Impacts of Intensive Management Practices on the Long-Term Sustainability of Soil and Water Conservation Functions in Bamboo Forests: A Mechanistic Review from Silvicultural Perspectives

Abstract

Bamboo forest ecosystems are an important component of the Earth’s terrestrial ecosystems and play an important role in addressing the global timber crisis as well as climate change. Bamboo is a typical shallow-rooted, fast-growing clonal plant species whose developed rhizome system and high canopy closure play an important role in soil and water conservation. The function of soil and water conservation services of bamboo forests can intuitively reflect the regional regulation of precipitation, the redistribution function of precipitation, and the function of soil fixation, which is one of the crucial ecological service functions in regional ecosystems. Bamboo forests are divided into monopodial bamboo forests, sympodial bamboo forests, and mixed bamboo forests, which are mainly distributed in tropical and subtropical mountainous areas. The region’s variable climate, abundant precipitation, and high potential risk of soil erosion, in conjunction with the frequent operation of bamboo forests and frequent occurrence of extreme weather events, have the potential to adversely affect the ecosystem function of bamboo forests. Presently, bamboo forests are primarily managed through the cultivation of bamboo, with the objective of enhancing productivity. Extensive research has been conducted on the long-term maintenance of bamboo forest productivity. However, there is a paucity of research on the mechanisms of management measures for ecosystem stability and the development of adaptive management technology systems suitable for soil and water conservation, carbon sequestration and sink enhancement, and biodiversity conservation. This paper is predicated on the biological characteristics of bamboo and, thus, aims to compile the extant research progress on the following subjects: the role of rainfall redistribution in bamboo forest canopies, the role of deadfall interception, and the mechanism of soil fixation mechanics of the root system. It also synthesizes the current status of research on the impact of traditional management measures on the soil and water conservation function of bamboo forests. Finally, it discusses the problems of current research and the direction of future development.

1. Introduction

The ecosystem service function refers to the important role that an ecosystem plays in the external manifestation of energy and material flow in ecological processes [1]. The provision of tangible services as natural resources by ecosystems is enabled by the presence of both biological and abiotic factors [2]. Notably, soil and water conservation represent a pivotal ecosystem service function, exerting a direct influence on the climate, hydrology, vegetation, productivity, and soil nutrient cycle within a region and its immediate surroundings [3]. Forest ecosystems (1) regulate hydrological processes through canopy interception, litter layer absorption, and soil moisture storage; (2) protect soils via root reinforcement and erosion prevention; (3) maintain nutrient cycles by organic matter decomposition and sediment retention; and (4) modulate microclimates through evapotranspiration and surface energy balance adjustment. These functions are crucial for maintaining ecosystem equilibrium, addressing global climate change, and preserving biodiversity [4,5,6,7].

Bamboo is a perennial species that belongs to the Bambusoideae subfamily of the Poaceae family. It is a classic example of clonal plant morphology. China is the country with the most abundant bamboo resources in the world, with 41 genera of bamboo, accounting for more than 50% of the world’s bamboo genera, and 857 species of bamboo, accounting for about 50% of the world’s bamboo species [8], known as the “world’s bamboo kingdom”. Bamboo is distinguished by its well-developed underground flagellar root system, which is distributed primarily in the 0–40 cm soil layer [9]. Through clonal asexual reproduction, bamboo can achieve high growth in a year. Its dense planting plays a crucial role in slope stabilization and is essential for maintaining soil and water. Concurrently, the brief harvesting cycle of bamboo constitutes a pivotal economic resource for individuals residing in bamboo-producing regions. Consequently, bamboo plants have been identified as superior plant species, exhibiting substantial economic, ecological, and social benefits. At the opening ceremony of the second World Bamboo and Rattan Conference in November 2022, the Chinese government and the International Network for Bamboo and Rattan (INBAR) will jointly release the initiative of “replacing plastic with bamboo”, which puts forward new requirements for bamboo forest management. Presently, the management objectives of bamboo forests are primarily oriented towards economic benefits, and the management measures are becoming increasingly sophisticated. However, the management process exerts a direct or indirect influence on the ecological functions of bamboo forests, given the necessity of maintaining their productivity level. In the context of the global timber crisis and global climate change, the question arises of how to maximize the economic benefits of bamboo forests while taking into account their ecological benefits. This is a subject that is gradually being emphasized, and the answer is of paramount importance for the sustainable management of bamboo forests. Therefore, adopting a biological characteristics-based approach, this paper systematically reviews the extant research on the canopy redistribution role, deadfall interception role, and root sequestration mechanics mechanism of bamboo forests, synthesizing the current. The status of research on the effects of traditional management measures on the soil and water conservation function of bamboo forests is also examined, with the aim of providing a reference for the assessment of the function of soil and water conservation services within bamboo forests.

