伊春地区红松和红皮云杉径向生长对气候变化的响应

树木生长-气候关系对准确评估气候变化对森林生态系统影响、预测森林生产力与植被动态及揭示树木对气候变化的响适应策略至关重要。在全球变暖背景下,升温可能会对树木的生长产生影响,从而改变区域森林生态系统的生产力或碳储量。本研究利用生长-气候响应函数、滑动相关分析等树木年轮学方法,探讨伊春地区阔叶红松林内红松和红皮云杉径向生长的主要限制因子及两者径向生长对快速升温(1980年后)响应的异同。结果表明:1980年前红松径向生长有明显加速的趋势,红皮云杉上升趋势较弱;而1980年后红松径向生长趋势显著下降,红皮云杉则下降不明显。红皮云杉径向生长与上一年9月及当年6月平均气温显著负相关,而红松径向生长与上一年12月及当年1月、4月和6月最低气温显著正相关。1980年快速升温后,高温对两树种生长的抑制作用增强,尤其是红松。生长季末(9月)降水对红松和红皮云杉的限制作用由升温前的负相关转变为升温后的显著正相关。温度是限制红松和红皮云杉径向生长的主要气候因子,降水影响相对较弱;其中红松径向生长对气候变化的响应比红皮云杉更敏感。快速升温后,红松和红皮云杉生长-气候关系的变化可能与升温导致的暖干旱化有关。若气...     

长白山北坡不同林型内红松年表特征及其与气候因子的关系

运用树木年轮学的基本原理和方法,选取了长白山北坡保存完好的典型性植被阔叶红松林,探讨了杨桦红松林和椴树红松林内建群种红松(Pinus koraiensis)径向生长对气候要素的响应.结果表明,长白山北坡红松的径向生长对降水较为敏感,杨桦红松林和椴树红松林中,红松年轮宽度均与当年7月以及上一年9月的降水呈显著正相关关系.不同林型内红松的生长与气候因子的关系也有差异.椴树红松的年轮宽度还与上年7月的降水显著负相关,与当年3、4月份的平均气温呈显著正相关.而杨桦红松林内红松年轮宽度和平均温度没有显著的相关关系.特征年分析进一步验证了响应函数相关分析的结果,即当年生长季以及上年生长季末的降水充足促进了红松的径向生长;椴树红松林中,初春温度的升高有利于红松的生长.     

Sensitivity of French temperate coniferous forests to climate variability and extreme events (Abies alba,Picea abies and Pinus sylvestris)

Questions: (1) How do extreme climatic events and climate variability influence radial growth of conifers (silver fir, Norway spruce, Scots pine)? (2) How do elevation and soil water capacity (SWC) modulate sensitivity to climate? Location: The sampled conifer stands are in France, in western lowland and mountain forests, at elevations from 400 to 1700 m, and an SWC from 50 to 190 mm. Methods: We established stand chronologies for total ring width, earlywood and latewood width for the 33 studied stands (985 trees in total). Responses to climate were analysed using pointer years and bootstrapped response functions. Principal component analysis was applied to pointer years and response function coefficients in order to elucidate the ecological structure of the studied stands. Results: Extreme winter frosts are responsible for greater growth reductions in silver fir than in Norway spruce, especially at the upper elevation, while Scots pine was the least sensitive species. Exceptional spring droughts caused a notable growth decrease, especially when local conditions were dry (altitude<1000 m and SWC<100 mm for silver fir, western lowlands for Scots pine). Earlywood of silver fir depended on previous September and November and current‐year February temperature, after which current June and July water supply influenced latewood. Earlywood of Norway spruce was influenced by previous September temperature, after which current spring and summer droughts influenced both ring components. In Scots pine, earlywood and latewood depended on the current summer water balance. Local conditions mainly modulated latewood formation. Conclusions: If the climate becomes drier, low‐elevation dry stands or trees growing in western lowlands may face problems, as their growth is highly dependent on soil moisture availability.     

