陕北刺槐林木生长及林下植被与土壤水分对种植密度的响应特征

以陕西省安塞县2000年左右退耕栽植的5种不同密度(830~3 330株/hm~2)刺槐林地为研究对象,分析不同栽植密度对刺槐林木生长、林下植被及土壤水分的影响,为黄土高原丘陵沟壑区刺槐人工林合理栽植密度的确定以及可持续经营提供理论依据。结果表明:(1)阳坡中不同密度间刺槐林木的胸径、树高、冠幅均差异显著;阴坡中2 500株/hm~2的刺槐林木平均胸径、树高与两个低密度林的差异显著,且平均冠幅与1 670株/hm~2差异显著,与2 000株/hm~2差异不显著。(2)当栽植密度为1 670株/hm~2时,刺槐林地水分含量相对较高,林下植被平均盖度及物种多样性也较高。(3)各栽植密度刺槐林地0~500cm土壤含水量均低于该地区土壤稳定湿度(12%)。(4)阳坡中3 330株/hm~2的林地0~500cm土层含水量仅为4.5%,土壤干旱化严重,而830株/hm~2的刺槐林地土壤水分为7.8%;阴坡中栽植密度为1 670~2 000株/hm~2的刺槐林地土壤含水量较高,为7.5%~8.2%。研究表明,在陕北黄土高原丘陵沟壑区,刺槐初始造林密度不宜超过1 670株/hm~2(株行距2m×3m),在进入刺槐生长高峰期后,应采取间伐管理以调整林分密度,使其维持刺槐人工林林地的稳定性与可持续性。     

控制性分根区交替滴灌对苹果幼树形态特征与根系水分传导的影响

采用固定滴灌(根区一侧固定供水)、控制性分根区交替滴灌(根区两侧交替供水)和常规滴灌(紧贴幼树基部供水)3种灌水方式和3种灌水定额(固定滴灌和交替滴灌均为10、20和30 mm,常规滴灌为20、30和40 mm),对比研究了控制性分根区交替滴灌对苹果幼树形态特征与根系水分传导的影响.结果表明： 交替滴灌的根区两侧土壤出现反复干湿交替过程,常规滴灌的根区两侧土壤含水率差异不显著.在灌水定额相同时,灌水侧的土壤含水率在3种灌水方式间差异不显著.与常规滴灌和固定滴灌相比,交替滴灌显著增加了苹果幼树的根冠比、壮苗指数和根系水分传导,在30 mm灌水定额处理下,交替滴灌的根冠比分别增加31.6%和47.1%,壮苗指数增加34.2%和53.6%,根系水分传导增加9.0%和11.0%.3种灌水方式下,根干质量和叶面积均与根系水分传导呈显著线性正相关.控制性分根区交替滴灌增强了苹果幼树根系水分传导的补偿效应,促进了根系对水分的吸收利用,有利于干物质向各个器官均衡分配,显著提高了根冠比和壮苗指数.     

不同滴灌方式和NaCl处理对苹果幼树生长和水分传导的影响

为了探讨不同滴灌方式和土壤盐分对苹果(Malus pumila)幼树生长和水分传导(简称水分传导K)的影响。采用3种滴灌方式(交替滴灌(ADI, 根区两侧交替灌水)、固定滴灌(FDI, 根区固定一侧灌水)和常规滴灌(CDI, 根区两侧均灌水))和4个NaCl浓度梯度(0 (CK)、0.2% (S₁)、0.3% (S₂)、0.4% (S₃))。结果表明: 滴灌方式和NaCl浓度对苹果幼树生长和水分传导有显著影响。在相同的滴灌处理下, 随着NaCl浓度的增大, 苹果幼树的干物质、叶面积和净生长量及水分传导均显著地下降。根系水分传导(K_r)与总根干重间, 冠层水分传导(K_sh)与冠层干重间均呈显著的线性相关关系。在相同的NaCl处理下, 与CDI处理相比, ADI处理节水达50%, 平均根系干重、冠层干重、总干重、叶面积、净生长量和K_r仅分别下降了8.7%、19.24%、13.47%、11.87%、32.96%和10.72%; 这说明ADI处理对果树的生长和K_r具有明显的促进作用。在高盐分S₂和S₃处理下, ADI处理的叶水分传导(K_l+p)分别降低了33.56%和44.26%, 但ADI处理的K_r反而高出了CDI达1.13%和10.91%, 说明ADI处理增强了苹果幼树根源水力信号的传输效率和调控苹果幼树体内水分平衡的能力及抗盐分胁迫能力。ADI处理的生长状况和K_r均高于FDI。采用ADI处理进行灌溉不仅提高了节水调控能力, 而且也增强了抗盐分胁迫能力。     