2. Biological Characteristics of Bamboo Forests

Compared with other plants, bamboo plants are characterized by fast growth, high reproductive capacity, and natural expansion. At present, a considerable body of research has been conducted on the cultivation of whip-growing bamboo by numerous scholars. Whip-growing bamboo forests are characterized by a well-developed whip-root system, which extends in all directions through underground bamboo whips, resulting in the formation of mixed bamboo-wood forests or pure forests. Consequently, the direction of expansion of the bamboo forest whip root system is a determining factor in the spatial distribution and developmental trajectory of the bamboo forest. Bamboo plants are classified as shallow-rooted species, and the vertical spatial distribution of the whip-root system exhibits significant stratification. For instance, Zheng et al. [9] examined the distribution of the bamboo root system on high-yield timber use of moso bamboo (Phyllostachys edulis), revealing that it was predominantly concentrated in the 0–40 cm soil layer, constituting over 90% of the total root system. The whipping root, on the other hand, accounted for a relatively minor proportion of the soil layer below 40 cm. Wang et al. [10] examined the vertical distribution characteristics of rhizome–root in the culm and shoot forest of moso bamboo. They concluded that rhizome–root were predominantly distributed in the 0–40 cm range, accounting for over 90% of the total root distribution. Xiong et al. [11] used ground-penetrating radar to non-destructively detect the distribution of moso bamboo rhizomes. Results show that rhizomes are mainly in the 0–40 cm soil layer. The well-developed underground rhizome system of bamboo forests, in conjunction with their numerous aged rhizomes, has been shown to have the capacity to anchor the surface soil. This phenomenon has been demonstrated to exert a positive impact on soil physical properties, to augment soil organic matter, to enhance soil erosion resistance, and to curtail surface water and soil loss [12,13].

The growth, development, reproduction, and renewal of bamboo forests differ from those of other trees, shrubs, and grasses. The biomass of the rhizome system of bamboo forests directly affects the health status of bamboo forests. Bamboo is an asexual clone plant that undergoes vegetative propagation through the development of rhizomes, which subsequently give rise to buds that subsequently swell into culms. Thus, bamboo forests are typical uneven-aged ones. Their ramets are connected by rhizomes or culm bases, forming a closed organic unit. Within the unit, material and energy exchanges occur, and it also exchanges materials with the outside. Through physiological integration, they adapt to environmental heterogeneity, ensuring the stability and development of the bamboo forest ecosystem and enhancing its stress resistance [8]. Secondly, the harvesting cycle of bamboo forests is brief, and the various stages of bamboo forests in the process of development exhibit distinct levels of neatness, density, and canopy structure. This results in discrepancies in hydrological characteristics, thereby influencing the soil and water conservation function of bamboo forests of varying types and development stages. Bamboo farmers generate revenue through the harvesting of bamboo timber and shoots. This practice underscores the economic benefits of bamboo forests. However, a critical concern that merits attention is the simultaneous consideration of the ecological benefits of bamboo forests. This is a pivotal issue that necessitates resolution. Based on the growth characteristics of bamboo, several scholars have conducted extensive research on its water-source conservation and soil-and-water conservation functions. The results indicate that bamboo forests can effectively conserve soil and water. Nevertheless, owing to variations in climate, topography, and management practices across study regions, the research findings exhibit considerable diversity [14,15,16]. Currently, the management of bamboo forests is transitioning from extensive approaches to more intensive practices. As management technologies continue to evolve and intensify, their impact on the ecological functions of bamboo forests becomes increasingly significant. Therefore, within the context of the “dual-carbon” initiative, the management of bamboo forests should entail a multifaceted regulatory framework, an optimally designed spatial configuration, and innovative cultivation strategies that achieve a harmonious balance between economic and ecological benefits.

3. The Soil and Water Conservation Functions of Bamboo Forests

3.1. Redistribution of Precipitation by the Forest Canopy

The redistribution of precipitation by the forest canopy has important hydrological and ecological significance. It helps quantitatively evaluate the rainfall-use efficiency of forest canopies across different regions, scales, and types. This evaluation provides a scientific basis for in-depth research on the regulatory role of forest canopy changes on regional water cycles. The moderating effect of the forest canopy on precipitation is characterized by two main components: canopy interception and rain penetration. Canopy interception refers to the portion of precipitation (rain, snow, frost, fog, etc.) that is captured by surface vegetation (forests, shrubs, grasses, etc.) and evaporates directly without infiltrating into the soil. It mitigates the direct impact of precipitation on the soil and reduces the volume of water entering the forest. This process alters the spatial pattern of precipitation and affects the material and energy cycles within the forest ecosystem [17]. Studies have shown that environmental factors (such as precipitation amount, intensity, and duration) and stand characteristics (such as tree height, DBH, and LAI) jointly affect the interception and redistribution of precipitation in forest ecosystems [18,19].

