Contribution of environmental factors to post-typhoon litterfall stability in subtropical montane cloud forests of the Asia-Pacific region
Journal
Forest Ecology and Management
Journal Volume
558
Date Issued
2024-04-15
Author(s)
Abstract
Tropical cyclones are primary perturbations in some tropical/subtropical regions, and Taiwan is one of the most frequently perturbed tropical cyclone (named “typhoon” in the region) areas in the world. Assessing ecological stability is challenging due to the high temporal frequency of typhoon occurrence. Surprisingly, there was a rare nontyphoon year in 2018. Along with regular (2017) and extreme (2016) typhoon years, these three years’ data permit the study of forest stability. We used post-typhoon season (November and December) mean monthly litterfall (MML) to assess factors influencing ecosystem recovery in subtropical montane cloud conifer forests in Chilan Mountain in northeast Taiwan. Previous studies of the same region during the observation period (2016–2018) found no difference in post-typhoon MML in recent years regardless of the severity of typhoon perturbations; here, we further investigated the factors stabilizing the post-typhoon MML. We investigated relationships among 17 forest biophysical, bioclimatic and topographic attributes of 15 field plots derived from field measurements and airborne lidar (light detection and ranging), and the corresponding MML using partial least squares regression to minimize the effect of variable multicollinearity. Additionally, we also compared long-term (1984–2019) satellite post-typhoon season greenness (the Enhanced Vegetation Index, EVI) time series with different degrees of typhoon perturbations occurred in the typhoon season of the region (June-October) to examine if the observed MML stability can also be found at the stand canopy abundance over a longer temporal extent. We found that the attributes related to forest stand maturity (mean and standard deviation of tree height), slope and wind exposedness may be crucial in maintaining the stability of post-typhoon MML regardless of the occurrence of typhoons in the previous months. Tree density and southwestness (related to solar radiation intensity) played additional roles in facilitating post-typhoon MML after the extreme typhoon. These results indicate that multiple biotic and abiotic factors might alleviate the effects of typhoons. Finally, no differences existed in the long-term post-typhoon season EVI, further highlighting the stability of canopy greenness. The findings may indicate the high stability (possibly high resilience) of montane cloud forests in this typhoon-prone ecoregion.
Subjects
disturbance | extreme meteorological event | Landsat | topography | tree density | tree height
Type
journal article