Diurnal and seasonal variations in carbon fluxes in bamboo forests during the growing season in Zhejiang province, China

Bamboo forest is an important forest type in subtropical China and is characterized by fast growth and high carbon sequestration capacity. However, the dynamics of carbon fluxes during the fast growing period of bamboo shoots and their correlation with environment factors are poorly understood. We measured carbon dioxide exchange and climate variables using open-path eddy covariance methods during the 2011 growing season in a Moso bamboo forest(MB, Phyllostchys edulis) and a Lei bamboo forest(LB, Phyllostachys violascens) in Zhejiang province,China. The bamboo forests were carbon sinks during the growing season. The minimum diurnal net ecosystem exchange(NEE) at MB and LB sites were-0.64 and-0.66 mg C m^(-2) s^(-1), respectively. The minimum monthly NEE, ecosystem respiration(RE), and gross ecosystem exchange(GEE) were-99.3 ± 4.03, 76.2 ±2.46, and^(-1)91.5 ± 4.98 g C m^(-2) month^(-1), respectively,at MB site, compared with-31.8 ± 3.44, 70.4 ± 1.41,and^(-1)57.9 ± 4.86 g C m^(-2) month^(-1), respectively, at LB site. Maximum RE was 92.1 ± 1.32 g C m^(-2) month^(-1) at MB site and 151.0 ± 2.38 g C m^(-2) month^(-1) at LB site.Key control factors varied by month during the growing season, but across the whole growing season, NEE and GEE at both sites showed similar trends in sensitivities to photosynthetic active radiation and vapor pressure deficit,and air temperature had the strongest correlation with RE at both sites. Carbon fluxes at LB site were more sensitive to soil water content compared to those at MB site. Both onyear(years when many new shoots are produced) and offyear(years when none or few new shoots are produced)should be studied in bamboo forests to better understand their role in global carbon cycling.

Estimation of bamboo forest carbon reserves and analysis of temporal and spatial variation characteristics in China

The study looks at the carbon reserves of bamboo forests in China from 2004 to 2018.The temporal and spatial variation characteristics of the carbon reserves of bamboo forests in China were analyzed.It enriches the research field of bamboo forest carbon reserve change at the national level.The bamboo forest carbon reserves of 20 provinces in China were estimated by using the calculation method of bamboo forest biomass and bamboo forest soil organic matter carbon reserves,and the temporal and spatial variation characteristics of bamboo forest carbon reserves in China were analyzed by GIS spatial analysis method.The results are as follows:(1)the carbon reserves of bamboo forests in China during 2004-2008,2009-2013 and 2014-2018 were 707.08 Tg C,802.83 Tg C and 845.05 Tg C respectively,with an average annual growth rate of 1.95%.Fujian,Jiangxi,Zhejiang,Hunan,Sichuan and Guangdong account for 78.01%-78.80% of the total bamboo forest carbon storage in China.(2)From 2004 to 2008,the carbon reserves of bamboo biomass in China were 380.63 Tg C-454.92 Tg C,accounting for 52.64%-52.91% of the total carbon reserves;The carbon storage of soil organic matter is 342.39 Tg C-406.33 Tg C,accounting for 47.01%-47.36% of the total carbon storage.(3)The spatial distribution of bamboo forest carbon reserves in China shows a high-high,low-low correlation trend.The relevant provinces are Zhejiang,Fujian,Guangdong and Jiangxi,which are concentrated in the southern provinces of China.The low-low related provinces are Inner Mongolia,Hebei and Liaoning,which are concentrated in the northern provinces of China.In the future,China’s bamboo forest carbon reserves will increase steadily.Bamboo forest carbon reserves are concentrated in southern provinces.China should further improve the level of spatial agglomeration and give full play to the role of bamboo forest carbon sink.

