Abstract
This study presents an analysis of the anatomical structure of the archaeological bamboo, complemented by an examination of its chemical composition, structural characteristics, cellulose crystallinity, and thermal stability. The degraded fibre cell walls exhibited distinct porosity, indicative of the loss of secondary cell wall substances. Partial separation of the secondary wall layers from the middle lamella was observed in certain cell types. The results revealed a predictable diminution in hemicellulose and cellulose content, contrasted by an augmentation in relative lignin and ash content. The cellulose content and cellulose crystallinity index of archaeological bamboo were sharply reduced to 7.2% and 8.2%, respectively. Prolonged entombment had resulted in the predominant degradation of cellulose and hemicellulose in the unearthed bamboo, while lignin had remained relatively stable. At the same maximum water content (MWC), the bamboo underwent more severe degradation of carbohydrates, including the crystalline cellulose. These findings underscored the importance of understanding the degradation processes of bamboo, especially the changes in its chemical properties, in order to accurately assess its preservation state.
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Introduction
Bamboo is a vital natural resource in Asia, particularly prominent in the central, southeastern, and southwestern regions of China, which has been an integral part of Chinese civilization, shaping production and daily life across generations1,2. In 2024, an extensive bamboo mat, exceeding 200 square metres, was discovered from the Wuwangdun Tomb in Anhui Province, dating back to the late Warring States period (475–221 BC)3,4,5,6. This mat, the largest of its kind discovered to date, provides unique insights into the cultural and funerary significance of bamboo in ancient China7. The tomb’s construction and the inclusion of the bamboo mat highlight bamboo’s essential role in funeral practices, with its herringbone pattern exemplifying the craftsmanship of the Chu era. Across Asia, the excavation of bamboo cultural relics not only reveals regional characteristics but also significantly contributes to the study of local culture.
A substantial number of bamboo and wooden cultural relics have been excavated from the humid burial environments of Asia. Extensive research has been dedicated to the analysis and preservation of these archaeological wood, focusing on their structural characteristics, physical and mechanical properties, and degradation mechanisms8,9,10,11. In contrast, research on the degradation of unearthed bamboo—encompassing its anatomical structure, chemical composition, and mechanical strength—remains comparatively scarce despite its historical and cultural significance.
Although bamboo and wood share similar primary chemical constituents, cellulose, hemicellulose, and lignin, which together account for over 90% of their composition, they differ significantly in extract type, content, and anatomical structure12. Unlike wood, bamboo lacks horizontal structures such as wood rays, making it more susceptible to longitudinal cracking during decay. These differences not only result in distinct chemical, physical, and mechanical properties but also highlight that the deterioration behaviour of bamboo fundamentally differs from that of wood. Currently, the impact of degradation on archaeological bamboo is poorly understood. This knowledge gap hinders the development of effective preservation assessment systems and the identification of appropriate protection methods for archaeological bamboo. Consequently, it is essential to consider bamboo’s unique characteristics, as well as its specific deterioration behaviour.
Bamboo exhibits distinct degradation behaviour compared to wood. Its higher density and increased concentration of syringyl units in lignin contribute to its greater resistance to deterioration under natural weathering conditions13,14. Bamboo also demonstrates reduced photodegradation, as evidenced by lower levels of carbonyl formation and lignin breakdown, which enhance its colour stability and durability in outdoor environments15. However, microstructural changes, such as the development of micro-checks in the secondary walls of thick-walled fibre and parenchyma cells, can expand over time, resulting in visible cracks on the transverse surfaces16. Given these, it’s essential to design preservation assessment systems and protective strategies tailored to bamboo’s unique features. Applying wood analysis and evaluation systems directly to bamboo preservation risks yielding inaccurate results and potentially damaging cultural relics.
