US EPA

6976385 

Journal Article 

N-15 tracer enrichment in response to winter soil temperature manipulation differs between canopy trees and juveniles 

Henry, HAL; Kreyling, J; Gebauer, G; Klisz, M; Weigel, Lei; Fu, S 

2020 

1 

Trees
ISSN: 0931-1890
EISSN: 1432-2285 

SPRINGER HEIDELBERG 

HEIDELBERG 

10.1007/s00468-020-02003-9 

WOS:000545060500001 

Key message Juveniles and canopy trees may not exhibit similar nitrogen acquisition responses to soil temperature change caused by variation in snow cover over winter. The use of(15)N tracer is a powerful tool for tracking the effects of variation in soil frost on plant nitrogen acquisition. While the responses of juvenile trees to environmental change are often used to infer the responses of canopy trees, the(15)N enrichment responses of juveniles and mature canopy trees may not be comparable. We conducted a winter soil temperature manipulation study (snow exclusion, ambient snow or soil insulation) in a lowlandFagus sylvaticaforest.N-15 tracer was applied the following spring and the(15)N enrichments of soil, juvenile and mature canopy trees were examined in late fall. Within canopy trees and juveniles, the relative treatment effects on(15)N enrichment were consistent among all sampled tissues (roots, stem cores, leaves, buds and the current year's shoot growth). For juveniles,N-15 enrichment was highest under snow exclusion (coldest soil) and lowest under soil insulation (warmest soil), and lower(15)N enrichment occurred under ambient conditions than under snow exclusion. For canopy trees,N-15 enrichment also was highest under snow exclusion and lowest under soil insulation, but there was no difference in(15)N enrichment between ambient conditions and the snow exclusion treatment. Therefore, our results indicate that sampling of juveniles may overestimate the nitrogen acquisition responses of mature trees to winter temperature variation. 

European beech; Forest ecology; Frost sensitivity; Nitrogen tracer; Snow manipulation; Winter ecology