万仙山油松径向生长与气候因子的关系

以万仙山油松(Pinus tabulaeformis)为样本,建立了油松树木年轮宽度序列的标准年表(STD)。与附近气象因子的相关结果表明:与当年6月平均温度呈较为显著的负相关,与前一年的9月和当年的5月以及春季(3-5月)的降水量呈显著正相关,显然影响万仙山油松生长的主要气候因子是5月(或说春季)降水和6月温度。树轮指数与各月PDSI相关值都很高(其中与当年5月的PDSI相关值高达0.614),都超过95%的置信水平,说明水热组合是该区域油松生长的主要限制因子。研究表明,影响本区油松生长的气候因子与我国北方地区油松生长的影响因子有较高的一致性,尤其是生长季前期的温度影响都很大;而其降水的影响及其与PDSI的相关都明显超前于黄土高原及北方地区,这既说明影响油松生长的大气候因子相似,又表明夏季风从东南向西北的不断推进。     

Climate‐diameter growth relationships of black spruce and jack pine trees in boreal Ontario,Canada

To predict the long‐term effects of climate change – global warming and changes in precipitation – on the diameter (radial) growth of jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] B.S.P.) trees in boreal Ontario, we modified an existing diameter growth model to include climate variables. Diameter chronologies of 927 jack pine and 1173 black spruce trees, growing in the area from 47°N to 50°N and 80°W to 92°W, were used to develop diameter growth models in a nonlinear mixed‐effects approach. Our results showed that the variables long‐term average of mean growing season temperature, precipitation during wettest quarter, and total precipitation during growing season were significant (alpha = 0.05) in explaining variation in diameter growth of the sample trees. Model results indicated that higher temperatures during the growing season would increase the diameter growth of jack pine trees, but decrease that of black spruce trees. More precipitation during the wettest quarter would favor the diameter growth of both species. On the other hand, a wetter growing season, which may decrease radiation inputs, increase nutrient leaching, and reduce the decomposition rate, would reduce the diameter growth of both species. Moreover, our results indicated that future (2041–2070) diameter growth rate may differ from current (1971–2000) growth rates for both species, with conditions being more favorable for jack pine than black spruce trees. Expected future changes in the growth rate of boreal trees need to be considered in forest management decisions. We recommend that knowledge of climate–growth relationships, as represented by models, be combined with learning from adaptive management to reduce the risks and uncertainties associated with forest management decisions.     

西昆仑山两种针叶树种径向生长及其对气候变化的响应

利用西昆仑山的雪岭云杉和昆仑圆柏树芯样本,建立其树轮宽度年表。通过分析两种针叶树种树木径向生长特征与气候要素的相关关系,探讨了树种间的树木生长气候响应异同及响应关系的稳定性。结果表明：研究区域内的雪岭云杉和昆仑圆柏年表间存在显著正相关。两种针叶树种在1994年气温突变前树轮宽度年表指数和基部断面生长增量（BAI）呈上升趋势,在气温突变后年表和BAI则呈下降趋势,并且昆仑圆柏的树木径向生长速率高于雪岭云杉。与气候要素的相关性分析结果表明,雪岭云杉径向生长与上年生长季（5—6月和8—10月）和当年生长季（3—6月和10月）气温呈显著负相关,而昆仑圆柏径向生长与上年10月和当年生长季前期（4—6月）气温呈显著负相关;两者均与当年春季降水呈显著正相关。滑动相关分析结果显示,上年和当年生长季气温对两个树种树木径向生长的负响应在增强,特别是在当年生长季前期更为显著。此外,当年生长季前期降水对树木径向生长的促进作用也在增强。在有可能的气候突变年份（1994年）之后,两种针叶树种对气温和降水的响应敏感性均有所增强,并且雪岭云杉对气温的响应敏感性强于昆仑圆柏,而对降水响应敏感性要弱于昆仑圆柏。     

丽江老君山海拔上限长苞冷杉(Abies georgei)和云南铁杉(Tsuga dumosa)径向生长对气候变化的响应

基于树木年轮学方法,利用丽江老君山海拔上限长苞冷杉（Abies georgei）和云南铁杉（Tsuga dumosa）树轮宽度资料,构建差值年表,运用响应函数和滑动响应分析研究树木径向生长与气温和降水的相关关系及其稳定性,进而阐明影响该区域2个针叶树种径向生长的主要气候要素。结果表明：2个树种对降水累积效应的响应较为一致,对逐月气候因子的响应存在差异,相关关系较为稳定,具体表现为（1）上年11月平均温升高和当年生长季盛期（7-8月）降水增加有利于老君山海拔上限长苞冷杉生长;（2）云南铁杉径向生长与当年3月、树木休眠期（1-3月）、生长季盛期（7-8月）的降水表现为显著正相关关系,与上年7月与当年5月的气温及当年生长季末期（9-10月）降水呈显著负相关;（3）上述相关关系的稳定性较强,在全部或大部分分析时段（1951-2017）内达到显著相关,云南铁杉的稳定性更强。研究结果可为气候变化背景下滇西北高原树木生长的管理及森林生态系统的保护提供理论依据。     