During the burial process, bamboo is subjected to both biological influences (such as anaerobic bacteria and soft rot fungi) and abiotic factors (including acids, alkalis, and salts present in the groundwater environment)11,17. These factors lead to varying degrees of degradation of bamboo’s principal chemical components, adversely affecting its anatomical structure and, consequently, its mechanical strength18,19. The transverse section of bamboo stems is characterized by numerous vascular bundles embedded within parenchyma tissue, with parenchyma cells typically undergoing more severe degradation compared to bamboo fibres. Despite the extensive degradation of the cell walls, their overall structural integrity is generally well-preserved20. Chemical component analysis reveals significant degradation of cellulose and hemicellulose of bamboo, with lignin, particularly that containing syringyl moieties, being the predominant residual cell wall components17. Previous studies on bamboo and its related materials have largely employed a unidimensional approach. For instance, research on archaeologically bamboo has often concentrated exclusively on measuring the degradation of holocellulose from a chemical perspective, overlooking a range of complex, interrelated factors and neglecting the broader environmental context. This approach lacks a comprehensive analysis of archaeological bamboo at the same time. Moreover, the preservation of bamboo cultural relics with archaeological value through long-term burial is rare, and assessing the degradation state of archaeological bamboo is crucial for its conservation.
The objective of this study was to evaluate the degradation and preservation state of archaeological bamboo excavated from an ancient Chinese tomb dating back over 2000 years. We performed a comprehensive analysis of the anatomical structure, chemical composition, cellulose crystallinity, and thermal stability of both modern and archaeological bamboo. The findings of this study will provide valuable scientific insights, which can support the selection of appropriate dehydration and reinforcement methodologies for the preservation of extensive archaeological bamboo weaving artifacts.
Methods
Materials
Typical fragments of these bamboo mats excavated from the Wuwangdun tomb are illustrated in Fig. 1a. The specific locations of five samples, taken from above the center and side chambers and designated as S15, E13, N3, W13, and C9, are indicated in Fig. 1b. To ensure the accuracy of analysis, all samples employed in this study were washed with deionized water to eliminate any soil contaminants. Moreover, all chemical reagents utilized throughout the experiments were of analytical grade.
a Orthographic view of the archaeological bamboo along with representative fragments, and b schematic of sampling locations. The red circles indicate the corresponding sampling positions of the bamboo mats.
Based on 2021 statistics regarding bamboo resources in Anhui Province, the total bamboo forest area amounted to 379,700 hm2. Within this, Moso bamboo forests occupied 313,200 hm2, representing 82.49% of the total bamboo forest area21. Consequently, Phyllostachys edulis, commonly referred to as Mao Zhu in Chinese, or Moso bamboo, was chosen to represent the modern bamboo samples (MB) for this study.
Anatomical characterization
The longitudinal and transverse sections of the archaeological bamboo sample S15 for observation were prepared by using free-hand sectioning techniques with a new double-sided razor blade. Subsequently, permanent sections were created through the processes of dyeing, dewatering, achieving transparency and sealing22. These sections were then examined under an optical microscope (BX 50, Olympus, Japan), which was equipped with a camera, at magnifications ranging from 40–600 times.
For scanning electron microscopy (SEM) analysis, the MB and archaeological bamboo samples (N3 and W13) were cut into appropriate dimensions. The thickness of the bamboo strip sample is approximately 0.3 mm, and its area is 2.0 mm × 2.0 mm (length × width). The samples were coated with gold using a Gressington sputter coater and observed under an SEM (Hitachi S-480, Hitachi, Japan) at an accelerating voltage of 10 kV. Energy-dispersive spectroscopy (EDS) was employed on the cross-section of the bamboo mat.
Basic physical parameters
Maximum water content (MWC) and basic density (BD) were measured. The weights of both waterlogged (mw) and dried (md) archaeological bamboo samples were measured using an electronic balance. The volumes (Vw) of the samples were determined through the application of the drainage method. The MWC and BD of all archaeological bamboo samples were calculated following the procedures outlined in a previous study23.
Chemical composition analysis
The National Renewable Energy Laboratory’s (NREL) Laboratory Analytical Procedure (LAP) method was employed for the purpose of chemical composition analysis24. The carbohydrates in the bamboo samples were isolated using a sulphuric acid solution, followed by the analysis of sugars via reversed-phase High-Performance Liquid Chromatography (HPLC) using an Agilent 1100 system (Agilent Technologies, Germany) equipped with a UV detector. The insoluble materials were quantified gravimetrically, while the ash contents were determined after incineration in a muffle furnace at 575 ± 25 °C for a duration of 24 ± 6 h25.
