Tree-covered　shallow　landslides　have　become　more　frequent　in　recent　years.　Tree　root　systems　play　a　crucial　role　in　influencing　shallow　landslides,　but　their　impact　on　water　infiltration　under　extreme　rainfall　remains　unclear.　This　study　investigates　the　effects　of　tree　roots　on　water　infiltration　under　extreme　rainfall　conditions　through　in-situ　artificial　rainfall　experiments,　root　distribution　surveys,　and　soil　physical　and　hydraulic　property　tests.Results　show　that　root　distribution　decreases　sharply　beyond　a　soil　depth　of　60　cm　and　is　almost　absent　beyond　190　cm.　Roots　increase　soil　porosity,　enhancing　soil　permeability　while　reducing　moisture　retention　capacity.　In　the　0–1　m　and　1–2　m　depth　ranges,　the　air　expulsion　value　(AExV)　of　bare　soil　is　2.1　and　1.9　times　that　of　rooted　soil,　respectively,　while　the　saturated　hydraulic　conductivity　(Ks)　of　rooted　soil　is　2.5　and　1.8　times　that　of　bare　soil.　Under　a　60　mm/h　rainfall　intensity,　volumetric　water　content　(VWC)　and　pore　water　pressure　(PWP)　in　rooted　soil　respond　faster　than　in　bare　soil,　the　time　required　for　water　infiltration　to　a　depth　of　2　m　in　bare　soil　is　1.53　times　longer　than　in　rooted　soil.　In　rooted　soils,　due　to　differences　in　hydraulic　conductivity　between　rooted　and　rootless　soil　layers,　an　infiltration　barrier　effect　causes　water　accumulation　at　170–200　cm　depth,　forming　a　saturated　perched　water　zone　and　generating　positive　PWP　(max.　2.2　kPa).　This　reduces　soil　effective　stress,　and　under　continuous　rainfall,　soil　strength　rapidly　decreases,　triggering　shallow　landslides.　A　modified　GAML-R　model　incorporating　root　effects　on　soil　hydraulics　was　developed　based　on　the　Green-Ampt-Mein-Larson　model,　showing　high　prediction　accuracy.　These　findings　enhance　understanding　of　rainfall-induced　shallow　landslides　in　vegetated　slopes.　©　2025　Elsevier　B.V.