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The carbon use efficiency (CUE) of soil microorganisms is a critical parameter for the first step of organic carbon (C) transformation by and incorporation into microbial biomass and shapes C cycling in terrestrial ecosystems. As C and nitrogen (N) cycles interact closely and N availability affects microbial metabolism, N addition to soil may shift the microbial CUE. We conducted a meta-analysis (100 data pairs) to generalize information about the microbial CUE response to N addition in soil based on the two most common CUE estimation approaches: (i) 13C-labelled substrate addition (13C-substrate) and (ii) 18O-labelled water addition (18O-H2O).The mean microbial CUE in soils across all biomes and approaches was 0.37. The effects of N addition on CUE, however, were depended on the approach: CUE decreased by 12% if measured by the 13C-substrate approach, while CUE increased by 11% if measured by the 18O-H2O approach. These differences in the microbial CUE response depending on the estimation approach are explained by the divergent reactions of microbial growth to N addition: N addition decreases the 13C incorporation into microbial biomass (this parameter is in the numerator by CUE calculation based on the 13C-substrate approach). In contrast, N addition slightly increases (although statistically insignificant) the microbial growth rate (in the numerator of the CUE calculation when assessed by the 18O-H2O approach), significantly raising the CUE. We explained these N addition effects based on CUE regulation mechanisms at the metabolic, cell, community, and ecosystem levels. Consequently, the differences in the microbial responses (microbial growth, respiration, C incorporation, community composition, and dormant or active states) between the 13C-substrate and 18O-H2O approaches need to be considered. Thus, these two CUE estimation approaches should be compared to understand microbially mediated C and nutrient dynamics under increasing anthropogenic N input and other global change effects.ReferenceHu J, Huang C, Zhou S, Kuzyakov Y 2022. Nitrogen deposition affects microbial carbon use efficiency: Meta-analysis of similarities and differences in 18O and 13C approaches. Global Change Biology 28 (16), 4977-4988. http://doi.org/10.1111/gcb.1622

Nutrient availability is a key regulator of soil respiration. Anthropogenic activities have dramatically accelerated the inputs of reactive nitrogen (N) and phosphorous (P) and increased the availability of N and P in soils. However, many previous studies of soil respiration have focused more on the effects of N, and less on the effects of P and its interaction with N. Therefore, the objective here was to examine the roles of N availability, P availability and their interaction in determining soil respiration. A manipulative N addition (100 kg N ha−1 year−1), P addition (50 kg P ha−1 year−1) and NP co-addition (100 kg N ha−1 year−1 + 50 kg P ha−1 year−1) experiment was conducted in a subtropical forest in Southwest China. N and P inputs were added monthly beginning in October 2017. The soil respiration rate was measured monthly from March 2018 to February 2019, and soil properties, microbial biomass carbon (MBC), and fine root biomass were measured in July 2018 and January 2019. The soil respiration rate in the control (without fertilizer added) treatment was 13.5% higher than that in the N treatment but 1.6% and 34.7% lower than those in the P treatment and NP treatment, respectively. Soil respiration was closely associated with soil temperature and soil moisture, and soil temperature played a more important role in regulating soil respiration than did soil moisture. The temperature sensitivity of respiration (Q10 values) in the CT, N, P and NP treatments did not differ significantly. Path analysis showed that nutrient additions changed soil respiration by regulating the MBC and fine root biomass. Our results highlight the divergent effects of N addition and NP co-addition on soil respiration. Ongoing N and P inputs may increase soil respiration by stimulating soil microbial and plant root activities in the subtropical evergreen broad-leaved forests of Southwest China.

