# Short-Term Effects of Pine Plantations on Vegetation and Soil in Northern Mongolia
## 3 Results  
### Understory Vegetation Composition and Its Change  
Understory vegetation was comprised of 92 species of plants, including 4 shrubs, 1 semi-shrub, species, and 84 herb species (5 annuals and 87 perennials) belonging to 78 genera of 35 families. The dominant families were Asteraceae (15 species, 16.3%), Rosaceae (10 species, 10.8%), Ranunculaceae, Poaceae, and Fabaceae (each with 7 species, 7.6%) followed by Lamiaceae (4 species, 4.3%), Iridaceae (3 species, 3.3%), and Caryophyllaceae (3 species, 3.3%). Dominant species were mesophytes (36 species, 39.1%), xerophytes (30 species, 32.6%), petrophytes (4.35%), and gigrophytes (1.08%). Mesophyte species dominated in the plantations (BBS 50%, MGS 56.7%, BDS 52%) and the naturally regenerated stand (NRS 52%); xerophytes were greater in the natural forest edge (NFM 52.6%) and the steppe (STP 46.9%) plots (Table S1). Species richness was significantly different between the six plots (\(p=0.0352\)), with higher total values registered in BBS (32 species) and the lowest total richness and cover detected in the NRS (8 species). Total plant coverage was significantly different (\(p=0.0001\)); BBS had the greatest (58.5%) and MGS had the lowest (26.5%) cover (Figure 3). Above-ground (AGB) and below-ground (BGB) biomass accumulation was highest in BBS (AGB = 1159.6 g m\({}^{-2}\), BGB = 3325 g m\({}^{-2}\)). The lowest above-ground biomass was observed in the NRS (AGB = 44.0 g m\({}^{-2}\)) and the lowest below-ground biomass was observed in BDS (BGB = 137.0 g m\({}^{-2}\)) (Figure 4). There were few significant correlations between stand characteristics and species richness, plant coverage, and above- and below-ground biomass (Table 2). Tree crown length and tree height were positively correlated with above- and below-ground biomass but negatively correlated with crown projection area. Correlations between the soil pH and bulk density understory biomass were negative (Table 3). Soil moisture was positively correlated with plant cover in the naturally regenerated (NRS) plot, species richness in the near forest (NFM) plot, and above-ground biomass in the steppe plots (STP). Plant coverage was negatively correlated with the soil pH, bulk density, and soil moisture at the NRS plot. Soil organic carbon was positively correlated with above-ground biomass in the steppe plot. Figure 4: The graphs show a consistent ratio between above- and below-ground biomass across plots and indicate variability or standard error for each plot. (**A**) Y-axis is above-ground biomass (gm\({}^{-2}\)), ranging from 0 to 140, (**B**) Y-axis: below-ground biomass (gm\({}^{-2}\)), ranging from 0 to 4000 and X-axis: different plot types: BBS, MCS, BDS, NRS, NFM, and STP. Figure 3: The graphs demonstrate the relationship between species richness and plant coverage percentage across different plot types, suggesting an ecological study comparing different plots. Mean species richness, plant coverage, and error bars indicate standard error of values in different plots. (**A**) Species richness (ranging from 0 to 40); (**B**) plant coverage, % (0%–80%). Importance values were used to describe and compare the species dominance, with the highest IV index considered to be most \"important\" in a specific plot. _Agrimonia pilosa_, _Festuca valesiaca_, and _Linum sibiricum_ species had high IV values and dominated in the 2003 plantation named a BBS plot. _Phlomis tuberosa_ and _Sibbaldia aptressa_ species dominated in the 2004 plantation, NGS. Therefore _Cleistogenes squarrosa_, _Crisium esculentum_, and _Elymus sibirica_ species dominated and had a high IV in the 2005 plantation, BDS (Table 4).