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摘要
伐桩在人工林生态系统地力维持、碳吸存、生物多样性保育、水土保持等方面具有十分重要的意义, 但对其储量及其分解特征的研究并不多见。因此, 该文作者基于马尾松(Pinus massoniana)人工林采伐档案, 2013年7月以1999-2013年间采伐残留的伐桩为研究对象, 调查了1-15年伐桩系统的木桩(SW)、树皮(B)、根桩(SR), 以及不同径级根系(R1: 0 mm <径级≤10 mm; R2: 10 mm <径级≤25 mm; R3: 25 mm <径级≤100 mm; R4: 径级> 100 mm)的储量与分解特征。研究结果表明: 马尾松人工林整个伐桩系统储量介于5-58 t·hm-2之间, 根桩储量最大, 木桩储量次之, 树皮储量最小, 根桩、木桩和树皮的储量均随着分解时间而降低。伐桩密度随分解时间而降低, 但木桩、根桩和粗根径级均显著影响密度的变化。木桩、树皮和根桩的分解常数分别为0.061、0.027、0.036, R1、R2、R3、R4根系的分解常数分别为0.079、0.042、0.047、0.119。由此可见, 马尾松人工林伐桩系统具有较高的储量, 但分解较慢, 且不同组分的降解速率具有显著差异。
关键词：
Abstract
Stump plays crucial roles in maintaining soil fertility, sequestering carbon, nursing biodiversity, and conserving soil and water in plantation ecosystems. However, little is known about the decay of stump and the related roots in Pinus massoniana plantations. This study aims to explore the characteristics of stump stock and decomposition in the P. massoniana plantation.
Based on log file records of P. massoniana plantation from Laifu Forestry Management Institute in Yibin City of Sichuan Province, we established a chronosequence of decaying P. massoniana stumps from 1999 to 2013. We then investigated the stock and density of stump wood (SW), bark (B), stomp root (SR), and linked roots with different diameters (R1: 0 mm < diameter ≤10 mm; R2: 10 mm < diameter ≤25 mm; R3: 25 mm < diameter ≤100 mm; R4: diameter > 100 mm).
In the investigated P. massoniana plantations, the stump stocks ranged from 5 to 58 t·hm-2, stocks in stump wood was the largest, in stump root as the second, and in bark was the smallest, which decreased with the decomposing time. Correspondingly, stump density decreased with decomposing time, while the changes in density varied with stump wood, stump root and roots with different diameters. The decomposition constants of stump wood, bark and stump root were estimated at 0.061, 0.027 and 0.036, respectively. The decomposition constants of roots were estimated to be 0.079 for R1, 0.042 for R2, 0.047 for R3 and 0.119 for R4, respectively. In conclusion, the P. massoniana plantation has a high stock, but decomposes slowly and the decomposition constant varies greatly with stump components in the P. massoniana plantation, which provides certain theoretical basis for the sustainable management of P. massoniana plantation in the region.
Keywords：
粗木质残体(CWD)是森林生态系统中重要的结构性和功能性组成要素(Harmon et al., 1986), 在地力维持、生物多样性保育、水源涵养和森林更新等方面具有十分重要的作用(侯平和潘存德, 2001)。作为人工林的采伐剩余物, 伐桩(stump)是人工林生态系统最重要的粗木质残体, 其在人工林地力维持、水土保持和碳吸存等方面具有重要的生态功能(Persson, 2013)。为了理解伐桩的生态系统功能, 国内外学者针对人工林伐桩的碳与养分动态(Stromgren et al., 2013)、大型真菌保育(Cleary et al., 2013)、无脊椎动物保育(Ols et al., 2013)、幼苗更新(Saksa, 2013)等进行了大量的科学研究。然而, 伐桩分解时间长(黄志群等, 2005), 受研究手段限制, 有关人工林伐桩分解过程的研究相对较少(Persson et al., 2013), 而且对人工林伐桩碳储量的估计误差为2%-10%。此外, 伐桩由木桩(树皮、木材)、根桩以及不同径级的根系组成, 而且所处的分解环境差异较大, 从而导致了不同的分解过程。但迄今为止, 尚未见相关的研究报道。事实上, 在人工林生态系统的经营与管理中, 不同采伐时间留下的伐桩剩余物为理解人工林伐桩储量及分解特征提供了重要的研究材料。因此, 根据人工林采伐记录档案, 采用倒推法建立伐桩分解序列实验, 可以较为清晰地了解人工林生态系统伐桩储量与分解特征。
马尾松(Pinus massoniana)具有耐干旱瘠薄、适应能力强等特点, 是我国南方低山丘陵区的主要造林树种, 在经济建设和生态建设中具有重要的作用(康冰等, 2009; 张克荣等, 2011)。为了可持续经营与管理马尾松人工林生态系统, 我国科研人员针对马尾松人工林生态系统的养分循环等进行了研究(项文化和田大伦, 2002; 莫江明等, 2002; 田大伦等, 2004; 杨会侠等, 2010)。然而, 有关马尾松伐桩分解特征的研究尚未见报道。因此, 本研究以地处长江上游地区不同采伐时期保留下来的马尾松伐桩为研究对象, 建立了马尾松伐桩分解序列(1-15年)实验, 研究了马尾松人工林伐桩储量及其分解特征, 以期为马尾松人工林可持续经营与管理提供科学依据。
研究区域位于宜宾市高县来复镇森林经营所林区(104.53°-104.57° E, 28.57°-28.60° N, 海拔412- 567 m), 地处长江上游和四川盆地南缘, 属中亚热带湿润季风气候。年平均气温18.1 ℃, 最高气温(7月) 36.8 ℃, 最低气温(1月) 7.8 ℃, 年降水量1021 mm。土壤为山地黄壤, 土层厚度约50 cm。原生植被为亚热带常绿阔叶林, 但现已基本垦殖为马尾松人工林。林下灌木为梨叶悬钩子(Rubus pirifolius)、枹栎(Quercus serrata)、油樟(Cinnamomum longepaniculatum)、野桐(Mallotus japonicas)、铁仔(Myrsine africana)、茶荚蒾(Viburnum setigerum)、野牡丹(Melastoma candidum)等。草本为蕨(Pteridium aquilinum)、金星蕨(Parathelypteris glanduligera)、芒(Miscanthus sinensis)、铁芒萁(Dicranopteris linearis)、皱叶狗尾草(Setaria plicata)、淡竹叶(Lophatherum gracile)等(谭波等, 2013; Justine et al., 2015)。
高县来复森林经营所建于1956年, 是一所以培育森林、生产与经营木材及木材加工等为主的事业单位。在长期的人工林经营与管理实践中, 保留了不同采伐时期的马尾松伐桩。2013年7月, 根据高县来复镇人工林经营所保存完善的采伐年代记录档案, 以1999-2013年间马尾松人工林采伐保留下来的伐桩为调查对象, 选择采伐林龄为29-30年、坡向与坡度基本一致、采伐后继续栽植马尾松人工林的立地(表1), 进行伐桩调查。在每个立地设立3个20 m × 20 m的样地, 对样地内所有伐桩进行调查, 测量每个伐桩的木桩直径、高度。根据调查结果, 建立1-15年的伐桩分解序列实验样地。由于2008年采伐的马尾松人工林的坡向、坡度和其他立地条件与其他年份的马尾松采伐迹地相比差异太大, 所以在伐桩分解序列中, 缺乏分解6年的伐桩。
在每个样地内选取5个与平均直径大小相近的伐桩, 将其掘出, 在挖掘过程中尽量保证树桩地上和地下部分的完整性。将伐桩分为木桩(SW)(树桩地上直径≥10 cm, 长度< 1 m的部分)、树皮(B)、根桩(SR)(伐桩地下直径≥15 cm, 长度< 1 m的部分)(阎恩荣等, 2005)和地下粗根4个部分, 且粗根按0-10 mm (R1)、10-25 mm (R2)、25-100 mm (R3)、>100 mm (R4)(Wang et al., 2014)分为4个径级。将解析后的各部分分别称质量, 并测量每个径级根长, 两端直径。木桩采样时, 先除去桩头5 cm, 再截取厚度为5 cm的圆盘, 将心材与树皮剥离, 分别称质量后带回; 根桩采样时, 分别在根桩的上部、中部、下部截取样品, 称量后带回。将测量过的粗根全部带回。
表1 研究样地基本概况
Table 1 The basic information of sampling plots
| 样地 Sampling plot | 坡向/坡度 Aspect/Slope (°) | 伐桩密度 Stump density (株·hm-2) | 根桩直径(平均值±标准误差) Stump diameter (mean ± SE) (cm) | 土壤pH值 pH value | 土壤容重 Soil bulk density (g·cm-3 ) | 土壤有机质含量 Soil organic matter content (g·kg-1) |
