Intra-annual density fluctuations (IADFs) inPinus nigra(J. F. Arnold) at high-elevation in the central Apennines (Italy)

Alma Piermattei,Filipe Campelo,Alan Crivellaro,Carlo Urbinati,Ulf Büntgen,Matteo Garbarino

doi:10.1007/s00468-020-01956-1

Abstract

Although wood anatomical features can provide yearly resolved climatic information at sub-seasonal resolution, the occurrence of intra-annual density fluctuations (IADFs) might be triggered by several abiotic factors under different ecological settings. Here, we use information on cambial age and tree-ring width to standardize the frequency of IADFs in European black pines from three different mountain slopes in the central Apennines (Italy). At each site, we sampled isolated 15–30-year pioneer pines above the forest limit, as well as close-grown 40–60-year planted pines at the forest limit. Mainly restricted to the latewood of both pioneer and planted trees, the occurrence of IADFs reveals a significant positive relationship with cambial age and ring width. Although the standardized IADFs are well synchronized between the planted and pioneer pines, the frequency of IADFs in narrow rings was higher in the pioneer pines. Drought conditions in July and August are responsible for the highest IADFs frequency in planted and pioneer pines, respectively. Our study underlines the value of IADFs to obtain a more nuanced understanding of the climatic drivers of wood formation at the intra-annual scale.

Highlights

Though tree-ring width records are among the most important and commonly used annually resolved climate proxies (Sheppard 2010), intra-ring wood anatomical traits, such as intra-annual density fluctuations (IADFs), resin canals density, and maximum wood density, can provide useful climate-growth information, albeit at sub-seasonal resolution (De Luis et al 2007; Esper et al 2015; Björklund et al 2017)
In planted pines (PLP), the stabilized IADFs frequency declines during the last 10–20 years, mainly at sites VET and OCR and the trend is left-skewed with a maximum peak in the juvenile phase
We demonstrate how using yearly resolved IADFs frequency can provide valuable tree-climate sensitivity information from trees that would otherwise be challenging to study using traditional dendroclimatic technique due to their young age

Summary

Introduction

Though tree-ring width records are among the most important and commonly used annually resolved climate proxies (Sheppard 2010), intra-ring wood anatomical traits, such as intra-annual density fluctuations (IADFs), resin canals density, and maximum wood density, can provide useful climate-growth information, albeit at sub-seasonal resolution (De Luis et al 2007; Esper et al 2015; Björklund et al 2017) It is not clearly understood, at the intraannual level, how the many climatic factors affecting wood formation operate at the anatomical level (Olano et al 2012). The occurrence of IADFs is not straightforward, since their formation is climate driven, and influenced by

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