Soil mesofauna plays an important role in decomposing organic matter, recycling nutrients, and increasing nutrient availability. The effects of nitrogen (N) deposition and reduced precipitation on the litter-dwelling mesofaunal community and how this process affects litter decomposition remain poorly understood. Herein, a two-year simulated N deposition and throughfall reduction experiment was carried out in a natural evergreen broad-leaved subtropical forest to examine the effects of N deposition and reduced precipitation on soil mesofauna during litter decomposition. Four treatments were established: control (CK), N deposition (N), reduced precipitation (RP), and combined N deposition and reduced precipitation (N + RP). We collected and identified 19,782 individuals of mesofauna in litterbags during the whole experiment. Mites (Prostigmata, Mesostigmata, and Oribatida) and Collembola comprised almost 90% of the total number of individuals collected and dominated the soil mesofauna in our study. Our results revealed the negative effects of N deposition on the density of Oribatida mites and Collembola and the total density of soil mesofauna. Reduced precipitation significantly increased the density of Collembola and Oribatida mites and the total density of mesofauna and marginally significantly increased the density of Mesostigmata mites but decreased the diversity of mesofauna. The interaction effects of N deposition and reduced precipitation significantly affected the density of Prostigmata mites, Oribatida mites, Collembola, and the diversity of mesofauna. N deposition combined with reduced precipitation significantly inhibited litter decomposition, whereas no significant interaction effects were observed. Furthermore, correlation analysis indicated that litter mass loss was significantly positively correlated with the density of Prostigmata, Mesostigmata, and Oribatida, as well as the diversity of mesofauna. Overall, during the two-year decomposition process, our results suggest that N deposition and reduced precipitation interactively affected mesofaunal diversity and that N deposition adversely affected the mesofaunal community, while reduced precipitation increased the density of some groups but decreased mesofaunal diversity, consequently cascading on the decomposition of leaf litter.

The carbon use efficiency (CUE) of soil microorganisms is a critical parameter for the first step of organic carbon (C) transformation by and incorporation into microbial biomass and shapes C cycling in terrestrial ecosystems. As C and nitrogen (N) cycles interact closely and N availability affects microbial metabolism, N addition to soil may shift the microbial CUE. We conducted a meta-analysis (100 data pairs) to generalize information about the microbial CUE response to N addition in soil based on the two most common CUE estimation approaches: (i)

Litter decomposition is a vital link between material circulation and energy flow in forest ecosystems and is intensely affected by global change factors, such as increased nitrogen (N) deposition and altered precipitation regimes. As essential nutrients, calcium (Ca), magnesium (Mg), and manganese (Mn) play crucial roles in plant energy metabolism, photosynthesis, and membrane transport of plants, and the major source of these nutrients is litter decomposition. However, the dynamics of Ca, Mg, and Mn during decomposition have been largely ignored. Thus, to better understand Ca, Mg, and Mn dynamics during leaf litter decomposition in the scenario of increasing N deposition and decreasing precipitation, we carried out a two-year field litterbag experiment in a natural evergreen broad-leaved forest in the central area of the rainy area of Western China. Two levels of N deposition (ambient N deposition and 150 kg·N·ha−1·y−1) and precipitation reduction (no throughfall reduction and 10% throughfall reduction) were set, i.e., control (Ctr: without nitrogen deposition or throughfall reduction), N deposition (N, 150 kg·N·ha−1·y−1), throughfall reduction (T, 10% throughfall reduction), and N deposition and throughfall reduction (NT, 150 kg·N·ha−1·y−1 and 10% throughfall reduction). We found that leaf litter Ca concentration increased in the early decomposition stage and then decreased, while Mg and Mn concentrations generally decreased during the whole period of decomposition. The amount of Ca showed an accumulation pattern, while Mg and Mn generally showed a release pattern. N deposition and throughfall reduction affected the Ca, Mg, and Mn dynamics, varying with different decomposition stages, i.e., N deposition significantly affected the concentration and amount of Ca, regardless of the decomposition stages, while throughfall reduction significantly affected the Ca concentration in the whole and early decomposition stages. N deposition significantly affected the concentration and amount of Mg in the whole and early decomposition stages, while throughfall reduction had no significant effects. Throughfall reduction significantly affected the concentration and amount of Mn in the whole and late decomposition stages, while N deposition had no significant effects. Ca concentration generally showed a significant positive linear relationship with mass loss in the early decomposition stage, Mg concentration showed a significant positive linear relationship with mass loss in the Ctr and N treatments in the early and late decomposition stages, Mn generally showed a significant negative linear relationship with mass loss, regardless of the decomposition stage. Overall, the results suggest that Ca accumulation is more likely affected by N deposition, while Mg and Mn releases are more likely affected by N deposition combined with throughfall reduction, particularly in the early decomposition stage.