|---|---|---|---|---|---|---|
| S1 | NW/21 | 2 050 | 16.4 ± 0.48 | 4.16 | 1.42 | 29.92 |
| S2 | NW/18 | 2 315 | 15.9 ± 0.65 | 4.14 | 1.39 | 28.96 |
| S3 | NW/20 | 2 100 | 17.2 ± 0.53 | 4.17 | 1.46 | 27.64 |
| S4 | NW/21 | 2 070 | 16.6 ± 0.44 | 4.14 | 1.40 | 27.44 |
| S5 | NW/17 | 2 405 | 15.6 ± 0.56 | 4.15 | 1.44 | 28.35 |
| S7 | NW/20 | 2 150 | 16.2 ± 0.39 | 4.16 | 1.41 | 27.43 |
| S8 | NW/19 | 2 190 | 16.4 ± 0.41 | 4.16 | 1.43 | 27.49 |
| S9 | NW/20 | 2 130 | 16.3 ± 0.47 | 4.18 | 1.45 | 27.64 |
| S10 | NW/18 | 2 350 | 15.9 ± 0.62 | 4.16 | 1.42 | 28.23 |
| S11 | NW/19 | 2 200 | 16.1 ± 0.32 | 4.15 | 1.44 | 28.06 |
| S12 | NW/20 | 2 085 | 17.1 ± 0.54 | 4.15 | 1.43 | 28.62 |
| S13 | NW/21 | 2 070 | 16.7 ± 0.29 | 4.16 | 1.39 | 29.26 |
| S14 | NW/20 | 2 125 | 16.8 ± 0.51 | 4.15 | 1.42 | 30.46 |
| S15 | NW/17 | 2 380 | 15.8 ± 0.48 | 4.15 | 1.40 | 31.45 |
将带回实验室的样品, 采用水置换法测定树桩各部分的体积, 计算树桩密度。70 ℃下烘干树桩, 测定树桩的干质量和含水率。
单位面积树桩的储量=树桩各部分质量的平均值×样地内树桩数/样地面积
密度=干质量/体积(g·cm-3)
含水率(%) = (鲜质量-干质量)/鲜质量×100%
基于Olson (1963)的分解模型, 采用下式计算根桩的分解速率(K):
K = (ln(Yo) - ln(Yt))/t
式中t为根桩保留在林地上的时间, Yo为当年采伐树桩的密度, Yt为t时的根桩密度。
数据统计分析采用SPSS 20.0和Excel 2003软件完成。采用单因素方差分析(one-way ANOVA)和最小显著差异法(LSD)检验不同分解时间树桩各部储量、密度的差异, 显著性水平设定为p = 0.05。
随着分解时间增加, 木桩的储量在4-36 t·hm-2范围内变化, 呈先迅速降低后缓慢降低的趋势 (图1), 表明伐桩分解释放了大量的有机物质与养分, 这对于维持土壤肥力和生态系统生物元素循环具有重要意义。经过15年的分解, 木桩的储量由36.52 t·hm-2逐渐降低到8.16 t·hm-2, 且变化极显著(p < 0.01)。SW、B、SR也呈同样的变化规律, SW储量降低显著(p < 0.05), SR储量降低极显著(p < 0.01), 但B储量降低不显著(p > 0.05) (图2)。
图1 马尾松人工林伐桩分解序列的储量变化(平均值±标准误差, n = 3)。不同小写字母表示不同分解年限间差异显著(p < 0.05)。
Fig. 1 Changes in stump stocks of Pinus massoniana plantations across a decomposition series (mean ± SE, n = 3). Different lowercase letters mean the level of significant differences among different decomposition years (p < 0.05).
随着分解的进行, SW、B、SR储量在整个树桩中所占的比例逐渐变化。树皮在其中所占的比例显著增大, 由1.604%增加到10.845%。木桩的比例也由14.337%增加到38.498%, 而根桩的比例由84.059%减小到50.657% (图3)。
图2 马尾松人工林伐桩的木桩、树皮和根桩储量随分解过程的变化(平均值±标准误差, n = 3)。不同小写字母表示不同分解年限间差异显著(p < 0.05), 不同大写字母表示同一分解时间不同部位间差异显著(p < 0.05)。B, 树皮; SR, 根桩; SW, 木桩。
Fig. 2 Changes in stump wood, bark and stump root stocks with stump decomposition in the Pinus massoniana plantations (mean ± SE, n = 3). Different lowercase letters mean the level of significant differences among different decomposition years (p < 0.05), and different uppercase letters indicate the level of significant differences among different stump parts (p < 0.05). B, bark; SR, stump root; SW, stump wood.
图3 马尾松人工林伐桩不同部位的储量比例随分解过程的变化(平均值±标准误差, n = 3)。B, 树皮; SR, 根桩; SW, 木桩。
Fig. 3 Changes in the relative ratios among stump wood, stump bark and stump root with stump decomposition in the Pinus massoniana plantations (mean ± SE). B, bark; SR, stump root; SW, stump wood.
根桩在分解过程中, 储量在1-22 t·hm-2 范围内变化, 其储量变化与木桩储量变化大致类似, 但有一个增加过程, 呈先增加后迅速降低再缓慢降低的趋势, 根桩的储量由17.49 t·hm-2逐渐降低到4.91 t·hm-2。单因素方差分析表明, 伐桩粗根储量随着分解的进行变化极显著(p < 0.01) (图4)。
图4 马尾松伐桩分解过程中根桩储量的变化(平均值±标准误差, n = 3)。不同小写字母表示不同分解年限间差异显著(p < 0.05)。
Fig. 4 Changes in stump root stocks with stump decomposition in the Pinus massoniana plantations (mean ± SE, n = 3). Different lowercase letters mean the level of significant differences among different decomposition years (p < 0.05).
随分解时间的增加, R1、R2储量一直缓慢降低, R1储量从0.62 t·hm-2减少到0.02 t·hm-2, R2储量从1.75 t·hm-2减少到0.17 t·hm-2。R1、R2径级根的储量变化极显著(p < 0.01), 而R3、R4径级根的储量变化趋势与粗根的整体储量变化趋势一致, 都是先增加后迅速降低再缓慢降低, R3储量从4.26 t·hm-2增加到6.17 t·hm-2, 经分解减少到2.30 t·hm-2, R4的储量从10.87 t·hm-2增加到17.78 t·hm-2, 随着分解的进行降低到 2.41 t·hm-2, 且R3径级的储量变化极显著 (p < 0.01), R4径级的储量变化显著(p < 0.05) (图5)。同时, 各径级根的储量R4 > R3 > R2 > R1, 而且R3、R4的储量明显大于R1、R2的储量, 说明R3、R4径级的根对粗根系统储量的贡献大, 它们的变化对粗根储量的变化较R1、R2影响大。
图5 马尾松人工林不同径级根分解过程中的储量变化(平均值±标准误差, n = 3)。不同小写字母表示不同分解年限间差异显著(p < 0.05), 不同大写字母表示同一分解时间不同部位间差异显著(p < 0.05)。R1, 0 mm <径级≤10 mm; R2 , 10 mm <径级≤25 mm; R3, 25 mm <径级≤100 mm); R4, 径级>100 mm。
Fig. 5 Changes in different class root decomposition stocks with stump decomposition in the Pinus massoniana plantations (mean ± SE, n = 3). Different lowercase letters mean the level of significant differences among different decomposition years (p < 0.05), and different uppercase letters indicate the level of significant differences among different stump parts (p < 0.05). R1, 0 mm < diameter ≤10 mm; R2, 10 mm < diameter ≤25 mm; R3, 25 mm < diameter ≤100 mm; R4, diameter >100 mm.
随分解时间的增加, SW、B、SR的密度呈降低的趋势, 且逐渐趋于稳定(图6)。经15年的分解, SW的密度由未分解时的0.89 g·cm-3降低到0.36 g·cm-3, SR的密度由未分解时的0.60 g·cm-3降低到0.40 g·cm-3。而B的密度呈现缓慢降低的趋势, 经15年的分解由未分解时的0.47 g·cm-3降低到0.32 g·cm-3。B密度趋于稳定的时间比SW和SR早, B分解到第5年后密度就趋于稳定, 而SW和SR分解到第8年以后密度才逐渐趋于稳定(图6)。
图6 马尾松人工林伐桩的木桩、树皮和根桩密度随分解过程的变化(平均值±标准误差, n = 3)。B, 树皮; SR, 根桩; SW, 木桩。
Fig. 6 Changes in stump wood, bark and stump root density with stump decomposition in the Pinus massoniana plantations (mean ± SE, n = 3). B, bark; SR, stump root; SW, stump wood.
