东北地区森林凋落叶分解速率与气候、林型、林分光照的关系

在东北长白山、张广才岭、小兴安岭、大兴安岭的主要森林类型中设置26块样地,进行为期3a(2004—2006年)凋落叶分解实验,以研究气候、林型、林冠透光率对凋落叶分解速率的相对影响大小。结果表明,不同林型凋落叶分解速率依次为:落叶阔叶林针阔叶混交林落叶针叶林常绿针叶林岳桦林。对分解速率影响因素的分析表明,气候因子(热量和水分)对分解速率有较强的解释力,分别解释了分解常数k和分解95%所需时间(t95%)的55.5%和65.0%的变异。但是,气候对分解速率的影响在很大程度上是通过与林型、林冠透光率的协同作用而实现的,其独立解释力并不大(9%)。气候的变化导致林型(物种组成)的变化、进而影响分解速率,这一因素解释了分解参数变异的46.8%(k)和56.8%(t95%)。与此同时,气候和林型的变化还导致林冠透光率的变化,随着热量水平的上升林冠透光率下降、间接提高分解速率。这一因素分别解释了k值和t95%变异的23.9%和22.3%。研究结果表明,气候对凋落叶分解的影响主要是通过对物种组成、林冠结构(影响透光率)等生物因素的间接作用实现的。忽视这些生物因素、简单研究气候和分解速率的关系可能难以正确预测未来气候变化对凋落物分解的影响。     

Review of mixed forest litter decomposition researches

The litter plays an important role in forest ecosystems. Decomposition of mixed leaf litters has recently become an active research area because it mimics the natural state of leaf litters in most of forests. Many studies reported effects of mixing litters on their decomposition, ranging from positive, negative to neutral. In this paper decomposition mechanisms of mixed litters concluded by researchers were summarized. Firstly, plant litter quality had been recognized as an important factor to affect decomposition rate. Some studies showed a positive significant correlation between initial N, P concentration and non-additive effect in litter mixture decomposition. Secondly, it has been suggested that litter mixture could increase abundance and diversity of fauna and microbial decomposers, especially fungi. Thirdly, compared with single litter decomposition, the nutrient exchange between different litter species is often considered as one of main non-additive effects observed in litter mixture. Some results showed that the active transport of nutrients by fungal hyphae derived positive effect on the decomposition of litter mixture. The multiple factors such as, leaf litter species, investigation method and plot, were also analyzed. In conclusion, it is necessary to enhance a further research on factors in mixed litter decomposition and an interaction between various factors due to the complex relationship. We are looking forward to using these theories of mixed litter decomposition to direct practical forest management.     

Review of mixed forest litter decomposition researches

The litter plays an important role in forest ecosystems. Decomposition of mixed leaf litters has recently become an active research area because it mimics the natural state of leaf litters in most of forests. Many studies reported effects of mixing litters on their decomposition, ranging from positive, negative to neutral. In this paper decomposition mechanisms of mixed litters concluded by researchers were summarized. Firstly, plant litter quality had been recognized as an important factor to affect decomposition rate. Some studies showed a positive significant correlation between initial N, P concentration and non-additive effect in litter mixture decomposition. Secondly, it has been suggested that litter mixture could increase abundance and diversity of fauna and microbial decomposers, especially fungi. Thirdly, compared with single litter decomposition, the nutrient exchange between different litter species is often considered as one of main non-additive effects observed in litter mixture. Some results showed that the active transport of nutrients by fungal hyphae derived positive effect on the decomposition of litter mixture. The multiple factors such as, leaf litter species, investigation method and plot, were also analyzed. In conclusion, it is necessary to enhance a further research on factors in mixed litter decomposition and an interaction between various factors due to the complex relationship. We are looking forward to using these theories of mixed litter decomposition to direct practical forest management.     

Factors regulating litter mass loss and lignin degradation in late decomposition stages

We studied late-stages decomposition of four types of coniferous needle and three types of deciduous leaf litter at two sites, one nutrient-poor boreal and one nutrient-rich temperate. The late stage was identified by that reached by litters at the onset of net loss of lignin mass, i.e. at about 1 year after the incubation when the highest amount of lignin had been detected; the study extended over the following 2 year period. Decomposition rates were significantly lower at the boreal than at the temperate site and did not differ between needle litter and leaf litter. In the boreal forest: (1) mass-loss was positively correlated with N and Mn release, (2) Mn concentration at the start of the late stage was positively correlated with lignin decay, (3) Ca concentration was negatively correlated to litter mass loss and lignin decay. In the temperate forest neither lignin, N, Mn, and Ca concentration at the start of the late stage, nor their dynamics were related to litter decomposition rates and lignin decay. In leaf litter mass-loss and lignin decay were positively correlated with N and Ca release and with Ca concentration. In needle litter mass-loss was positively correlated to Mn release and N concentration negatively with lignin decay. We concluded that Ca, N and Mn have different roles in controlling lignin decay depending on type of litter and site conditions.     