Chemical group analysis
To illustrate the alterations in the chemical group of archaeological bamboo and MB, FTIR spectroscopy was conducted using a standard FTIR spectroscope (Nexus6700, Thermo Nicolet Corporation, USA). The samples for analysis were prepared by blending 2 mg of bamboo powder with 200 mg of KBr to form pellets. Each sample was analysed through direct transmittance, with 32 scans conducted at a resolution of 4 cm−1 across the wavenumber range of 500–4000 cm−1. Each sample was tested with at least three replicates, and the average FTIR spectra from triplicates were corrected for baseline variations.
XRD analysis
XRD patterns were recorded using a diffractometer (XRD-6, Spectrometer, China) at a scanning speed of 2 °/min within the angular range of 5° to 45°, with an operating voltage of 36 kV and a current of 20 mA. The maximum peak of diffraction observed near 2θ = 22.5° (I002) and the peak intensity near 2θ = 18° (Iam) on the XRD scanning curve were used to calculate the relative crystallinity index (CrI) of bamboo samples26,27,28.
Thermogravimetric analysis (TGA)
Thermal stability analysis of the bamboo samples was conducted using a thermogravimetric analyser (TGA Q5000, TA Instruments, USA) over a temperature range of 30–700 °C, with a heating rate of 10 °C/min and a nitrogen flow rate of 1.0 mL/min.
Results and discussion
Micromorphological characteristics
The optical micrographs of archaeological bamboo specimens are presented in Fig. 2. These cross-sectional images reveal the presence of vascular bundles and parenchyma cells, which are predominantly distributed throughout the optical micrographs of archaeological bamboo29. Notably, the vascular bundles exhibit semi-open configuration, and no fully open vascular bundle is visible within the observed field of view30. The bamboo mat samples are tentatively identified as belonging to the Poaceae family, Bambusoideae, prompting the selection of bamboo species with similar structural traits as reference samples31.
a–c Cross-section, and d–f longitudinal section.
The prolonged burial process could lead to the decomposition of constitutes within bamboo cell walls, ultimately causing the rupture and deterioration of vessels and cells within vascular bundles32, as evidenced in Fig. 2a, b. Minerals deposits were present inside the parenchyma cells in Fig. 2c. To fully comprehend these alterations in chemical composition, further exploration is imperative. Vascular bundles play a pivotal role in nutrient transport and providing structural support33. Consequently, the disruption of vascular bundle structure adversely influences its physical and mechanical properties. Upon examining the longitudinal section of bamboo mat samples, parenchyma cells could be categorized into long cells and short cells, both exhibiting longitudinal growth (Fig. 2e). The walls of both large and small pores, as well as the parenchyma cells, display clearly visible ladder-like pits (Fig. 2f). Furthermore, fungal hyphae were discovered within the vessels, suggesting that potential fungal infestation affecting the archaeological bamboo to some extent (Fig. 2f). This susceptibility is likely attributed to bamboo’s organic composition, particularly its starch content, which makes it highly prone to microbial infestation.
SEM images of archaeological bamboo samples are presented in Fig. 3. These images highlight the significant microstructural alterations induced by the degradation of bamboo components over the course of thousands of years. The cross-sectional views of sample N3 reveal the formation of micro-cracks and micro-pores within the secondary walls of bamboo cells (Fig. 3a–c). These observations are consistent with previously documented microstructural changes observed in chemically treated tropical bamboo34. The extensive encroachment by fungi and bacteria poses a considerable threat to organic materials. Two distinct decay patterns have been identified in bamboo fibres. Erosion grooves and depressions in the cell wall caused by bacterial activity, were clearly observed (Fig. 3d). Additionally, fungal degradation leads to the formation of cracks and small cavities. These microbial-induced damages collectively contribute to the separation of secondary wall layers from the middle lamella, resulting in a ‘sponge-like’ structure within the secondary wall. This porous structure contrasts sharply with the denser structure of modern bamboo fibres, thereby significantly increasing the water storage capacity of the degraded bamboo cell wall compared to that of healthy bamboo. A notable characteristic of these microorganisms is the abundant presence of extracellular mucilaginous material. The fungi play a particularly pivotal role in the extensive breakdown of the secondary cell wall layers, which is a crucial factor contributing to the long-term degradation of bamboo during burial.
