Adaptive management and debarking schedule optimization of Quercus suber L. stands under climate change: case study in Chamusca, Portugal

Abstract

Cork oak stands are one of the major sources of income from Portuguese Mediterranean forests. Future climate is projected to increase temperatures, reduce precipitation and decrease current forests’ productivity and therefore, adapting management, is a key strategy to mitigate impacts of future climate on cork supply. The central objective of this research was to compare conventional and adaptive management regimes under scenarios of climate change. The adaptive management focussed on adopting optimal harvest schedules while considering different management objectives. The study focused on the Chamusca region, one of the most productive areas of cork, and considered four distinct spatial scales for analysis. For each scale, the management objective was defined according to field information and considered the maximization of cork production while targeting different cork harvesting flows: (a) more frequent and regular or (b) less frequent and concentrated. A forest growth model was used to simulate climate change impact on future yield of cork oak stands under different forest management alternatives. A mixed integer programming model was developed to find the most adequate cork debarking cycle calendar for cork oak stands. Our results suggest that (1) business as usual management under climate change scenarios could decrease cork supply and carbon stock in the tree component of the forests by up to 20 and 30 %, respectively, (2) the development of adaptive management strategies, including cork extraction schedule optimization, to address climate change has advantages over traditional practices and (3) may contribute further to increase cork production (up to double productivity in mid-long term) while addressing concerns with the regulation of cork extraction flows through the adaptation of debarking periods. The mixed integer programming allowed the spatial visualization of the debarking cycle delay. Furthermore, results underline the relevance of an approach to develop adaptive management strategies that can consider different management goals, with different constraints to address climate change.