黑河上游祁连山区青海云杉生长状况及其潜在分布区的模拟

根据Hutchinson的n维超体积概念以及物种与资源利用之间的关系, 构建了青海云杉(Picea crassifolia)在三维环境资源空间中的生物-地理模型, 并利用该模型模拟了青海云杉的潜在分布及其对环境资源的利用状况。结果表明: 青海云杉在生长季平均气温、多年平均降水量及太阳直接辐射三维环境资源空间上的最佳配置为9 ℃、360 mm和1.9 × 10³ kW·h·m^-2; 用三元方程式的拟合结果在大范围上预测了青海云杉的潜在分布区, 并给出了其在对应地理位置上的生长状况。     

Climate sensitivity of purple cone spruce (Picea purpurea) across an altitudinal gradient on the eastern Tibetan Plateau

Picea purpurea (Purple cone spruce) is a dominant and widely distributed tree species in the subalpine area of the Wanglang Nature Reserve. We investigated variations in radial growth and its response to climate in P. purpurea along an altitudinal gradient. In this study, P. purpurea chronologies were developed from three altitudinal sites ranging from 2850 to 3250 m above sea level. Correlation analysis and principal component analysis were used for all the chronologies to detect the growth patterns at different altitudes. Correlation analysis was used to assess the relationships between chronologies and climatic factors. Tree-ring widths among the three elevations were all positively correlated with June maximum temperature in the current year. Radial growth at the higher altitude was more sensitive to temperature than those of the two lower altitudes. Ring-widths at the low and middle sites were mainly negatively affected by temperatures in the previous growing season (June and August). Spruce growth at the upper site was strongly positively affected by temperatures in the previous winter, the current spring and current growing season. Climatological analysis revealed that elevation-dependent and elevation-independent signals were present in this semi-humid subalpine area. Precipitation was not the main factor affecting the tree growth in the growing season throughout the study area. The noteworthy findings were that the lag effects of temperatures to spruce growth was more significant at the low and middle altitude sites, and spruce growth at the high altitude site clearly benefited from the warmer climate before and during the growing season. This study will provide a basis for better predicting forest dynamics and carrying out vegetation restoration in the future.     

Intra-annual radial growth of Schrenk spruce (Picea schrenkiana Fisch. et Mey) and its response to climate on the northern slopes of the Tianshan Mountains

Schrenk spruce (Picea schrenkiana Fisch. et Mey.) is widely distributed in the Tianshan Mountains. In this study, four Schrenk spruce trees were continuously monitored with dendrometers from 27 April to 30 September 2014 on the northern slopes of the Tianshan Mountains in northwest China. The goal of this monitoring study was to determine the main growing season of Schrenk spruce and to analyze intra-annual radial growth variability and its relation to daily meteorological factors. Our studies have shown that the critical growing season of Schrenk spruce is from late May to late July and that the rapid growth stage is from mid-June to early July. Meanwhile, in the growing season, changes in the radial growth of Schrenk spruce were negatively correlated with daily temperature, evaporation, sunshine hours and vapor pressure deficit (VPD), and were positively correlated with precipitation and relative humidity (RH). The correlation coefficient between radial growth and RH can be as high as 0.750 (Pearson, p < 0.0001, n = 60). Dates in which precipitation occurred corresponded to periods of rapid growth. The results of the climate-growth analysis show that changes in radial growth reflect the effect of water stress on tree growth, whether or not the changes are positively or negatively correlated with the above climatic factors. This indicates that moisture plays a major role in the growth of Schrenk spruce. We suggest that precipitation between late May to late June is a limiting factor for radial growth of Schrenk spruce on the northern slopes of the Tianshan Mountains.     