全球气候变暖对凋落物分解的影响

凋落物分解作为生态系统核心过程,参与生态系统碳的周转与循环,影响生态系统碳的收支平衡,调控生态系统对全球气候变暖的反馈结果。全球气候变暖通过环境因素、凋落物数量和质量以及分解者3个方面,直接或间接地作用于凋落物分解过程,并进一步影响土壤养分周转和碳库动态。气候变暖可通过升高温度和改变实际蒸散量等环境因素直接作用于凋落物分解。气候变暖可引起植物物种短期内碳、氮和木质素等化学性质的改变以及群落中物种组成的长期变化从而改变凋落物质量。在凋落物分解过程中,土壤分解者亚系统作为主要生命组分(土壤动物和微生物)彼此相互作用、相互协调共同参与调节凋落物的分解过程。凋落物分解可以通过改变土壤微生物量、微生物活动和群落结构来加快微生物养分的固定或矿化,以形成新的养分利用模式来改变土壤有机质从而对气候变化做出响应。未来凋落物分解的研究方向应基于大尺度跨区域分解实验和长期实验,关注多个因子交互影响下,分解过程中碳、氮养分释放、地上/地下凋落物分解生物学过程与联系、分解者亚系统营养级联效应等方面。     

Changes in leaf litter decomposition of primary Korean pine forests after degradation succession into secondary broad‐leaved forests

Forest degradation succession often leads to changes in forest ecosystem functioning. Exactly how the decomposition of leaf litter is affected in a disturbed forest remains unknown. Therefore, in our study, we selected a primary Korean pine forest (PK) and a secondary broad‐leaved forest (SF) affected by clear‐cutting degradation, both in Northeast China. The aim was to explore the response to changes in the leaf litter decomposition converting PK to SF. The mixed litters of PK and SF were decomposed in situ (1 year). The proportion of remaining litter mass, main chemistry, and soil biotic and abiotic factors were assessed during decomposition, and then, we made an in‐depth analysis of the changes in the leaf litter decomposition. According to our results, leaf litter decomposition rate was significantly higher in the PK than that in the SF. Overall, the remaining percent mass of leaf litter''s main chemical quality in SF was higher than in PK, indicating that leaf litter chemical turnover in PK was relatively faster. PK had a significantly higher amount of total phospholipid fatty acids (PLFAs) than SF during decomposition. Based on multivariate regression trees, the forest type influenced the soil habitat factors related to leaf litter decomposition more than decomposition time. Structural equation modeling revealed that litter N was strongly and positively affecting litter decomposition, and the changes in actinomycetes PLFA biomass played a more important role among all the functional groups. Selected soil abiotic factors were indirectly driving litter decomposition through coupling with actinomycetes. This study provides evidence for the complex interactions between leaf litter substrate and soil physical–chemical properties in affecting litter decomposition via soil microorganisms.     

Mangrove associates versus true mangroves: a comparative analysis of leaf litter decomposition in Sundarban

Mangrove species are broadly classified as ‘true mangroves’ and ‘mangrove associates’. We hypothesized that the leaf litter decomposition rates of true mangroves differ significantly from the mangrove associates under the same ecological and bio-climatic conditions. In order to test this hypothesis, the leaf litter decay rates of 24 true mangrove species and 10 mangrove associates along with the concomitant carbon and nitrogen dynamics of the litters were studied in the tropical mangrove forest of Sundarban by means of litter bags. The decomposition was monitored for six consecutive weeks in the pre-monsoon, monsoon and post-monsoon season. All the species in general went through a rapid decay phase in the first 2 weeks, however, the rate substantially decreased in the following 4 weeks. Most of the species studied had significant seasonal variability (p < 0.05) in the decay rate. Species-specific decay was highest throughout the monsoon and least during the post-monsoon season. The mean dry weight composition (i.e. percentage of dry weight of the leaf litters remaining at the end of weekly intervals) of the true mangroves was 10–12 % higher than the mangrove associates throughout the sampling period. The mean decay constants (K in week^?1) of the true mangroves were 0.15 ± 0.05, 0.20 ± 0.06 and 0.16 ± 0.05 in the pre-monsoon, monsoon and post-monsoon season respectively. The mangrove associates had significantly higher decay constants in the respective seasons that followed the order 0.23 ± 0.09, 0.25 ± 0.06 and 0.24 ± 0.09. As a consequence, the computed mean half-life period of the true mangrove litters (32 ± 11 days) was much higher than the mangrove associates (23 ± 11 days). This showed that collectively the leaf litters of mangrove associates degraded at a much faster rate than the true mangroves throughout the annual cycle and thus our hypothesis was justified.     