Stemflow, the process by which rainwater flows down tree trunks to the roots, accounts for less than 5% of rainfall in most places. It is often overlooked in studies. However, stemflow also alters the spatial distribution of precipitation, concentrates precipitation, enhances root infiltration [20], and is an important source of soil moisture that can slightly increase water availability around forest plant roots [21]. Thus, stemflow plays an important role in forest water and nutrient cycling and is also one of the most important adaptive and competitive strategies for plants in certain arid habitats [22].

Bamboo forests are an important component of forest ecosystems and play an important role in maintaining ecosystem stability. Many scholars have observed the redistribution of rainfall by bamboo forests through long-term positioning over many years, showing that throughfall > canopy retention > stemflow and bamboo stemflow < 10% [23,24,25]. Specifically, the study revealed a highly significant linear relationship between precipitation and stemflow, as well as a substantial linear correlation with canopy interception. These findings imply that rainfall exerts a significant influence on the redistribution of water from the bamboo forest canopy [23]. Furthermore, forest canopy interception exhibited a significant correlation with leaf area index (LAI). During the peak growth season of moso bamboo forests, the monthly total canopy interception increases with the monthly average leaf area index (LAI), yet the monthly average canopy interception rate shows a downward trend [26]. However, Kong et al. [25] studied the hydrological and ecological characteristics of the artificial bamboo forest and found that with the increase in precipitation outside the forest, penetration rainfall and stem flow increased linearly, while canopy interception increased rapidly at first, and when the precipitation outside the forest reached 10 mm, the growth rate of canopy interception slowed down and tended to be stable (5–6 mm). Xie’s [27] research indicates that sympodial Bamboo is more prone to stemflow, with the minimum rainfall required being 2.1 mm/per event.

3.2. The Functions of the Litter Layer

The litter layer, as the second hydrological layer in forest ecosystems, primarily functions to increase soil organic matter and enhance soil physical and chemical properties, porosity, and erosion resistance while delaying surface runoff and improving soil infiltration [28,29]. In addition, the litter layer plays an important role in forest soil development, microbial activity, ecosystem material cycling, and energy flow processes [30].

The water-holding capacity of the litter layer is closely related not only to litter composition, forest age, water content, decomposition degree, and accumulation amount but also to topography and precipitation characteristics [31]. The water-holding capacity of litter is an important index reflecting the hydrological effect of the litter layer, and the water-holding capacity of litter is closely and positively correlated with the amount of litter present and the maximum water-holding rate. Bamboo forests, like other forest types, have a strong water-holding capacity in the litter layer, which can hold up to 2–4 times its own dry mass. This is not only closely related to the water-holding capacity of the litter but also to the thickness of the litter and habitat conditions [32]. Among them, the average maximum water-holding capacity of the litter layer of moso bamboo forests was 314% [33]; the average water-holding capacity of the litter layer of sympodial bamboo forests was 270%–290% [27]. At present, domestic and foreign studies still use the traditional indoor soaking method or artificial rainfall method to study the maximum water-holding capacity, water-holding characteristics, and water-holding process of the litter layer [34], which cannot objectively reflect the water-holding status of litter layer in a specific period or specific rainfall event [31] and is comprehensively affected by environment, vegetation type, climate, and other factors. This leads to different conclusions about the same study [35]. In contrast to other types of forest, the litter of a bamboo forest has a lower maximum water-holding capacity. For example, Sun et al. [36] studied five forest types: fir forest, moso bamboo forest, deciduous forest, mixed coniferous forest, and ponytail pine forest, and the litter volume of moso bamboo forest, the maximum water-holding capacity, and the effective storage capacity were all at the lowest level. The litter of mixed bamboo-wood forests can improve the retention capacity of bamboo forests. Gao et al. [35] studied five forest types, including moso bamboo forest, bamboo and broad-leaved mixed forest, and broad-leafed forest. The interception capacity of litter was ranked as follows: broad-leaved forest > bamboo and broad-leaved mixed forest > pure moso bamboo forest > reclamation moso bamboo forest. Song et al. [37] studied the impact of bamboo expansion on the hydrological function of litter in secondary evergreen broad-leaved forests. The results showed that bamboo expansion led to the transformation of evergreen broad-leaved forests into bamboo forests, and the hydrological ecological function of litter was enhanced. While the total amount of water absorbed by litter is limited, it plays a significant role in preventing soil erosion caused by precipitation, increasing soil organic matter, and improving soil physical and chemical properties.

