黄檗是国家二级保护植物.通过定量分析黄檗阔叶混交林中主要乔木种群的生态位特征,可以为黄檗的保护和维持物种多样性提供理论依据.基于吉林省第九次森林资源连续清查数据,通过对长白山地区黄檗阔叶混交林群落的典型样地进行调查,利用重要值、Levins生态位宽度、Shannon-Wiener生态位宽度和Pianka生态位重叠度计算方法,分析黄檗阔叶混交林主要乔木种群的生态位特征.结果表明,长白山地区黄檗阔叶混交林有25 个阔叶树种,占比96.15%,黄檗的重要值最大;Levins和Shannon-Wiener生态位宽度指数大小排序基本一致,生态位宽度最大的树种均为黄檗,其次为胡桃楸;黄檗、枫桦、胡桃楸和裂叶榆等物种的生态位重叠值较大,生态位宽度和生态位重叠度表现出明显的一致性.但是存在部分物种生态位宽度和生态位重叠度具有相反性,如鹅耳栎与槲树、刺槐、椴树,以及黄檗与红松,这与生态宽度受到物种生态习性、生境特征和空间分布等因素有关.

[Objective]The response of the radial growth of Picea koraiensis to climate change was studied by using the radial growth and climate factors of Picea koraiensis in Xiaoxing'an Mountains.[Method]The methods of the chronology characteristics of Picea koraiensis in Xiaoxing'an Mountains,ring index characteristics,and Pearson correlation test were used.[Result]The radial growth of Picea koraiensis was significantly negatively correlated with the temperature at the end of the previous year's growing season(September),the current year's growing season(June),and the end of the current year's growing season(September);The radial growth of Picea koraiensis was significantly positively correlated with the monthly minimum temperature in the winter(February)and the monthly average temperature in the early growing season(April)of the current year.Precipitation had little effect on the radial growth of Picea koraiensis.The correlation between the radial growth of Picea koraiensis and the temperature at the end of the growing season(September)of the previous year had changed from a significant positive correlation before the temperature rise to a significant negative correlation after the temperature rise;The correlation between the radial growth of Picea koraiensis and the precipitation at the end of the previous year's growing season(September)and the end of the current year's growing season(September)had changed from a negative correlation before the temperature rise to a significant positive correlation after the temperature rise.The relationship between the radial growth of Picea koraiensis and the precipitation before the growing season(March)changed from a positive correlation before the temperature rise to a significant negative correlation after the temperature rise.[Conclusion]Temperature was the main limiting factor for the radial growth of Picea koraiensis,the inhibitory effect of temperature increase on tree growth was strengthened.

本研究利用小兴安岭34株对象木(水曲柳)和198株竞争木,通过Hegyi竞争指数模型分析了水曲柳种内和种间竞争关系.研究结果表明:水曲柳种间竞争指数大于种内竞争指数,其中,水曲柳的种内竞争指数为135.80,种间竞争指数为165.17;随着水曲柳径级的增加,种内竞争和种间竞争指数出现减小趋势,当水曲柳胸径<20 cm时,随着胸径的增加,竞争指数逐渐减小;当水曲柳胸径>20 cm时,随着胸径的增加,竞争指数变化不明显,并最终维持在较低的水平.

文章以大兴安岭呼中区兴安落叶松林为研究对象,结合径级结构、静态生命表、存活率曲线、死亡率曲线和消失率曲线,对兴安落叶松种群的年龄结构和生态特征进行了研究.研究发现在不同龄级下落叶松种群的个体数量有明显差异,Ⅰ～Ⅲ龄级落叶松种群个体数占绝大多数,Ⅳ～Ⅵ龄级落叶松种群个体数相对较少;落叶松种群的存活曲线呈Deevey Ⅱ型(对角线型);消失率和死亡率曲线变化趋势基本一致,均呈现单峰型,Ⅰ～Ⅲ龄级落叶松种群的消失率和死亡率逐渐增加,Ⅳ～Ⅵ龄级落叶松种群消失率和死亡率逐渐减少.

