ORCID ID

John Van Stan, https://orcid.org/0000-0002-0692-7064

Document Type

Article

Publication Date

3-2026

Publication Title

Biotropica

Disciplines

Biology | Forest Management

Abstract

Trees can redirect large volumes of rainwater to the base of their stems. This stemflow not only redistributes water but also channels canopy-derived solutes to the forest floor. Building on research showing canopy geometry and bark properties govern stemflow volumes, we examined how those same traits modulate the biogeochemical side of this flux. Over a 12-month period in Jamari National Forest (Brazil), we quantified stemflow volume and solute chemistry for 19 trees grouped by diameter at breast height (D: < 10, 10-20 and > 20 cm), crown area (CA: < 30, 30-60 and > 60 m(2)) and bark texture (smooth, fissured and rough). Small-stemmed, smooth-barked trees produced the greatest stemflow yields, whereas large-stemmed, rough-barked trees generated lower volumes but higher mean ion concentrations. Macronutrient-rich species appear to flip the usual water-flux story on its head. For example, calcium and potassium (two key nutrients for plant growth) rose sharply from 1.1 kg-Ca2+ ha(-1) and 4.9 kg-K+ ha(-1) in small, smooth-barked trees to 6.3 and 7.7 kg ha(-1), respectively, in large rough-barked individuals. In contrast, trace anions such as chloride and bromide declined with size and roughness (Cl-: 1.3 to 0.4 kg ha(-1); Br-: 0.20 to 0.03 kg ha(-1)). These contrasting patterns show that although small, smooth trees may dominate stemflow water routing, older, structurally complex trees disproportionately deliver the nutrients that drive forest productivity. Consequently, conserving structural diversity-including mature, rough-barked specimens-is essential for maintaining biogeochemical cycling in Amazonian forests threatened by deforestation and climate change.

Comments

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico, 312562/2021-7; Fundação de Amparo ao Desenvolvimento das Ações Científicas e Tecnológicas e à Pesquisa do Estado de Rondônia (Fapero).

DOI

10.1111/btp.70193

Version

Publisher's PDF

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Volume

58

Issue

2

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