What Might a Sustainable Population of Trees in Wood-Pasture Sites Look Like?

Abstract

Wood-pastures are important for their open-ground biodiversity and for the old trees they contain. However, younger trees to replace the current generation of old trees are often scarce, a potential threat to the future of the habitat mosaic and of species dependent on the trees. A simple model was used to illustrate how many younger trees might be expected under different assumptions of desired final density of old trees and rates of loss as trees age for an oak-dominated wood-pasture. From these the overall canopy cover of the landscape was estimated under an active pollarding regime and where the trees grow to full crown size. Canopy cover was often five times as great under full crown as under a pollarding regime; much of the canopy cover was in the younger (often missing) cohorts. The openness of current wood-pastures is in part a consequence of the absence of a sustainable tree population structure. Some protected sites may be too small to allow space for the missing generation of trees and at the same time retain current levels of openness. Analogies between current wood-pasture structures and ‘natural wood-pastures’ of the pre-Neolithic era must take account of the missing generations of trees.

The effects of different canopy covers on the herb layer in the forest-steppes of the Grazer Bergland (Eastern Alps, Austria)

“…Breshears, 2006;Kirby, 2015). In particular, the coexistence of the woody and herbaceous species raises important questions concerning spatial heterogeneity and temporal dynamics (House et al, 2003).…”

Environmental determinants of the old oaks in wood-pastures from a changing traditional social–ecological system of Romania

“…These trees are often older than many old buildings from the villages, which are considered cultural heritage elements. The long term sustainability of the old trees should be in the hearth of the farmland biodiversity conservation policies (Kirby 2015).…”

“…With this study we aim to start filling this gap, by presenting the environmental factors affecting the number of old oaks in wood-pastures from a changing traditional cultural landscape from Central Romania. We selected wood-pastures because these landscape elements typically contain larger number of old trees than other managed ecosystems from the same region Butler 2014;Kirby and Perry 2014;Kirby 2015). Moreover, while wood-pastures, ancient wood-pastures in particular, went through sharp decline in most of Europe (Bergmeier et al 2010;Hartel and Plieninger 2014;Plieninger et al 2015), they are still well represented in the traditional landscapes from our region .…”

“…The approach adopted by us is commonly used in landscape ecological studies exploring the relationship between organismal occurrence and abundance and the habitat-and landscape features (e.g., amphibians -Ficetola et al 2009, birds-Dorresteijn et al 2013, plants and butterflies-Loos et al 2014, 2015. All these variables can be considered as proxies for human impact in cultural landscapes, like the historical landscapes from Southern Transylvania (see below).…”

Historical maps confirm the accuracy of zero‐inflated model predictions of ancient tree abundance in English wood‐pastures

“…In addition, there is a lack of tree planting and appropriate management to ensure the continuity and replacement of ancient tree populations and dead-wood habitats (Read, 2000). To add to this, wood-pasture is also considered an increasingly threatened habitat, particularly across Europe (Forejt et al, 2017;Hartel & Plieninger, 2014), where overgrazing, the decline of old trees, and land-use intensification and conversion are having major impacts (Kirby, 2015). Additionally, although the connection between wood-pasture and ancient trees is generally agreed upon, few studies, with the exception of Hartel et al (2013Hartel et al ( , 2018 and Moga et al (2016) in Romania, have investigated the true abundance or distribution of ancient trees within wood-pastures at an international or even a national scale.…”