a–c Cross-section of sample N3, d–f sample W13, and g–i sample MB. Arrows indicate c cracks, d erosion, e fungal hyphae, and f bacteria.
MWC and BD
MWC and BD are frequently employed to evaluate the preservation states of archaeological wood35,36. Due to the serious degradation and the low quantity of archaeological bamboo strips, the MWC and BD of bamboo were not analysed in previous studies17. The MWC and BD values of archaeological bamboo samples are presented in Fig. 4. After degradation, the voids in the bamboo cell walls increased, leading to a decrease in physical density and an expansion in water absorption capacity, thereby increasing the maximum water content. Previous research on waterlogged archaeological wood showed a the very high correspondence between standard MWC and BD. If the MWC ranges from 100% to 200%, then the corresponding BD lies in the range of 0.38 g/cm3 to 0.56 g/cm3 37. The BD of these archaeological samples ranged from 0.34 g/cm3 to 0.67 g/cm3, demonstrating an inverse correlation with the MWC values. According to the grading criteria for archaeological wood, the sample was categorized as moderately preserved with an MWC below 400%38. Notably, given that the bamboo mat was buried below the groundwater level, it was difficult to determine whether the bamboo has undergone compression. Such compression could potentially undermine the effectiveness of MWC and BD as standalone indicators of degradation severity in these samples. Consequently, a comprehensive evaluation of their degraded state necessitates a consideration of their chemical components in conjunction with these parameters.
MWC and BD of archaeological bamboo samples.
Chemical composition analysis
The main components of bamboo are vital for understanding the degradation state of archaeological bamboo. Figure 5 delineates the chemical alterations observed among bamboo samples. The MB comprises 41.3% cellulose, 22.4% xylan, 30.4% lignin, and 0.9% ash. After 2000 years of burial, a considerable decline in cellulose and xylan content was noted, accompanied by an increase in lignin and ash content across bamboo samples sourced from different positions on the mats. The ash content exhibited a minor elevation, ranging from 0.7% to 5.3%, in samples situated above the chamber. The presence of ash complicates the precise assessment of the preservation condition of archaeological bamboo based on MWC and BD37. Previous studies have indicated that cellulose plays a pivotal role in bamboo performance, with cellulose and xylan being more susceptible to degradation, while lignin demonstrates greater resistance to decomposition during the burial process17. Notably, the lignin content of samples W13 and C9, soared to 73.9% and 72.6%, respectively, while cellulose content dwindled to merely 8.7% and 7.2%, respectively. The differences in chemical characteristics between archaeological bamboo and modern bamboo can be attributed to a combination of factors, including prolonged exposure to environmental conditions, microbial activity, waterlogged conditions, original species and growth condition. Compared to the archaeological bamboo from the Han Dynasty (B.C. 202 ~ A.D. 220)17, the cellulose in these samples exhibited even greater degradation. Moreover, as lignin content increased, the colour of bamboo transitioned a transition from yellow-green to dark brown.
a The contents of cellulose and xylan, and b the contents of lignin and ash.
