武夷山米槠林群落凋落物动态及与气象因子的关系

Litter Dynamics and Its Relationship with Meteorological Factors in Castanopsis carlesii Forest Community in Wuyi Mountain

为探索森林凋落物动态及与气象因子间的关系,选择武夷山米槠林群落为研究对象,于2016—2019年对其凋落物量和气象因子开展为期4a的定位监测,探索凋落物量的季节格局及其气象影响因子。结果表明:米槠林群落年均凋落物量为(487.24±11.63) g/(m^(2)·a),其中落叶是米槠林群落凋落物中的绝对优势组分,占凋落物总量的(77.03±1.93)%;其次为落枝和碎屑组分,繁殖器官仅占(1.15±0.17)%。米槠林群落凋落物总量和落叶年内动态模式呈双峰曲线,峰值和次峰值分别出现在4月和11月。而落枝和凋落碎屑年内出现3次峰值,谷值均出现在8月;凋落繁殖器官主要集中在4—7月和10—12月,这与其物候节律相关。除凋落繁殖器官与落叶、落枝未达到显著相关,其他凋落物不同组分间均显著相关。月凋落物量与当月降水量、日最大降水量及其太阳辐射显著相关,而与当月气温和风速无显著相关。然而,月凋落物量与当月前2~4个月的最高气温、最低气温和平均气温显著正相关。因此,基于长期凋落物动态的数据分析有利于更好地理解在气候变化背景下森林生态系统功能变化。

To explore the relationship between the dynamics of forest litter production and meteorological factors. In Castanopsis carlesii forest community in Wuyi Mountain, we have monitored forest litter production and meteorological factors for 4 years from 2016 to 2019, and explored seasonal pattern of litter production and its driving factors. The findings indicated that the average annual litter production of C. carlesii forest was(487.24 ±11.63) g/(m^(2)·a), in which leaf litter accounted for 77.03% ± 1.93% of the total litter, followed by twig and fragment litter, and reproductive organ litter only accounted for 1.15% ± 0.17%, indicating that leaf litter was the dominant component in C. carlesii forest litters. Seasonal patterns of total litter and leaf litter displayed a bimodal curve in this C. carlesii forest, and the peak value and the sub-peak value appeared in April and November, respectively. The peak values of twigs and fragment litter appeared 3 times within a year, and their valley values appeared in August. Reproductive organs litter was mainly concentrated in 2 periods from April to July and from October to December, associated with tree phenological rhythm. Litter components displayed the significant correlations, except for between reproductive organ litter and leaf, twig litter. Monthly litter productions were significantly correlated with precipitation, daily maximum precipitation and solar radiation in monitoring month, but had no significant correlation with air temperature and wind speed in monitoring month. However, litter productions were significantly positively correlated with maximum, minimum and average air temperature before 2-4 months. Therefore, data analyses on long-term forest litter production dynamics have important implications for better understanding the variations in forest ecosystems function under climate changes.