Effects of Topography on Radial Growth of Tree Species with Different Mycorrhizal Types

In the dynamic monitoring fixed sample plot of 25 ha of coniferous broad-leaved mixed forest in the temperate zone of Northeast China, we used the data from two surveys (2013 and 2018) and microtopography data of the sample plot, and the mycorrhizal type data of tree species to explore whether the different microtopography types and single terrain factors will affect the radial growth of tree species with different mycorrhizal types on a regional scale. We studied the adaptability of tree species with different mycorrhizal types in the north end of Changbai Mountain and the south slope of Laoyeling mountain, and which provided basis for further revealing the response mechanism of tree species with different mycorrhizal types to the microtopography in this area. We found that: the tree species with different mycorrhizal types have higher radial growth rates on gentle slopes than on steep slopes. Tree species on sunny slopes have higher growth rates and survival rates than tree species of the same mycorrhizal type on shady slopes. The quantity and radial growth of AM (Arbuscular mycorrhiza) type, EcM (Ectomycorrhiza) type, and ErM (Ericoid mycorrhiza) type tree species were significantly positively correlated with different microtopography types. The quantity and radial growth of AM type tree species and EcM type tree species were significantly positively correlated with slope. The quantity of AM type tree species, EcM type tree species and the radial growth of EcM type tree species were significantly negatively correlated with slope aspect. The quantity and radial growth of ErM type tree species and radial growth of EcM type tree species the were significantly positively correlated with slope position. We believe that the reasons for these conclusions may be caused by the differences in soil temperature, humidity, and water distribution caused by different slopes.