Cumulative effects of nitrogen additions on litter decomposition in three tropical forests in southern China

A field-scale experiment with nitrogen (N) addition treatments was performed in three forest types – a pine (Pinus massoniana Lamb.) forest, a pine-broadleaf mixed forest (mixed) and a mature monsoon evergreen broadleaf forest (mature) – in tropical China. Two kinds of leaf litter, Schima superba Chardn. & Champ. and Castanopsis chinensis Hance, were studied using the litterbag technique after more than 2 years of continuous N additions. The objective of this study was to understand the cumulative effect of N addition on litter decomposition in the tropical forests and to determine if the initial effects of N addition changes over time. Results indicated that leaf litter decomposition was significantly faster in the mature forest than in the mixed or pine forests. The mean fraction of mass remaining after 12-months of decomposition was: mature (0.22) < mixed (0.50) < pine (0.51) for the two litters. Nitrogen addition significantly depressed litter decomposition in the pine forest and the mature forest, but had no significant effect in the mixed forest. These results suggest that N deposition has significant cumulative effect on litter decomposition.     

森林凋落物研究进展

对森林凋落物的概念、研究方法及主要研究内容作了阐述,特别就凋落物收集面积和分解袋孔径大小、凋落量时空动态和凋落物分解速率等问题进行了综合分析。目前森林凋落物研究的重要结论有：海拔和纬度因子是通过对光、温、水等生态因子的再分配来影响凋落量,其中主导气候因子是年均温。凋落物的分解与化学组成和环境因子有关,C／N和N含量在凋落物分解过程中起着重要作用。土壤水分是影响凋落物分解主要环境因子之一;土壤微生物对凋落物的影响,前期是通过真菌破碎凋落物表层使内居性动物得以侵入凋落物内部,后期则以细菌降解有机物为主。凋落量、凋落物分解的影响因子,以及凋落物的生态作用等内容应是凋落物研究的重要方向。     

Variations in leaf litter decomposition across contrasting forest stands and controlling factors at local scale

Aims Litter decomposition is a critical pathway linking the above- and belowground processes. However, factors underlying the local spatial variations in forest litter decomposition are still not fully addressed. We investigated leaf litter decomposition across contrasting forest stands in central China, with objective to determine the spatial variations and controlling factors in forest floor leaf litter decomposition in relation to changes in forest stands in a temperate forest ecosystem.Methods Leaf litter decomposition was studied by using litterbag method across several typical forest stand types in Baotianman Nature Reserve, central China, including pure stands of Quercus aliena var. acuteserrata, Q. glandulifera var. brevipetiolata and Q. variabilis, respectively, and mixed pine/oak stands dominated by Pinus armandii and Q. aliena var. acuteserrata, as well as stands of pure Q. aliena var. acuteserrata trees ranging in stand age from ~40 to>160 years. Measurements were made on litter mass remaining and changes in litter chemistry during decomposition over a 2-year period, along with data collections on selective biotic and environmental factors. A reciprocal transplant experiment involving Q. aliena var. acuteserrata and Q. variabilis was concurrently carried out to test the occurrence of 'home-field advantage (HFA)' in local forests when only considering contrasting oak tree species. Correlation analyses and path analyses were performed to identify the dominant drivers and their relative contributions to variations in leaf litter decomposition.Important findings Significant variations were found in the rate of leaf litter decomposition among stands of different tree species but not among stand age classes. The values of decay constant, k, varied from 0.62 in Q. aliena var. acuteserrata stands to 0.56 in Q. variabilis stands. The reciprocal litter transplant experiment showed that the rate of leaf litter decomposition was on average 5% slower in home-fields than on reciprocal sites. Path analysis identified litter acid-unhydrolyzable residue (AUR) to N ratio, soil microbial biomass carbon (MBC), soil pH and soil organic carbon (SOC) as most prominent factors controlling the rate of leaf litter decomposition, collectively accounting for 57.8% of the variations; AUR/N had the greatest negative effect on k value, followed by weaker positive effects of SOC and MBC. Our findings suggest that tree species plays a primary role in affecting forest floor leaf litter decomposition by determining the litter quality, with site environment being a secondary factor contributing to the local variations in leaf litter decomposition in this temperate forest ecosystem.     

