Long quantitative records from 16 MASTREE+ studies did not show a clear mean change in spatial synchrony of seed, fruit and cone production

We tested whether annual seed, fruit and cone production became more or less synchronous between sites of the same species. We used MASTREE+ V2 quantitative stand and patch records. The sample had 412 fixed site pairs, 123 series, 17 species and 16 studies. Each pair had 24 to 53 consecutive shared years within 1948-2022 and a distance of 1-1000 km. We compared Spearman correlation in equal early and late halves. Pairs were averaged within species and study, then studies received equal weights. Mean correlation was 0.548 early and 0.559 late. The mean change was +0.011, with a study t 95% interval of -0.137 to +0.159 and a study-bootstrap interval of -0.117 to +0.144. Trend removal, annual differences, longer runs and removal of cone-scar records did not establish a direction of average change. A study and 3-year time-block sampling check gave a wider range of -0.176 to +0.205. The seed-only subset decreased by 0.129 across 10 studies, but this unadjusted subgroup result does not establish a difference from cones. All 824 primary half correlations passed an independent numerical check. This work extends an earlier SCI synchrony test of the same source database. It provides a fixed-pair benchmark, code, source data and provenance. The limited study sample and different calendar periods do not permit a global trend or a climate effect to be inferred.

masting · spatial synchrony · plant reproduction · MASTREE+ · seed production · reproducible analysis