长白山红松不同树高处径向生长特征及其对气候的响应

利用长白山红松不同树高(0.3、1.3、4、10、15、20、25 m)处的径向生长资料,分析各树高处径向生长特征,建立红松生长与气候因子的相关关系,以期完善红松种群对气候变化的响应机制。结果表明:(1)红松不同树高处年径向生长量变化趋势基本一致,除在1980年前后,20 m处径向生长量出现异常增加外,其他各高度径向生长均出现下降趋势,红松基部和顶端(0.3、1.3 m和20 m)处径向生长年际变化更明显。随着树高增加,各处年径向生长率有所降低,0.3m处生长速率最大,且与10 m和15 m处径向生长差异显著(P < 0.05)。(2)不同树高处径向生长对气候因子的响应存在明显差异,10 m树高是红松径向生长对温度和降水响应差异的分界线。10 m以下红松径向生长主要受到生长季温度的负作用,尤其是4 m处,与当年生长季初期(4月和5月)温度显著负相关(P < 0.05)。0.3 m和1.3 m处径向生长分别与上年9月平均温度显著正相关(P < 0.05),当年6月平均和最高温度显著负相关(P < 0.05)。随着树高上升,降水对径向生长的促进作用增强,而温度对径向生长的作用也发生改变。10 m(含)以上则受到温度和降水的共同作用。10 m处径向生长对气候因子响应最敏感,受到当年生长季高温的抑制作用,还与上年和当年生长季末(9月)降水显著正相关(P < 0.05)。15 m处径向生长与上年9月最低温度和降水显著正相关(P < 0.05),而与当年5月月平均温度显著负相关(P < 0.05)。20 m处径向生长与当年3月月平均、最低和最高温度,当年7月月平均温度以及当年5月降水显著正相关(P < 0.05),而与当年1月降水显著负相关(P < 0.05)。     

Growth of mycorrhizal jack pine (Pinus banksiana) and white spruce (Picea glauca) seedlings planted in oil sands reclaimed areas

The effectiveness of ectomycorrhizal inoculation at the tree nursery seedling production stage on growth and survival was examined in jack pine (Pinus banksiana) and white spruce (Picea glauca) planted in oil sands reclamation sites. The seedlings were inoculated with Hebeloma crustuliniforme strain # UAMH 5247, Suillus tomentosus strain # UAMH 6252, and Laccaria bicolor strain # UAMH 8232, as individual pure cultures and in combinations. These treatments were demonstrated to improve salinity resistance and water uptake in conifer seedlings. The field responses of seedlings to ectomycorrhizal inoculation varied between plant species, inoculation treatments, and measured parameters. Seedling inoculation resulted in higher ectomycorrhizal colonization rates compared with non-inoculated control, which had also a relatively small proportion of roots colonized by the nursery contaminant fungi identified as Amphinema byssoides and Thelephora americana. Seedling inoculation had overall a greater effect on relative height growth rates, dry biomass, and stem volumes in jack pine compared with white spruce. However, when examined after two growing seasons, inoculated white spruce seedlings showed up to 75 % higher survival rates than non-inoculated controls. The persistence of inoculated fungi in roots of planted seedlings was examined at the end of the second growing season. Although the inoculation with H. crustuliniforme triggered growth responses, the fungus was not found in the roots of seedlings at the end of the second growing season suggesting a possibility that the observed growth-promoting effect of H. crustuliniforme may be transient. The results suggest that the inoculation of conifer seedlings with ectomycorrhizal fungi could potentially be carried out on a large scale in tree nurseries to benefit postplanting performance in oil sands reclamation sites. However, these practices should take into consideration the differences in responses between the different plant species and fungal strains.     

川西亚高山不同年龄紫果云杉径向生长对气候因子的响应

运用树木年轮气候学的基本方法,建立王朗自然保护区紫果云杉在集中分布上限区域的年轮宽度年表,选取差值年表分析不同年龄云杉的径向生长同逐月气候因子的相关及响应关系,结果显示:幼龄组云杉年表的敏感度高于中龄组和老龄组云杉,幼龄组云杉对生长季前及生长季的气温状况显著正相关;中龄组云杉年表仅与当年4月份和7月份的月平均最低气温显著正相关;老龄组云杉的年轮宽度指数同上年生长季(上年8月份)的月平均气温和月平均最低温显著负相关,上年生长季高温的"滞后效应"在老龄组云杉体现的更为突出;幼龄组与中龄组云杉对当年6月份降水持续增加显示出明显的负相关关系,上年12月份的降水会对幼龄组和老龄组云杉径向生长不利。研究表明幼龄组云杉包含的气候信息要优于中龄组和老龄组云杉,在该区域进行相关研究时应根据研究需要选取不同年龄跨度的云杉年表。     

Responses of radial growth and stable carbon isotopes to climate in the northern Tianshan Mountains

Climate change has profound effects on forest ecosystems. Schrenk spruce (P. schrenkiana) is a natural conifer species endemic to the arid inland areas of Asia. In this study, the relationship between tree-ring parameters of P. schrenkiana and major meteorological factors were analyzed, and the main limiting factors for tree radial growth and stable carbon isotope fractionation were explored. Our results indicate that moisture stress before and during the growing season have an important influence on radial growth of P. schrenkiana, especially, the correlation coefficient between tree-ring width and vapor pressure deficit (VPD) from previous August to current July is as high as −0.622 (n = 51, p < 0.01). Collinearity analysis further supports the conclusion that the limiting factor for the radial growth of P. schrenkiana is moisture. Although the correlation analysis results show that the tree-ring δ¹³C_corr is significantly positively correlated with sunshine duration (SD), additional analysis based on first order difference variables suggests that the climate factor may not be the only limiting factor for the stable carbon isotope fractionation of tree rings in the Sayram Lake Basin. This lays the foundation for the assessment of forest management practices and carbon sink capacity in light of future climate change.     