根系分区交替滴灌对苹果幼苗生理特性和水分利用效率的影响

以矮化红富士苹果幼苗为试验材料,采用交替滴灌(ADI)、固定滴灌(FDI)和常规滴灌(CDI)3种滴灌方式和3种灌水量对苹果幼苗的生理特性和水分利用效率进行了研究,以阐明根系分区交替灌溉下苹果幼苗生理特性和节水机理.结果表明:与CDI方式相比,当灌水定额由20 mm增大到30 mm时,ADI方式提高了苹果幼苗根干重、根系导水率、叶水势和净光合速率,降低了其蒸腾速率、棵间蒸发量和蒸散量,从而使得ADI方式下的叶片水分利用效率、总水分利用效率和灌溉水分利用效率较CDI方式大大提高;3种滴灌方式的根系导水率均存在显著的季节变化,并以8月份最大,12月份最小;与CDI方式相比, ADI和FDI方式在节水达33.3%时的平均根系导水率仅分别降低了5.81%和14.7%,但水分利用效率、灌溉水利用效率分别较CDI方式高出16.31%和14.48%、40.52%和27.65%.可见,局部根区灌溉方式能促进苹果幼苗生长和光合作用,并主要通过提高根系导水率的途径来提高水分利用效率.     

控制性分根区交替滴灌对苹果幼树形态特征与根系水分传导的影响

采用固定滴灌(根区一侧固定供水)、控制性分根区交替滴灌(根区两侧交替供水)和常规滴灌(紧贴幼树基部供水)3种灌水方式和3种灌水定额(固定滴灌和交替滴灌均为10、20和30 mm,常规滴灌为20、30和40 mm),对比研究了控制性分根区交替滴灌对苹果幼树形态特征与根系水分传导的影响.结果表明： 交替滴灌的根区两侧土壤出现反复干湿交替过程,常规滴灌的根区两侧土壤含水率差异不显著.在灌水定额相同时,灌水侧的土壤含水率在3种灌水方式间差异不显著.与常规滴灌和固定滴灌相比,交替滴灌显著增加了苹果幼树的根冠比、壮苗指数和根系水分传导,在30 mm灌水定额处理下,交替滴灌的根冠比分别增加31.6%和47.1%,壮苗指数增加34.2%和53.6%,根系水分传导增加9.0%和11.0%.3种灌水方式下,根干质量和叶面积均与根系水分传导呈显著线性正相关.控制性分根区交替滴灌增强了苹果幼树根系水分传导的补偿效应,促进了根系对水分的吸收利用,有利于干物质向各个器官均衡分配,显著提高了根冠比和壮苗指数.     

黄土高原西北部春小麦集雨微灌的产量及水分效应

为探讨集雨微灌对春小麦的产量及水分效应 ,于 2 0 0 1年在黄土高原西北部的甘肃省皋兰县进行了灌水方式 (管灌、滴灌和微喷灌 3个水平 )和灌水量 (0 mm、2 2 .5mm、45.0 mm和 67.5mm 4个水平 ) 2因素试验 ,分别在拔节期、孕穗期和开花前期灌水 ,试验共设 36个小区 ,小区面积 3× 5m2 。试验结果表明 :小麦生育期土壤水分变化动态受降水量、灌水量和小麦生育期耗水量的影响 ,总体呈下降趋势。微喷灌处理能显著地增加上层 (0～ 40 cm)土壤含水量 ,以微喷灌 67.5mm处理最为明显。对产量的方差分析结果表明 ,尽管灌水方式间的差异不显著 ,但从产量表现来看 ,其大小顺序依次是微喷灌、滴灌、管灌和对照 ;灌水量和互作间的差异达极显著水平 ;灌水有增加公顷穗数 ,降低穗粒数和千粒重的趋势 ;随灌水量的增加 ,千粒重对产量的贡献减小 ,而公顷穗数对产量的贡献增加 ,穗粒数对产量的贡献表现在这一过程之中。作物田间耗水量和水分利用效率随补灌量的增加而增加 ;以微喷灌 67.5mm的水分利用效率最高 ;供水效率以微喷灌 45.0 mm和 67.5mm处理为高。     