Generally, the cellulose/lignin ratio could be employed as an indicator for analysing the degradation levels in archaeological woods39. Calculations revealed a significant drop in the cellulose/lignin (C/L) ratio in archaeological bamboo, from 1.36 in mature Moso bamboo to 0.10–0.21 in the archaeological bamboo sample. Fungi, particularly brown rot fungi, predominantly attack cellulose and hemicellulose, leading to the depolymerization of hemicellulose and the production of fragile, lignin-rich bamboo40. These findings offer quantitative evidence tracing the degradation of excavated bamboo, providing insights into the preferential loss of carbohydrates. The cellulose-to-lignin ratio in modern oak (C/L = 1.43) is comparable to that in modern bamboo. In contrast, the cellulose in waterlogged archaeological wood from the Lusatian culture site (Biskupin, Poland), with the MWC of 544%, has degraded to only half the extent of that in healthy wood, resulting in a C/L ratio of 0.5541. This is significantly higher than the C/L ratio observed in archaeological bamboo. Therefore, the classification of waterlogged archaeological wood studied by predecessors is not applicable to waterlogged archaeological bamboo.
Chemical group analysis
FTIR spectra of MB and archaeological bamboo were employed to scrutinize the spatial distribution of their chemical constituents (depicted in Fig. 6). Notably, two prominent absorption peaks within the 3600–2500 cm−1 range, specifically at 3400 cm−1 (attributable to the hydroxyl O–H stretching) and 2890 cm−1 (corresponding to the C–H stretching vibration of the methyl/methylene group), are indicative of holocellulose and lignin42,43. In Fig. 6, the C–H stretching peak at 2890 cm−1 for sample MB exhibited the weakest intensity, while the hydroxyl absorption peak exhibited insignificant variation in strength. This result may suggest degradation stemming from the absence of low molecular weight compounds in amorphous carbohydrates, as well as the lignin demethoxylation caused by microbial activity.
The FTIR spectra of MB and archaeological bamboo.
The most representative FTIR bands within the spectral range of 1800–800 cm−1 were identified and listed in Table 144,45. Notably, a significant reduction in transmittance at 1736 cm−1 and 1236 cm−1 signifies the depletion of unconjugated ester linkages within lignin–carbohydrate complexes under buried conditions. The substantial decline in spectral intensity at 1736 cm−1 reflects the widespread degradation of xylan, a crucial component of hemicellulose, across all archaeological bamboo samples, corroborating the findings presented in Fig. 5. The absorption peaks at 1596 cm−1 and 1506 cm−1, respectively, correspond to the C=C vibration, C=O stretching, and aromatic skeletal vibration within the aromatic rings of lignin46,47. The slight augmentation in these two peaks suggests that lignin in the archaeological bamboo has remained relatively stable over time, contributing to the darker hue (as illustrated in Fig. 1a). The changes observed at the O–H in-plane bending wavenumbers of 1336 cm−1 and 1317 cm−1, as well as the C–H deformation at 897 cm−1, resulted in decreased intensities following significant decay. This confirms that the cellulose in bamboo had undergone severe degradation. Given that hemicellulose and cellulose microfibrils are intricately interwoven, the removal of either component can expedite the process for both48. Therefore, cellulose and hemicellulose are the primary components affected by burial conditions, which is consistent with the results obtained from the chemical composition analysis (Fig. 5).
The I1737/I1373 ratio served as an indicator of the relative variations in lignin and carbohydrate content among the samples. The values of I1737/I1373 did not exhibit a discernible trend, in fact, sample S15 demonstrated a higher value compared to sample MB, potentially due to the minimal degradation of lignin in S15. Furthermore, the I1737/I1506, I1373/I1506, I1160/I1506 and I897/I1506 ratios in the archaeological bamboo samples were all elevated compared to those in sample MB. This increase could be attributed to the more pronounced degradation of cellulose and hemicellulose relative to lignin during the burial process. The peak ratio at 1425 cm−1 and 897 cm−1 (I1425/I897) was utilized to ascertain the cellulose crystallinity index49, as depicted in Fig. 7f. The I1425/I897 ratio of MB (1.00) was marginally higher than that of archaeological bamboo (0.90 for sample C9), primarily due to the degradation of the crystalline region of cellulose in the archaeological samples.
a The ratio of transmittance at 1737 cm−1 to that at 1373 cm−1, b that at 1737 cm−1 to that at 1506 cm−1, c that at 1373 cm−1 to that at 1506 cm−1, d that at 1160 cm−1 to that at 1506 cm−1, e that at 897 cm−1 to that at 1506 cm−1, f that at 1425 cm−1 to that at 897 cm−1.
