Above-ground carbon storage in Pinus pumila along an alpine altitude in Khingan Mountains, Inner Mongolia of China

The carbon (C) cycle in alpine ecosystems is sensitive to climate change, but information about the C storage in its undergrowth is scarce. In October 2017, a total of 6231 Pinus pumila (Pall.) Regel trees were investigated for above-ground growth and density in 60 sub-plots (10×10 m) from 12 stands (50 × 50 m) along the altitudinal gradient (800-1500 m a.s.l.) in Great Khingan Mountains, Inner Mongolia, Northeast China. Sites were characterized by different crown densities (CDs) from 20% to 90%. Height and root-collar diameter (RCD) were higher in stands with CDs of 40-70% than CDs of 20-30%. Stem density (SD) and crown area (CA) had a positive correlation with altitude and CD. Equations from local shrub models were used to adapt the allometric growth models for estimation. There were variations in estimated above-ground C density depending on the model and the involvement of the canopy area. Above-ground C storage in P. pumila individuals ranged from 0.05-2.46 kg tree-1, which corresponds to C storage density ranged from 0.17-37-ton ha-1. The C density in P. pumila increased with crown density instead of stem density along increasing altitudinal gradients and increasing RCD. Hence, the crown density and diameter of a P. pumila plant can be used to predict the above-ground C density of its natural population.

Ectomycorrhizal fungal communities associated with Larix gemelinii Rupr. in the Great Khingan Mountains, China

Larix gemelinii is an important tree species in the Great Khingan Mountains in Northeast China with a high economic and ecological value for its role in carbon sequestration and as a source of lumber and nuts. However, the ectomycorrhizal (EM) fungal diversity and community composition of this tree remain largely undefined. We examined EM fungal communities associated with L. gemelinii from three sites in the Great Khingan Mountains using Illumina Miseq to sequence the rDNA ITS2 region and evaluated the impact of spatial, soil, and climatic variables on the EM fungal community. A total of 122 EM fungal operational taxonomic units (OTUs) were identified from 21 pooled-root samples, and the dominant EM fungal lineages were /tricholoma, /tomentella-thelephora, /suillus-rhizopogon, and /piloderma. A high proportion of unique EM fungal OTUs were present; some abundant OTUs largely restricted to specific sites. EM fungal richness and community assembly were significantly correlated with spatial distance and climatic and soil variables, with mean annual temperature being the most important predictor for fungal richness and geographic distance as the largest determinant for community turnover. Our findings indicate that L. gemelinii has a rich and distinctive EM fungal community contributing to our understanding of the montane EM fungal community structure from the perspective of a single host plant that has not been previously reported.

Method on Distinguishing Permafrost and Talik Regions in the Great Khingan Mountains by Analyzing the Characteristics of Specific Plants

In the fieldwork in the Great Khingan Mountains, it is practical and easy to distinguish permafrost region or talik region by analyzing the characteristics of the plants growing on them. Generally speaking, permafrost there tends to degenerate from south to north, but there are some individual places where remind original ecology of permafrost. After permafrost degenerate into the talik region, the condition of plant growth has changed. We can distinguish permafrost and talik region by the difference of plants growing status there. Some common species that specifically grow in permafrost or talik region have also been listed and introduced in this paper. Specifically, plants growing in permafrost region include larix gmelini, birch, vaccinium uliginosum, ledum palustre, vaccinium vitis-idaea, bilberry, pinus sylvestnis var. mongolica litv, low birch thicket, adina racemosa and so on. Meanwhile the plants live in talik region include peridium aquilinum, xylosma racemosum, daylily, milkvetch. The list of plants can be used to distinguish permafrost region and talik in the field. It is crucial for constructions to recognize if the construction area is permafrost or talik region. The change of talik has its two sides to constructions. On the upside, it can increase groundwater storage, and we can regard the future projects as thawing projects. On the downside, existing projects would arise thawing settlement.