3.3. Root–Soil Mechanical Fixation Mechanism

The root system serves as a vital plant organ for nutrient acquisition, fulfilling essential biological functions, including water and nutrient absorption, mechanical anchorage for aboveground structures, and synthesis/storage of organic compounds. As a critical component of ecosystems, plant root systems contribute significantly to soil stabilization through bioengineering approaches. Vegetation-based soil reinforcement is increasingly recognized as an environmentally sustainable and low-carbon biotechnical solution. The extensive subterranean root networks mechanically enhance soil properties by stabilizing pedological structures and improving shear strength parameters. This rhizospheric reinforcement mechanism effectively mitigates soil erosion processes and demonstrates remarkable efficacy in enhancing slope stability in mountainous terrains [38,39]. Extensive research has demonstrated that the biomechanical properties of plant root systems are significantly influenced by root diameter [40], developmental stage [41], hydraulic status [42], decomposition status [43], and topological architecture [44]. Current research efforts predominantly focus on three principal domains: (1) mechanistic elucidation of root–soil stabilization dynamics, (2) quantification of root tensile strength properties, and (3) experimental determination of root-mediated shear resistance parameters. These investigations collectively establish the empirical foundation for vegetation-reinforced slope stabilization strategies. Boldrin et al. [41] examined the effects of developmental stages and hydrological conditions on root biomechanical properties in woody perennials. Their results demonstrated two critical insights: (1) during early establishment phases, the relationship between root diameter and tensile strength often deviates from the classical negative power-law correlation with pronounced interspecific variation, and (2) hydraulic regimes substantially modulate key biomechanical traits, including tensile strength and elastic modulus. The mechanical effects of vegetation roots are primarily reflected in two aspects: (1) the reinforcement effect of shallow root systems, which helps to restrict soil deformation [45]; (2) the anchoring effect of deep root systems, which contributes to stabilizing superficial unstable soil layers [46]. Vegetation roots play a crucial role in soil reinforcement, stabilizing soil layers, and enhancing shear strength, which is vital for soil conservation and slope protection [47]. Plant root systems are made up of many individual roots. Each individual root is the basic unit where mechanical interactions between roots and soil occur. The tensile strength and deformation resistance of individual roots determines the overall deformation of the plant and its ability to constrain the soil when external forces are applied. Therefore, root systems composed of individual roots with greater tensile strength can enhance soil stability and strength. Current research on the tensile properties of plant roots has mainly focused on herbaceous and shrub species [48]. Studies in this area are typically conducted through indoor pull-out tests to measure the tensile characteristics of individual roots [49]. Studies show that plant root systems can significantly enhance soil strength. The increase in shear strength of root–soil composites mainly stems from heightened soil cohesion. As root systems become more complex, they can mobilize a broader soil volume to resist shear deformation. Consequently, the shear zone and plastic zone around roots expand and focus more on the root vicinity, boosting the composite’s shear strength [50]. Fine roots enhance soil particle cohesion and overall soil strength. The shear strength boost in root–soil composites mainly comes from increased soil cohesion. As root diameter grows, this cohesion increment rises. There is a positive correlation between the composite’s uplift and shear strengths. Root systems with greater tensile strength provide better soil stabilization [51]. The increase in root content enhances the cohesion of root–soil composites with little effect on the soil’s internal friction angle. The shear strength of root–soil composites shows an exponential relationship with root content [52]. The root–soil composite’s cohesion decreases with soil depth. Different plants vary in reinforcing soil at various depths, which is tied to the main root distribution depth [53]. Yang et al. [40] demonstrated a biphasic response of root tensile properties to moisture variation: moderate water loss enhances tensile strength through cellulose fibril densification, whereas excessive desiccation triggers progressive disruption of the diameter-strength power-law relationship, concomitant with marked reductions in elongation capacity. Zhang et al. [54] revealed an inverse relationship between root diameter and tensile strength, mechanistically attributed to diametric shifts in cell wall composition. Their work established that increasing root diameter correlates with elevated cellulose content but reduced lignin concentration, collectively diminishing tensile strength. This biochemical scaling law fundamentally explains why fine roots contribute disproportionately to slope stabilization through enhanced strength-to-mass ratios compared to coarse roots.

Bamboo forests, as archetypal clonal plants, possess a unique underground rhizome–root complex where interconnected physiological units (culm–rhizome–shoot) form an integrated self-sustaining system. This phalanx growth strategy confers exceptional soil stabilization capacity through three-dimensional reinforcement networks. A number of scholars have previously conducted research on the mechanical properties of bamboo roots. The findings of the study demonstrated a positive correlation between the ultimate tension resistance of monopodial bamboo single roots and its diameter [55]. This correlation exhibited a power function relationship, indicating an increase in strength with an increase in diameter. However, the study also noted a negative correlation between the tensile resistance of monopodial bamboo single roots and its diameter [56,57,58,59]. This correlation followed an approximate power function, suggesting a decrease in strength with an increase in single-root diameter [55]. Zhong et al. [60] conducted a pull-out test on the entire bamboo plant and found that the frictional force between the root system and soil played a significant role in resisting tensile force, but deep roots contribute less to tensile resistance. The tensile force of the entire bamboo plant increased with the increase in the diameter of the bamboo root system. For moso bamboo, the ultimate tensile resistance of single roots ranges from 10~250 N for diameters between 0 and 5 mm, and the shear strength of the root–soil composite increases with diameter. The mechanical properties of sympodial bamboo roots are similar to those of monopodial bamboo. Li et al. [61] conducted research on the distribution and biomechanical properties of dendrocalamopsis oldhami roots and found that there is a power function positive correlation between different diameter grades of green bamboo roots and maximum tensile force under different moisture contents. The tensile strength increases with the increase in diameter grade, while the tensile strength decreases with the increase in system diameter grade. Roots with a diameter ≤ 1 mm have the highest tensile strength, while those ≥2 mm have the lowest. At 12% moisture content, tensile strength is significantly higher than at saturation, with moisture content having less impact on tensile strength as root diameter increases. Soil shear strength in bamboo forests is linearly and positively correlated with root content. The above research indicates that root diameter and moisture content are key factors affecting bamboo soil stabilization, and the protective ability of bamboo to soil gradually increases with the increase in the total root system [62,63].