Nitrogen (N) and phosphorus (P) control biogeochemical cycling in terrestrial ecosystems. However, N and P addition effects on litter decomposition, especially biological pathways in subtropical forests, remain unclear. Here, a two-year field litterbag experiment was employed in a subtropical forest in southwestern China to examine N and P addition effects on litter biological decomposition with nine treatments: low and high N- and P-only addition (LN, HN, LP, and HP), NP coaddition (LNLP, LNHP, HNLP, and HNHP), and a control (CK). The results showed that the decomposition coefficient (k) was higher in NP coaddition treatments (P0.05), and lower in N- and P-only addition treatments than in CK (P0.05). The highest k was observed with LNLP (P0.05). The N- and P-only addition treatments decreased the losses of litter mass, lignin, cellulose, and condensed tannins, litter microbial biomass carbon (MBC), litter cellulase, and soil pH (P0.05). The NP coaddition treatments increased the losses of litter mass, lignin, and cellulose, MBC concentration, litter invertase, urease, cellulase, and catalase activities, soil arthropod diversity (S) in litterbags, and soil pH (P0.05). Litter acid phosphatase activity and N:P ratio were lower in N-only addition treatments but higher in P-only addition and NP coaddition treatments than in CK (P0.05). Structural equation model showed that litter MBC, S, cellulase, acid phosphatase, and polyphenol oxidase contributed to the loss of litter mass (P0.05). The litter N:P ratio was negatively logarithmically correlated with mass loss (P0.01). In conclusion, the negative effect of N addition on litter decomposition was reversed when P was added by increasing decomposed litter soil arthropod diversity, MBC concentration, and invertase and cellulase activities. Finally, the results highlighted the important role of the N:P ratio in litter decomposition.

Stand-density management and fertilization practices are the main two factors affecting bamboo-shoot yield. However, the appropriate density and fertilization rates are still unclear for improving the bamboo-shoot yield and its economic benefits, especially for a high economic value bamboo-shoot forest. To fill this gap, we conducted a two-year split-plot design experiment in a Chimonobambusa pachystachys shoot forest. The main plots were assigned to five density rates, 40,000, 50,000, 60,000, 70,000, and 100,000 culms ha−1, and the subplots were assigned to four fertilization rates (nitrogen:phosphorus:potassium = 23:3:15): 0, 820, 1640, and 2460 kg ha−1 a−1. Results showed that the bamboo-shoot yield increased first and then decreased with stand density, while it increased with fertilization rates. Density management and fertilization regulate bamboo-shoot yield by changing the soil’s Olsen P, available nitrogen, organic matter, and available potassium contents. The maximum bamboo-shoot yield was 9315.92 kg ha−1, which appeared in the density of 60,000 culms ha−1 and the fertilization of 2460 kg ha−1 a−1. However, the maximum bamboo-shoot net profit was 135,242.63 CNY ha−1, which appeared at the density of 60,000 culms ha−1 and the fertilization of 1640 kg ha−1 a−1. The economic-benefit analysis shows that density management achieves a net-profit growth comparable to fertilizer application at a much lower cost. The study results provide a basis for the scientific management of C. pachystachys shoot forests and bamboo farmers to improve their income.

Background and Aims Human activities-mediated input of nitrogen (N) and phosphorus (P) to ecosystem may significantly affect soil hydrolyzing enzyme activities (Hy-EAs). However, the mechanisms underlying the responses of soil Hy-EAs to change in N and P availability remains unclear. Methods Here, a two-year field N and P addition experiment was conducted in a subtropical evergreen broad-leaved forest to elucidate the effects of N addition, P addition, and NP co-additions on soil Hy-EAs and biochemistry properties. Results The invertase, cellulase, and acid phosphatase activities were increased in N treatment but reduced in P treatment. The urease activity was reduced in N treatment but did not alter in P treatment. NP treatment significantly increased the invertase and cellulase activities. Furthermore, the cellulase activity was positively correlated with soil organic carbon concentration. The acid phosphatase activity was negatively correlated with microbial biomass carbon (MBC), total P, and available P concentrations. Whereas the urease activity was not strongly dependent on total N concentrations, but positively correlated with soil pH and MBC. These Hy-EAs were significantly correlated with C-to-P and N-to-P ratios, while no significantly correlation with C-to-N ratio. Conclusions Overall, our results indicated that N and P addition significantly affected the soil C-, N-, and P-hydrolyzing enzyme activities. With ongoing imbalanced N and P input in our studied subtropical evergreen broad-leaved forest, N addition may exacerbate the limitation of soil C and P availability, while the exogenous P addition may improve the soil C and P availability.

