Figure 4
Examples of bark slash sampled from trees along the Brazil-French Guiana border for DNA barcoding analysis from cambium tissue. A - Protium sp.; B - Arecaceae; C - Helicostylis pedunculata Benoit; D - Swartzia sp. (possibly Swartzia cf. canescens Torke, based on the bark slash); E - Sapotaceae; F - Sapotaceae; G - Vochysiaceae; H - Conceveiba guianensis Aubl.; I - Brosimum alicastrum S
Figure S1
Examples of panoramas of the vegetation along the 320-km transect along the border between southern French Guiana and Brazil. A - 2.324275N, 54.5391W, creek between hills, with Euterpe oleracea Mart., Socratea exorrhiza (Mart.) H.Wendl. (Arecaceae), Symphonia globulifera L.f. (Clusiaceae) and Rapatea paludosa Aubl. (Rapateaceae); B - 2.279289N, 54.5253W, granite inselberg, with Mandevilla surinamensis (Pulle) Woodson (Apocynaceae), Oreopanax capitatus (Jacq.) Decne. & Planch. (Araliaceae), Topobea parasitica Aubl. (Melastomataceae), Clusia palmicida Rich. (Clusiaceae) and Sapium argutum (Müll. Arg.) Huber (Euphorbiaceae); C - 2.256044N, 54.4826W, forest on ridge, with Astrocaryum sciophyllum (Miq.) Pulle (Arecaceae); D - 2.207178N, 54.438W, granite inselberg. In damp areas on the rock the species included Sipanea wilson-brownei R.S. Cowan (Rubiaceae), Paepalanthus oyapockensis Herzog (Eriocaulaceae), Rhynchospora subdicephala T. Koyama (Cyperaceae), Utricularia hispida spp. (Lentibulariaceae), Sinningia incarnata (Aubl.) D.L.Denham (Gesneriaceae), among others; E - 2.168647N, 54.3391W, forest on ridge, with Astrocaryum sciophyllum (Miq.) Pulle (Arecaceae); F - 2.166903N, 54.2006W, forest on ridge, with the massive Huberodendron swietenioides (Gleason) Ducke (Malvaceae); G - 2.207217N, 53.973027W, forest on ridge, dominated by Fabaceae and Meliaceae. Fluted trunks on the left are Minquartia guianensis Aubl. (Olacaceae); H - 2.300701N, 53.885363W, forest on ridge with young stems of Oenocarpus sp. (Arecaceae); I - 2.347966N, 53.804337W, swamp forest dominated by Euterpe oleracea Mart. (Arecaceae); J - 2.369397N, 53.772392W, hilltop forest on inselberg, close to Milestone 4, with Ananas comosus (L.) Merr. (Bromeliaceae), and Syagrus inajai (Spruce) Becc. (Arecaceae) which are possible clues of past human occupations.
Figure S2
Examples of specimen identification by other botanists, five years after the images became available on iNaturalist (https://www.inaturalist.org/home). A - Rhabdodendron amazonicum (Spruce ex Benth.) Huber; B - Styrax pallidus A.DC.; C - Elleanthus graminifolius (Barb.Rodr.) Løjtnant; D - Nautilocalyx pictus (Hook.) Sprague; E - Sinningia incarnata (Aubl.) D.L.Denham; F - Maieta poeppigii Mart. ex Cogn.; G - Sapium argutum (Müll.Arg.) Huber; H - Carpotroche longifolia (Poepp.) Benth.
Figure S3
Brief description of the seven 25x25-m plots sampled for tree cambium along a 320-km transect along the Brazil-French Guiana border (further details in Table 1). 1 - Forest approximately 100 m from an open granite inselberg, on shallow soil, with few large trees and a low canopy (approx. 15 m). The most abundant tree families were Burseraceae (Protium spp.) and Sapotaceae; 2 - Trees larger than in Plot 1 (DBH and height), and more diverse in families and species and with deeper soil. Several trees were felled next to the clearing (for a helicopter landing), where collections were made. These included: Aspidosperma excelsum Benth. (Apocynaceae), Oenocarpus bacaba Mart. (Arecaceae), Protium morii Daly, Protium robustum (Swart) D.M. Porter, Protium spruceanum (Benth.) Engl. (Burseraceae), Caryocar microcarpum Ducke (Caryocaraceae), Dicorynia guianensisAmshoff, Ormosia amazonica Ducke, Swartzia panacoco (Aubl.) R.S.Cowan (Fabaceae), Goupia glabra Aubl. (Goupiaceae), Licaria debilis (Mez) Kosterm (Lauraceae), Eschweilera coriacea (DC.) S.A.Mori (Lecythidaceae), Trichilia micrantha Benth. (Meliaceae), Trymatococcus oligandrus (Moraceae), Iryanthera sp. (Myristicaceae), Touroulia guianensis Aubl. (Ochnaceae), Rhabdodendron amazonicum (Spruce ex Benth.) Huber (Rhabdodendraceae), Talisia carinata Radlk., Toulicia sp. (Sapindaceae), Manilkara huberi (Ducke) Standl. (Sapotaceae), Styrax cf. macrophyllus Schott ex Pohl (Styracaceae), Coussapoa angustifolia Aubl. and Pourouma minor Benoist (Urticaceae). It is likely that Protium sp. in the DNA identifications may have been one of the three species collected, that all the Arecaceae (DNA) were Oenocarpus bacaba, and that Swartzia sp. (DNA) was S. panacoco (identified correctly by matK); 3 - This was the plot highest in tree density, and second for basal area, with 52.53 m² ha-1, mostly small trees (DBH max = 38.3 cm) of Fabaceae and Meliaceae. Located on top of a little plateau, partly on a slope, and likely an old secondary forest, with few species represented by several individuals, but Protium sp. (Burseraceae), (identified as P. decandrum (Aubl.) Marchand by rbcLa determination) appeared three times and Rhabdodendron amazonicum (Spruce ex Benth.) Huber (Rhabdodendraceae) twice; 4 - Located at the top of an inselberg, but on a draining substrate (not directly on the rocky outcrop), with an open understory and a low tree density (544 trees ha-1). The largest tree was measured on this plot. Dominated by Fabaceae and Myristicaceae, with three individuals of Carapa guianensis Aubl. (Meliaceae); 5 - Located on a ridge. Plot with the fewest trees (density of 528 tree ha-1). Dominated by Burseraceae, with both Protium spp. and Protium excelsior Byng & Christenh. (rbcLa); 6 - Plot with the lowest canopy, with open understory and many small diameter stems. Dominated by Burseraceae and Vochysiaceae, in which Erisma uncinatum Warm. (rbcLa) is probably the most abundant species; 7 - Low-density plot (576 tree ha-1) on a well-drained flatland close to the seventh milestone. Dominated by Burseraceae, with both Protium spp. and Protium excelsior (rbcLa), as in Plot 5.