/A:1009727109920"},{"key":"e_1_3_1_21_2","unstructured":"We compared forests by calculating confidence limits for the mean values of log(\u03a9 0\u201310 ) within abundance categories each species being a single datum using t statistics. Tests were done separately on all categories listed in Table 2 and significant differences between plots were assumed when 95% confidence limits did not overlap. Lambir HKK and Sinharaja had significantly higher \u03a9 0\u201310 than Pasoh and BCI in at least two abundance categories and Lambir and Sinharaja were significantly higher than Pasoh in most abundance categories."},{"key":"e_1_3_1_22_2","unstructured":"P. A. Palmiotto thesis Yale University New Haven CT 1998."},{"key":"e_1_3_1_23_2","doi-asserted-by":"publisher","DOI":"10.1023\/A:1009779424279"},{"key":"e_1_3_1_24_2","unstructured":"Dispersal mode (wind animal or explosive) was estimated from our own experience and from a published account (30). Species were classified as canopy or understory (at their largest size) at BCI and Pasoh from our experience and from published floras (30 31). Significance was tested with confidence limits for log(\u03a9 0\u201310 ) (20)."},{"key":"e_1_3_1_25_2","unstructured":"At Pasoh the median \u03a9 0\u201310 for canopy species was 2.8 and for understory it was 3.1; the difference is not significant. At BCI the medians were 2.9 and 4.2 and the difference is significant."},{"key":"e_1_3_1_26_2","unstructured":"The median \u03a9 0\u201310 for wind- or explosively dispersed species at BCI was 4.5; for animal-dispersed species it was 3.0 but the difference was not significant."},{"key":"e_1_3_1_27_2","unstructured":"At Pasoh the 24 dipterocarp species with N \u2265 50 individuals had a median \u03a9 0\u201310 of 5.1 compared with 2.8 for all other species. At Lambir 65 dipterocarps had \u03a9 0\u201310 = 21.8; for other species \u03a9 0\u201310 = 5.3. Both differences are significant. At Sinharaja 12 dipterocarps were slightly but not significantly more aggregated than nondipterocarps. HKK and Mudumalai had just three and one dipterocarp species respectively."},{"key":"e_1_3_1_28_2","doi-asserted-by":"publisher","DOI":"10.1098\/rspb.1999.0799"},{"key":"e_1_3_1_29_2","doi-asserted-by":"publisher","DOI":"10.1038\/35006630"},{"key":"e_1_3_1_30_2","unstructured":"H. M. Hastings and G. Sugihara Fractals: A User's Guide for the Natural Sciences (Oxford Univ. Press Oxford 1993)."},{"key":"e_1_3_1_31_2","unstructured":"T. R. Croat Flora of Barro Colorado Island (Stanford Univ. Press Stanford CA 1978)."},{"key":"e_1_3_1_32_2","unstructured":"T. C. Whitmore Ed. Tree Flora of Malaya: A Manual for Foresters (Longman London 1972)."},{"key":"e_1_3_1_33_2","unstructured":"N. Manokaran et al. Stand Table and Distribution of Species in the 50-ha Research Plot at Pasoh Forest Reserve Research Data (Forest Research Institute of Malaysia Kepong Malaysia 1992) vol. 1."},{"key":"e_1_3_1_34_2","doi-asserted-by":"crossref","unstructured":"R. Condit Tropical Forest Census Plots (Springer-Verlag and R. G. Landes Co. Berlin and Georgetown TX 1998).","DOI":"10.1007\/978-3-662-03664-8"},{"key":"e_1_3_1_35_2","unstructured":"Supported by the Indian Institute of Science the University of Peradeniya (Sri Lanka) the Sarawak Forest Department (Malaysia) the Forest Research Institute of Malaysia the Royal Thai Forest Department the Smithsonian Tropical Research Institute the Japanese National Institute of Environmental Studies the Japanese Ministry of Education and Science the National Science Foundation and the John D. and Catherine T. MacArthur Foundation. R.C. thanks J. Franklin's group in the College of Forest Resources at the University of Washington for support during a sabbatical."}],"container-title":["Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.science.org\/doi\/pdf\/10.1126\/science.288.5470.1414","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,1,13]],"date-time":"2024-01-13T10:50:13Z","timestamp":1705143013000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.science.org\/doi\/10.1126\/science.288.5470.1414"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000,5,26]]},"references-count":34,"journal-issue":{"issue":"5470","published-print":{"date-parts":[[2000,5,26]]}},"alternative-id":["10.1126\/science.288.5470.1414"],"URL":"https:\/\/doi.org\/10.1126\/science.288.5470.1414","relation":{},"ISSN":["0036-8075","1095-9203"],"issn-type":[{"value":"0036-8075","type":"print"},{"value":"1095-9203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2000,5,26]]}}}