XRD analysis
XRD is predominantly employed to assess the degree of crystallinity within lignocellulosic materials. In bamboo, cellulose exhibits a certain degree of crystallinity due to intra- and intermolecular hydrogen bonding among the free hydroxyl groups in cellulose macromolecules, facilitating various ordered crystalline configurations50. As illustrated in Fig. 8a, the characteristic cellulose diffraction peaks situated at approximately 16°, 22° and 35°, corresponding to the (110) and (002) and (040) planes, respectively51, signify that the cellulose I crystal structure remained intact in sample MB. Additionally, the XRD spectrum of the archaeological bamboo reveals an additional diffraction peak at 2θ = 27°, unrelated to bamboo components, potentially stemming from crystalline compounds formed through soil and groundwater interactions. Minerals, such as carbonates and silicates, can deposit on the bamboo surface or react with its components, as confirmed by the EDS pattern. SEM-EDS results on the cross-section of bamboo mat surface are presented in Supplementary Fig. S1 and S2. The elements identified through EDS analysis include carbon (C), oxygen (O), calcium (Ca), silicon (Si), and aluminium (Al). Notably, strong peaks associated with cellulose were evident in MB, while the diffraction intensity of MB was slightly higher than that of the archaeological bamboo, indicating a decrease in the content of cellulose in the archaeological bamboo samples.
a Diffraction patterns, and b crystallinity index.
The reflection spanning between 16° and 18° was attributed to the amorphous regions of lignocellulosic materials52. The results pointed towards a considerably lower crystallinity degree and a greater proportion of amorphous regions in the archaeological bamboo samples. The CrI, calculated using the Segal method, is depicted in Fig. 7b. The notable decline in CrI attributed to prolonged burial could stem from the degradation of structured cellulose molecules by fungi or bacteria, resulting in a weakened structural integrity. Compared to the other archaeological bamboo samples, the reflection peaks in sample C9 were considerably weaker, aligning with the trend observed in the I1425/I897 ratio (Fig. 7f), which may be attributed to its advanced age and a heightened degree of degradation. The archaeological wood from the Luoyang Canal No. 1 Ancient Ship, with the MWC ranging from 135% to 225%, had values close to those of archaeological bamboo. The CrI of the archaeological wood was determined to be 38%, which is slightly lower than the 42% found in recent healthy wood53. In contrast, the degree of cellulose degradation in bamboo is more pronounced, with the CrI decreasing from 30% to 15%.
TG analysis
The TG and differential thermogravimetry (DTG) curves were employed to determine the chemical composition and assess the thermal stability of the samples, as depicted in Fig. 9. The decomposition process could be divided into three distinct stages: below 200 °C (representing dehydration), from 200 °C to 380 °C (indicating hemicellulose and amorphous fraction of cellulose depolymerization), and from 380 °C to 500 °C (corresponding to lignin thermal oxidation), consistent with archaeological wood54,55. Consequently, the percentage content of the primary bamboo components could be inferred from the TG curves56. When compared to MB, the charcoal residue of archaeological bamboo revealed a higher lignin content than that of MB. This discovery was consistent with the results of chemical component and chemical group analysis57. The primary mass loss occurred within the temperature range of 200–380 °C, with the sample MB experiencing the greatest mass loss of 23.23%. As the temperature increases, the characteristic peak observed at 350 °C was predominantly attributed to the thermal decomposition of cellulose, while the shoulder at approximately 300 °C was associated with the pyrogenic decomposition of hemicellulose. It is noteworthy that the relative intensities of the two peaks described above changed in the degraded archaeological samples, i.e. the main and shoulder peaks. This could be attributed to a lower quantity of crystalline cellulose in the most degraded bamboo and a reduced amount of degradation products. For instance, in comparison to MB, the shoulders of archaeological bamboo samples around 300 °C were less pronounced, particularly in sample W1358, suggesting significant degradation of hemicellulose over the course of 2000 years. Related research has indicated that the amorphous region of MB was destroyed at 265 °C, whereas the crystalline region of cellulose was completely pyrolyzed at approximately 450 °C59. The Tmax value, representing the decomposition temperature at which the maximum weight loss occurs, served as an indicator of thermal stability60. Sample MB exhibited the lowest Tmax and the highest mass loss within the range of 200–380 °C. Typically, the primary degradation of lignin occurs above 350 °C61, with no distinct peak observed for MB. In contrast, W13 displayed a broad peak above 350 °C due to its higher lignin content (Fig. 9b), reflecting the composition of archaeological bamboo.
