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Decay and nutrient dynamics of coarse woody debris in the Qinling Mountains, China

View Article: PubMed Central - PubMed

ABSTRACT

As an ecological unit, coarse woody debris (CWD) plays an essential role in productivity, nutrient cycling, carbon sequestration, community regeneration and biodiversity. However, thus far, the information on quantification the decomposition and nutrient content of CWD in forest ecosystems remains considerably limited. In this study, we conducted a long-term (1996–2013) study on decay and nutrient dynamics of CWD for evaluating accurately the ecological value of CWD on the Huoditang Experimental Forest Farm in the Qinling Mountains, China. The results demonstrated that there was a strong correlation between forest biomass and CWD mass. The single exponential decay model well fit the CWD density loss at this site, and as the CWD decomposed, the CWD density decreased significantly. Annual temperature and precipitation were all significantly correlated with the annual mass decay rate. The K contents and the C/N ratio of the CWD decreased as the CWD decayed, but the C, N, P, Ca and Mg contents increased. We observed a significant CWD decay effect on the soil C, N and Mg contents, especially the soil C content. The soil N, P, K, Ca and Mg contents exhibited large fluctuations, but the variation had no obvious regularity and changed with different decay times. The results showed that CWD was a critical component of nutrient cycling in forest ecosystems. Further research is needed to determine the effect of diameter, plant tissue components, secondary wood compounds, and decomposer organisms on the CWD decay rates in the Qinling Mountains, which will be beneficial to clarifying the role of CWD in carbon cycles of forest ecosystems.

No MeSH data available.


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Decomposition of CWD in the P. armandi and Q. aliena var. acuteserrata plots.The relationship between density and decomposition was simulated using a single exponential decay model.
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pone.0175203.g005: Decomposition of CWD in the P. armandi and Q. aliena var. acuteserrata plots.The relationship between density and decomposition was simulated using a single exponential decay model.

Mentions: The CWD density of Q. aliena var. acuteserrata was significantly higher than that of P. armandi at different decay times (Fig 5, P<0.0001); the CWD density decreased significantly with the decomposition of Q. aliena var. acuteserrata and P. armandi (P<0.0001). The relationship between CWD density and the decay time was simulated using a single exponential decay model, and the average decay rate (k) of P. armandi CWD was 0.04±0.002 a-1 (R2 = 0.97±0.01), while that of Q. aliena var. acuteserrata CWD was 0.07±0.003 a-1 (R2 = 0.98±0.006). The single exponential decay model predicted that it would take 16 and 67 years to decompose 50% and 95% of P. armandi CWD, compared with 10 and 44 years to decompose 50% and 95%, respectively of Q. aliena var. acuteserrata CWD. Based on long-term observations, we calculated the average annual DCWD of P. armandi forest, i.e., 0.44±0.08 t·ha-1, while that of the Q. aliena var. acuteserrata forest was 0.56±0.09 t·ha-1 from 1997–2013. The average annual mass decay rate (k') of Q. aliena var. acuteserrata CWD (0.07±0.02 a-1) was significantly higher than that of P. armandi CWD (0.05±0.01 a-1) from 1997–2013 (Fig 6, P<0.0001). There was no significant difference between the two methods with respect to the estimated decay rate of P. armandi CWD (P = 0.33) and Q. aliena var. acuteserrata CWD (P = 0.13). With an increase in annual temperature, the annual k' of P. armandi and Q. aliena var. acuteserrata CWD increased significantly (P<0.0001), and annual temperature was strongly exponentially correlated with annual k'. Moreover, there was a significant correlation between the annual precipitation and the annual k' (P<0.0001, r = 0.53).


Decay and nutrient dynamics of coarse woody debris in the Qinling Mountains, China
Decomposition of CWD in the P. armandi and Q. aliena var. acuteserrata plots.The relationship between density and decomposition was simulated using a single exponential decay model.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383274&req=5

pone.0175203.g005: Decomposition of CWD in the P. armandi and Q. aliena var. acuteserrata plots.The relationship between density and decomposition was simulated using a single exponential decay model.
Mentions: The CWD density of Q. aliena var. acuteserrata was significantly higher than that of P. armandi at different decay times (Fig 5, P<0.0001); the CWD density decreased significantly with the decomposition of Q. aliena var. acuteserrata and P. armandi (P<0.0001). The relationship between CWD density and the decay time was simulated using a single exponential decay model, and the average decay rate (k) of P. armandi CWD was 0.04±0.002 a-1 (R2 = 0.97±0.01), while that of Q. aliena var. acuteserrata CWD was 0.07±0.003 a-1 (R2 = 0.98±0.006). The single exponential decay model predicted that it would take 16 and 67 years to decompose 50% and 95% of P. armandi CWD, compared with 10 and 44 years to decompose 50% and 95%, respectively of Q. aliena var. acuteserrata CWD. Based on long-term observations, we calculated the average annual DCWD of P. armandi forest, i.e., 0.44±0.08 t·ha-1, while that of the Q. aliena var. acuteserrata forest was 0.56±0.09 t·ha-1 from 1997–2013. The average annual mass decay rate (k') of Q. aliena var. acuteserrata CWD (0.07±0.02 a-1) was significantly higher than that of P. armandi CWD (0.05±0.01 a-1) from 1997–2013 (Fig 6, P<0.0001). There was no significant difference between the two methods with respect to the estimated decay rate of P. armandi CWD (P = 0.33) and Q. aliena var. acuteserrata CWD (P = 0.13). With an increase in annual temperature, the annual k' of P. armandi and Q. aliena var. acuteserrata CWD increased significantly (P<0.0001), and annual temperature was strongly exponentially correlated with annual k'. Moreover, there was a significant correlation between the annual precipitation and the annual k' (P<0.0001, r = 0.53).

View Article: PubMed Central - PubMed

ABSTRACT

As an ecological unit, coarse woody debris (CWD) plays an essential role in productivity, nutrient cycling, carbon sequestration, community regeneration and biodiversity. However, thus far, the information on quantification the decomposition and nutrient content of CWD in forest ecosystems remains considerably limited. In this study, we conducted a long-term (1996&ndash;2013) study on decay and nutrient dynamics of CWD for evaluating accurately the ecological value of CWD on the Huoditang Experimental Forest Farm in the Qinling Mountains, China. The results demonstrated that there was a strong correlation between forest biomass and CWD mass. The single exponential decay model well fit the CWD density loss at this site, and as the CWD decomposed, the CWD density decreased significantly. Annual temperature and precipitation were all significantly correlated with the annual mass decay rate. The K contents and the C/N ratio of the CWD decreased as the CWD decayed, but the C, N, P, Ca and Mg contents increased. We observed a significant CWD decay effect on the soil C, N and Mg contents, especially the soil C content. The soil N, P, K, Ca and Mg contents exhibited large fluctuations, but the variation had no obvious regularity and changed with different decay times. The results showed that CWD was a critical component of nutrient cycling in forest ecosystems. Further research is needed to determine the effect of diameter, plant tissue components, secondary wood compounds, and decomposer organisms on the CWD decay rates in the Qinling Mountains, which will be beneficial to clarifying the role of CWD in carbon cycles of forest ecosystems.

No MeSH data available.


Related in: MedlinePlus