Aboveground Phytomass of Larch Plantation in the Shilyin Bogd Mountain of Sukhbaatar Aimag, Mongolia

Abstract

This study aimed at determination of main stand characteristics and estimate the aboveground tree biomass allocation by biomass component in Larix sibirica Ledeb. plantations in Mongolia. The study was carried out in 20-year-old Larch plantations established in the Shiliyn Bogd mountains of Sukhbaatar aimag, Mongolia using 2-yr-old seedlings. The results of our assessments showed the mean diameter and height amount for 8.8 cm and 5.76 m, and therefore the stem density and volume were 2400 ind. ha^–1 and 47.33 m³ ha^–1, respectively. Our findings revealed that mean values of stand characteristics were quite similar to mean values at the natural young larch stands growing in the northern part of the country. Aboveground biomass in the study area was averaged 29.68 T ha^–1. We found a strong correlation (R² = 0.99) between stem diameter at breast height (DBH) and aboveground biomass. The polynomial equation P_kg = 0.228\(D_{{1.3}}^{2}\) – 0.6944D_1.3 + 0.8223 was selected as a most optimal equation to estimate aboveground biomass of larch trees in the plantation. Our results revealed a relatively higher proportion of water content (69.9%) in aboveground biomass than absolute dry biomass (30.1%). Moreover, biomass component analyses indicated that the dominant part of aboveground biomass belongs to only stem wood (55.5%), and followed by branch (20.0%), bark (15.1%) and needles (9.4%). Based on our assessments we concluded that the establishment of larch tree plantation in the dry-steppe is possible via transplanting of 2-year-old containerized seedlings in Mongolia. The introduction of this afforestation technology plays important contribution to mitigation of land degradation in Central Asia. Therefore, the initial high planting density positively affected to tree survival post-planting period and creation of better microclimate in plantation area. We found that the predominant tree biomass belonged to stem biomass which exceed 55.5% in total aboveground biomass, and the water content amounted for 64% in fresh biomass. The polynomial equation P_kg = 0.228\(D_{{1.3}}^{2}\) – 0.6944D_1.3 + 0.8223 was selected most optimal equation to estimate the total aboveground mass. This planting method, planting design and outputs play an important contribution in development of dry steppe afforestation in Central Asia.