ABSTRACT
China is one of the countries with serious forest fires. Besides the methods of strengthening management of fire source and increasing forest fire monitoring and rescue efforts, improving the ability of forest itself to resist fire is also the key to prevent forest fires. In this study, we examined the characteristics of the bark across 11 main tree species in Korean pine broad-leaved forest at Jiaohe Forestry Experimental Area in Jilin Province. Fire resistance of bark acorss the tree species was evaluated comprehensively with four indices of water content, ash content, calorific value and oxygen index, using the methods of entropy weight, variance analysis and cluster analysis. Results showed that water content of bark was the highest in Phellodendron amurense. Calorific value of bark was the lowest and ash content was the highest in Ulmus davidiana. Oxygen index of bark was the highest in Fraxinus mandshurica. Bark fire resistance of 11 tree species followed the order of U. davidiana > Acer mono > Acer triflorum > Acer mandshuricum > F. mandshurica > Quercus mongolica > P. amurense > Tilia amurensis > Juglans mandshurica > Pinus koraiensis > Betula costata. The tree species in Korean pine broad-leaved forest could be classified to five categories according to bark fire resistance: U. davidiana belonged to the category of strongest fire-resistance; A. mono and A. triflorum belonged to the category of strong fire-resistance; A. mandshuricum, F. mandshurica, Q. mongolica, P. amurense, T. amurensis belonged to the category of common fire-resistance; J. mandshurica and P. koraiensis belonged to the category of weak fire-resistance; and B. costata belonged to the category of poor fire-resistance.
Subject(s)
Pinus , Trees , China , Forests , Plant BarkABSTRACT
The pTEN/AKT/mTOR signaling pathways play a critical role in balancing cell proliferation, differentiation, and survival. Recent studies researched the associations of core genes in the pTEN/AKT/mTOR pathway polymorphisms with the cancer susceptibility; however, the results are inconclusive. Therefore, a systematically meta-analysis was performed to evaluate the association between the five SNPs (mTOR rs2295080 and rs2536, AKT1 rs2494750 and rs2494752, pTEN rs701848) and cancer risk by systematic review of the literature in 31 eligible studies. The results showed a significant decreased risk between rs2295080 TG, GG genotype, and GG/TG genotypes and overall cancer [TG vs.TT: OR(95% CI) = 0.82(0.76, 0.89), GG/TG vs. TT: OR(95% CI) = 0.82(0.76, 0.88), and GG vs. TG/TT: OR(95% CI) = 0.67(0.51, 0.88)] and the subgroup of urinary system cancer and digestive system cancer. Moreover, the SNP rs701848 CC, TC genotype showed significantly increased the overall cancer risk both in dominant model [CC/TC vs. TT: OR(95% CI) = 1.25(1.15, 1.36)] and recessive model [CC vs. TC/TT: OR(95% CI) = 1.20(1.09, 1.32)], and digestive system cancer and urinary system cancer. In addition, AG genotype and GG/AG genotype of rs2494752 was associated with increased risk of cancer. Therefore, this meta-analysis provided genetic risk factors for carcinogenesis and the most valid cancer prevalence estimate for Asian population.