Regional patterns and controls of leaf decomposition in Australian tropical rainforests

Future climates have the potential to alter decomposition rates in tropical forest with implications for carbon emissions, nutrient cycling and retention of standing litter. However, our ability to predict impacts, particularly for seasonally wet forests in the old world, is limited by a paucity of data, a limited understanding of the relative importance of different aspects of climate and the extent to which decomposition rates are constrained by factors other than climate (e.g. soil, vegetation composition). We used the litterbag method to determine leaf litter decay rates at 18 sites distributed throughout the Australian wet tropics bioregion over a 14‐month period. Specifically, we investigated regional controls on litter decay including climate, soil and litter chemical quality. We used both in situ litter collected from litterfall on site and a standardized control leaf litter substrate. The control litter removed the effect of litter chemical quality and the in situ study quantified decomposition specific to the site. Decomposition was generally slower than for other tropical rainforests globally except in our wet and nutrient‐richer sites. This is most likely attributable to the higher latitude, often highly seasonal rainfall and very poor soils in our system. Decomposition rates were best explained by a combination of climate, soil and litter quality. For in situ litter (native to the site) this included: average leaf wetness in the dry season (LWDS; i.e. moisture condensation) and the initial P content of the leaves, or LWDS and initial C. For control litter (no litter quality effect) this included: rainfall seasonality (% dry season days with 0‐mm rainfall), soil P and mean annual temperature. These results suggest that the impact of climate change on decomposition rates within Australian tropical rainforests will be critically dependent on the trajectory of dry season moisture inputs over the coming decades.     

The importance of mesofauna and decomposition environment on leaf decomposition in three forests in southeastern Brazil

We examined the effects of soil mesofauna and the litter decomposition environment (above and belowground) on leaf decomposition rates in three forest types in southeastern Brazil. To estimate decomposition experimentally, we used litterbags with a standard substrate in a full-factorial experimental design. We used model selection to compare three decomposition models and also to infer the importance of forest type, decomposition environment, mesofauna, and their interactions on the decomposition process. Rather than the frequently used simple and double-exponential models, the best model to describe our dataset was the exponential deceleration model, which assumed a single organic compartment with an exponential decrease of the decomposition rate. Decomposition was higher in the wet than in the seasonal forest, and the differences between forest types were stronger aboveground. Regarding litter decomposition environment, decomposition was predominantly higher below than aboveground, but the magnitude of this effect was higher in the seasonal than in wet forests. Mesofauna exclusion treatments had slower decomposition, except aboveground into the Semi-deciduous Forest, where the mesofauna presence did not affect decomposition. Furthermore, the effect of mesofauna was stronger in the wet forests and belowground. Overall, our results suggest that, in a regional scale, both decomposers activity and the positive effect of soil mesofauna in decomposition are constrained by abiotic factors, such as moisture conditions.     

Effects of microclimate,litter type,and mesh size on leaf litter decomposition along an elevation gradient in the Wuyi Mountains,China

Litter decomposition is an important ecosystem process regulated by both biotic factors (e.g., decomposers and litter types) and abiotic factors (e.g., temperature and moisture). This study examined the regulatory effects of soil fauna and microclimate on decomposition of two substrates (Castanopsis carlesii and Pinus taiwanensis) along an elevation gradient in four ecosystems of zonal vegetation types in southeastern China: evergreen broadleaf forest (EVB), coniferous forest (COF), dwarf forest (DWF), and alpine meadow (ALM). Our objective was to identify the mechanisms by which microclimate, substrate, and fauna control litter decomposition, especially where variations in ecosystem structure and environment are markedly shown across an elevation gradient. The hypotheses were as follows: (1) litter decomposition within the same litter type would decrease across the elevation gradient, (2) litter decomposition would be lower in poorer nutrient quality substrate across the four sites, and (3) litter dynamics, influenced by strong interactions among ecosystem type, litter type, and decomposers, would vary by elevation gradient due to microclimate effects (i.e., temperature and moisture). The decomposition rates of C. carlesii were significantly higher than those of P. taiwanensis at EVB, COF, and DWF sites; however, they were not significantly different at the ALM site. Low elevation forests possessed a microclimate (warm and humid) that favors decomposer activities and also appeared to possess a decomposer community adapted to consuming large amounts of leaf litter, as indicated by the rapid leaf litter loss. Litter decomposition in micro-mesh bags proceeded more slowly compared to litter in meso-mesh and macro-mesh litterbags across the elevation gradient, indicating that restricting some detritivore access to litter reduced litter mass loss. We suggest that microclimate and faunal contributions to plant litter decomposition differ markedly across the ecosystems in the Wuyi Mountains.     