基于AHC模型的辽西北花生膜下滴灌灌水量优化

为评价AHC模型在辽西北半干旱地区的适用性及寻求花生膜下滴灌条件下的最优灌水量,本研究以2016、2017年花生田间试验数据为基础,首先对模型参数进行全局敏感性分析,然后对土壤水分、作物生长模块参数进行率定及验证,最后应用AHC模型分析了试验年份花生产量和水分利用效率对不同灌水量的响应。结果表明: 模型的极敏感参数为土壤第1、2层的饱和导水率。校验过程中,土壤含水率模拟值与实测值的均方根误差(RMSE)和平均相对误差(MRE)分别在0.02～0.03 cm³·cm^-3和1.5%～2.3%,叶面积指数、株高的RMSE和MRE分别在0.3～0.6、4.2～4.5 cm和5.0%～8.9%、5.2%～6.8%,花生产量和耗水量的MRE都在5%以内,模型适用于辽西北地区土壤水分与花生生长模拟研究。随着灌水量增加,花生产量增加,而水分利用效率却减小。综合考虑产量和水分利用效率,试验年份(平水年)辽西北半干旱地区膜下滴灌花生优化灌水量为80～97 mm。     

沙埋对樟子松幼树生长及光合水分代谢的影响

为了解沙埋对樟子松幼树生长特性及光合水分代谢的影响,2013年在内蒙古科尔沁沙地研究了不同沙埋深度下3年生樟子松幼树的存活率、株高、地上生物量等生长特性及光合速率、蒸腾速率等光合水分代谢特征的变化。结果表明:樟子松幼树最大可耐受大于株高2 cm的沙埋,沙埋超过该深度其幼树全部死亡;低于株高以上2 cm的沙埋有利于促进樟子松幼树的株高生长,但不利于其地上生物量的积累;低于株高以上2 cm的沙埋可以导致樟子松幼树的光合速率、蒸腾速率、气孔导度、胞间CO2浓度显著增加,但以50%株高沙埋处理的光合速率、蒸腾速率、气孔导度增加幅度最大,胞间CO2浓度以株高以上2 cm沙埋处理的增加幅度最大;沙埋并不造成樟子松幼树的水分胁迫,但随着沙埋深度的增加其水分利用效率趋于下降,并以株高以上2 cm沙埋处理的水分效率最低。樟子松幼树的高生长与其光合速率、蒸腾速率呈显著正相关,光合蒸腾速率与气孔导度、胞间CO2浓度呈显著正相关,水分利用效率与植物含水量、蒸腾速率呈显著正相关,地上生物量与光合效率、蒸腾速率的相关性未达到显著水平。     

不同膜下滴灌方式对设施黄瓜生理特性及水分利用效率的影响

为了探明黄瓜膜下分根交替滴灌的节水效果,为设施黄瓜节水灌溉提供理论依据和技术参数,以‘津优3号’黄瓜为试材,采用随机区组设计,以土壤田间持水量的65%为灌水下限,田间持水量的90%为灌水上限,研究了分根交替滴灌(APDI)、固定1/2根区滴灌(FPDI)和传统滴灌(CDI)3种灌溉模式对黄瓜生长、生理特性、产量与品质及水分利用效率的影响,结果表明:(1)随灌溉处理时间的延长,3种灌溉模式的单株叶面积和株高的差异越来越显著,而茎粗和叶片数差异不显著;(2)与传统滴灌相比,分根交替滴灌模式下黄瓜叶片净光合速率略有下降而蒸腾速率显著降低,水分利用效率显著提高;(3)分根交替滴灌处理下黄瓜可溶性蛋白、可溶性糖含量与传统滴灌相比差异不显著,Vc含量却显著增加;(4)分根交替滴灌模式下黄瓜产量比传统滴灌下降1.5%,而灌水量减少17%,水分利用效率提高18.6%,节水效果显著。综上所述,分根交替滴灌可以在保证设施黄瓜产量没有显著下降的前提下,改善品质和显著提高水分利用效率,可作为设施节水提质增效的一种灌溉模式,推广应用前景广阔。     

喷灌灌水量对冬小麦生长、耗水与水分利用效率的影响

于2006-2008年在中国科学院通州农田水循环与节水灌溉试验基地进行田间试验,研究灌水量对冬小麦生长、耗水、产量和水分利用效率的影响.试验设置了不同的灌水量处理,灌水量以布置在冬小麦冠层顶部20 cm标准蒸发皿蒸发量(E)的倍数表示.试验结果表明:2006-2007生长季节中0.75 E处理和2007-2008生长季节中0.625 E处理所对应的冬小麦产量最高.当灌水量小于0.25 E时,冬小麦生长受到水分胁迫,其产量下降25%以上.两个生长季节中冬小麦耗水量为219～486 mm,耗水量随灌水量的增加而增大.冬小麦产量和水分利用效率与耗水量之间呈二次函数关系.北京地区冬小麦返青后的生长季节内,其适宜喷灌水量为0.50～0.75 E.     