4. The Impact of Management Practices on the Soil and Water Conservation Functions of Bamboo Forests

Precipitation is the main source of surface soil and water loss, and forest trees can conserve soil and water by redistributing precipitation. The soil and water conservation function of bamboo forests mainly includes three levels: canopy layer, litter layer, and soil layer, which suppress the formation of surface runoff, increase the infiltration of surface water, and thus reduce the amount of surface soil erosion. The management measures have a significant impact on the stand structure, biomass allocation, and soil properties of bamboo forests; therefore, the management measures are closely related to the soil and water conservation function of bamboo forests.

4.1. Density Regulation

Bamboo grows fast and becomes timber early, occupying a large number of soil resources and space resources in a short period of time, intensifying competition within the species, which is not conducive to the long-term maintenance of the productivity of bamboo forests, so that the density of bamboo forests can reach a suitable state through artificial logging to ensure the healthy and sustainable development of bamboo forests.

Harvesting is a critical method of regulating the density of bamboo forests. Bamboo forest harvesting mainly includes three methods: clear cutting, selective cutting, and gradual cutting. Presently, selective logging constitutes the primary technical instrument for bamboo forest harvesting and management, having attained widespread popularity. Selective logging, which involves the removal of mature and senescent bamboo plants, has been identified as a key factor in altering the distribution of precipitation within bamboo forests. This approach has been shown to reduce bamboo density and increase the forest window area, thereby modifying the distribution of precipitation by the forest canopy. Park et al. [64] studied the canopy precipitation penetration rate of five tropical woodlands under low rainfall intensity (within 20 mm). They found that canopy features like leaf area index (LAI), canopy depth, and the spread of the canopy all influence the penetration rate. Bamboo forest density, affecting rainfall redistribution, is closely related to canopy interception, throughfall, stemflow, and surface runoff formation. Throughfall is divided into two types. One is the drip rainfall that makes contact with the branches and leaves of the forest canopy, which leads to a reduction in the kinetic energy of the raindrops. The other is the free-falling rainfall that passes through the gaps between branches and leaves without making contact, and this type of rainfall has greater kinetic energy than the former [65]. Studies show a significant positive correlation between bamboo stem flow, canopy interception, and bamboo forest density [27]. Conversely, throughfall within the forest is negatively correlated with stand density [66]. This implies that thinning operations, which reduce bamboo forest density, also lower the leaf area index, canopy closure, and canopy cover. As a result, the canopy’s ability to intercept precipitation diminishes, leading to increased throughfall [67,68], which provides favorable conditions for the formation of surface runoff.

Harvesting affects not only the canopy interception of rainfall in bamboo forests but also the amount of litter on the forest floor. The litter in the bamboo forest covered the ground surface, which hindered the direct contact between soil and penetrating raindrops and reduced the erosion ability of raindrops on the ground surface. Secondly, the litter layer has a certain capacity for water conservation [35], which can prolong the formation time of surface runoff, reduce the flow rate of surface runoff, and reduce the amount of water and soil loss. At present, the research on bamboo forest density and litter water holding capacity is relatively lacking. Studies on other forest types showed that the effect of thinning intensity on litter was closely related to forest types, litter decomposition status, and restoration years [69,70]. Bamboo forest is an important ecological forest and economic forest in the bamboo production area. The bamboo timber is harvested and managed every year, and the cutting residues are removed from the forest, which increases the bare area of soil and has an important impact on the water and soil conservation function of bamboo forests. Some scholars have studied the reuse of cutting residues, but they mainly focus on soil improvement, nutrient cycling, tree growth and other aspects, and lack of research that takes into account economic and ecological benefits. In summary, density regulation is closely related to the soil- and water-conservation functions of bamboo forests. However, there is a lack of corresponding quantitative analysis, and further research is needed in this area.