Different responses of Korean pine (Pinus koraiensis) and Mongolia oak (Quercus mongolica) growth to recent climate warming in northeast China

Different tree species growing in the same area may have different, or even contrasting growth responses to climate change. Korean pine (Pinus koraiensis) and Mongolia oak (Quercus mongolica) are two crucial tree species in temperate forest ecosystems. Six tree-ring chronologies for Korean pine and Mongolia oak were developed by using the zero-signal method to explore their growth response to the recent climate warming in northeast China. Results showed that Mongolia oak radial growth was mainly limited by precipitation in the growing season, while Korean pine growth depended on temperature condition, especially monthly minimum temperature. With the latitude decrease, the relationships between Korean pine growth and monthly precipitation changed from negative to positive correlation, while the positive correlation with monthly temperature gradually weakened. In the contrary, Mongolia oak growth at the three sampling sites was significantly and positively correlated with precipitation in the growing season, while it was negatively correlated with temperature and this relationship decreased with the latitude decrease. The radial growth of Korean pine at different sites showed a clearly discrepant responses to the recent warming since 1980. Korean pine growth in the north site increased with the temperature increase, decreased in the midwest site, and almost unchanged in the southeast site. Conversely, Mongolia oak growth was less affected by the recent climate warming. Our finding suggested that tree species trait and sites are both key factors that affect the response of tree growth to climate change. In addition, the suitable distribution area of Korean pine may be moved northward with the continued global warming in the future, but Mongolia oak may not shift in the same way.     

普达措国家公园2个针叶树种径向生长对温度和降水的响应

基于树轮年代学方法,利用普达措国家公园海拔上、下限丽江云杉(Picea likiangensis)和长苞冷杉(Abies georgei)树轮宽度资料,构建差值年表并分析其与温度和降水的关系,阐明影响该区域2个主要针叶树种径向生长的主要气候要素。结果表明:(1)海拔下限丽江云杉径向生长同时受到温度和降水的影响:与上年11月平均温、当年生长季后期(9—10月)平均温和上年7月降水呈显著正相关;(2)海拔上限丽江云杉径向生长只受温度影响,与上年生长季后期平均温呈显著负相关,与当年生长季盛期(6—8月)平均温呈显著正相关;(3)长苞冷杉径向生长只与温度表现出显著相关性,海拔下限的生长与上年11月平均温呈显著正相关,海拔上限的生长与当年生长季盛期平均温呈显著正相关。结果可为气候变化对滇西北高原树木生长影响研究提供参考,为滇西北高原森林生态系统管理与保护提供理论依据。     

Different climate responses of spruce and pine growth in Northern European Russia

We report new data on tree-ring growth in northern European Russia, a region with a hitherto relatively sparse tree-ring network. We explore its associations with climate variability. Areas, sampling locations and trees were selected for representativeness rather than climate sensitivity. Using tree rings from 651 conifers from six widely dispersed areas we show strong intercorrelation between trees within each major conifer species within and between areas. Regional composite tree-ring series for spruce and pine contain a major fraction of decadal and multidecadal variability. The most likely driver of this common variability is interannual to multidecadal climate variability. Gridded monthly instrumental climate data for the period 1902–2008, particularly mean temperature and total precipitation, were tested as predictors of each local species-specific tree-ring site chronology. The most consistent pattern emerged for spruce at all but the southernmost area. Cool and moist summers the year before growth were consistent drivers of spruce ring growth throughout the period, with no change in recent decades. Self-calibrating Palmer Drought Severity Index for prior summer was also a strong and consistent driver of spruce ring growth. For pine, there was a weaker but similarly stable association between larger rings and warm, moist conditions, in this case in the current summer. These associations were also identified at multidecadal time scales, particularly for spruce. On the other hand, the specific role of moisture variability in determining interannual to multidecadal variability in tree growth in this high latitude region raises questions about the relative vulnerability of spruce and pine there under global warming.     