The soil quality index (SQI) is based on several key indicators and is used to assess soil quality. More than 250,000 ha of walnut saplings (Juglans regia L.) were planted in previous cropland areas in the Sichuan Basin, China, using a range of soil cover types that may affect soil quality with effects that are unclear. We investigated the effects of white film (WF), black film (BF), shade netting (SN), and maize straw (MS) soil cover types and an uncovered control type (CK) on soil chemical and biological indicators and the SQI in the 0-15 cm soil layer in a young walnut forest in the Sichuan Basin over a 27-month study period. The results showed that all soil cover types increased the soil organic matter (SOM), total potassium (TK), and available potassium (AK) concentrations (p &lt, 0.05), whereas the total nitrogen (TN) and available nitrogen (AN) concentrations were greater only in soils covered by MS than in CK (p &lt, 0.05). The available phosphorus concentrations were 64.1 and 193.2% greater in soils covered by BF and MS treatments, respectively, than in the CK (p &lt, 0.05). The numbers of soil faunal groups (N) were 45.7, 36.4, 37.2, and 101.5% higher in WF, BF, SN, and MS, respectively, than in CK (p &lt, 0.05), the individual numbers (S) were 92.3, 36.2, 100.8, and 154.5% greater in WF, BF, SN, and MS, respectively, than in CK (p &lt, 0.05). The microbial biomass carbon (MBC) was 15.5, 32.3, 45.0, and 77.1% greater in WF, BF, SN, and MS than in CK, respectively (p &lt, 0.05). Redundancy discriminant analysis revealed strong positive interactions between biological indicators (MBC, N, and S) and SOM, AN, and AK concentrations. SOM, TN, AK, S, and MBC were the minimum required variables for the effective assessment of the SQI. All four soil cover types led to an improved SQI (p &lt, 0.05), and MS had the greatest effect on SOM, TN, AN, AP, N, S, MBC, and SQI (p &lt, 0.05). In conclusion, all four soil cover types increased the SOM levels, TK, AK, and MBC concentrations, soil faunal diversity, and SQI. The MS treatment was the most cost-effective and efficient measure to improve soil fertility, ecological function, and overall soil quality in the studied walnut forest.

Litter decomposition is a fundamental process of biogeochemical cycles and plays a critical role in regulating carbon (C) and nutrient mineralization in terrestrial ecosystems. Examining responses of litter decomposition to altered precipitation is crucial to understand terrestrial C dynamics and its feedback to climate change. To understand the effects of reduced precipitation on litter decomposition, a two-year throughfall reduction experiment was carried out in a natural evergreen broad-leaved forest in western China. Five throughfall reduction levels were investigated: control without throughfall reduction (Ctr), 5% (W1), 10% (W2), 20% (W3) and 50% throughfall reduction (W4). Throughfall reduction significantly reduced soil moisture, which was most pronounced in W3 and W4 treatments, and this was associated by significantly reduced cumulative litter mass loss and lower decomposition constants. Also, throughfall reduction significantly altered litter C, N and P dynamics. In particular in W2, W3 and W4 treatments the release of C and N was significantly reduced, whereas in W2 and W3 the immobilization of P was increased. Overall, the results suggest that future decrease in precipitation will suppress litter decomposition, whereas microbial P limitation in litter may be aggravated in broad-leaved forest ecosystems.

Litter, an essential component of forest ecosystems, plays an important role in maintaining soil fertility, sequestering carbon (C) and improving soil biodiversity. However, litter decomposition is affected by increased nitrogen (N) deposition. Numerous reports have presented N deposition experiments in different forest ecosystems to investigate the effects of N deposition on litter decomposition, but the effects remain unclear, especially in ecosystems receiving increasingly higher levels of ambient N deposition. To address this gap, we performed a litterbag experiment to understand the effects of increasing N deposition on the litter decomposition process in natural evergreen broad-leaved forest in the Rainy Area of Western China. A 2-year field litter decomposition experiment was conducted using the litterbag method. Four levels of N deposition were established: control (CK; 0 kg·N·ha−1·year−1), low N deposition (LN; 50 kg·N·ha−1·year−1), medium N deposition (MN; 150 kg·N·ha−1·year−1), and high N deposition (HN; 300 kg·N·ha−1·year−1). The simulated N depositions ranged from 50% to 320% of the ambient rate of wet N deposition. Simulated N deposition significantly increased the remaining mass, C, N, lignin and cellulose of the litter. The LN treatment decreased the remaining phosphorus (P); conversely, the HN treatment increased it. In the late stage of the study period, the mass remaining was positively closely correlated to the lignin and cellulose remaining during the decomposition process. Simulated N deposition significantly suppressed the litter decomposition in the natural evergreen broad-leaved forest, despite the high rate of ambient N deposition, and the inhibitory effects increased with the N deposition levels. The suppressive effect of N deposition on litter decomposition may be primarily explained by the inhibition of lignin and cellulose degradation by the exogenous inorganic N. With ongoing N deposition in future, N deposition may have a potentially significant impact on C and N cycles in such forest ecosystems.