4.2. Fertilization Management

Fertilization can directly supplement the nutrient elements lacking in the soil, promote the decomposition and transformation of organic matter, and improve soil fertility in the short term [71]. Although fertilization can effectively increase soil fertility in the short term, the harm of nutrient loss on the ecological environment after fertilization has attracted more and more attention. There is a close relationship between nutrient loss and fertilization methods [57]. The nutrient utilization rate is also different with different fertilization methods, so the nutrient loss rate after fertilization is significantly different. It has been shown that bamboo forests are fertilized by cavity injection fertilization, surface fertilizer application, sink pattern, and hole pattern. Broadcast fertilization involves spreading fertilizer evenly across the soil surface. It does not directly reach the soil for root absorption [72]. This method is highly efficient but has low fertilizer utilization. The cavity injection fertilization involves applying fertilizer within the bamboo culm, where it is directly absorbed by the cavity walls. This method enhances fertilization efficiency, minimizes soil disturbance, and accelerates stump decomposition. Fertilized stumps typically take 3–5 years to decay, which is 3–5 times faster than natural decomposition [73]. Gully fertilization involves digging parallel trenches spaced 2–3 m apart along contour lines, with each trench 20 cm deep and 20 cm wide [74]. Fertilizer is applied into the trenches and then covered with soil. The fertilizer, placed at a 20 cm soil depth, dissolves and moves through the soil. This process leverages the rhizome’s tendency to grow towards nutrients, guiding rhizome growth to 20–30 cm depths and forming a robust underground rhizome structure. Additionally, gully fertilization creates terraces and loose soil zones along contour lines, enhancing water retention. The hole application refers to digging a ditch about 30 cm along the bamboo stump, with a depth of 15–20 cm and a width of 10–15 cm. The best ditch length is semi-circular. Apply fertilizer to the ditch and cover it with soil. The characteristics of this fertilization method are minimal soil disturbance and low nutrient loss rate [74]. The nutrient loss rate of cavity injection fertilization, sink pattern, and hole pattern is significantly lower than that of surface fertilizer application, and the difference between sink pattern and hole pattern is not significant [75]. Studies on moso bamboo forests using soil fertilization with isotope ¹⁵N labeling showed that the N recovery efficiency of urea-¹⁵N was significantly higher for deep applications (30.62%–31.14%) than for shallow applications (26.68%–27.49%), whereas no significant difference was found between the furrow and hole applications. The highest N recovery efficiency (31.34%) and lowest N loss (49.91%) were observed for the furrow application at 20–40 cm [76]. The uptake of broadcast-applied N fertilizer is relatively low in moso bamboo forests, and it has been shown that the N recovery efficiency was only 13.96% [76]. Chen et al. [77] compared and analyzed the fertilizer utilization rate of three fertilization methods—cavity injection fertilization, surface fertilizer application, and hole pattern fertilization—and the results showed that cavity injection fertilization has the highest utilization rate. It can effectively make the bamboo root and stem decay and decompose and accelerate the nutrient cycle. Root fertilization is more conducive to the absorption and utilization of nutrients, the fertilizer loss rate is low, and the pollution to the environment is reduced. In addition, due to the disturbance of fertilization management on soil, the original soil structure was destroyed. Therefore, fertilization has a certain impact on soil physical properties. For example, Fan et al. [78] studied the effect of different management times on the soil permeability of Phyllostachys edulis forest and showed that the soil permeability of Phyllostachys edulis forest tended to increase with the extension of fertilization time. Ni et al. [79] investigated the effects of management intensity on the stability of soil aggregates in moso bamboo forests and found that intensified management was not conducive to the formation of macroaggregates in the 0–10 cm soil layer and carbon sequestration in microaggregates. It was beneficial to the accumulation of organic carbon in soil aggregates and nitrogen and phosphorus in microaggregates with less human disturbance.

4.3. Reclamation Management

Reclamation management is one of the important measures of bamboo forest management. It can reduce soil bulk density, increase non-capillary porosity, improve soil permeability of bamboo forests, and have a great role in water conservation [80]. Through deep tillage, bamboo forest improved the deep soil environment, increased the content of soil aggregates and water-stable aggregates, and promoted the growth of the rhizome system. At the same time, the rhizome of bamboo forest is mainly distributed in the 0–40 cm soil layer. With the elongation and growth of the rhizome, the soil porosity is further improved, and the soil structure is improved [81,82,83]. However, in the short term, reclamation destroys the surface soil structure, reduces the surface coverage, is not conducive to the formation of large aggregates in 0–10 layers [84], reduces the soil erosion resistance, increases the amount of surface soil erosion, and increases the nutrient loss. For example, Qiu et al. [84] compared and analyzed the effects of reclamation with different intensities on the dynamics of surface nutrient loss of Dendrocalamus latiflorus forests in mountainous areas and showed that both total and strip overturning increased the nutrient loss of surface runoff. Gao et al. [85] conducted a study on the surface runoff and nitrogen nutrient loss of Phyllostachys praecox forests in slope mines under different reclamation methods. The study indicated that reclamation reduced surface runoff, with the degree of reduction being block reclamation > strip reclamation > full reclamation. Conversely, full reclamation led to an increase in surface runoff sediment, suggesting that reclamation facilitates water infiltration in bamboo forests and enhances their capacity to retain water. However, this process was accompanied by an increase in soil loss in the short term. Zheng et al. [86] also concluded that the surface runoff and sediment content of moso bamboo forests were the largest in the bamboo forest with full tillage, followed by the belt reclamation and the hole reclamation. The above analysis shows that reasonable reclamation operation improves the soil quality of bamboo forests, promotes the healthy growth of bamboo forests, improves the ability of soil and water conservation of bamboo forests, and plays a positive role in giving full play to the ecological function of bamboo forests.