高山林线的形成机理一直是高山生态学讨论的一个焦点问题,其中林线树木生长的阈值温度一直是研究热点.利用川西高原九寨沟弓杠岭林线岷江冷杉(Abies faxoniana)树木径向生长数据,通过树轮宽度-气候因子关系分析,探讨阈值温度和积温对林线岷江冷杉径向生长的影响.结果表明:林线岷江冷杉径向生长主要受到温度限制,其中林线岷江冷杉径向生长与当年生长季(7、8和9月)、冬季(12、1和2)及上一年9、10月温度显著正相关(P＜0.05),但与降水的相关性较弱.林线岷江冷杉径向生长与不同起始温度的初日负相关,与不同起始温度的终日正相关,且与9.5℃阈值温度的初日负相关最强(P＜0.05),与6.5℃阈值温度的终日正相关最强(P＜0.05).林线岷江冷杉径向生长还与7-9.5℃的积温及9.5℃持续天数显著正相关(P＜0.05),说明7-9.5℃可能是形成层活动的阈值温度,尤其7℃可能是林线岷江冷杉生长的起始温度.林线岷江冷杉生长期从4月中旬开始到10月初结束,随着1980年后温度的显著升高,生长期活动积温开始增加,生长期初日提前(4.6d/10a,r2=0.19,P=0.01),生长期终日延后(1.8 d/10a),使得生长期延长(6.4 d/10a),进而对林线岷江冷杉径向生长有显著的促进作用.未来气候变暖可能会使川西林线树木生长增加,林线可能会上移.

大兴安岭地区森林覆盖率高,生态环境良好,非常适于发展林下经济.文章就大兴安岭地区林下经济发展过程中的优势与存在的问题进行了分析总结,并提出了意见和建议.

[目的]进一步揭示不同种源樟子松在帽儿山地区的生长差异性,选择出优良种源.[方法]以1981年采种、1982年育苗、1984年春造林到帽儿山地区的高峰、图强、卡伦山、红花尔基、罕达盖、金山、阿尔山等7个种源31年生樟子松试验林为研究对象,通过对樟子松胸径、树高、材积、冠幅、年轮宽度及保存率等6个生长性状进行方差分析、多重比较、相关性分析、主成分分析等,选择优良种源.[结果]种源间胸径达到极显著差异(P＜0.01),材积和冠幅达到显著差异(P＜0.05),树高没有显著差异(P＞0.05);区组间各性状均没有显著差异(P＞0.05).图强种源的年轮宽度最大(3.69 mm),保存率则最小(56.67％);不同种源胸径、树高、材积、冠幅及年轮宽度与原产地地理气候因子之间没有显著相关性.樟子松种源各性状地理变异模式不明显,而保存率与纬度呈极显著负相关(P＜0.01),与经度呈显著负相关(P＜0.05),与海拔呈显著正相关(P＜0.05);主成分分析结果发现,图强种源综合指数得分最高(2.972).[结论]31年生樟子松人工林生长性状不同种源之间存在差异,红花尔基、高峰种源生长较好;图强种源表现最好,应用潜力大.

[Objective]To understand the difference in growth of Scots pine (Pinus sylvestris var.mongolica)prov-enances at Maoershan area,Heilongjiang Province in Northeast China,and to study the climate factors’influence to the width growth of Scots pine.[Method]By tree ring and climatic response analysis,correlation analysis and principal components analysis,the response differences between tree rings and climatic factors were conducted. [Result]Results showed a similar trend of the tree rings from different Scots pine provenances in the study area.A-mong 7 provenances,the ring width of six provenances showed an increasing trend in the initial stage.The radial growth of provenances from Aershan,Gaofeng,Honghuaerji and Kalunshan had significantly positive correlation with the temperature in current February.The radial growth of provenance from Handagai had significantly positive correlation with the temperature in last April.The radial growth of provenances from Gaofeng,Tuqiang and Kalun-shan had significantly positive correlation with monthly precipitation in current June.The radial growth of prove-nances from Aershan,Gaofeng,Jinshan,Kalunshan,Honghuaerji and Tuqiang had significantly negative correlation with monthly precipitation in last August.[Conclusion]It is concluded that the width growth of different Scots pine provenances grew faster at early stage,the width growth had positive correlation with temperature in February and&nbsp;precipitation in June,but negative correlation with precipitation in last August.In this study,the tree-ring chronolo-gies of 7 Scots pine provenances in Moershan were developed.

