Survival Rate, Chemical and Microbial Properties of Oak Seedlings Planted with or without Oak Forest Soils in a Black Locust Forest of a Dryland

Chikae Tatsumi,Fujio Hyodo,Takeshi Taniguchi,Sheng Du,Ryunosuke Tateno,Norikazu Yamanaka

doi:10.3390/f12060669

Abstract

Native tree species are frequently unable to effectively grow in non-native tree cultivation scenarios. In the Loess Plateau, China, it is difficult to find native oak (Quercus liaotungensis) seedlings in non-native black locust forests. Black locust is an arbuscular mycorrhizal (AM) tree, but oak is an ectomycorrhizal (ECM) tree. Plants highly depend on their symbiotic mycorrhizal fungi to take up water, nitrogen (N) and other nutrients. We hypothesized that black locust forests would not provide ECM inoculum to oak seedlings, limiting their water and nutrient uptake, which would be improved by ECM inoculum. Here, we (1) sowed seeds, with or without oak forest soils, (2) transplanted seedlings collected in oak forests, with or without oak forest soils, and (3) planted seedlings germinated in autoclaved or unautoclaved oak forest soils. We measured the survival and growth rate for all three experiments, along with chemical properties, and root ECM colonization. Oak seeds sowed with oak forest soils had higher mycorrhizal colonization, leaf N concentrations and survival rate, and lower root δ13C than the seeds sowed without oak forest soils. Planting with oak forest soils also increased the survival rate of the germinated seedlings, but not the transplanted seedlings. Overall, our study suggested that the use of oak forest soils in the black locust forest to improve the water and N uptake of oak seedlings by providing the ECM inoculum, resulting in a high survival rate. Our study also implies that the method of sowing seeds was effortless and effectively compared to transplanting wild/nursery seedlings.

Highlights

There are many reports around the world of forests dominated by non-native trees due to either plantation or invasion, and the replacement of native trees is needed for ecological balance [1,2,3]
This study was conducted in a black locust (Robinia pseudoacacia) forest and an oak (Quercus liaotungensis) forest in the central part of the Loess Plateau of China
The timing of the planting of the seedlings in Experiment 2 could have affected the survival rate; seedlings were not planted in the best season, as early spring is typically better for the planting of seedlings

Summary

Introduction

There are many reports around the world of forests dominated by non-native trees due to either plantation or invasion, and the replacement of native trees is needed for ecological balance [1,2,3]. In many cases, native tree species cannot grow well under nonnative cultivations [4,5,6]. There are many studies which have investigated the reasons behind the inability of native tree species to grow in non-native tree plantations, but the reasons for slow succession are various, making management difficult. To achieve a better understanding of these implications, more case studies are needed to investigate the chemical and microbial properties of seedlings and soils. Since natural succession is sometimes very slow, especially in drylands [8,9], making it an inefficient, difficult, and expensive management strategy in some countries, it is important to develop an easy way to grow these native seedlings which incorporates the understanding of the chemical and microbial properties of the seedlings

Methods

Results

Discussion

Conclusion