Carbon storage of bamboo forest ecosystem in China

National forest inventory materials and data from China Forest Ecosystem Location Research Network （CFERN） were obtained for estimating four periods of carbon storage of Bamboo forest ecosystem from 1977 to 2003 in China. The spatial and temporal patterns, vertical distribution and potential carbon storage of the bamboo forest ecosystem were analyzed. The results showed that carbon storage of Chinese bamboo forest ecosystem was 537.6 Mt C during 1977 and 1981, 598.61 Mt C during 1984 and 1988, 710.14 Mt C during 1994 and 1998, and 837.92 Mt C during 1999 and 2003. It showed that the carbon storage was increasing during that time. Zhejiang, Jiangxi, Fujian, Hunan, Guangdong and Sichuan were the major carbon pools in China, with the percentages of carbon storage between 80.04 and 83.13 percent in all. The percentages of carbon storage of vegetation, litter, and soil were between 23.85 and 24.48 percent, between 0.92 and 0.96 percent, and between 74.56 and 75.23 percent respectively. Therefore, it is concluded that the carbon storage in different layers were similar vertically. Carbon storage was 837.92 Mt C from 1999 to 2003, and it will be increased to 947.54 Mt C after one age period with a rate of 54.81Mt carbons stored in ecosystem every year.

Changes in Soil Carbon Pools Induced by Substitution of Plantation for Native Forest

Changes in soil carbon pools under Chinese fir (Cunninghamia lanceolata) andbamboo (Phyllostachys pubescens) plantations substituted for a native forest (Quercus acutissima,Cyclobalanopsis glauca, Cas-tanopsis sclerophylla, Platycarya strobilacea, Lithocarpus glaber) werestudied on the hills with acid parent rock and soils classified as red soils (Ferrisols) in Huzhou,Zhejiang Province of east China. It was found that total soil organic carbon (TSOC), easilyoxidisable carbon (EOC) and water-soluble organic carbon (WSOC) under bamboo plantation wereincreased, but microbial biomass carbon (MBC) was decreased. On the contrary, Chinese fir induceddeclines of all fractions of C including TSOC, EOC, WSOC and MBC. The percentages of the activefractions of soil C (EOC and WSOC) were increased in the plantations as compared to the nativebroad-leaved forest, but proportions of soil organic C as MBC were decreased. It could be concludedthat bamboo plantation had a great ability of not only fixing C but also accelerating soil C poolcycle, improving nutrient and microorganism activity; therefore, it is a good ecosystem and could berecommended for wide development. Chinese fir would shrink the soil C pool and deteriorate soilbiological fertility, so it did not benefit CO2 fixing and land sustainable utilization.

Assessing stand structure in successional stages of dark coniferous forests in western Sichuan, China

Subalpine dark coniferous forests in the western Sichuan Province of China play an important role in the hydrological processes in the upper reaches of the Yangtze River. Second-growth forests, with different stand successional stages, have developed as a result of logging over the past 50 years. Forest cover and stand structure changed greatly with concomitant degradation of forest ecosystem functions. To understand how the stand structures of the second-growth forests change during the stand succession process, we analyzed stand structure characteristics and an old-growth state index of the bamboo and moss-forest types. We found that stand structure at the young successional stage featured one-third of the structure characteristics of the old-growth dark coniferous forests,while the structure of the medium-aged stage had reached half the structure of the old-growth state. The two forest types were similar in the rate of development at the young successional stage but differed at the medium-aged stage;the moss-forest type had more advanced development than the bamboo-forest type at the medium-aged successional stage.

Returning to Nature

IN the dense forest of the Daxiangling Mountains in Sichuan Province grows the favorite food of giant pandas—various bamboo species including arrow bamboo.The slopes are usually covered with snow from the end of November to the end of March the following year.As in the wild,giant pandas generally live at relatively high altitudes and prefer cool environments with rich food resources,rugged terrain,and abundant water,making the mountain range an ideal habitat for them.