Patterns of Cross-Continental Variation in Tree Seed Mass in the Canadian Boreal Forest

Seed mass is an adaptive trait affecting species distribution, population dynamics and community structure. In widely distributed species, variation in seed mass may reflect both genetic adaptation to local environments and adaptive phenotypic plasticity. Acknowledging the difficulty in separating these two aspects, we examined the causal relationships determining seed mass variation to better understand adaptability and/or plasticity of selected tree species to spatial/climatic variation. A total of 504, 481 and 454 seed collections of black spruce (Picea mariana (Mill.) B.S.P.), white spruce (Picea glauca (Moench) Voss) and jack pine (Pinus banksiana Lamb) across the Canadian Boreal Forest, respectively, were selected. Correlation analyses were used to determine how seed mass vary with latitude, longitude, and altitude. Structural Equation Modeling was used to examine how geographic and climatic variables influence seed mass. Climatic factors explained a large portion of the variation in seed mass (34, 14 and 29%, for black spruce, white spruce and jack pine, respectively), indicating species-specific adaptation to long term climate conditions. Higher annual mean temperature and winter precipitation caused greater seed mass in black spruce, but annual precipitation was the controlling factor for white spruce. The combination of factors such as growing season temperature and evapotranspiration, temperature seasonality and annual precipitation together determined seed mass of jack pine. Overall, sites with higher winter temperatures were correlated with larger seeds. Thus, long-term climatic conditions, at least in part, determined spatial variation in seed mass. Black spruce and Jack pine, species with relatively more specific habitat requirements and less plasticity, had more variation in seed mass explained by climate than did the more plastic species white spruce. As traits such as seed mass are related to seedling growth and survival, they potentially influence forest species composition in a changing climate and should be included in future modeling of vegetation shifts.     

北亚热带马尾松年轮宽度与NDVI的关系

北亚热带地处暖温带向亚热带的过渡地区,对环境变化较为敏感。因此,研究北亚热带马尾松年轮宽度与森林NDVI的关系对于揭示陆地生态系统对全球气候变化的响应具有重要意义。以马尾松自然分布北界的南郑县和河南省鸡公山自然保护区为研究地点,利用北亚热带马尾松年轮宽度指数和1982-2006年逐月NOAA/AVHRR的归一化植被指数(NDVI)数据及气候数据,在分析年轮宽度及NDVI与气候因子关系的基础上,重点讨论了北亚热带马尾松径向生长与NDVI之间的关系。结果表明:北亚热带NDVI受水热条件的共同控制,其中与月均温相关性较强,且以正相关为主,与月降水量和干旱度指数多负相关;马尾松的径向生长与上一生长季的温度呈正相关,降水和干旱度指数为负相关,当年生长季内的温度和降水以促进作用为主,而与干旱度指数的关系在两地区内相反;南郑县和鸡公山地区年轮宽度与NDVI年值之间关系均不显著(P>0.05)。单月来讲,南郑县3、4、12月NDVI值与年表显著相关,鸡公山地区9月份的NDVI值与差值年表RES相关性最大;南郑县树木生长受温度影响最大,而鸡公山地区受温度和降水的综合作用。因此,在北亚热带地区,长时间序列的年轮宽度数据并不能很好反应NDVI的长期变化,利用树轮宽度指数来重建北亚热带地区NDVI需要进一步研究。     

Reproductive development and maternal effects in the pine weevil Hylobius abietis

1. In a laboratory study of maturation feeding of female pine weevil Hylobius abietis on current and 1‐year‐old stem bark of transplants of Scots and Corsican pine, Norway and Sitka spruce, Douglas fir, and hybrid larch, the length of the pre‐oviposition period was influenced by the species on which weevils fed. The shortest pre‐oviposition period was on hybrid larch (11.8 days) and the longest on Douglas fir (15.5 days). 2. The species on which weevils fed also affected fecundity but there was evidence of a species–year interaction. Over a period of 36 days, most eggs were laid by weevils feeding on current stem of Norway spruce and Corsican and Scots pine and fewest on current stem of Sitka spruce. 3. Significant maternal effects on egg size were observed both in relation to female size and conifer species. The largest eggs were laid on Corsican pine and the smallest on Douglas fir, with no evidence of a trade‐off between number of eggs laid and their size. 4. There was a positive relationship between egg and larval size and between larval size and survival on logs of four conifer species. Residual resistance mechanisms in the bark of recently cut stumps and larval competition are discussed briefly in relation to the importance of the observed maternal effects on weevil population dynamics.