Pollarded forests of narrow-leaved ash trees constitute silvopastoral systems of important cultural and environmental interest and configure landscapes with great conservation values in Central Spain. In a recent study, we reconstructed the historical patterns of pruning management since the 18th century by identifying sudden growth changes and anatomical markers through dendrochronological analysis. Tree-ring growth revealed traditional management cessation in 1970 and property-specific management patterns.
Tree pollarding was a dominant management strategy of European forests for centuries creating open agroforestry landscapes with unquestionable cultural and environmental values. This traditional practice has been widely abandoned in last decades with a subsequent impact in terms of biodiversity and cultural loss.
Central Spain hosts the largest and best-preserved area of pollarded narrow-leaved ash (Fraxinus angustifolia) woodlands in Europe. These trees have traditionally been pruned to use fodder as food for livestock during summer season. However, there are no rigorous historical records of the variation patterns of this silvicultural treatment.
In this article published in Trees – Structure and Function, we used dendrochronological techniques to evaluate temporal changes of pollarding frequency and rotation length. We analysed the stand level synchrony and the effect of land property (public vs. private) on pollarding activity in several stands in Central Spain. Pollarding events were unequivocally identified at tree level by a characteristic change in growth pattern, with the first event dated in 1777 and getting a reconstruction of approximately 250 years of pollarding events.
Historical pruning recurrence ranged between 5 and 10 years with higher pollarding frequency on private lands. Additionally, pruning events within each site were synchronous, suggesting the existence of a rotational schema within each stand. This forest exploitation collapsed in the 1970s matching with the depopulation of rural areas and the general abandonment of traditional practices. However, after several decades of almost no pollarding activity, pruning has recovered due to economic and/or conservational purposes albeit with much lower intensity and lacking the synchronic historical patterns.
250-Year reconstruction of pollarding events reveals sharp management changes in Iberian ash woodlands
Providing technical and economic support to make this traditional activity profitably would have strong environmental revenue due the multiple ecosystem services provided by pollarded ashes. Moreover, supporting this recovery would have multiple benefits, but may also contribute to the reduction of the environmental impact of meat production, one of the largest greenhouse gas emission issues.