随分解时间的增加, 根桩内营养物质被逐渐分解, 不同径级根系的密度呈降低趋势并逐渐趋于稳定(图7)。单因素方差分析表明, 不同径级根系在分解初期的密度与其他时间分解密度的差异显著(p < 0.05)。在根桩分解初期, R1、R2和R3径级的密度缓慢降低, 而R4径级的密度迅速减小。从采伐1年到15年的伐桩密度来看, R1径级的密度由0.68 g·cm-3降低到0.21 g·cm-3, R2径级的密度由0.58 g·cm-3降低到0.31 g·cm-3, R3径级的密度由0.59 g·cm-3降低到0.29 g·cm-3, 且在采伐5-7年后变化趋于稳定, 而R4径级的密度由1.66 g·cm-3降低到0.28 g·cm-3, 并且还有继续降低的趋势。与采伐1年后的各径级根系密度相比, R1、R2、R3和R4分别大约分解为原来的31%、53%、49%、17%。
图7 马尾松人工林不同径级根分解过程中的密度变化(平均值±标准误差, n = 3)。 R1, 0 mm <径级≤10 mm; R2 , 10 mm <径级≤25 mm; R3, 25 mm <径级≤100 mm); R4, 径级> 100 mm。
Fig. 7 Changes in different class root decomposition density with stump decomposition in the Pinus massoniana plantations (mean ± SE, n = 3). R1, 0 mm < diameter ≤10 mm; R2, 10 mm < diameter ≤25 mm; R3, 25 mm < diameter ≤100 mm; R4, diameter > 100 mm.
拟合树桩分解过程中不同部位的密度(Y)与时间(t)的对数函数方程(表2)反映了马尾松伐桩不同部位密度变化, 可以为研究马尾松伐桩整个分解过程的分解特征提供依据。
表2 树桩分解过程中不同部位的密度(Y)与时间(t)的对数函数方程
Table 2 The density (Y) of different components and the logarithmic function equation of time (t) in stump decomposition process
| 树桩的部位 Parts of the stump | 对数函数方程 Logarithmic function equation | r |
|---|---|---|
| 树皮 Barks | Y = -0.0051ln(t) + 0.4778 | 0.001 3 |
| 木桩 Stump wood | Y = -0.1989ln(t) + 0.8153 | 0.567 9 |
| 根桩 Stump root | Y = -0.1444ln(t) + 0.6522 | 0.237 9 |
| 0 mm <径级 Diameter ≤10 mm | Y = -0.1470ln(t) + 0.6937 | 0.271 4 |
| 10 mm <径级 Diameter ≤25 mm | Y = -0.0352ln(t) + 0.5470 | 0.016 1 |
| 25 mm <径级 Diameter ≤100 mm) | Y = -0.1043ln(t) + 0.5951 | 0.241 5 |
| 径级 Diameter > 100 mm) | Y = -0.4042ln(t) + 1.2127 | 0.724 1 |
伐桩分解过程中, SW、B、SR的分解速率随分解时间的增加先增大后减小且逐渐趋于一致(图8)。SW的分解速率整体大于B和SR。分解初期, SW的分解速率变化按照慢→快→慢节奏增加, 到第4年达到最大值, 而B和SR的分解速率变化呈现缓慢增加趋势, 分别到第6年和第7年达到最大值。
图8 马尾松人工林伐桩的木桩、树皮和根桩分解速率随分解过程的变化(平均值±标准误差, n = 3)。B, 树皮; SR, 根桩; SW, 木桩。
Fig. 8 Changes in stump wood, bark and stump root decomposition rate with stump decomposition in the Pinus massoniana plantations (mean ± SE, n = 3). B, bark; SR, stump root; SW, stump wood.
在分解初期, R1、R2和R3有一个分解特别缓慢的停滞阶段, 从第2年前中期分解速率开始增大, 分别在分解第7年、第9年、第4年增大到整个分解过程中分解速率的最大值0.22、0.19、0.14, 此后它们的分解速率分别逐渐降低到0.08、0.04、0.05, 并趋于稳定; R4在分解初期没有明显的停滞阶段, 而是分解速率迅速增大, 在分解第3年中期达到最大值0.95, 此后分解速率迅速降低, 从第7年后分解速率就缓慢降低到0.26, 且逐渐趋于稳定(图9)。
图9 马尾松人工林不同径级根分解过程中的分解速率变化(平均值±标准误差, n = 3)。R1, 0 mm <径级≤10 mm; R2 , 10 mm <径级≤25 mm; R3, 25 mm <径级≤100 mm); R4, 径级> 100 mm。
Fig. 9 Changes in different class root decomposition rate with stump decomposition in the Pinus massoniana plantations (mean ± SE, n = 3). R1, 0 mm < diameter ≤10 mm; R2, 10 mm < diameter ≤25 mm; R3, 25 mm < diameter ≤100 mm; R4, diameter > 100 mm.
理论上, 采伐时间越久, 人工林的伐桩储量越小(杨方方等, 2009; 张修玉等, 2009; 袁杰等, 2012)。本研究表明, 分解15年后, 马尾松伐桩的储量由58 t·hm-2降低到5 t·hm-2, 且木桩、根桩和不同径级的根系均表现出相似的变化趋势。这意味着, 在物理、化学和生物因子的综合作用下, 伐桩将归还大量碳和养分到土壤库中(杨玉盛等, 2003), 保持了土壤肥力, 促进了人工林生态系统的物质循环与能量循环。其中, 根桩的储量降低速度高于木桩, 不同径级的根系相比, 径级越大, 储量变化越大。这表明, 树皮中不利于微生物分解的木质素、纤维素等多酚类物质含量高, 所以变化规律不明显(常晨晖等, 2015)。木桩与根桩的营养物质成分相似, 但根桩更接近于土壤, 不仅有利于土壤动物的作用, 而且有利于微生物的附着, 同时能更快地将营养物质释放到土壤中, 所以根桩的储量变化大。径级小的根微生物定植与着生的滞后时间比较久, 这也许是由于非近地面土壤动物种群少, 作用弱, 而径级大的根本身生物量大, 适合微生物利用分解的物质比重大。然而, 伐桩的储量还受到树木基径和采伐高度等影响。与其他地区森林的CWD储量相比, 马尾松人工林CWD储量总体偏高, 高于温带地区东北长白山云冷杉倒木储量(杨丽韫等, 2002), 高于西双版纳热带季节雨林(宋泽伟和唐建维, 2008)、亚热带武夷山甜槠(Castanopsis eyrei)林(李凌浩等, 1996)、鼎湖山阔叶林(唐旭利等, 2003)、秦岭巴山冷杉(Abies fargesii)林(李凌浩等, 1998)、大明山阔叶林(温琳华等, 2010)、小陇山锐齿栎(Quercus aliena var. acuteserata)林(何帆等, 2011), 但低于川西高山森林倒木储量(肖洒等, 2014)。本研究中, 伐桩的木桩储量、根桩储量在分解第二年降低, 第三年升高, 之后呈现逐渐下降的趋势。原因可能是分解第三年, 即2011年采伐的马尾松人工林生长相对较好、基径较大。具体原因尚待进一步调查研究。
随着分解时间增加, 整个伐桩系统及其组分的密度均表现为降低的趋势, 但由于其质量和对环境的响应差异, 不同组分的密度变化明显不同。相对于其他组分, 树皮包裹于伐桩系统之外, 最先受到土壤生物的侵入, 也最易受环境变化的影响。因此, 树皮密度趋于稳定的时间早。伐桩中木桩、根桩及不同径级的根中, 有利于微生物分解的养分元素(如: N、P、K和有机质等)被微生物分解利用, 难分解化学组分(如: 纤维素、木质素和单宁等)在组织里累积, 所以伐桩各组分的密度逐渐降低并趋于稳定。但由于径级大的根分解初期生物量大, 分解速率大, 所以密度变化大, 经15年分解, 密度也没有趋于稳定的趋势。
马尾松人工林伐桩不同组分的腐烂速率存在较大差异。这是因为能影响微生物生长与发育的因子就能影响伐桩的分解, 分解初期某些土壤动物也起一定作用(Stohlgren, 1988)。这些影响因子包括有机质本身的质地和外界理化环境。有机质本身的质地包括化学属性(C、能源、养分和调节因子)和物理属性(表面性质、硬度、大小等)两个主要方面; 外界理化环境包括温度、湿度、pH值、淋洗及其他因子等。因此, 马尾松人工林伐桩不同组分的分解差异与其本身的化学性质、物理结构及所处的外界环境有关, 且不同植物残体的分解速率也会相差很大。例如, Chen等(2001)对美国俄勒冈州几种树种木质树根分解的研究发现, 树种之间的分解速率相差很大。同一片林分中云杉(Picea sitchensis)树根的分解常数在0.016-0.021之间, 而加州铁杉(Tsuga heterophylla)树根的分解常数在0.033-0.049之间。在另一片林分中, 黑松(Pinus contorta)树根的分解常数在0.025-0.030之间, 而北美黄松(Pinus ponderosa)树根的分解常数在0.073-0.077之间。黄志群等(2005)研究了连栽杉木(Cunninghamia lancelata)林中伐桩的分解过程, 其分解常数为0.027 ± 0.004。本研究表明, 马尾松人工林木桩与根桩的分解常数分别为0.061 ± 0.021、0.027 ± 0.005, 分解相对较慢, 这可能与其较高的C/N比有关(Blumfield et al., 2004)。研究结果与伐桩的实际分解过程还存在一定偏差, 但基本上能反映马尾松人工林伐桩分解过程中各组分的储量变化与分解特征, 不仅为马尾松伐桩分解过程中营养元素变化与影响伐桩分解因素的研究提供了依据, 而且也可以对马尾松人工林的经营与调控发挥一定的参考作用, 但由于CWD在林地表面存留时间相对较长(Hood et al., 2004), 其存在状态及其生态功能对森林生态系统碳循环的影响还有待于长期深入的追踪研究。
致谢 感谢肖洒在采样和实验工作中给予的帮助。
The authors have declared that no competing interests exist.