Neighborhood effects on soil properties,mycorrhizal attributes,tree growth,and nutrient status in afforested zones

A harmonious interspecies relationship is the key to the success of mixed afforestation. This study was conducted to assess the responses of afforestation species to their neighboring trees. We examined five types of stands—monocultures of Chinese pine (Pinus tabuliformis), black locust (Robinia pseudoacacia), sea‐buckthorn (Hippophae rhamnoides), and two mixtures (Chinese pine × black locust mixture and Chinese pine × sea‐buckthorn mixture)—in the Loess Plateau, northwestern China. The height and diameter at breast height of each tree species were measured, and rhizosphere soil, shoot, and root were sampled. In monocultures, black locust was taller than Chinese pine and sea‐buckthorn, while the height of Chinese pine and sea‐buckthorn was similar. In mixtures, Chinese pine grew better with sea‐buckthorn than alone as a result of modified soil properties and plant nutrition, but not with black locust. When Chinese pine was used as neighbors, it affected the level of arbuscular mycorrhizal (AM) colonization of black locust, soil properties and AM fungal spore density of black locust and sea‐buckthorn, but did not significantly affect their growth. Our results suggest that the reciprocal effects between tree species in mixture are not symmetric, and thus planning for efficient mixed afforestation requires knowledge of species‐specific growth rate, nutrient requirements, and species interactions.     

Nitrogen stocks in a riparian area invaded by N-fixing black locust (Robinia pseudoacacia L.)

Fixation of river flow passages and riverbed degradation may facilitate the development of higher floodplains with the establishment of exotic species such as black locust (Robinia pseudoacacia L.). We quantitatively evaluated the relationship between nitrogen (N) levels in black locust trees and in sediments under different flood disturbance regimes in a riparian area of the Chikuma River. In this study, allometric equations were developed for relating leaf N content to diameter at breast height of black locust. The amount of leaf N in black locust increased with distance from the river, reaching 159 kg N ha⁻¹ at 180 m from the river. There was a small difference in N content between green and fallen leaves (0.2%), and so the leaf N was almost equivalent to N input to riparian sediments. Fine sediments accumulated on the riparian area, where the amount of sediments N increased with distance from the river, ranging from 1091 ± 767 to 4953 ± 2953 kg N ha⁻¹. The N accumulation rates also increased with distance from the river, corresponding with the amount of leaf N in black locust per unit area, but the former exceeded the latter. The sediment N accumulation might be accelerated by sediment trapping effect due to riparian vegetation itself. A large input of N provided by invaded black locust might alter nutrient dynamics and native plant community structure in the riparian area.     

Why does oriental arborvitae grow better when mixed with black locust: Insight on nutrient cycling?

To identify why tree growth differs by afforestation type is a matter of prime concern in forestry. A study was conducted to determine why oriental arborvitae (Platycladus orientalis) grows better in the presence of black locust (Robinia pseudoacacia) than in monoculture. Different types of stands (i.e., monocultures and mixture of black locust and oriental arborvitae, and native grassland as a control) were selected in the Loess Plateau, China. The height and diameter at breast height of each tree species were measured, and soil, shoot, and root samples were sampled. The arbuscular mycorrhizal (AM) attributes, shoot and root nutrient status, height and diameter of black locust were not influenced by the presence of oriental arborvitae. For oriental arborvitae, however, growing in mixture increased height and diameter and reduced shoot Mn, Ca, and Mg contents, AM fungal spore density, and colonization rate. Major changes in soil properties also occurred, primarily in soil water, NO₃‐N, and available K levels and in soil enzyme activity. The increase in soil water, N, and K availability in the presence of black locust stimulated oriental arborvitae growth, and black locust in the mixed stand seems to suppress the development of AM symbiosis in oriental arborvitae roots, especially the production of AM fungal spores and vesicles, through improving soil water and N levels, thus freeing up carbon to fuel plant growth. Overall, the presence of black locust favored oriental arborvitae growth directly by improving soil water and fertility and indirectly by repressing AM symbiosis in oriental arborvitae roots.     