毛竹扩张对幕阜山区森林土壤碳氮磷含量及生态化学计量特征的影响

以幕阜山区同一片毛竹林向两侧杉木林和阔叶林扩张形成的连续生态界面为研究对象,分析不同林型土壤有机碳(SOC)、全氮(TN)、全磷(TP)、硝态氮(NO_(3)^(−)−N)、铵态氮(NH_(4)^(+)−N)含量及其生态化学计量比,探讨毛竹不同扩张模式对森林土壤碳(C)、氮(N)、磷(P)的影响。结果表明:在2种扩张模式下,随土壤层次的增加,除NO_(3)^(−)−N呈不规律变化外,SOC、TN、TP、NH_(4)^(+)−N含量均呈逐渐降低趋势。在毛竹向杉木林扩张过程中,杉木林、竹杉混交林、毛竹林同一土层SOC、TN、TP含量均无显著差异;在毛竹向阔叶林扩张过程中,毛竹林0~10 cm土层SOC和TN含量较阔叶林和竹阔混交林分别降低了27.71%、30.45%和36.67%、31.11%,而在10~20 cm和20~30 cm土层则无显著差异;毛竹扩张对杉木林和阔叶林各土层TP含量无显著影响;毛竹向杉木林扩张增加了0~10 cm和20~30 cm土层NH_(4)^(+)−N含量,毛竹向阔叶林扩张增加了10~20 cm土层NH_(4)^(+)−N含量及20~30 cm土层NO_(3)^(−)−N含量;毛竹向杉木林扩张对土壤C/N、C/P、N/P无显著影响,毛竹向阔叶林扩张导致0~10 cm土层N/P明显降低、10~20 cm土层C/N显著增加。综上,毛竹向杉木林扩张对土壤SOC、TN、TP影响不显著,但提升了表层和深层土壤NH_(4)^(+)−N含量,毛竹向阔叶林扩张造成表层土壤SOC、TN含量显著降低,并导致中层土壤NH_(4)^(+)−N含量和深层土壤NO_(3)^(−)−N含量明显增加。

Returning To Nature

In the dense forest of the Daxiangling Mountains in Sichuan Province grows the favourite food of giant pandas-various bamboo species including arrow bamboo.The slopes are usually covered with snow from the end of November to the end of March the following year.As in the wild,giant pandas generally live at relatively high altitudes and prefer cool places with rich food resources,rugged terrain and abundant water,making the mountain range an ideal habitat for them.

竹笋采挖下克隆整合对毛竹林发笋成竹规律的影响

【目的】为研发毛竹林高产高效生态经营技术提供一定参考。【方法】调查浙西南地区采挖毛竹林竹笋后的笋-幼竹生长过程,通过存活曲线分析毛竹林挖笋后的发笋成竹规律,探讨挖笋对竹笋中单宁、粗脂肪、粗蛋白等品质指标的影响。【结果】竹笋采挖提高了毛竹林地的发笋能力,挖笋样地的发笋数比未挖笋样地增加了12.8%(P<0.05),而挖笋后选留竹笋的存活率也显著高于未挖笋样地;与未挖笋样地相比,挖笋样地内毛竹新分株的平均胸径并未发生显著改变(P>0.05),挖笋不会降低新分株胸径而使林分衰退;竹笋间的非对称性竞争有利于竹笋地径的径级为Ⅰ-Ⅲ级竹笋的生长与存活,随着地径的提高竹笋死亡率显著降低,而径级Ⅳ级以上竹笋则有着较高的死亡率。盛笋早期以后,径级相对较小(Ⅳ级以上)的竹笋开始大量萌发,这类竹笋若不及时采挖,大部分会出现退笋,造成资源浪费;挖笋和未挖笋样地竹笋的含水率、蛋白质和粗脂肪含量在各笋期均未见显著差异(P>0.05),尽管挖笋样地竹笋的单宁含量在末笋期显著高于未挖笋样地,但两种样地其他笋期单宁含量均未见显著差异。【结论】毛竹林竹笋的采挖,可缓解竹笋间的非对称性的资源竞争,有效避免大量退笋导致的毛竹母株营养消耗,实现母株资源的克隆整合,增加竹笋产量。因此,合理的竹笋采挖有利于毛竹笋用林的高效生产及可持续性经营。