降水量变化对蒙古栎落叶分解过程的间接影响

分析了在4种不同降水量条件下蒙古栎叶凋落物基质质量的变化,并应用分解袋法研究其凋落物在蒙古栎次生林内的分解过程.结果表明：与对照相比,降水量减少条件下,蒙古栎叶凋落物的初始N、P、K浓度显著升高,初始木质素浓度显著降低,凋落物分解速率大,N、P、K矿化率高,N和P固持时间缩短;降水量增加情况下,其凋落物初始N浓度显著降低、木质素浓度显著升高,N、P、K矿化率低,N和P固持时间延长.4种类型叶片凋落物的质量损失过程均符合指数降解模型,分解速率可以由凋落物木质素/N来预测.相关性分析显示,木质素浓度高、N浓度低的两种凋落物的分解速率与N浓度相关性最大;而木质素浓度低、N浓度高的两种凋落物的分解速率与木质素浓度相关性最大.说明降水量的变化显著地改变了蒙古栎叶凋落物的基质质量,进而间接地改变了凋落物的分解过程.     

鼎湖山季风常绿阔叶林凋落叶分解与土壤动物群落动态和多样性

2001年12月~2002年12月,采用不同孔径分解凋落叶样袋法,对鼎湖山季风常绿阔叶林3类凋落叶的分解进行了研究,并对落叶分解过程中凋落叶袋内和袋下土样中的土壤动物群落和多样性进行了调查。结果表明,3种孔径袋内凋落叶的分解速率为大孔>中孔>微孔;混合凋落叶的分解速率大于单种凋落叶;蜱螨目在凋落叶分解的整个过程中相对数量都较高,弹尾目在凋落叶的分解过程中在凋落叶袋和土壤间移动,数量变化较大。凋落叶袋内大、中型土壤动物的个体数量在分解前期较多,中、小型土壤动物在分解的中期数量剧增;凋落叶袋内土壤动物的个体数量、密度以及多样性指数都随着落叶的分解而增加,9月最高;土壤样内则在分解的前期较高,以后逐渐降低。凋落叶的分解和土壤动物群落动态及多样性受凋落叶基质质量以及样地温度、降雨量等综合因素的影响。     

Controls on long-term root and leaf litter decomposition in neotropical forests

Litter decomposition represents one of the largest annual fluxes of carbon (C) from terrestrial ecosystems, particularly for tropical forests, which are generally characterized by high net primary productivity and litter turnover. We used data from the Long-Term Intersite Decomposition Experiment (LIDET) to (1) determine the relative importance of climate and litter quality as predictors of decomposition rates, (2) compare patterns in root and leaf litter decomposition, (3) identify controls on net nitrogen (N) release during decay, and (4) compare LIDET rates with native species studies across five bioclimatically diverse neotropical forests. Leaf and root litter decomposed fastest in the lower montane rain and moist forests and slowest in the seasonally dry forest. The single best predictor of leaf litter decomposition was the climate decomposition index (CDI), explaining 51% of the variability across all sites. The strongest models for predicting leaf decomposition combined climate and litter chemistry, and included CDI and lignin ( R ²=0.69), or CDI, N and nonpolar extractives ( R ²=0.69). While we found no significant differences in decomposition rates between leaf and root litter, drivers of decomposition differed for the two tissue types. Initial stages of decomposition, determined as the time to 50% mass remaining, were driven primarily by precipitation for leaf litter ( R ²=0.93) and by temperature for root litter ( R ²=0.86). The rate of N release from leaf litter was positively correlated with initial N concentrations; net N immobilization increased with decreasing initial N concentrations. This study demonstrates that decomposition is sensitive to climate within and across tropical forests. Our results suggest that climate change and increasing N deposition in tropical forests are likely to result in significant changes to decomposition rates in this biome.     