We present a reconstruction of July–August mean maximum temperature variability based on a chronology of tree-ring widths over the period AD 1646–2013 in the northern part of the northwestern Sichuan Plateau (NWSP), China. A regression model explains 37.1 % of the variance of July–August mean maximum temperature during the calibration period from 1954 to 2012. Compared with nearby temperature reconstructions and gridded land surface temperature data, our temperature reconstruction had high spatial representativeness. Seven major cold periods were identified (1708–1711, 1765–1769, 1818–1821, 1824–1828, 1832–1836, 1839–1842, and 1869–1877), and three major warm periods occurred in 1655–1668, 1719–1730, and 1858–1859 from this reconstruction. The typical Little Ice Age climate can also be well represented in our reconstruction and clearly ended with climatic amelioration at the late of the 19th century. The 17th and 19th centuries were cold with more extreme cold years, while the 18th and 20th centuries were warm with less extreme cold years. Moreover, the 20th century rapid warming was not obvious in the NWSP mean maximum temperature reconstruction, which implied that mean maximum temperature might play an important and different role in global change as unique temperature indicators. Multi-taper method (MTM) spectral analysis revealed significant periodicities of 170-, 49–114-, 25–32-, 5.7-, 4.6–4.7-, 3.0–3.1-, 2.5-, and 2.1–2.3-year quasi-cycles at a 95 % confidence level in our reconstruction. Overall, the mean maximum temperature variability in the NWSP may be associated with global land–sea atmospheric circulation (e.g., ENSO, PDO, or AMO) as well as solar and volcanic forcing.

By using an empirical 'signal-free' standardization approach, we constructed four Picea purpurea and Abies faxoniana tree-ring chronologies at southeast and northwest slope aspects of Erdaohai and east slope aspect of Zharisi, Songpan, west Sichuan, China. The response analysis and multivariate analysis of variance between tree rings and climatic variables were conducted to explore the divergent responses of tree growth at different slope aspects to the recent warming climate. Results showed that tree growth of P. purpurea at east slope aspect was obviously accelerated (0.011 a-1) since rapid warming in 1980, whereas those at northwest slope aspect was significantly reduced (-0.006 a-1). Tree growth of P. purpurea at southeast slope aspect and A. faxoniana at northwest slope aspect decreased in significantly. With the rapid warming, growth-climate relationships of P. purpurea and A. faxoniana at different slope aspects changed significantly. After rapid warming in 1980, the promoting effects of growing season temperature (GST) on P. purpurea growth at east slope increased significantly, while the inhibitory effects of GST on its growth at southeast and northwest slopes also increased significantly. However, the effects of GST on A. faxoniana growth at northwest slope did not change significantly before and after rapid warming. The effects of precipitation in May (PM) on P. purpurea growth at east slope was changed from inhibition before rapid warming to significant promotion after rapid warming, while the inhibitory effects of PM on P. purpurea growth at southeast and northwest slopes increased significantly. For A. faioniana at northwest slope, however, it did not change obviously before and after rapid warming. The response analysis between tree growth and the Palmer drought severity index (PDSI) showed that soil moisture variations at different slope aspects were an important reason of tree-ring growth response difference since rapid warming. In addition, the results of multivariate analysis of variance indicated that the combined effects of slope aspect, temperature and precipitation factors were the most important limited factors for tree growth variability in western Sichuan. Therefore, we should consider the combined effects of temperature, precipitation and different slope aspects when simulating and predicting tree-growth response to the recent climate warming trend.