Modeling forest plantations for carbon uptake with the LPJmL dynamic global vegetation model
Modeling forest plantations for carbon uptake with the LPJmL dynamic global vegetation model
复制标题
DOI：
10.5194/esd-10-617-2019
复制
发表时间：
2019-10-15
影响因子：
7.3
通讯作者：
van Vuuren, Detlef P.
中科院分区：
文献类型：
--
作者：
Braakhekke, Maarten C.;Doelman, Jonathan C.;van Vuuren, Detlef P.
我们提出了一个动态全球植被模型的扩展，Lund-Potsam-Jena管理土地(LPJML)，以模拟用于碳(C)固定的人工林。我们实现了三种功能类型来模拟温带、热带和北方气候中的种植园树木。这些功能类型的参数被优化以拟合目标生长曲线(TGC)。这些曲线代表了典型人工林中树干C随时间的演变，是通过结合实地观察和LPJML对同等天然林的估计得出的。虽然校准后的模型低估了与TGC相比的树干C增长率，但与使用天然林代表植树造林相比，它代表了实质性的改善。基于模拟实验，我们比较了全球天然林和全球森林人工林，我们发现，在100年的时间尺度上，森林人工林允许更大的碳吸收速率，最大差异为1.9倍，约为54年。在随后对一个雄心勃勃但现实的情景进行的模拟中，650 MHA(占全球管理土地的14%，占全球陆地表面的4.5%)在85年内被转化为森林，我们发现天然林占37PGC，而森林种植园占48PGC。将这些结果与实现2摄氏度气候目标所需的碳固存估计进行比较，我们得出结论，植树造林可以为气候缓解做出重大贡献。对作为气候变化缓解战略的植树造林进行全面评估需要进行综合评估，其中考虑到所有相关方面，包括成本、生物多样性以及与其他土地利用类型的权衡。我们的扩展版本的LPJML可以通过改进对森林种植园的碳吸收速率的估计来为这种评估做出贡献。
We present an extension of the dynamic global vegetation model, Lund-Potsdam-Jena Managed Land (LPJmL), to simulate planted forests intended for carbon (C) sequestration. We implemented three functional types to simulate plantation trees in temperate, tropical, and boreal climates. The parameters of these functional types were optimized to fit target growth curves (TGCs). These curves represent the evolution of stemwood C over time in typical productive plantations and were derived by combining field observations and LPJmL estimates for equivalent natural forests. While the calibrated model underestimates stemwood C growth rates compared to the TGCs, it represents substantial improvement over using natural forests to represent afforestation. Based on a simulation experiment in which we compared global natural forest versus global forest plantation, we found that forest plantations allow for much larger C uptake rates on the timescale of 100 years, with a maximum difference of a factor of 1.9, around 54 years. In subsequent simulations for an ambitious but realistic scenario in which 650 Mha (14% of global managed land, 4.5% of global land surface) are converted to forest over 85 years, we found that natural forests take up 37 PgC versus 48 PgC for forest plantations. Comparing these results to estimations of C sequestration required to achieve the 2 degrees C climate target, we conclude that afforestation can offer a substantial contribution to climate mitigation. Full evaluation of afforestation as a climate change mitigation strategy requires an integrated assessment which considers all relevant aspects, including costs, biodiversity, and trade-offs with other land-use types. Our extended version of LPJmL can contribute to such an assessment by providing improved estimates of C uptake rates by forest plantations.