Over the last several decades, human activities have increased the nitrogen input in terrestrial ecosystem, and the alteration of the N cycle has profoundly affected the cycles of many other elements, especially carbon (C). Litter decomposition is an important ecosystem process that plays a key role in the balance of global carbon and nitrogen cycles. To investigate the effects of simulated nitrogen (N) deposition on litter decomposition, a one-year field experiment on litter decomposition following N addition treatments was conducted in a natural evergreen broad-leaved forest in a rainy area of Western China. Beginning November 2013, we conducted a field experiment using the litterbag method that included four treatments: 0, 50, 150, and 300 kg N hm − 2 a − 1 as the control (CK), low (L), medium (M), and high (H) nitrogen deposition, respectively. Every 15 days, NH 4 NO 3 was added to the N-treated plots. The results indicated that after one year of decomposition, the remaining rate in each treatment was between 54.71% and 63.52%, L, M, and H rates were 4.18%, 6.53%, and 8.81% higher, respectively than the CK. N deposition significantly increased the remaining rate and inhibited the decomposition of leaf litter in this ecosystem because of the addition of N. Greater increases in N strengthened the inhibition effect. N addition significantly increased the concentration of carbon and nitrogen in leaf litter. The decomposition coefficient of C and N were in the order k (CK) > k (L) > k (M) > k (H), although N was released faster. The time for 95% C decomposition of foliar litter increased by 0.92–2.20 a from 4.09 a ( T 95% of CK) because of N addition, and that for N decomposition increased by 0.64–1.22 a from 3.73 a. After decomposing for 1 a, the C remaining rates for L, M, and H were 6.00%, 9.89%, and 14.11%, respectively, higher than CK, whereas the N remaining rate was 4.13%, 6.75% and 10.08%, respectively. Thus, nitrogen addition significantly increased the C and N remaining rates and significantly inhibited the release of carbon and nitrogen. The L, M, and H treatments increased the C/N ratio of the leaf litter by 3.33%, 5.40% and 6.38%, respectively, suggesting that the M and H treatments significantly increased the C/N ratio. Nitrogen treatments weakened the correlation between the mass remaining and C and N remaining, but strengthened the correlation between mass remaining and the C/N ratio. The correlation coefficient of mass remaining and C and N remaining was reduced by N deposition, whereas the C/N ratio was increased. Under simulated N deposition, C remaining was still a good indicator of litter decomposition relative to the N remaining and C/N ratio.

The increase in the nitrogen/phosphorus (N/P) ratio with rising N deposition is changing the biodiversity and function of terrestrial ecosystems at an unprecedented speed. However, the specific effects of P addition and its interaction with N on soil arthropods during litter decomposition in forests are unclear. A two-year experiment was carried out in western China to examine the effects of N and P addition on soil arthropods during litter decomposition. We applied a factorial design in a litterbag experiment combining two levels of low and high N and P alone addition (LN, HN, LP, and HP) and their coaddition (LNLP, LNHP, HNLP, and HNHP), including a no-addition control treatment (CK). The results show that soil pH, litter microbial biomass carbon (MBC), soil arthropod group number (G), individual number (I), diversity index (S), and richness index (M) were lower in the LN and HN treatments than in CK. Compared with CK, the LP and HP treatments reduced I but did not alter G, S, and M. The MBC, soil pH, and G, I, S, and M were higher and the cellulose and lignin concentrations and soil arthropod dominance index values were lower in the LNLP, LNHP, HNLP, and HNHP treatments than in CK. The positive effects of the LNLP, LNHP, HNLP, and HNHP treatments on the soil arthropods were related to the increased MBC and soil pH and decreased cellulose and lignin concentrations and litter N/P ratio. The litter N/P ratio was inversely related to the soil arthropod diversity. In conclusion, the negative effect of N addition on soil arthropod diversity during litter decomposition was reversed when P was added by shifting the MBC, cellulose and lignin concentrations, soil pH, and litter N/P ratio. Thus, increased P availability under rising N deposition scenarios may enhance soil arthropod diversity in this forest.