不同肥料类型对阔叶箬竹修剪后生长及土壤养分含量的影响

选用菌肥(T1)、控释肥(奥绿肥318s,T2)、复合肥(T3)、有机肥(羊粪,T4)4种肥料类型,以不施肥为对照(T5),研究了不同肥料类型对阔叶箬竹地上部分剪除后的竹林生长及土壤养分的影响。结果显示:1)在促进阔叶箬竹生长方面,控释肥(T2)整体表现较好,施用后竹林的母株成活量、出笋量、竹笋地茎、竹笋高度分别比对照增加243.7%、300.0%、55.7%、129.7%,退笋数量较对照减少37.5%;叶片全氮、全磷、全钾、总钙和总镁含量分别比对照提高8.3%、3.2%、18.3%、4.7%和24.9%;5种处理在促进竹林生长的综合效应方面表现为T2>T1>T3>T4>T5。2)在改善土壤养分状况方面,控释肥(T2)的效果最好,施用后土壤碱解氮、有效磷、速效钾含量分别比对照提高50.8%、44.8%、56.7%,土壤EC值提高160%,pH值降低0.7%;5种处理对于改善林地土壤肥力的综合效果表现为T2>T1=T3=T4>T5。阔叶箬竹地上部分剪除后,施用控释肥(奥绿肥318s)为最佳施肥方案。

集体林权制度下的安吉竹林经营认证模式探索与实践

分析了安吉县林业生产与社会经济条件、竹林认证历程和认证模式,阐述了集体林权制度下安吉县毛竹股份合作社的组织形式、经营管理与“协会+合作社”模式开展竹林经营认证的运行机制,总结了“协会+合作社”模式开展竹林经营认证对提高竹林经济效益、促进竹林生态效益、加快农村城镇建设进程中的作用。提出在当前我国南方集体林权制度下引入新型竹林经营主体、推进竹林专业化经营、健全竹林经营管理体系,对开展竹林经营认证有积极作用。安吉县以“协会+合作社”开展竹林经营认证,对促进我国南方集体林权制度下的林业可持续发展具有示范作用。

生物炭对毛竹林土壤有机碳组分及碳库管理指数的影响

为探究不同生物炭施用量对毛竹林土壤有机碳组分及碳库管理指数的影响,本研究以广西桂林漓江上游毛竹林土壤为研究对象,以毛竹废弃物高温热解制备的生物炭为供试材料,通过一年野外施用试验,探究不同生物炭施用量下(0(CK)、10 t·hm^(-2)(BC1)、20 t·hm^(-2)(BC2)、40 t·hm^(-2)(BC4))毛竹林土壤有机碳活性组分和土壤碳库管理指数变化特征,分析环境因素对其影响。结果表明:与对照(CK)相比,高添加量生物炭(BC4)后土壤pH值、速效磷、速效钾、铵态氮、可溶性有机氮、微生物量氮等含量显著提高,但土壤全磷含量显著降低(P<0.05)。生物炭对总有机碳、易氧化有机碳、颗粒有机碳及碳库管理指数等有显著的促进作用,均在生物炭施用量为40 t·hm^(-2)时达到最大值。相关分析表明,土壤碳库管理指数与pH、NH_(4)^(+)-N、EOC、POC均呈极显著正相关关系(P<0.01)。路径分析模型表明在生物炭添加下,土壤性质和可利用性养分直接影响活性碳组分,进而影响土壤碳库管理指数。综上所述,毛竹林中施用生物炭是提高土壤质量、促进土壤碳固存及合理利用竹林废弃物的有效手段,其中生物炭添加量为40 t·hm^(-2)的处理效果最优。

