After scaling to 0–10, two plant nutrient score systems gave different 20-year changes on 3,564 Swedish forest plots

We tested whether recorded plant lists shifted toward species associated with greater nutrient supply on 3,564 Swedish forest plots. Each plot had two 100 square metre productive-forest surveys exactly 20 years apart, in 1999-2004 and 2019-2024. The primary test used 181 vascular species and European EIVE 1.0 scores. Mean nutrient score rose by 0.0110 on a 0-10 scale, with a 95% interval of -0.0012 to +0.0235 from 4,999 spatial block resamples. Thus, this test did not establish a clear rise. Original Swedish scores, scaled to 0-10, gave +0.0249 (0.0053 to 0.0450). On the same 179 species, the Swedish-minus-European change was +0.0143 (0.0042 to 0.0253). The difference remained after division by each system's species-score SD. Exact-name matching alone omitted six source-confirmed synonyms and gave a European nutrient rise of +0.0188 (0.0118 to 0.0254). The paired omission effect included zero; exploratory deletion of fireweed alone increased the estimate by 0.0109 (0.0046 to 0.0173). Mean vascular richness rose by 0.742 species. Under an exact accounting identity, species gains and losses contributed +0.0585 and -0.0474 to European nutrient change. Overall light-score change was uncertain. These results describe recorded preferences under specified scores. They do not measure soil nitrogen, correct detection error, or estimate a national area-weighted trend. The package preserves source data, complete name links, code, provenance, all results, figures, an independent calculation, and repeat instructions.

forest vegetation · plant indicators · nitrogen · light · paired surveys · taxonomic matching · Sweden · reproducibility