红松人工林优势木竞争指数影响因子

在温带湿润气候区东段不同立地条件下的红松人工林内设置面积为600 m~2(20 m×30 m)的70块矩形固定样地。在每个样地内,选取5颗最高且长势较好的优势木作为研究的对象木,用Voronoi图确定优势木相应的竞争木,测定每一块样地内优势木与竞争木之间的距离。采用Hegyi单木竞争指数模型,分析优势木在不同样地水平上的种内竞争强度,探讨林分生长因子、地形因子、土壤养分因子对优势木竞争指数的影响,并对这3类因子与优势木竞争指数进行相应的拟合和相关性分析。结果表明：红松人工林优势木竞争强度随着优势木胸径的增大而变小,并且两者之间的关系服从幂函数;红松优势木的竞争指数与其树高、胸径、冠幅呈极显著的相关关系(P<0.01);坡向、坡位、海拔对竞争指数影响极显著(P<0.01);红松人工林优势木竞争指数的大小与土壤氮磷钾含量均呈极显著的相关关系(P<0.01);pH值对优势木竞争指数的影响不显著。当红松人工林优势木平均胸径达到45cm,优势木平均树高和冠幅大于周围竞争木时,其对周围资源的利用程度增大,林木会发生自然稀疏现象,其所受的竞争压力减小。红松喜光性强,对水分的要求高,...     

Effects of Sika deer on the regeneration of aFagus crenata forest on Kinkazan Island,northern Japan

Kinkazan Island, a sanctuary island that has been conserved for over 100 years, is inhabited by a Sika deer population of high density (60 km⁻²). AFagus crenata forest, a climax forest of this region, was composed of only large sized trees (30–60 cm diameter breast height) and lacked young trees. However, many saplings were found inside a deer proof fence, indicating this forest had a potential to produce seedlings. They were tentatively protected by shrubs ofLeucothoe grayana var.glabra, an upalatable ericaceous shrub, but did not exceed the shrub height. Heavy browsing by the deer suppressed recruitment of saplings ofF. crenata. The forest will be reduced without population control of the deer.     

桂林岩溶石山阴香种群结构的研究

探讨了桂林岩溶石山阴香种群的高度、胸径和冠幅结构以及三者间的相互关系,并采用分异指数量化了种群个体间高度、胸围和冠幅结构的差异程度。结果表明:阴香种群个体高度集中分布在2-8m;胸径集中分布在2-6cm;冠幅多集中分布在1-4m,少数分布在5-7m之间;阴香种群个体的高度、胸围和冠幅多数为中等分异;阴香种群以幼树和小树个体占多数,自然更新能力较好,处于稳定的增长状态,这将有利于增加种群结构的复杂性和稳定性。     

四川理县杂谷脑干旱河谷岷江柏造林恢复效果评价

在岷江干旱河谷杂古脑河流域,选择岷江柏(Cupressus chengiana)5个不同年份的造林地,调查了岷江柏的生长情况、植物群落特征与土壤理化性质,总体评价干旱河谷乡土树种的造林成效及造林后的生态效果。结果表明:不同年份造林地岷江柏幼树生长状况良好,2003年造林地生长最好,基径、树高和冠径分别达到4.39cm、4.17m和1.01m,当年生长量超过43cm;2001年和2005年造林地次之,基径为4.19cm和4.52cm,冠径为0.55m和0.61m,当年生长量37cm左右,树高为2.50和2.17m;2007年和2009年造林地由于幼树生长时间较短,其基径、树高和冠径都较小,但当年生长量也都超过20cm。不同年份造林地的植被覆盖度变化相对复杂,除2001年造林地外,灌木层盖度随造林时间的增加而逐渐降低;草本层盖度变化较小,2005造林地最高,其他年份造林地没有显著差异。同时,不同年份造林地的群落结构都比较单一,随造林时间的增长,群落物种数量反而降低。在5个不同年份造林地,土壤pH、有机质和养分含量差异相对较小,土壤含水量尽管存在较大差异,但没有明显的变化趋势。综合分析认为,在杂谷脑干旱河谷中山区岷江柏作为造林树种具有一定的生长优势,但造林地的植被和土壤并没有得到改善,需要更加长期的观测评估。     