4.4. Surface Cover

Understory vegetation is one of the most effective surface coverings, which can effectively reduce the impact of rainwater and prevent soil erosion. However, the understory vegetation exhibits a competitive relationship with the bamboo forest, thereby reducing its productivity and hindering its sustainable development. During bamboo forest management, the remaining bamboo branches, after cutting, are periodically removed, which reduces the amount of ground cover. The litter in the forest land accumulates on the ground to form an organic covering layer, which can slow down the impact of raindrops. The small dead branches and leaves can prevent the speed of water flow and reduce the risk of soil and water loss. At the same time, the litter layer has good water-holding capacity. The decomposed litter can increase the content of organic matter on the soil surface, improve the structure of soil aggregates, enhance soil anti-erodibility, promote precipitation infiltration, and improve the water conservation capacity of the forest [87]. For example, Chen et al. [88] found that the air drying rate of water-stable aggregates (>0.5 mm) and the content of organic matter were the best indicators to reflect the soil erosion resistance of bamboo forests. Wang et al. [87] studied the effects of vegetation coverage of moso bamboo forests on soil permeability and biological characteristics and showed that coverage could increase the content of soil organic matter and total N and improve soil physical properties in the short term, but the long-term coverage reduced soil quality and soil infiltration performance. In contrast, Jiang et al. [89] studied that the natural enclosure of Phyllostachys edulis forest litter significantly improved the water-holding capacity of litter and the water-holding efficiency of topsoil, and the water conservation function was enhanced with the extension of enclosure years. Zhang et al. [90] studied the soil consolidation and erosion prevention effect of the litter on the surface of moso bamboo forest under the condition of artificial rainfall and showed that the increase in runoff on the slope covered with litter was about 25% lower than that on the bare slope, which had a significant effect on the control of water and soil loss. Yu et al. [91] studied the hydrological characteristics of the litter layer of moso bamboo forest with different densities and found that the density of moso bamboo forest was closely related to the hydrological characteristics of the litter layer. It can be seen that the utilization of harvesting residues should be considered comprehensively after bamboo forest harvesting.

4.5. Mixed Silvicultural Management

Bamboo-wood mixed management significantly impacts bamboo forest community structure, ecological functions, and soil properties, making it a key measure for sustainable bamboo forest management [92]. At present, the research on bamboo–wood mixed forests mainly focuses on bamboo–broad mixed forests and bamboo–needle mixed forests. Due to the different characteristics of mixed tree species, canopy closure, amount of dead leaves, and root growth, different types of bamboo–wood mixed forests have significant differences in precipitation redistribution and soil water storage capacity. For instance, Liu et al. [93] investigated the rainfall redistribution characteristics of five forest types: fir pure forest, evergreen broad-leaved forest, bamboo–fir mixed forest, moso bamboo pure forest, and bamboo–broadleaved mixed forest. Their findings indicated that moso bamboo pure forest exhibited superior retention capacity for small to medium rainfall, while bamboo–fir and bamboo–broad-leaved mixed forest demonstrated enhanced retention capacity for large to heavy rainfall. The canopy interception rate is influenced by a variety of factors in addition to mixed-tree species. These include rainfall amount [94], raindrop diameter and rainfall velocity [95], slope position [96], and altitude [97]. Due to the interception of rainfall by a canopy, the rainfall reaching the surface is reduced, which has an impact on the surface runoff generation time. Yu et al. [98] conducted a study on the subject of soil infiltration in various moso bamboo forests located in northern Fujian. Their findings indicated that evergreen broadleaf forests exhibited superior soil infiltration capabilities in comparison to bamboo–broadleaf and moso bamboo pure forests. The study further revealed that soil infiltration levels decrease with increasing soil depth across all forest types. Wang et al. [99] conducted a study on the water conservation function of various types of moso bamboo forests in Northern Fujian. The study concluded that the soil permeability of bamboo broadleaved mixed forests was optimal, while that of moso bamboo forests was suboptimal. However, contradictory results have been obtained by other researchers. For instance, Liao et al. [100] conducted a study on the soil permeability of moso bamboo pure forest, bamboo–broad-leaved mixed forest, and bamboo–coniferous mixed forest in central Fujian, which indicated that the soil permeability of the former was optimal. The above shows that the impact of bamboo–wood mixed forest on soil permeability is closely related to the general situation of the study area in addition to the mixed bamboo species. Research on soil erosion resistance under different mixed-silvicultural systems shows that evergreen broad-leaved forests have the strongest soil erosion resistance, and pure fir forests have the worst. Bamboo–broad-leaved mixed forests have better erosion resistance than pure bamboo forests. Among these, soil organic matter content and litter amount most significantly affect soil erosion resistance [101]. Evergreen broad-leaved forests have dense canopies and abundant litter layers, effectively preventing rainwater from eroding the soil. Mixed tree species in bamboo–wood mixed forests, such as evergreen broad-leaved tree species, can increase the coverage of understory vegetation and litter species, slow down the impact of rain, and effectively protect the soil. Therefore, bamboo–wood mixed management can improve the water conservation function of bamboo forests and reduce the amount of soil erosion.

