Spatial Variability of Throughfall in a Larch (Larix gmelinii) Forest in Great Kingan Mountain, Northeastern China

Abstract

Larix gmelinii forest is one of the dominant forest types in boreal forest and plays a unique eco-hydrological role in the terrestrial ecosystem. However, the throughfall variability in boreal forest ecosystems, which plays a crucial role in regulating hydrology, remains unclear. Here, we investigated the spatial variability and temporal stability of throughfall within a Larix gmelinii forest in the full leaf stage in Great Kingan Mountain, Northeast China, and the effects of rainfall properties and canopy structure on throughfall variability were systematically evaluated. The results indicate that throughfall represented 81.26% of the gross rainfall in the forest. The throughfall CV (coefficient of variation of throughfall) had a significant and negative correlation with the rainfall amount, rainfall intensity, rainfall duration, and distance from the nearest trunk, whereas it increased with increasing canopy thickness and LAI (leaf area index). The correlation analysis suggested that the throughfall variability was mainly affected by the rainfall amount (R2 = 0.7714) and canopy thickness (R2 = 0.7087). The temporal stability analysis indicated that the spatial distribution of the throughfall was temporally stable. Our findings will facilitate a better understanding of the spatiotemporal heterogeneity of throughfall and help the accurate assessment of throughfall and soil water within boreal forests.

Effects of Trunk Distance and Rainfall on Throughfall and Associated Chemical Alterations within a Subtropical Deciduous Forest

“…Although we have detected the effect of distance from the tree trunk on throughfall water and chemical components, other canopy structure factors, such as canopy cover and leaf area index over each throughfall collector, were not considered in this study. Some previous studies have shown that canopy cover or leaf area index have an impact on the spatial variations in throughfall and chemical deposition on a small spatial scale [23,24], while some other studies found that the leaf area index had no impact on the spatial distribution of throughfall amount, but had a great effect on throughfall deposition [19]. These results suggest that the complex canopy structures and largely different nutrient statuses among different tree species led to these opposite relationships.…”

“…The relationships between the spatial variability in throughfall and trunk distance have been widely reported under different forest canopies [6,19], but there are significant differences among different forest systems. For example, there was a positive relationship between throughfall amount and distance from the trunk in a Larix gmelinii forest in northeastern China [23], while there was a negative relationship in a Pinus massoniana plantation in the subtropical area of southern China [31], and no significant correlation in a Pinus sylvestris L. stand with an admixture of Quercus petraea, Betula pendula Roth, and Sorbus aucuparia L. in central Poland [19]. Moreover, throughfall volume increased with distance from the trunk during summer, but decreased during winter in a mature Fagus sylvatica L. forest stand in northeastern Germany [6], which could be attributed to leaved or leafless periods.…”

“…Refs. [6,8,[12][13][14][15][18][19][20][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] have been cited in the supplementary materials.…”

“…Distance from the tree trunk is one of the most important canopy structure factors that influence throughfall variability [19,22]. Numerous studies have explored the relationship between throughfall amounts and distance from the tree trunk, e.g., [6,8,[12][13][14][15][18][19][20][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. As shown in Table S1, there are differences in this relationship among different forest types and tree species.…”