Acid deposition from the emission of nitrogen (N) and sulfur (S) has become an important factor affecting the soil nutrient balance and biogeochemical cycling in terrestrial ecosystems. The average levels of N and S deposition in the rainy area of southwestern China from 2008 to 2010 were 9.5 g N m−2 y−1 and 19.3 g S m−2 y−1, respectively. External additions of N and S fertilizers combined with high levels of acid deposition may affect the soil ecological stoichiometry in the region’s widely distributed subtropical evergreen broad-leaved forest. Therefore, we investigated the responses of the soil stoichiometric ratios and enzyme activities to added N (+N), added S (+S), added N and S (+NS), and a control (Ctr) in the 0–20 cm layer in an evergreen broad-leaved forest in the rainy area of southwestern China from April 2013 to April 2015. The results showed that the soil total N (TN) concentration and N/P ratio were higher and the soil organic C (SOC) concentration and C/N ratio were lower in the fertilization treatments than the Ctr, although N and S additions did not significantly alter the soil total P (TP) concentration. The +N, +S, and +NS treatments increased the soil acid phosphatase activity and reduced the soil invertase, cellulase, catalase, and polyphenol oxidase activities. The +N and +NS treatments increased the soil urease activity and reduced soil peroxidase activity. The +S treatment reduced the soil urease activity and did not alter soil peroxidase activity. N and S additions had synergistic decreasing effects on the SOC concentration, C/N ratio, and soil cellulose and catalase activities. Moreover, structural equation models identified that N and S additions regulated the SOC, TN, and TP concentrations via shifting the activities of soil enzymes and the pathways differed between N addition and S addition. In conclusion, N and S additions decreased the SOC concentration, C/N ratio, and most soil C-cycle enzyme activities and increased the TN concentration, N/P ratio, and soil acid phosphatase activity. All these results indicated that external N and S additions combined with acid deposition increased soil N concentrations and exacerbated soil C and P limitations in this forest.

Soil respiration is the second largest terrestrial carbon (C) flux; the responses of soil respiration to nitrogen (N) deposition have far-reaching influences on the global C cycle. N deposition has been documented to significantly affect soil respiration, but the results are conflicting. The response of soil respiration to N deposition gradients remains unclear, especially in ecosystems receiving increasing ambient N depositions. A field experiment was conducted in a natural evergreen broadleaf forest in western China from November 2013 to November 2015 to understand the effects of increasing N deposition on soil respiration. Four levels of N deposition were investigated: control (Ctr, without N added), low N (L, 50 kg N ha-1·a-1), medium N (M, 150 kg N ha-1·a-1), and high N (H, 300 kg N ha-1·a-1). The results show that (1) the mean soil respiration rates in the L, M, and H treatments were 9.13%, 15.8% (P < 0.05) and 22.57% (P < 0.05) lower than that in the Ctr treatment (1.56 ± 0.13 μmol·m-2·s-1), respectively; (2) soil respiration rates showed significant positive exponential and linear relationships with soil temperature and moisture (P < 0.01), respectively. Soil temperature is more important than soil moisture in controlling the soil respiration rate; (3) the Ctr, L, M, and H treatments yielded Q10 values of 2.98, 2.78, 2.65, and 2.63, respectively. N deposition decreased the temperature sensitivity of soil respiration; (4) simulated N deposition also significantly decreased the microbial biomass C and N, fine root biomass, pH and extractable dissolved organic C (P < 0.05). Overall, the results suggest that soil respiration declines in response to N deposition. The decrease in soil respiration caused by simulated N deposition may occur through decreasing the microbial biomass C and N, fine root biomass, pH and extractable dissolved organic C. Ongoing N deposition may have significant impacts on C cycles and increase C sequestration with the increase in global temperature in evergreen broadleaf forests.