Abstract:
Objective To explore the needle functional traits, understory species diversity and understory soil factors of different forest types (Pinus thunbergia pure forest, Pinus thunbergia -Robinia pseudoacacia mixed forest, Pinus thunbergia -Quercus acutissima mixed forest) for providing basis and reference for the construction and management of Pinus thunbergia in the coastal shelter forest.
MethodsBased on Pinus thunbergia in the coastal shelter forest of Muping, Yantai, the needles and understory 0~20cm soil samples of Pinus thunbergia were collected, and the understory species diversity was investigated. The related functional traits of needles and soil physical and chemical properties were measured, and the understory species diversity index was calculated. Also the effects of understory soil factors on needle functional traits and understory species diversity were analyzed by RDA.
Results(1) Different stand types had significant effects on leaf structural traits such as leaf area (LA), leaf length (LL), specific leaf area (SLA), specific leaf weight (SLW), leaf dry matter mass (LDMC) and leaf water content (LWC), while only C and N contents were significantly affected by leaf chemical traits. (2) Different stand types had significant effects on understory vegetation diversity indexes. Simpson index was the highest in the Pinus thunbergia -Quercus acutissima mixed forest, Shannon-Wiener index, Margalef index and Pielou index were the highest in the Pinus thunbergia -Robinia pseudoacacia mixed forest, and all indexes were the lowest in the Pinus thunbergia pure forest. Digitaria sanguinalis and Pennisetum alopecuroides were dominant in each community. (3) Different stand types had significant effects on soil EC, SOC, TN, NO3−-N, NH4+-N and AK. (4) SOC, AK and NH4+-N had significant effects on leaf functional traits and understory species diversity, while TP and NO3−-N had significant effects on functional traits and species diversity, respectively.
Conclusion Under the experimental conditions, the functional traits of Pinus thunbergii needles and the diversity of understory species under different stand types have certain responses to the understory soil factors. The construction and management of shelterbelt should comprehensively consider the role of stand type, understory vegetation and soil nutrients.