立竹密度对不同发笋期毛竹叶片功能性状的影响

【目的】探究长周期母竹留养模式下毛竹叶片功能性状对立竹密度的响应及在不同发笋期的变化,并筛选出适宜的经营密度。【方法】以漳平市长周期母竹留养经营模式下笋用毛竹林为研究对象,设置(1350±100)、(1950±100)、(2550±100)、(3150±100)株·hm^(-2)4个不同立竹密度处理组,选用传统经营模式下生产效益较优的笋用毛竹林作为对照组,分析立竹密度对不同发笋期毛竹叶片功能性状的影响。【结果】毛竹林的叶面积指数、叶平均倾角、全氮含量、全磷含量、全钾含量和叶绿素含量均在立竹密度为(2550±100)株·hm^(-2)时达到最高,且不同处理组间差异显著(P<0.05);各处理组的叶面积指数、叶平均倾角及全氮含量均在发笋前期达到最高,冠层开度和叶绿素含量在发笋盛期达到最高,全磷和全钾含量则在发笋后期达到最高;毛竹叶片各功能性状间存在显著相关性。【结论】在长周期母竹留养经营模式下,当立竹密度为(2550±100)株·hm^(-2)时,毛竹林的冠层结构得到显著改善,叶片的空间分布更加合理,且叶片养分及叶绿素含量显著提高。

毛竹扩张过程中竹与树空间关系的点格局分析

毛竹与树木相互作用关系是解释毛竹扩张的关键。在井冈山自然保护区选取典型竹阔界面样地(50×100 m)调查样地内毛竹和树木的植株空间分布距离,采用Programita软件对树木与毛竹、毛竹母竹与新竹的空间关联性进行O-ring统计分析:结果发现:(1)0—100 m的整个界面区域,毛竹与树木在0—10 m任何尺度都是负关联。由毛竹纯林向混交林过渡,毛竹与树木的负相关距离加大,由2—3 m增加到2—9 m;(2)毛竹与不同生态型树木的空间关联性表现出较大差异,无论在任何区域,从0—10 m尺度上毛竹与落叶树都无关联,但在0—100 m整个界面区域,除<1.0 m尺度外,毛竹与常绿树是负关联;扩张前期(前沿区)毛竹与乔木的负相关距离比与灌木树的大;(3)毛竹母竹与新竹在不同时期不同区域的空间关联性有较大差异,在0—40 m区域内,仅2013年在1 m尺度下母竹与新竹呈正关联,在40—80 m区域内,随扩张年份增加,母竹与新竹关联尺度距离由2007年的6—7 m下降到2013年1 m和3—6 m。结果表明毛竹与树木间存在明显的相互排斥作用,竹与树的作用强弱与树木的生态型特征、扩张阶段和二者相对密度有关。毛竹扩张方式可表现为前期远距离放置新竹,扩张后期进行密度填充。研究结果可为竹子扩张程度判定及扩张预测、防控提供参考。

浙江安吉竹产业改造升级碳汇能力提升项目经济效益评价

随着乡村青壮年人口流出和人口老龄化加剧,林区基础设施建设落后,竹林经营效益不断下降,大量竹林逐渐被荒弃,竹产业产值下降。为此,近年来浙江省安吉县实施了"竹产业改造升级碳汇能力提升项目",旨在通过对竹林资源集约化经营,全面提升安吉县竹产业经济效益以及竹林增汇能力,在保护好绿水青山的同时,实现村民共同富裕。文章从投资估算、经营收入、还款能力3个方面分析评价了"竹产业改造升级碳汇能力提升项目"的经济效益,结果认为该项目是可行的。项目的实施可为其他类似地区升级竹产业、带动乡村振兴提供借鉴和参考。

中国竹林认证不符合项分析

为揭示竹林认证对竹林可持续经营的影响,文章概述了我国竹林认证现状,重点对认证审核提出的不符合项进行了系统分析,从而揭示竹林认证对竹林经营管理带来的变化,具体从竹林经营管理体系优化、经营环境友好、林区社会和谐、经营经济可行4个方面分析了认证对竹林可持续经营的影响。在此基础上,结合对竹林认证不符合项的分析,提出了促进中国竹林认证发展的政策建议。