a Thermogravimetric curves, and b differential thermogravimetry curves.
This study collected and analysed a series of archaeological bamboo excavated from the Wuwangdun tombs dating to the period between 475 and 221 BC, providing profound insights into the degradation processes of bamboo through comprehensive morphological and chemical characterization. It should be noted that the degradation classification of archaeological wood by MWC is inapplicable to archaeological bamboo. Microscopic images unveiled fungi playing a pivotal role in the extensive decomposition of the secondary cell wall layers, albeit with the overall cell wall integrity remaining preserved. Notably, the lignin content in these archaeological bamboo samples remained largely unaffected, albeit with a higher ash content attributed to burial conditions. The relative decline in hemicellulose and cellulose mirrored the degradation patterns observed in archaeological bamboo. Detailed analysis of chemical composition, functional groups, cellulose crystallinity, and thermal stability in the bamboo samples confirmed discernible differences between archaeological bamboo and MB. Among these samples, the I1425/I897 ratio derived from FTIR and the CrI exhibited consistent trends, serving as potential indicators of bamboo degradation. Under the same MWC, bamboo experienced more severe degradation of carbohydrates. Moreover, significant changes have occurred in the crystalline structure of cellulose within bamboo. Thermal analysis further emphasized that bamboo degradation primarily involved the decomposition of cellulose and hemicellulose, while lignin retains its relative stability. Generally, the archaeological bamboo samples retrieved from different positions within the ancient mat displayed diverse states of preservation. Among them, samples W13 and C9 underwent the most pronounced degradation. These findings significantly enhance our understanding of bamboo degradation, contributing invaluable insights for future conservation endeavours aimed at preserving this cultural heritage. Despite the apparent preservation of the bamboo samples excavated from tombs over 2000 years old, the structural cellulose has undergone considerable degradation. Furthermore, the high inorganic salt content in the bamboo may undermine its physical and mechanical stability. Therefore, conservation efforts for bamboo artifacts, such as those excavated from Wuwangdun tombs, should focus on mitigating the detrimental effects of these salts and reinforcing the fibres. Future research should delve deeper into the relationship between bamboo’s structural integrity and its environmental degradation mechanisms, thereby fostering a richer understanding of bamboo preservation.
Data availability
No datasets were generated or analysed during the current study.
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Acknowledgements
This research was supported by Technical Service Project of the National Centre for Archaeology of China, grant number 2024-H-KJ-006. The authors would like to thank Xiaomei Jiang, Yonggang Zhang, Shenjie Han and Mengruo Wu for data analysis and linguistic assistance during the preparation of this manuscript.
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Conceptualization, Jiajun W. and Min Y.; methodology, Zhiguo Z.; formal analysis, Jiajun W. and Jiawei C.; investigation, Ling F. and Junjun Z.; resources, Ling F. and Zhiguo Z.; writing—original draft preparation, Jiajun W.; writing—review and editing, Jiajun W., Ling F., Jiawei C., Min Y. and Zhiguo Z.; visualization, Jiajun W. and Jiawei C.; supervision, Min Y. and Zhiguo Z.; funding acquisition, Zhiguo Z. All authors have read and agreed to the published version of the manuscript.
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Wang, J., Chu, J., Fang, L. et al. Degradation state and preservation quality of archaeological bamboo from a 2000-year-old Chinese royal tomb. npj Herit. Sci. 13, 223 (2025). https://doi.org/10.1038/s40494-025-01758-z
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DOI: https://doi.org/10.1038/s40494-025-01758-z
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