作者声明没有竞争性利益冲突.
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Decomposition of nitrogen. |
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Changes in log quality at different decay stages in an alpine forest. 高寒森林倒木在不同分解阶段的质量变化 .https://doi.org/10.17521/cjpe.2015.0002 URL Magsci [本文引用: 1] 摘要
<p>倒木是高寒森林生态系统重要的碳(C)库和养分库, 其不同分解阶段的质量变化, 是认识倒木分解过程中C和养分释放的重要基础。以一个分解序列的岷江冷杉(<em>Abies faxoniana</em>)倒木为研究对象, 研究了心材、边材和树皮在5个分解阶段的C:N:P化学计量特征, 以及木质素和纤维素含量动态。结果显示: I至III分解阶段, 随着分解程度加深, 树皮C含量升高, 而心材和边材C含量降低, 从IV分解阶段开始倒木各组分C含量均开始显著降低。除III分解阶段的心材外, 倒木各组分N含量总体表现为随着分解程度加深而增加的趋势, 除边材N含量在V分解阶段时显著升高外, 其余组分均未达到显著性水平。心材和树皮P含量表现为先降后升的变化趋势, 最小值分别出现在III和II分解阶段; 边材P含量表现为随着分解程度加深而增加。在同一分解阶段, 树皮相对于边材和心材均具有最低的C:N:P化学计量比, 易分解比例<em>F</em><sub>m</sub>也表明树皮更易于分解。边材在I和II分解阶段的C:N:P化学计量比最高, 心材在III到V分解阶段C:N:P化学计量比最高。心材C:P、树皮和边材的C:N和C:P临界值与N和P的初始值成反比。纤维素含量随着倒木分解而降低, 不同分解阶段的纤维素含量表现为: 心材>边材>树皮; 但木质素含量随着分解程度加深而增加, 表现为: 树皮>边材>心材; 倒木3个组分纤维素含量下降均快于木质素, 此外, IV和V分解阶段的树皮木质素与纤维素比值显著增高, 且一直处于较高水平。统计分析结果表明: 倒木N含量显著影响不同分解阶段木质素和纤维素分解。由生态化学计量学理论推测: 树皮分解前期易受N限制, 整个分解阶段均易受P限制, 心材和边材在整个分解阶段均易受N和P限制。</p>
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Decomposition and nitrogen release from decomposing woody roots in coniferous forests of the Pacific Northwest: A chronosequence approach. |
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Stump removal to control root disease in Canada and Scandinavia: A synthesis of results from long-term trials. https://doi.org/10.1016/j.foreco.2012.05.040 URL Magsci [本文引用: 1] 摘要
Heterobasidion annosum sensu lato (s.l.), Armillaria ostoyae, and Phellinus sulphurascens are economically important fungal pathogens in temperate forests of the northern hemisphere that cause decay, growth reduction and tree mortality of coniferous hosts. Fungal inoculum residing in roots and stumps after final felling can remain viable for decades and place stands at an increased risk of mortality in subsequent rotations. Stump removal is one strategy that can be used to reduce the impact of root rot fungi in regenerating stands. This paper presents results from five long-term stump removal trials in Canada, Denmark, and Sweden. In all studies, stumps were extracted and larger roots removed. After a period of time ranging between 21 and 50 years, tree mortality, infection or both caused by A. ostoyae, P. sulphurascens and H. annosum s.l. was compared between stumped and non-stumped areas. In all but one trial, efficacy of stump removal to reduce disease occurrence over the long-term was 80-100% for A. ostoyae, 85-100% for P. sulphurascens, and 20-72% for H. annosum s.l. Stump removal for H. annosum s.l. was more effective in the Swedish trial than in the Danish trial, but in both locations the frequency of root disease increased with tree age. Results from trials indicate that stump removal is effective in reducing disease incidence and likely improves site productivity in subsequent rotations. Forest managers should consider stump removal as a routine operation when harvesting, especially on sites that have high hazard for A. ostoyae, P. sulphurascens, or both. Even though stump removal can provide adequate control against H. annosum, use of the biocontrol agent Phlebiopsis gigantea on freshly cut stump surfaces after harvest and following thinnings is perhaps a more cost effective control measure to reduce the frequency of H. annosum rot in next rotation forests. New initiatives involving harvesting of stumps for bioenergy may offer the additional benefit of minimizing disease impacts in next rotation forests. (C) 2012 Crown Copyright and Elsevier B.V. All rights reserved.
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Ecology of coarse woody debris in temperate ecosystems. https://doi.org/10.1016/S0065-2504(03)34002-4 URL [本文引用: 1] 摘要
Coarse woody debris (CWD) is an important component of temperate stream and forest ecosystems. This chapter reviews the rates at which CWD is added and removed from ecosystems, the biomass found in streams and forests, and many functions that CWD serves. CWD is added to ecosystems by numerous mechanisms, including wind, fire, insect attack, pathogens, competition, and geomorphic processes. Despite the many long-term studies on tree mortality, there are few published rates of CWD input on mass-area -1 time -1 basis. CWD is significantly transformed physically and chemically. Movement of CWD, especially in streams, is also an important but poorly documented mechanism whereby CWD is lost from ecosystems. Many factors control the rate at which CWD decomposes, including temperature, moisture, internal gas composition of CWD, substrate quality, size of CWD, and types of organisms involved. However, the importance of many of these factors has yet to be established in field experiments. CWD performs many functions in ecosystems, serving as autotrophic and heterotrophic habitat and strongly influencing geomorphic processes, especially in streams. It is also a major component of nutrient cycles in many ecosystems and is an important functional component of stream and forest ecosystems.
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Reserves of litter and woody debris of two main forests in the Xiaolong Mountains, Gansu, China. 小陇山林区主要森林群落凋落物及死木质残体储量 .https://doi.org/10.3724/sp.j.1145.2011.00046 URL [本文引用: 1] 摘要
采用固定面积样方取样法研究了小陇山林区锐齿栎和油松天然林死木质残体及凋落物的总储量.结 果表明：小陇山林区锐齿栎天然林粗死木质残体（Coarse woody debris,简称CWD）和细小木质残体（Fine woody debris,简称FWD）储量分别为29 350.92 kg hm-2和2 298.41 kg hm-2,分别为油松天然林的3.8和1.3倍.油松林CWD组成中枯立木占到85.65%,倒木只占14.35%,而锐齿栎天然林枯立木和倒木所占的比 例基本为1.从CWD的径级结构上来说,锐齿栎林内以大径级CWD为主（≥20 cm）,占样地CWD总储量的60.81%,天然油松林以小径级（20 cm≥小径级≥10 cm）CWD为主,大、小径级分别占CWD储量的55.33%和44.67%.油松林内凋落物储量为30 472.31 kg hm-2,是天然锐齿栎凋落物储量8 902.29 kg hm-2的3倍以上.凋落物和死木质残体储量的不同是锐齿栎天然林和油松天然林种群结构、林分更新和群落内部竞争状况及凋落物分解状况差异所导致的结果.
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Colonisation of podocarp coarse woody debris by decomposer basidiomycete fungi in an indigenous forest in the central North Island of New Zealand. https://doi.org/10.1016/S0378-1127(04)00220-8 URL [本文引用: 1] 摘要
Populations of basidiomycete fungi were determined in fallen trees of two species (rimu, Dacrydium cupressinum and matai, Prumnopitys taxifolia ) in a dense podocarp forest in the central North Island, in order to assist in explaining observed patterns and rates of decay. Fungi were isolated from discs cut at measured intervals along the stems of 8 trees of each species that had been studied 16 years previously. Yields of basidiomycete cultures were greater 20 years after windfall than after 4 years at radial depths exceeding 6cm within the rimu stems, but were not significantly different beyond 12cm in most matai trees, in which the heartwood was more resistant to colonisation. Certain basidiomycete species were associated with specific decay patterns. Prominent in both hosts were Armillaria novae-zelandiae , Ganoderma cf. applanatum , and less frequently, in the outer wood, Sistotrema brinkmannii and Hyphodermopsis polonensis . Armillaria limonea and Rigidoporus concrescens were also important towards the periphery of rimu stems. G. cf. applanatum had penetrated right to the centre of many rimu and some matai stem segments after 20 years, and large woody perennial fruitbodies present on 9 study trees were a reliable predictor of internal colonisation by this species. Presence and absence disparities between the 4- and 20-year samplings suggested that some less common basidiomycetes showed successional trends. In a more intensive examination of one tree of each species, G. cf. applanatum occupied the rimu stem in the form of multiple sets of longitudinally elongated single-genet dikaryotic colonies separated by brown pseudosclerotial plates. Genets were unique to each stem segment, indicating that colonisation occurred by means of basidiospores after the earlier sampling. On the other hand, one genet each of A. novae-zelandiae (in matai) and A. limonea (in rimu) extended to more than one segment, implying some vegetative spread, either before the first sampling or subsequently by means of rhizomorphs in soil or litter. Future research will investigate how these basidiomycete populations compare with those in the same and other tree species in relation to rates of decomposition on different sites.
