Forest Modelling Lab., Institute for Agriculture and Forestry Systems in the Mediterranean, National Research Council of Italy (CNR-ISAFOM), Via Madonna Alta 128, 06128, Perugia, Italy; geoLAB - Laboratory of Forest Geomatics, Dept. of Agriculture, Food, Environment and Forestry, Università degli Studi di Firenze, Via San Bonaventura 13, 50145, Firenze, Italy.
Forest Modelling Lab., Institute for Agriculture and Forestry Systems in the Mediterranean, National Research Council of Italy (CNR-ISAFOM), Via Madonna Alta 128, 06128, Perugia, Italy; National Biodiversity Future Centre (NBFC), Piazza Marina 61, 90133, Palermo, Italy.
J Environ Manage. 2024 Aug;366:121822. doi: 10.1016/j.jenvman.2024.121822. Epub 2024 Jul 16.
Stand age significantly influences the functioning of forest ecosystems by shaping structural and physiological plant traits, affecting water and carbon budgets. Forest age distribution is determined by the interplay of tree mortality and regeneration, influenced by both natural and anthropogenic disturbances. Unfortunately, human-driven alteration of tree age distribution presents an underexplored avenue for enhancing forest stability and resilience. In our study, we investigated how age impacts the stability and resilience of the forest carbon budget under both current and future climate conditions. We employed a state-of-the-science biogeochemical, biophysical, validated process-based model on historically managed forest stands, projecting their future as undisturbed systems, i.e., left at their natural evolution with no management interventions (i.e., forests are left to develop undisturbed). Such a model, forced by climate data from five Earth System Models under four representative climate scenarios and one baseline scenario to disentangle the effect of climate change, spanned several age classes as representative of the current European forests' context, for each stand. Our findings indicate that Net Primary Production (NPP) peaks in the young and middle-aged classes (16- to 50-year-old), aligning with longstanding ecological theories, regardless of the climate scenario. Under climate change, the beech forest exhibited an increase in NPP and maintained stability across all age classes, while resilience remained constant with rising atmospheric CO and temperatures. However, NPP declined under climate change scenarios for the Norway spruce and Scots pine sites. In these coniferous forests, stability and resilience were more influenced. These results underscore the necessity of accounting for age class diversity -lacking in most, if not all, the current Global Vegetation Models - for reliable and robust assessments of the impacts of climate change on future forests' stability and resilience capacity. We, therefore, advocate for customized management strategies that enhance the adaptability of forests to changing climatic conditions, taking into account the diverse responses of different species and age groups to climate.
林龄通过塑造结构和生理植物特征来显著影响森林生态系统的功能，影响水和碳预算。森林年龄分布由树木死亡和再生的相互作用决定，受自然和人为干扰的影响。不幸的是，人为改变树木年龄分布是增强森林稳定性和恢复力的一个未被充分探索的途径。在我们的研究中，我们研究了年龄如何影响当前和未来气候条件下森林碳预算的稳定性和恢复力。我们使用了一种基于科学的生物地球化学、生物物理、经过验证的基于过程的模型，对历史管理的森林林分进行了研究，将它们作为未受干扰的系统进行预测，即让它们自然进化，不进行任何管理干预（即，让森林不受干扰地发展）。该模型根据五个地球系统模型的气候数据进行驱动，在四个代表性气候情景和一个基准情景下进行模拟，以区分气候变化的影响，跨越了几个年龄组，以代表当前欧洲森林的情况，对于每个林分。我们的研究结果表明，净初级生产力（NPP）在年轻和中年（16 至 50 岁）的林龄中达到峰值，这与长期以来的生态理论一致，无论气候情景如何。在气候变化下，山毛榉林表现出 NPP 的增加，并在所有年龄组中保持稳定，而随着大气 CO 和温度的升高，恢复力保持不变。然而，云杉和挪威松林的 NPP 在气候变化情景下下降。在这些针叶林中，稳定性和恢复力受到更大的影响。这些结果强调了考虑年龄组多样性的必要性——目前的大多数（如果不是全部）全球植被模型都缺乏这一点——以便对气候变化对未来森林稳定性和恢复力的影响进行可靠和稳健的评估。因此，我们提倡采用定制的管理策略，提高森林对气候变化的适应能力，同时考虑到不同物种和年龄组对气候的不同反应。
