Forest structure of Mediterranean yew (Taxus baccata L.) populations and neighbor effects on juvenile yew performance in the NE Iberian Peninsula

Abstract

<p class="Cos"><em>Aim of study: </em>In the Mediterranean region, yew (<em>Taxus baccata</em> L.) usually grows with other tree species in mixed forests. Yew recruitment and juvenile growth may depend on the structure of the forest and the net balance between competition for soil water and nutrients with neighbors and facilitation that these neighbors exert by protecting the plants from direct sun exposure. This study aims, at a regional scale, to analyze the structure of forests containing yew, and, on an individual level, to analyze the effect of the surrounding vegetation structure on the performance of yew juveniles.</p><p class="Cos"><em>Area of study: </em>The structural typologies of yew populations were defined based on field inventories conducted in 55 plots distributed in 14 localities in the North-Eastern (NE) Iberian Peninsula, covering a wide range of yew distribution in the area. In a second step, an analysis of neighboring species' effects on juveniles was conducted based on the data from 103 plots centered in yew juveniles in five localities.<em></em></p><p class="Cos"><em>Main Results: </em>A cluster analysis classified the inventoried stands into four forest structural types: two multi-stratified forests with scattered yew and two yew groves. Multiple regression modeling showed that the δ<sup>13</sup>C measured in last year's leaves positively relates to the basal area of conifer neighbors, but negatively with the cover of the yew crown by other trees.</p><p class="Cos"><em>Research highlights: </em>At a stand-level, the density of recruits and juveniles (625 ± 104 recruits ha<sup>-1</sup>, 259 ± 55 juveniles ha<sup>-1</sup>) in mixed forests was found to be higher than that on yew dominant stands (181 ± 88 recruits ha<sup>-1</sup> and 57 ± 88 juveniles ha<sup>-1</sup>). At an individual-level, the water stress (estimated from leaf δ<sup>13</sup>C) of yew juveniles seems alleviated by the crown cover by neighbors while it increases with the basal area of conifers. Yew conservation should focus on selective felling for the reduction of basal area of neighbors surrounding the target tree, but avoid affecting the canopy cover to contribute to enhanced yew juvenile growth.</p><p class="Cos"><strong>Keywords: </strong>Biodiversity conservation; δ<sup>13</sup>C; forest management; plant-plant interaction; recruitment; <em>Taxus baccata</em>; water use efficiency.</p>

A study of late Holocene local vegetation dynamics and responses to land use changes in an ancient charcoal making woodland in the central Pyrenees (Ariège, France), using pedoanthracology

“…1c, 5). Yew, an evergreen non-resinous gymnosperm tree is a European native species, with an ecological niche restricted to regions with mild winters and high rainfall, but it is well adapted to a range of edaphic conditions (Thomas and Polwart 2003;Casals et al 2015). Leuthold (1998) The high degree of hyphal infestation observed in the charcoal from all pits could show the burning of dead wood, either from standing trees or on the ground and/or ageing mature trees several centuries old (Fig.…”

Impact of long and short-term conservation periods on structure of English yew (Taxus baccata L.) in Arasbaran forests, Iran

“…Other studies have emphasized the importance of conservation in the improvement of the quantitative indices of the stand (Ghanbari Sharafeh et al 2010;Devaney et al 2014;Casals et al 2015;Dobrowolska et al 2017;Jafari Afrapoli et al 2018). In northwestern Iran, the proximity of the village affects access of local people to tree stands at the sites we studied.…”

“…Interest in yew conservation has been prevalent throughout Europe in recent years (Devaney et al 2014;Casals et al 2015;Dobrowolska et al 2017). Conservation-based management practices like selective stand thinning to reduce the basal area of other species is one approach that may be effective at increasing yew prevalence throughout forest systems (Dobrowolska et al 2017).…”

Patterns of density and structure of natural populations ofTaxus baccatain the Hyrcanian forests of Iran

“…To date, some studies of the stand structure of yew have been conducted in different regions of the world, and these all demonstrating the importance of the structure of natural stands (Iszkuło and Boratyński , Iszkulo et al , Dobrowolska et al , Casals et al , Vessella et al , Ghanbari et al ). Most of these studies, however, have used measures that quantify forest structures at very local scales.…”