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Coarse woody debris and its function in forest ecosystem. 森林生态系统中的粗死木质残体及其功能 .https://doi.org/10.1007/s11769-001-0027-z URL [本文引用: 1] 摘要
粗死木质残体(Coarse Woody Debris，CWD)是指所有地上和地下小头直径＞2．5cm的死木质物．林分中CWD主要来源于个体的死亡和干扰所造成的死亡，在森林群落的生长发育 过程中，CWD的数量变化呈“U”型．CWD的分解是动物和微生物吸收养分、淋溶和自然破碎综合作用的结果，CWD的分解过程就是其发挥功能的过程，在此 过程中各阶段都会有不同类型的生物群体利用其提供生境或食物；CWD具有吸收和释放养分的能力，是植物生长的营养库，是森林树木更新的良好介质；CWD是 许多陆生生物和水生生物的食物来源、栖息地、避难所、哺育地、迁移通道等，在生物多样性保持方面发挥着不可替代的作用；大CWD的形成过程产生了林窗斑 块，推动了森林生态系统的小循环．因此，CWD是森林生态系统中重要的结构性和功能性组成要素，在保持森林生态系统和水生生态系统的生物多样性及其生态过 程完整性等方面起着不可替代的作用，应当给予充分的重视．
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Chemical composition trend in Cunninghamia lancelata (Lamb.) Hook. stump decomposition process. 连栽杉木(Cunningh- amia lancelata (Lamb.) Hook.)林中树桩分解过程中的化学组分变化趋势 .
采用以空间代替时间的方法, 对连栽杉木(<I>Cunninghamia lancelata</I> (Lamb) Hook)人工林中采伐剩余树桩的分解过程进行了研究. 根据Olson的分解模型, 计算出连栽杉木纯林中树桩的分解速率为0.02695, 树桩在分解过程中的前2年是一个氮素增加积累过程, 当杉木树桩的C/N在463.2 ± 27.3时开始净氮释放. 树桩磷含量的变化与氮变化模式相类似, 但钾的表现不同, 钾的含量在树桩分解过程中一直是单调降低. 利用固体高分辨核磁共振技术结合魔角旋转(MAS)和交叉极化(CP)技术, 研究了杉木树桩的腐殖化过程及碳结构的变化. 树桩中由纤维素和半纤维素组成的多糖碳和乙缩醛被首先分解, 而由蜡质和表皮素等化合物组成的烷基碳, 由酚类、木质素、单宁和石蜡等化合物组成的芳香族碳, 及由酯、有机酸、酮和醛等化合物组成的羧基碳的分解速度较多糖碳和乙缩醛慢.
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Biomass stock and carbon sequestration in a chronosequence of Pinus massoniana plantations in the upper reaches of the Yangtze River. https://doi.org/10.3390/f6103665 URL [本文引用: 1] 摘要
Planted forest plays a significant role in carbon sequestration and climate change mitigation; however, little information has been available on the distribution patterns of carbon pools with stand ages in Pinus massoniana Plantations. We investigated the biomass stock and carbon sequestration across a chronosequence (3-, 5-, 7-, 9-, 12-, 15-, 19-, 29-, 35- and 42-year) of stands with the main objectives: (1) to determine the biomass and carbon stock of the forest ecosystem; and (2) to identify factors influencing their distribution across the age series. Simple random sampling was used for collecting field data in the ten (10) stand ages. Three 20 01— 20 m standard plots were laid out in February 2015 across the chronosequence. The diameter at breast height (DBH) and tree height (H) of each tree within each plot were measured using calipers and height indicator. Sub-plots of 2 01— 2 m were established in each main plot for collecting soil samples at a 0-30- and 30-60-cm depth. Plantation biomass increased with increasing stand ages, ranging from 0.84 tonnes per hectare (t00·ha-1) in the three-year stand to 252.35 t00·ha-1 in the 42-year stand. The aboveground biomass (AGB) contributed 86.51%; the maximum value is 300-times the minimum value. Carbon concentrations and storage in mineral soil decreased with increasing soil depth, but were controlled by the management history of the ecosystem. The total ecosystem carbon storage varies with stand ages, ranging from 169.90 t00·ha-1 in the five-year plantation to 326.46 t00·ha-1 in the 42-year plantation, of which 80.29% comes from the mineral soil carbon and 19.71% from the vegetation. The ratio of the total carbon sequestration by the 42-year to the three-year stand was 1.70, implying substantial amounts of carbon accumulation during the transition period from young to mature-aged trees. The forest ecosystem had the capacity of storing up to 263.16 t00·ha-1 carbon, assisting in mitigating climate change by sequestrating 965.83 t00·ha-1 of CO2 equivalents, indicating that the forest is an important carbon sink.
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| [11] |
Effects of Pinus massoniana plantation stand density on understory vegetation and soil properties. 马尾松人工林林分密度对林下植被及土壤性质的影响 .
采用样方调查及取样分析方法,研究广西大青山南亚热带不同密度马 尾松人工林林下植被及土壤特征.结果表明:马尾松人工林自然发育14 a后,林分密度从1050株·hm~(-2)增加到1800株·hm~(-2),林下灌木层物种多样性指数增高.密度为1800株·hm~(-2)时,多 样性指数最高.当林分密度继续增大到2250株·hm~(-2),灌木层物种多样性指数却呈降低趋势.林下草本物种多样性指数对林分密度变化的响应不敏 感;在林分密度影响下,林下灌木生物量与灌木层物种多样性指数变化规律一致.随着林分密度的增大,林下草本生物量呈降低趋势;不同密度马尾松人工林土壤理 化特性差异显著(P＜0.05).除全K、速效K和速效P外,土壤表层(0～20 cm)养分含量与林下灌木层物种多样性指数变化趋势一致.不同密度林地速效K和速效P含量变化波动较大.密度为2100株·hm~(-2)的林分土壤全P 含量较高.中密度(1800株·hm~(-2))林地的土壤持水量和孔隙度均较高,土壤容重较低.
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| [12] |
Coarse woody debris in an Abies fargesii forest in the Qinling Mountains. 秦岭巴山冷杉林粗死木质残体研究 .
对秦岭巴山冷杉林粗死木质残体的研究表明：1)林内粗死木质残体的现存量为15.848t·hm-2，平均死亡增枯量1.877t·hm-2·a-1，平均分解量1.310t·hm-2·a-1，周转时间约为12.09年；2)粗死木质残体在碳素和养分的保持方面具有一定作用，在野生动植物生境构成中的作用较大。
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| [13] |
Storage and dynamics of coarse woody debris in Castanopsis eyrei forest of Wuyi Mountain, with some considerations for its ecological effects. 武夷山甜槠林粗死木质残体的贮量、动态及其功能评述 .
本文对武夷山甜槠林76龄成熟林内粗死木质残体的贮量、增枯量和分解量等进行了研究，对不同林龄甜槠林粗死木质残体的贮量动态进行了对比分析，并初步评述了它们在森林生态系统养分循环中的作用。研究结果表明：(1)甜槠林成林粗死木质残体贮量为7.349t·hm-2，增枯量为1.425t·hm-2·a-1，分解量为0.512t·hm-2·a-1；(2)随着林龄增长，不同林龄甜槠林的粗死木质残体贮量呈“S”型动态模式，至58龄阶段达到最大值，其后渐趋稳定；(3)粗死木质残体是甜槠林生态系统中较为重要的组成部分，其各养分元素贮量占该系统生物量分室总贮量的0.09%～1.91%，由增枯量实现的各养分元素归还量占养分元素归还总量的l.94%～4.48%。
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| [14] |
Role of understory plants on nutrient cycling of a restoring degraded pine forests in a MAB reserve of subtropical China. 林下层植物在退化马尾松林恢复初期养分循环中的作用 .