LITTER FALL PRODUCTION IN RELATION TO ENVIRONMENTAL FACTORS IN NORTHEAST CHINA'S FORESTS

 在中国东北长白山、帽儿山、凉水、根河的主要森林类型中设置27个样地, 连续3年(2004~2006年)观测森林凋落物的生产量, 以研究我国东北地区森林凋落物产量及其与环境因子的关系。结果表明, 不同森林类型凋落物年产量存在显著差异, 针阔叶混交林显著高于落叶针叶林和常绿针叶林, 落叶针叶林、常绿针叶林、落叶阔叶林和针阔叶混交林的年平均产量分别为2 337、2 472、3 130和4 146 kg&;#8226;hm^–2; 树叶、枝条、繁殖器官和其它组分占总凋落量的平均比例为71%、22%、6%和1%, 不同森林类型凋落物组分的比例差异较大。森林凋落物产量主要受温度限制, 降水、森林类型和群落结构无显著影响。不同组分凋落物量的影响因素不同: 树叶凋落量主要受温度和森林类型的影响; 枝条凋落量主要受降水和蓄积量的影响; 而繁殖器官凋落量则与树种的繁殖特性以及年降水有关。各组分占总凋落量的比例主要受降水影响, 树叶占凋落物比例随降水增加而下降, 枝条所占比例很小, 表现出与叶相反的变化趋势。     

Litterfall interception by understorey vegetation delayed litter decomposition in Cinnamomum camphora plantation forest

Aims

This study was carried out to improve our understanding of the interception effect of understorey vegetation on litter decomposition in Cinnamomum camphora plantation forest of subtropical China.

Methods

The interception simulation experiment in field was performed to determine how the litterfall interception delayed the leaf litter decomposition of C. camphora, by comparing the difference in variables among 4 litter interception locations.

Results

The results showed that total mass loss, lignin loss, cellulose loss, microbial activities (CO₂ release, fungal biomass and enzyme activities), and water content except nitrogen for litters on the crown were significantly lower than that of litters without interception. The maximum mass loss difference value among litter locations reached 35 %, indicative of obvious decomposition delay by the understorey. Litter CO₂ release, enzyme activities and water content exhibited a clear seasonal pattern, suggesting a strong relation between the degree of microbial activities and the succession of cold and warm as well as moist and dry periods. A clear nitrogen increase was observed in this experiment, indicating persistent immobilization. No clear variation pattern in nitrogen content was observed in this study, which was probably mixed by the N precipitation from acid rain.

Conclusions

The litterfall interception delayed the decomposition of leaf litter, displaying slow decomposition rate and inhibitive microbial activities by interception, which presumably resulted from low water content on the crown.     

Long-term dynamics of pine and hardwood litter in contrasting environments: toward a global model of decomposition

We analysed data on mass loss after five years of decomposition in the field from both fine root and leaf litters from two highly contrasting trees, Drypetes glauca, a tropical hardwood tree from Puerto Rico, and pine species from North America as part of the Long‐Term Intersite Decomposition Experiment (LIDET). LIDET is a reciprocal litterbag study involving the transplanting of litter from 27 species across 28 sites in North and Central America reflecting a wide variety of natural and managed ecosystems and climates, from Arctic tundra to tropical rainforest. After 5 years, estimated k‐values ranged from 0.032 to 3.734, lengths of Phase I (to 20% mass remaining) from 0.49 to 47.92 years, and fractional mass remaining from 0 to 0.81. Pine litter decomposed more slowly than Drypetes litter, supporting the notion of strong control of substrate quality over decomposition rates. Climate exerted strong and consistent effects on decomposition. Neither mean annual temperature or precipitation alone explained the global pattern of decomposition; variables including both moisture availability and temperature (i.e. actual evapotranspiration and DEFAC from the CENTURY model) were generally more robust than single variables. Across the LIDET range, decomposition of fine roots exhibited a Q₁₀ of 2 and was more predictable than that of leaves, which had a higher Q₁₀ and greater variability. Roots generally decomposed more slowly than leaves, regardless of genus, but the ratio of above‐ to belowground decomposition rates differed sharply across ecosystem types. Finally, Drypetes litter decomposed much more rapidly than pine litter in ‘broadleaved habitats’ than in ‘conifer habitats’, evidence for a ‘home‐field advantage’ for this litter. These results collectively suggest that relatively simple models can predict decomposition based on litter quality and regional climate, but that ecosystem‐specific problems may add complications.