青藏高原典型人工林幼树生物量模型构建

森林生物量计算是全球碳储量估算的基础,现已纳入全球国家森林清单项目。普遍的森林碳汇计量采用的材积源生物量法针对胸径5 cm以上的树木,幼树(胸径<6 cm,树高>0.3 m)的碳汇量并未被完整计入其中,导致生态系统碳汇能力被低估。基于青藏高原137株5种典型人工林幼树的实测生物量数据,以地径代替胸径作为预测变量,采用加权广义最小二乘法建立独立生物量模型,选择比例总量直接控制及代数和控制2种结构形式的相容性生物量模型,并通过加权非线性似乎不相关回归进行方程组估算,建立了整株及各组分的相容性生物量方程。结果表明: 二元相容性模型优于一元以及独立模型,对整株生物量来说,R²达到0.90～0.99,两种相容性模型对于不同树种来说各有优势但精度差距可以忽略,从林业生产实践角度考虑,比例总量直接控制生物量模型更有实践意义,从遥感技术的变量提取角度考虑,本研究构建了更适于遥感估算的幼树生物量模型,其整体上拟合精度高,可以准确地进行类似气候环境中的幼树整株和各组分生物量的估算。     

Combining sap flow and trunk diameter measurements to assess water needs in mature olive orchards

Sap flux (Q) and trunk diameter variation (TDV) are among the most useful plant-based measurements to detect water stress and to evaluate plant water consumption. The usefulness of both methods decreases, however, when applied to species that, like olive, have an outstanding tolerance to drought and a remarkable capacity to take up water from drying soils. Evidence shows that this problem is greater in old, big trees with heavy fruit load. Our hypothesis is that the analysis of simultaneous measurements of Q and TDV made in the same trees is more useful for assessing irrigation needs in old olive orchards than the use of any of these two methods alone. To test our hypothesis, we analysed relations between Q, TDV, midday stem water potential (Ψ_stem), relative extractable water and atmospheric demand in an olive orchard of 38-year-old ‘Manzanilla’ trees with heavy fruit load. Measurements were made during one irrigation season (May-October), in fully irrigated trees (FI, 107% of the crop evapotranspiration, ET_c, supplied by irrigation), and in trees under two levels of deficit irrigation (DI60, 61% ET_c; DI30, 29% ET_c). Time courses of Q and TDV measured on days of contrasting weather and soil water conditions were analysed to evaluate the usefulness of both methods to assess the crop water status. We calculated the daily tree water consumption (E_p) from Q measurements. For both DI treatments we calculated a signal intensity by dividing daily E_p values of each DI tree by those of the FI tree (SI−Ep). We did the same with the maximum daily shrinkage (MDS) values (S_I−MDS). Neither SI−Ep nor S_I−MDS rendered useful information for assessing the crop water needs. On the contrary, the daily difference for maximum trunk diameter (MXTD) between each of the DI trees and the FI tree (D_MXTD) clearly indicated the onset and severity of water stress. A similar analysis with the E_p values, from which DEp values were derived, showed the effect of water stress on the water consumption of the trees. We concluded that the simultaneous use of D_MXTD and DEp values provides more detailed information to assess water needs in mature olive orchards than the use of Q or TDV records alone.     

我国特有植物银杉的资源、分布及其环境

我国银杉自1955年发现以来,陆续发现了它的新分布,至今已知在四省、区7个分布区的30多个分布点上,自然生长着银杉3200余株。它们是:广西花坪林区(越城岭南部)6个点有银杉1040抹,其中高5米以上的68株,1～5米的49株,1米以下的923株,最高21.1米,最大胸径83厘米;广西大瑶山4个点有银杉143株,其中高10米以上的94株,1～3米的3株,1米以下的46株,最高30米,最大胸径79.2厘米;湖南罗汉洞(越城岭北部)2个点有银杉58株,5米以上的有45株,最高18米,最大胸径43厘米;湖南罗霄山脉八面山有银杉707株,高1米以上的334株,最高24米,最大胸径46厘米;四川南川金佛山(大娄山东段北部)6个点有银杉527株,其中成年树400余株,最高17米,最大胸径50厘米;百枝山有银杉52株,最高8米,最大胸径27厘米;贵州道真沙河林区(大娄山东段南部)3处12个点有银杉729株,其中高5米以上的105株,2～5米的209株,1～2米的111株,1米以下的304株,最高18.8米,最大胸径48厘米;贵州桐梓白菁有银杉10株,高4～5米的2株,1～3米的6株,1米以下的2株。 银杉分布区范围自北纬24°5′～29°13′14″,东经107°10′～113°40′。其垂直分布自海拔940～1840米,金佛山银杉分布最高,为1600～1840米;罗汉洞银杉分布最低,为940～1060米。分布区内,年均温8.2°～17℃,绝对最低温