以鼎湖山退化马尾松 (Pinusmassoniana)林恢复过程中林下层植物凋落物、分解和养分动态为对象 ,研究了林下层植物在退化马尾松林恢复初期养分循环中的作用。结果表明 ,林下层年凋落物量除在第 5年有所下降外均随时间逐年上升 ,但其增加速率随年份不同而异 ,总平均年增长速率为 3 8%。第 4年凋落物量为 0 .2 0 t· hm- 2 · a- 1,第 1 1年为 1 .1 7t·hm- 2·a- 1。凋落物养分元素平均浓度为 (% ) :N0 .95 ,P0 .0 4,K0 .5 7,Ca0 .1 3和 Mg0 .0 8,基本上以夏季和秋季最高冬春交替月份最低。第 1 1年凋落物各元素养分归还量为 (kg· hm- 2·a- 1) :N1 1 .1 0 ,P0 .47,K6.65 ,Ca1 .48和 Mg 0 .91。凋落物在分解过程中失重率呈直线模型变化 ,第 1年的分解速率为 3 1 % ,至试验结束时凋落物的残存量占起始量的 66%。在凋落物分解过程中 ,N和 P浓度随时间逐渐上升 ,但 N增加的速度较 P快 ,其余元素浓度均下降 ,但 K下降的速度最快。在凋落物分解过程中 ,N是唯一表现残留量呈先上升然后下降变化的元素。P的残留量变化与凋落物的失重率变化几乎一致。各元素在分解试验结束时残留量占起始量的百分比分别为：N 90%，P 67%，K 9%， Ca 30%和Mg 14%。可见，林下层凋落物在退化马尾松林恢复初期碳及其它营养元素循环方面起着极其重要的作用。
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| [15] |
Saproxylic insect fauna in stump on wet and dry soil: Implications for stump harvest. https://doi.org/10.1016/j.foreco.2012.08.040 URL Magsci [本文引用: 1] 摘要
An increasing demand for bioenergy has stimulated interest in harvesting of tree stumps after felling operations. To reduce the amount of soil disturbance, it is recommended to retain stumps in wet areas. We wanted to evaluate if that strategy is beneficial also for saproxylic (wood-living) insects, which will have less habitat to breed in at stump harvest, and therefore also need mitigation. We tested if stumps in wet positions on a clear-cut harbour fewer species and a different assemblage of saproxylic insects than do stumps in dry positions. Insects were reared out from wood pieces taken from 100 stumps (50 Norway spruce, Picea abies and 50 birch, Betula spp.) sampled in pairs: one stump from wet and one from dry soil in each pair. In the lab 2201 individuals representing 49 beetle and 6 moth species were encountered. Fewer species were found in spruce stumps on wet soil than on dry soil, both when measured per stump or as an accumulated value over all stumps within the categories. No difference was detected between the number of species found in wet and dry birch stumps. However, three beetle species that live mainly in birch were more common in dry stumps than in wet. No species showed an association with wet stumps. We conclude that stumps in wet positions form an inferior habitat to stumps in dry positions, and that this should be considered when making recommendations concerning the harvesting of stumps for bioenergy. (C) 2012 Elsevier B.V. All rights reserved.
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| [16] |
Energy storage and the balance of producers and decomposers in ecological systems. https://doi.org/10.2307/1932179 URL 摘要
See full-text article at JSTOR
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| [17] |
Environmental consequences of tree-stump harvesting. https://doi.org/10.1016/j.foreco.2012.09.024 URL Magsci [本文引用: 1] |
| [18] |
Which macroarthropods prefer tree stumps over soil and litter substrates. https://doi.org/10.1016/j.foreco.2012.09.009 URL Magsci 摘要
Tree stumps are a potential bioenergy resource to replace fossil fuels and meet the targets for reduced CO2 emissions. However, the effects of stump harvesting on wood-dependent organisms are poorly known. This study assessed the abundances of macroarthropods, especially non-coleopteran groups, in wood, bark and 'periphery' of stumps in comparison with soil to evaluate which species/taxa prefer stumps over soil and would risk a significant population decline following extensive stump harvesting. To assess the effects of stump age on species and individual numbers, 5-, 10- and 20-yr-old stumps were studied at three sites in southern and central Sweden. For each site and age class, stumps of Scots pine (Pious sylvestris) and Norway spruce (Picea abies) were compared. Samples of wood and bark were taken from the full height of the stump and samples of periphery and soil to a depth of 10 cm. The samples were placed in Tullgren funnels for animal extraction during 4 days. A total of 56 species or other taxonomic groups not belonging to Coleoptera were identified. Bark (including the space between bark and wood) had significantly lower species richness of non-coleopteran macroarthropods but higher abundance per m(2) (of cut stump surface) than soil in 10-yr-old stands, which on average contained higher abundances than the other age classes. No significant differences were found between spruce and pine stumps, indicating that one of the tree species can act as a substitute after stump harvesting of the other. Viewed over all substrates, Diplopoda, Coleoptera, Diptera (larvae) and Homoptera contributed most to the total abundance (29, 20, 17 and 15%, respectively). Of these groups, Diplopoda were much more abundant in bark (98%) than in soil (2%). The most common diplopod species was Proteroiulus fuscus, which often demonstrated 100-fold higher abundances (per sample unit) in bark and wood than in soil. Six species/taxa had clearly higher abundances in stumps than in soil. Stump harvesting would thus markedly reduce preferred habitats for these taxa. It is also possible that some species generally considered as soil animals might be occasionally dependent on stumps for, e.g. egg-laying and hatching. For such species, stump harvesting would be more detrimental than indicated by this population survey. (C) 2012 Elsevier B.V. All rights reserved.
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| [19] |
Regeneration after stump harvesting in southern Finland. |
| [20] |
Coarse woody debris mass and its nutrients stock in tropical seasonal rain forest in Xishuangbanna, Southwest China. 西双版纳热带季节雨林的粗死木质残体及其养分元素 .
对西双版纳热带季节雨林的粗死木质残体及养分元素贮量进行了研究。结果表明，西双版纳热带季节雨林粗死木质残体的贮量为16.2 t·hm<SUP>-2</SUP>，约占地上活体生物量的4%左右。其中枯立木占32.5%，倒木占33.2%，倒木残体占12.6%，大枝占21.7%。本研究的粗死木质残体贮量低于巴西和东南亚的热带雨林，处于全球热带雨林的下限。粗死木质残体的氮、磷、钾、钙、镁5种元素的贮量分别为61.8、3.4、30.4、118.3和16.5 kg·hm<SUP>-2</SUP>。其中倒木所占比例最大，为31.9%～44.8%；枯立木次之（21.5%～28.7%）；倒木残体占10.3%～25.5%；3个径级的大枝占14.4%～28.9%。枯立木的C/N、C/P和N/P要高于倒木、倒木残体和大枝。
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| [21] |
Litter dynamics in two Sierran mixed conifer forests. II. Nutrient release in decomposing leaf litter. https://doi.org/10.1139/x88-175 URL [本文引用: 1] 摘要
The factors influencing leaf litter decomposition and nutrient release patterns were investigated for 3.6 years in two mixed conifer forests in the southern Sierra Nevada of California. The giant sequoia–fir forest was dominated by giant sequoia ((Lindl.) Buchh.), white fir (Lindl. & Gord.), and sugar pine (Dougl.). The fir–pine forest was dominated by white fir, sugar pine, and incense cedar ((Torr.) Florin). Initial concentrations of nutrients and percent lignin, cellulose, and acid detergent fiber vary considerably in freshly abscised leaf litter of the studied species. Giant sequoia had the highest concentration of lignin (20.3%) and the lowest concentration of nitrogen (0.52%), while incense cedar had the lowest concentration of lignin (9.6%) and second lowest concentration of nitrogen (0.63%). Long-term (3.6 years) foliage decomposition rates were best correlated with initial lignin/N (68=680.94, 68<680.05), lignin concentration (68=680.92, 68<680.05), and acid detergent fiber concentration (68=680.80, 68<680.05). Patterns of nutrient release were highly variable. Giant sequoia immobilized N and P, incense cedar immobilized N and to a lesser extent P, while sugar pine immobilized Ca. Strong linear or negative exponential relationships existed between initial concentrations of N, P, K, and Ca and percent original mass remaining of those nutrients after 3.6 years. This suggests efficient retention of these nutrients in the litter layer of these ecosystems. Nitrogen concentrations steadily increase in decomposing leaf litter, effectively reducing the C/N ratios from an initial range of 68–96 to 27–45 after 3.6 years.