云南昭通中小径笋用竹造林中乔木树种配置

在系统整理金佛山方竹、筇竹等中小径笋用竹相关研究成果的基础上,结合云南省昭通市的实际情况,分析中小径笋用竹的特点和乔木对中小径笋用竹林的作用,总结了在营造中小径笋用竹林中乔木树种配置的原则和方法。中小径笋用竹林竹鞭分布较浅,常与乔木或灌木混生,较耐荫;在中小径笋用竹林中配置乔木,具有庇荫、增加土壤肥力、改善土壤结构、增加群落稳定性、提高竹林生物量等作用;选择乔木树种应遵循生长快、价值高、寿命长、深根性、喜光、以落叶乔木为主的原则,根据树种生物学特性、乔木层郁闭度并结合林分经营目的、经营水平选择合适的配置密度。为昭通市中小径笋用竹造林推荐了19个乔木树种,适宜的乔木种植密度为5~42株/667 m^(2)。

浙江省竹林碳汇测算研究

采用生物量法测算浙江省竹林固碳量,运用能源活动二氧化碳排放测算法估算浙江省碳排放量,将二者进行对比分析竹林碳汇贡献。结果表明:1973—2021年浙江竹林固碳量从1820.64万t增长到3570.88万t,净增长量为1750.24万t,增长率高达96.13%,总体呈现增加的趋势,其中毛竹林为主要固碳林种;浙江省碳排放量呈现出稳定增长的趋势,增长率在2004—2021年有所下降;竹林固碳量与碳排放量呈现趋同的增长趋势,但竹林固碳量对于整体的碳排放量而言占比较小,固碳贡献小。为有效助力浙江省碳达峰、碳中和目标进程,提出应注重稳定竹林碳汇增量、切实巩固竹林碳汇发展,规范引导碳汇经营方案、合理提高竹林碳汇潜力,有效结合企业碳汇主体、科学管控企业排放数量,以此有效发挥竹林碳汇价值。

毛竹林林下种植中药材对土壤有效态中、微量营养元素的影响

【目的】探究毛竹林林下种植中药材对土壤有效态中、微量营养元素的影响,为毛竹林林下种植土壤养分资源管理及我国南方竹产区林药复合经营模式的推广提供科学参考。【方法】以广西桂林漓江源区毛竹人工林林下种植的3种中药材样地为研究对象,采用完全随机区组设计,设4个处理,即未种植中药材的毛竹林对照、林下种植黄花倒水莲(Polygala fallax)、林下种植多花黄精(Polygonatum cyrtonema)、林下种植草珊瑚(Sarcandra glabra),在种植后的第2年测定土壤基本理化性质和中、微量营养元素有效态含量,分析其相关性,明确毛竹林林下种植不同中药材土壤中、微量营养元素的变化及其主要影响因素。【结果】毛竹林林下种植中药材降低了土壤容重、总碳和有效磷含量,增加了可溶性有机碳和微生物生物量碳、氮、磷含量,种植多花黄精对上述指标的影响相对较大,除微生物生物量氮外均与对照差异显著(P<0.05,下同);林下种植多花黄精和草珊瑚显著降低了土壤交换性钙和交换性镁含量,而种植黄花倒水莲和草珊瑚显著增加了土壤有效硫含量;林下种植中药材显著增加了土壤有效锌含量,显著降低了土壤有效钼含量,种植多花黄精和草珊瑚也显著增加了土壤有效锰含量,而种植3种中药材对土壤有效铁和有效铜含量无显著影响(P>0.05,下同),种植多花黄精和草珊瑚对土壤微量营养元素有效态含量的影响大于种植黄花倒水莲。相关分析结果表明,土壤中量营养元素钙、镁、硫有效态含量主要受土壤容重、有效磷及微生物生物量碳和磷影响,而微量营养元素铁、锰、铜、锌、钼有效态含量除受以上因素影响外,还与土壤pH及中量营养元素钙和镁有效态含量有关。【结论】土壤中、微量营养元素有效态含量对毛竹林林下种植不同中药材的响应存在较大差异,林下种植多花黄精对土壤养分的影响最大,种植黄花倒水莲和草珊瑚次之。在毛竹林林下种植中药材实践中需适当补充中、微量营养元素,尤其是钙镁肥的供应,且需根据种植中药材的种类采取不同施肥策略。