5. Conclusions and Directions for the Future Research

Compared to other plants, bamboo is a typical clonal plant that easily forms uneven-aged forests. It has a well-developed underground rhizome system and a large above-ground biomass. Bamboo plays a significant role in soil and water conservation, ecological balance maintenance, and biodiversity conservation. Bamboo resource adaptive management technology is crucial for fully leveraging and enhancing the ecological functions of bamboo forests. Current bamboo forest management research mainly focuses on economic benefits and maintaining productivity, with little work performed on the mechanisms of biological responses, site quality, and ecosystem services under different management practices. Furthermore, bamboo forest research was mostly project-oriented and lacked long-term fixed-point monitoring data, so the future changes in bamboo forest stands remain uncertain. The unclear evaluation criteria and imperfect assessment system lead to inaccurate evaluations of bamboo forests’ ecological functions. The screening of superior bamboo species and the optimization of management practices remain pivotal to the sustainable management of bamboo forests, particularly in the context of addressing global timber shortages and climate change. Therefore, how to ensure the sustainable management of bamboo forests and give full play to their ecological service function is a major challenge for future research. To address this, strengthening research in the following areas is necessary.

(1) Establish and improve a long-term fixed sampling monitoring system for bamboo forests. Bamboo forest management, a long-term process, has continuous impacts on bamboo’s phenotypic traits (density, canopy structure, root functional traits), site quality, and ecological functions. Long-term fixed-sample monitoring data of bamboo forests serve as the foundation for studying the underlying mechanisms of bamboo forest biology and ecological processes. In China, most bamboo forest studies rely on short-term, project-based monitoring, yielding data with poor comparability. This makes it difficult to analyze the long-term structural dynamics and changes in ecosystem services of bamboo forests.

(2) Research on the impact of management practices on the soil and water conservation effects of bamboo forests. Currently, some artificially operated bamboo forests have encountered common and urgent problems such as blind application of chemical fertilizers leading to soil quality decline, decreased yield returns, decreased stand quality, ecosystem stability, and stress resistance. Shifting bamboo forest management from economic-gain-centered to a high-yield, low-consumption system that balances economic and ecological benefits can effectively solve the problem of incompatibility between economic yield and ecological functions in bamboo forest management. Enhancing the economic benefits of bamboo forests while leveraging their ecological functions will promote the healthy and sustainable development of the bamboo industry. In light of the unique biology of bamboo forests, promoting their sustainable management is essential. This involves researching bamboo species with strong soil- and water-conservation capabilities, optimizing cultivation techniques, developing reasonable growing and mixing methods, creating optimal management models for bamboo–broadleaf mixed forests, exploring no-till practices, and restoring bamboo forest understory vegetation.

(3) Research into adaptive management technologies for bamboo forests is necessary to enhance their ecosystem functions. Bamboo forests, a unique ecosystem in China, play a vital role in maintaining ecological balance. Some artificially managed bamboo forests face issues like soil quality decline and reduced productivity due to excessive fertilizer use. This calls for research into how climate change and management practices affect key ecological functions such as carbon sequestration, water conservation, and soil erosion control in bamboo forests. It is crucial to develop an adaptive management-technology system for bamboo forests to address climate change and resolve the conflict between economic yield and ecological function in bamboo forest management.

(4) Developing and assessing a sustainable management indicator system for bamboo forest ecosystems. Research on site-quality evaluation techniques for major bamboo forest types is needed. This involves analyzing the relationship between bamboo forest productivity and site conditions and developing a site-quality evaluation index system that is both comprehensive and easy to use. Using fixed-plot and remote-sensing monitoring, evaluate and classify key bamboo forest site qualities. Then, develop a scientific classification system and create a bamboo forest site-quality distribution map for precise bamboo resource management. Focus on the quantitative analysis of the relationship between the dynamic changes in key factors in long-time series, the dynamics of runoff, and the function of soil and water conservation service. A comprehensive summary of the scientific monitoring and evaluation indicators or indicator systems and evaluation methods for bamboo forests is imperative. A qualitative and quantitative evaluation of the functional benefits of soil and water conservation services of bamboo forests is to be carried out, and evaluation models and early warning mechanisms are to be established so as to provide a scientific basis for the reasonable and safe construction of regional bamboo forest resources.