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Significant gaps remain in understanding the response of plant reproduction to environmental change. This is partly because measuring reproduction in long-lived plants requires direct observation over many years and such datasets have rarely been made publicly available. Here we introduce MASTREE+, a data set that collates reproductive time-series data from across the globe and makes these data freely available to the community. MASTREE+ includes 73,828 georeferenced observations of annual reproduction (e.g. seed and fruit counts) in perennial plant populations worldwide.These observations consist of 5971 population-level time-series from 974 species in 66 countries. The mean and median time-series length is 12.4 and 10 years respectively, and the data set includes 1122 series that extend over at least two decades (≥20 years of observations). For a subset of well-studied species, MASTREE+ includes extensive replication of time-series across geographical and climatic gradients. Herewe describe the open-access data set, available as a.csv file, and we introduce an associated web-based app for data exploration. MASTREE+ will provide the basis for improved understanding of the response of long-lived plant reproduction to environmental change. Additionally, MASTREE+ will enable investigation of the ecology and evolution of reproductive strategies in perennial plants, and the role of plant reproduction as a driver of ecosystem dynamics.

Abstract. Many managed northern hardwood forests are characterized by low-diversity tree regeneration. Small harvest gaps, competition from shrub-herb vegetation, and browsing by white-tailed deer (Odocoileus virginianus) contribute to this pattern, but we know little about how these factors interact. With a stand-scale experiment, we examined the effects of gap size (0-3234 m 2 ), vegetation (weeded:unweeded), and deer (fenced:unfenced) on seedling growth and survival for 18 tree species. With increasing gap size and light, shrub-herb vegetation density increased, while deer browsing on seedlings in unweeded plots decreased. Fenced:weeded seedlings of all species increased in height up to 35-45% light, with optimal growth in large-group selection and patch cut harvest gaps. Height growth rank order among tree species changed between gap sizes, but growth varied little in small, low-light gaps. Instead, a low-light survival (i.e., shade tolerance) vs. high-light growth tradeoff we observed is likely more important for species sorting of gap sizes. Shrub-herb vegetation decreased seedling survival and growth, especially in larger harvest gaps, shifting gap size optima to smaller gaps, but had little effect on growth/survival rank order among species. In contrast, deer had strong impacts on growth rank order, especially in larger gaps where species differences in growth potential were trumped by differences in deer browsing pressure responses. However, contrary to their consistently negative main effects, vegetation and deer had two positive interacting effects: dense shrub-herb vegetation in large gaps protected seedlings of faster-growing species from browsing and deer browsing of shrub-herb vegetation modestly increased light and growth of short, suppressed, browsing-avoided species. In summary, harvest gap size-mediated light availability, shrub-herb vegetation, and deer herbivory had strong interacting effects on tree seedling interspecific performance ranks and intraspecific optimal gap sizes. For management, a broad range of harvest gap sizes and rapid establishment of tree regeneration (naturally or planted) to minimize shrub-herb competition should increase tree diversity in forests with few deer. However, with deer browsing pressure, a more limited set of lesser-browsed species are likely to recruit successfully regardless of gap size, except in large patch cut gaps, where recruitment of faster-growing, shade-intolerant species is possible.

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