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| [22] |
Carbon stocks in four forest stands in Sweden 25 years after harvesting of slash and stumps. https://doi.org/10.1016/j.foreco.2012.06.052 URL Magsci [本文引用: 1] 摘要
The long-term effect of slash and stump harvesting on carbon (C) stocks in soil, tree biomass, and total ecosystem were studied in four field experiments that commenced in 1980-1982 along a climatic gradient from north to south Sweden. The treatments consisted of complete tree harvesting, i.e., harvesting of slash, stumps, and stems (SSS); harvesting of stumps and stems, but leaving logging residues on site (SS); and, conventional stem-only harvesting (S). The northern site with Pinus sylvestris represented a relatively harsh, boreal climate (N-pine). Two additional sites were established in south-central Sweden with Picea abies (M-spruce) and Pinus sylvestris (M-pine) in a south-boreal climate. The fourth site with Picea abies (S-spruce) was established in south-west Sweden in the temperate zone.<br/>Ecosystem C stock in tree and soil was lower after SSS than after SS and S, however, there was no significant difference between S and SS.<br/>The treatment effect on C stock in tree biomass was site-specific rather than general. Stump-harvest (SS, SSS) increased C stock in N-pine, whereas a decrease was only observed for SSS in M-spruce. A logical explanation for the decreased C stock was the increased nutrient removal caused by harvest intensity. However, this could be counteracted by an increase in release of nutrients from the organic layer and a decrease in competition from the field vegetation promoted by soil disturbance due to stump harvesting.<br/>Soil C stock was lower after SSS than after S, due to lower C content in the organic layer after SSS (12 Mg ha(-1)) than S(18 Mg ha(-1)): no difference was detected in the mineral soil (0-20 cm). Soil C stocks after SS did not differ from S and SSS, but were lower in the organic soil layer after SS than after S.<br/>These results implied that stump harvest caused a lower C stock in the soil organic layer, 25 years after the harvest. However, this study did not show whether this difference would remain over time as remaining stumps and logging residues continue to decompose and the regenerated stand develops. The effects on the C stock in trees appear site- or time specific. More studies are needed to investigate the factors that control this stock, and the final carbon balance should be evaluated over at least one rotation period. (C) 2012 Elsevier B.V. All rights reserved.
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| [23] |
Population structure of soil arthropod in different age Pinus massoniana plantations. 不同林龄马尾松人工林土壤节肢动物群落结构 .
<div style="line-height: 150%">于2011年春季(5月)和秋季(10月)，研究了长江上游地区3、8、14、31和40年生马尾松林土壤节肢动物群落结构.结果表明：试验共捕获土壤动物4045只，隶属57科.土壤节肢动物的个体密度和类群数量随土壤深度增加显著降低，且这种趋势随林龄的增加而增加.不同林龄马尾松林土壤节肢动物的优势类群和常见类群差异较大，且土壤节肢动物的个体密度和类群数量差异显著.与其他林龄相比，造林3年的马尾松林土壤节肢动物的群落结构及多样性差异显著，群落相似度低.马尾松林的土壤节肢动物个体密度和类群数量及生物多样性在8年生阶段最高，此后，随林龄的增加明显降低.马尾松林地力可能随林龄的增加而衰退，对马尾松人工林的植被调控和改造宜在8年生阶段进行.</div><div style="line-height: 150%"></br> </div>
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| [24] |
Coarse woody debris in a monsoon evergreen broad-leaved forests of Dinghushan Nature Reserve. 鼎湖山季风常绿阔叶林粗死木质残体的研究 .
在3次样地调查的基础上对鼎湖山季风常绿阔叶林内粗死木质残体的贮量、输入量进行了研究,并 通过比较林窗范围内土壤养分含量,初步评述了粗死木质残体在森林生态系统养分循环中的作用.研究结果表明:1)季风常绿阔叶林粗死木质残体的贮量为 25.278 t*hm-2,立木、倒木、大枝所占的比例分别为32.02%、49.62%和18.36%; 2)1994～1999年间群落的死亡率为2.4%*a-1,死亡个体以胸径小于5 cm的为主,粗死木质残体的平均输入量为4.128 t*hm-2*a-1; 3)倒木主体所在的样方土壤有机质和速效钾的含量较高.
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| [25] |
Comparison of biomass dynamic and nutrient cycling between Pinus massoniana plantation and Pinus elliottii plantation. 马尾松与湿地松人工林生物量动态及养分循环特征 .
对乡土树种马尾松和引进外来树种湿地松人工林的生物量动态变化、养分积累与分配以及养分循环特征进行比较 ,结果表明 :在林分生长发育早期 ,马尾松生长慢 ,而湿地松生长快 ,生长发育后期马尾松生长速度比湿地松快。马尾松人工林生物量的数量成熟年龄为 36 a,采伐利用时的最大生物量为 4 34t/ hm2 ;湿地松的为 2 6 a,采伐利用时的最大生物量为 338t/ hm2。湿地松人工林各器官和总的养分积累量均高于马尾松 ,其中养分的总积累量是马尾松的 2倍多 ,树干高达 5倍多。在采伐利用时 ,不管是全树利用还是仅利用干材 ,同马尾松相比 ,湿地松林将带走更多的养分 ,对地力的养分消耗量更大。同时 ,湿地松林养分循环速率低 ,周转时间长 ,需要的养分多 ,比马尾松林维持地力的能力差。因此 ,在湿地松人工林的经营管理过程 ,更应处理好养地与用地之间的关系 ,否则会造成林地生产力的下降。
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| [26] |
Effects of litter types, microsite and root diameters on litter decomposition in Pinus sylvestris plantations of northern China. https://doi.org/10.1007/s11104-013-1902-y URL [本文引用: 1] 摘要
ABSTRACT
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| [27] |
Preliminary study on storage of coarse woody debris in evergreen broad-leaved forests of Damingshan Mountain Nature Reserve. 大明山常绿阔叶林粗死木质残体贮量的初步研究 .https://doi.org/10.3969/j.issn.1006-1126.2010.04.006 URL [本文引用: 1] 摘要
以2008年初遭受特大冰雪灾害干扰的大明山国家级自然保护区常 绿阔叶林为研究对象,分别坡位设计调查样区,样区内采用相邻网格样方法设置调查样地27个,样地总面积为10 800 m2.采用样方收获法测定林地上的粗死木质残体(Coarse Woody Debris,CWD)贮量及其腐解等级特征.结果表明:大明山常绿阔叶林的粗死木质残体贮量为33.142 t/hm2,其中倒木占CWD总贮量的95.75%.各腐解等级的贮量百分比序列为2级(60.8%)＞3级(21.7%)＞4级(13.6%)＞5级 (3.9%).2008年初的冰雪灾害干扰造成大明山常绿阔叶林的非正常CWD贮量骤然增大,高达20.172 t/hm2.
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| [28] |
Nutrient cycling in Pinus massoniana stands of different age classes. 不同年龄阶段马尾松人工林养分循环的研究 .
对马尾松(Pinus massoniana)人工林内N、P、K、Ca、Mg 5种养分元素的含量、积累、分配和生物循环以及它们随林分年龄的变化趋势进行了研究。结果表明：针叶的养分含量最高，树干材的养分含量最低，凋落物的养分含量与树枝或树皮的养分含量接近，土壤中K、Mg元素丰富，N、P、Ca 3种元素亏缺。树叶、树枝、树皮和树根中各元素含量大小顺序为K>N>Ca>Mg>P，树干材中则是Ca>K>N>Mg>P，5种元素含量随马尾松林分年龄的增加呈逐渐减少的趋势。5种元素贮存总量为460.19～1950.32 k
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| [29] |
Understory biomass and its characteristics as affected by forest gap in the alpine forest ecosystem in West Sichuan. 川西高山森林生态系统林下生物量及其随林窗的变化特征 .https://doi.org/10.3969/j.issn.1674-5906.2014.09.018 URL [本文引用: 1] 摘要
作为森林生态系统的重要组成部分，林下植被及其残体的分布受到林 冠层的影响，但迄今有关林窗对林下植被和残体生物量的影响尚无研究报道。于2013年8月2日至20日，以海拔3600 m的川西岷江冷杉原始林林下植被为研究对象，根据区域内的坡向和林分组成等因素设置3个100 m×100 m的典型样地，调查其生物量及其随林窗的变化特征。在每个样地内选择3个大林窗，在林窗、林缘和林下分别设置3个20 m×20 m的样方，调查粗木质残体长度或高度、大小头直径、枯立木记录胸径、腐烂等级等；在林窗、林缘和林下分别设置3个5 m×5 m的样方，采用“收获法”收集样方内直径在2.5~10 cm之间的细木质残体和灌木生物量；在林窗、林缘和林下分别设置3个1 m×1 m的样方来调查凋落物储量和草本生物量；在1 m×1 m的样方内随机选择1个20 cm×20 cm的小样方来调查地被植物生物量。结果表明，（1）川西高山森林生态系统总生物量为72.75 t·hm-2，其中林下生物量为67.92 t·hm-2，占生态系统生物量的95.17%。活体植被以灌木为主，其生物量为9.81 t·hm-2；残体部分以粗木质残体为主，其储量为53.00 t·hm-2；（2）林窗对灌木、草本、地被植物的影响各不相同，且不同物种的灌木生物量表现出不同的分布规律；草本生物量表现出明显的“边缘效应”，在 林缘显著高于林下；林窗和林缘的地被植物生物量相对较低；（3）粗木质残体储量从林下到林窗呈现减小的趋势，但总体储量仍然较大，林窗和林缘的细木质残体 储量高于林下。这些结果为认识高山森林生态系统林下生物量及其格局，以及林窗在森林生态系统的重要作用提供了基础理论依据。
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Concept and classification of coarse woody debris in forest ecosystems. 森林粗死木质残体的概念及其分类 .
