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Large old trees influence patterns of δ 13 C and δ 15 N in forests
Author(s) -
Weber Pascale,
Bol Roland,
Dixon Liz,
Bardgett Richard D.
Publication year - 2008
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3433
Subject(s) - scots pine , litter , crown (dentistry) , chemistry , δ13c , forestry , stable isotope ratio , pinus <genus> , botany , ecology , geography , biology , medicine , physics , dentistry , quantum mechanics
Large old trees are the dominant primary producers of native pine forest, but their influence on spatial patterns of soil properties and potential feedback to tree regeneration in their neighbourhood is poorly understood. We measured stable isotopes of carbon ( δ 13 C) and nitrogen ( δ 15 N) in soil and litter taken from three zones of influence (inner, middle and outer zone) around the trunk of freestanding old Scots pine ( Pinus sylvestris L.) trees, to determine the trees' influence on below‐ground properties. We also measured δ 15 N and δ 13 C in wood cores extracted from the old trees and from regenerating trees growing within their three zones of influence. We found a significant and positive gradient in soil δ 15 N from the inner zone, nearest to the tree centre, to the outer zone beyond the tree crown. This was probably caused by the higher input of 15 N‐depleted litter below the tree crown. In contrast, the soil δ 13 C did not change along the gradient of tree influence. Distance‐related trends, although weak, were visible in the wood δ 15 N and δ 13 C of regenerating trees. Moreover, the wood δ 15 N of small trees showed a weak negative relationship with soil N content in the relevant zone of influence. Our results indicate that large old trees control below‐ground conditions in their immediate surroundings, and that stable isotopes might act as markers for the spatial and temporal extent of these below‐ground effects. Copyright © 2008 John Wiley & Sons, Ltd.