森林粗死木残体 (Coarse woody debris,CWD)在不同的文献中有不同的定义 ,没有通用而确切的概念用来描述 CWD,对研究结果的比较造成了很大障碍。 2 0世纪 90年代以来 ,随着景观生态学的发展 ,以及对 CWD生态功能的深入研究 ,国外的森林管理和研究机构 (例如 USDA Forest Service和 L TER)为了把 CWD放在区域以及景观尺度上进行比较 ,对 CWD的概念等进行了统一 ,将其直径标准由原来的≥ 2 .5 cm调整到≥ 10 cm,但是我国在此方面还没有与国际接轨 ,仍采用旧标准 (≥ 2 .5 cm ) ,这样的研究结果难于和国外进行比较 ,不利于我国 CWD的长期深入研究。另外 ,有关 CWD的分类一直以来也没有形成一个完整的分类系统 ,我国也缺少 CWD分类方法的介绍。鉴于以上情况 ,综合国内外近年来在 CWD方面的研究动态 ,综述了 CWD的概念和分类情况 ,并初步提出较综合的 CWD概念及其分类系统 ,以供相关研究者讨论和参考 ,为我国的 CWD研究起到推动作用。
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Decomposition of coarse woody debris in Schima superba of Dinghushan. 鼎湖山木荷(Schima superba)粗死木质残体的分解研究 .
以鼎湖山国家自然保护区季风常绿阔叶林优势种之一木荷的粗死木质残体为研究对象,采用目前国际较认可的腐解等级划分方法,对木荷粗死木质残体3个腐解等级(Ⅰ、Ⅱ、Ⅲ)的密度及养分含量进行测定分析.结果表明:①木荷粗死木质残体的密度随腐解等级的增加从0.58 g/cm3下降到0.16 g/cm3,分解速率常数K值为0.144 7/a,在自然状态下,木荷粗死木质残体分解95%所需时间约为21 a;②粗死木质残体C/N比值随分解的进行先降后升而N/P则相反;③K、Ca、Na、Mg离子浓度随腐解等级的增加出现不同程度的增加,但增幅不明显.研究结果旨在为系统评估粗死木质残体的分解行为在生态系统养分循环中的作用提供基础数据.
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Dynamics of nutrients in an age sequence of Pinus massoniana plantation. 马尾松人工林发育过程中的养分动态 .
<p>为了解马尾松人工林不同发育时期的养分动态，利用空间代替时间的方法对7、17、31和51年生4个年龄阶段的马尾松人工林养分积累、分配及循环进行了研究.结果表明：马尾松人工林发育过程中，生物量积累与养分积累具有不同步性，从17年生到51年生，生物量积累增长速率是N、P、K、Ca和Mg积累增长速率的3.3、5.4、3.3、3.7和9.8倍；各器官中养分的分配与养分库增长速率有关，随着林龄的增长，树干养分的比重和养分的根冠比增大；单位养分生产的干物质量随林龄增长而提高，51年生时林分的养分循环系数较高，具有低存留、高归还的特点，养分利用效率最高.缩短轮伐期降低了养分高效利用的机会.为维持林地的长期生产力，建议将马尾松人工林轮伐期延长到50年以上，同时降低收获强度.</p>
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Storage and decomposition of fallen wood in dark coniferous forest on the north slope of Changbai Mountain. 长白山北坡暗针叶林倒木贮量和分解的研究 .https://doi.org/10.3321/j.issn:1000-0933.2002.02.007 URL [本文引用: 1] 摘要
对长白山北坡海拔1260m和1620m暗针叶林中倒木蓄积、生物量和倒木的分解进行了比较研究,结果表明,暗针叶林中倒木的蓄积为180.87m3·hm-2,占林分蓄积的21.83%.低海拔的倒木蓄积和生物量均比高海拔的低,海拔1260m的倒木蓄积为52.57m3·hm-2,生物量为26.21t·hm-2;海拔1620m的倒木蓄积为193.85m3·hm-2,生物量为53.33t·hm-2.用单项指数衰减模型对倒木的分解进行模拟可知,倒木的分解常数随树种和海拔高度的不同而不同.冷杉倒木的分解常数比云杉倒木大;倒木在低海拔的分解常数比在高海拔的大,表明云杉倒木完全分解需要较长的时间.
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Litter production, nutrient return and leaf-litter decomposition in natural and monoculture plantation forests of Castanopsis kawakamii in subtropical China. 格氏栲天然林与人工林凋落物数量, 养分归还及凋落叶分解 .
通过对中亚热带格氏栲天然林 ( natural forest of Castanopsiskawakamii,约 1 5 0年生 )、格氏栲和杉木人工林 ( monoculture plantations of C.kawakamii and Cunninghamia lanceolata,33年生 )凋落物数量与季节动态、养分归还及凋落叶分解与其质量的关系为期 3a的研究表明 ,林分年均凋落量及叶所占比例分别为 :格氏栲天然林 1 1 .0 1 t/hm2 ,5 9.70 t/hm2 ;格氏栲人工林 9.5 4 % ,71 .98% ;杉木人工林 5 .47t/hm2 ,5 8.2 9%。格氏栲天然林与人工林凋落量每年只出现 1次峰值 ( 4月份 ) ,而杉木林的则出现 3次 ( 4或5月份、8月份和 1 1月份 )。除杉木林的 Ca和格氏栲人工林的 Mg年归还量最大外 ,N、P、K及养分总归还量均以格氏栲天然林的为最大 ,杉木人工林的最小。分解 1 a后格氏栲天然林中格氏栲叶的干重损失最大( 98.1 6% ) ,杉木叶的最小 ( 60 .78% )。C/N及木质素 /N比值与凋落叶分解速率呈显著负相关，而N、水溶性化合物初始浓度与分解速率呈显著正相关。与针叶树人工林相比，天然林的凋落物数量大、养分归还量高、分解快，具有良好自我培肥地力的能力。因此，保护和扩大常绿阔叶林资源已成为南方林区实现森林可持续经营的重要措施之一。
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| [35] |
Storage and decomposition of fallen wood in a Pinus tabulaeformis secondary forest at Huoditang forest region in the Qinling Mountain. 秦岭火地塘天然次生油松林倒木储量与分解 .https://doi.org/10.11707/j.1001-7488.20120621 Magsci [本文引用: 1] 摘要
<p>粗头直径≥10 cm,长度通常≥1 m,倾斜度超过45°的死木质残体称为倒木(Harmon <em>et al</em>., 1996)。倒木是森林生态系统的重要组成部分,在森林生态系统中倒木与生产者、消费者、分解者之间都有着密切的营养关系,其结构与功能相互制约,相互影响。</p>
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Community types and species diversity of Pinus massoniana forests of Yuelu Mountain, Changsha. 长沙岳麓山马尾松林的群落类型划分及物种多样性分析 .https://doi.org/10.11707/j.1001-7488.20110414 Magsci [本文引用: 1] 摘要
<p>运用TWINSPAN,flexible beta clustering,DCA,NMDS(non-metric multidimensional scaling)对岳麓山马尾松林群落类型进行划分,并采用Patrick指数、Simpson指数、Shannon-Wiener指数、Pielou指数研究群落的物种多样性。结果表明:1) flexible beta clustering和NMDS相结合要优于TWINSPAN和DCA,是比较理想的群落数量分类方法; 2) 岳麓山马尾松分布于10种群落中,马尾松除了组成较大面积的纯林外,还与其他本土阔叶树种组成6种针阔混交林; 3) 马尾松纯林物种多样性低,丰富度指数、均匀度指数、多样性指数、优势度指数均为最低值,尤其是草本层物种多样性极低。相比之下,针阔混交林,尤其是马尾松＋苦槠林物种多样性较高; 4) 样地中马尾松的重要值与乔木层的各物种多样性指数、与草本层的均匀度指数、优势度指数存在负相关,与灌木层的物种多样性不存在相关关系。</p>
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| [37] |
Characteristics of storage and decomposition of coarse woody debris (CWD) under three forests in Guangzhou. 广州三种森林粗死木质残体(CWD)的储量与分解特征 .
粗死木质残体(Coarse Woody Debris, CWD)对森林生态系统的稳定性具有不可忽视的贡献。对广州3种森林CWD的储量与分解特征进行了调查分析，结果表明：（1）CWD储量及其与相应森林总生物量比值均表现为常绿阔叶林>针阔混交林>针叶林；枯立木与倒木为CWD的主要成分，其中，针叶CWD主要物种为马尾松(Pinus massonianai)，阔叶CWD物种主要为荷木(Schima superba)与黄杞(Engelhardtia chrysolepis)等。（2）CWD径级主要集中在<10cm的范围内，存在状态主要为中级腐烂状态，干扰与竞争是3种森林CWD产生的主要因素。（3）针叶林、针阔混交林与常绿阔叶林CWD的分解常数k分别为00244、0.0407和0.0487，即分解速率为常绿阔叶林>混交林>针叶林；随着CWD的分解，N、P与木质素的含量逐渐升高，C、C/N与木质素/N呈降低趋势。
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