Natural regeneration on planted clear‐cuts in boreal Sweden

Natural regeneration was registered on 97 clear‐felled and scarified sites in northeastern Sweden ten growing seasons after planting. On each site, three fix plots were laid out at planting and the planted seedlings were mapped. Ten years later all healthy non‐planted seedlings were registered in an anulus of size 15.7 m². Non‐planted seedlings were also observed in four 4 m² squares on each fix‐plot to estimate the zero‐square frequency. Species were classified as Pinus sylvestris, L., Picea abies (L) Karst. and deciduous species (Betula pendulajpubescens Roth./Ehrh., Populus tremula L., Alnus incana (L) Moench.). On average, 7 133 non‐planted seedlings ha^‐1 were found, of which 29% were conifers. Among the conifers, 71% were P. abies. More than 2 500 conifer non‐planted seedlings ha^‐1 were found on 27% of the plots. The number of non‐planted seedlings was correlated to the presence of neighbouring seed‐producing stands within 100 m and decreased with rising altitude. Pinus sylvestris seedlings were more frequent on dry soils while the deciduous seedlings were more frequent on wet sites. In the 4 m² squares, the zero‐square frequency was 29% if both conifers were and deciduous seedlings were considered and 63% if only conifers were considered. Mean height of the tallest seedling per species and square was 62 cm for P. sylvestris, 42 cm for P. abies and 107 cm for the deciduous seedlings. Key words: Alnus incana, Betula, broad‐leaves, deciduous, Norway spruce, Picea abies, Pinus sylvestris, Populus tremula, reforestation, Scots pine.     

贵州茂兰喀斯特山地顶部森林群落种子库研究

在茂兰喀斯特森林山顶地段设置固定样地,定期观察植物的开花结实、种子雨、种子库的结构、组成及其萌发。结果表明:900m2样地内共有种子植物36种,其中21种已进入繁殖阶段,每年产生成熟种子520.9粒·m-2。种子雨量大,每年达910.3粒·m-2,其中对群落有用的成熟有效种子314.7粒·m-2。在天然萌发开始时的种子库中,有大量现存植物的活力种子,群落更新潜力很好。在天然情况下,1月上旬到5月中旬种子库中活力种子萌发。在天然萌发季节,900m2样地内每年共萌发出18种苗(7245株),当年存活幼苗2970株,群落更新良好。裸子植物华南五针松、短叶黄杉和翠柏在喀斯特山顶地段有良好的适应性,能长期稳定存在。     

长白落叶松林分进界模型的研究

利用吉林省汪清林业局金沟岭林场落叶松林分连续观测数据,以计数类模型为基础,分别利用Poisson回归模型、负二项模型、零膨胀模型和Hurdle模型拟合林木进界株数,并通过AIC值,Pearson残差图以及Vuong检验对这些模型进行了详细分析比较.结果表明:Poisson回归模型不适用于模拟林木枯损株数;负二项回归模型相对于Poisson回归模型比较适用,但是对于零枯损过多的数据,这两类模型拟合效果较差;零膨胀模型和Hurdle模型对这类数据有很好的解决办法,而且,零膨胀负二项模型拟合效果最好.     

A soil seed bank in a mature conifer plantation and establishment of seedlings after clear-cutting in southwest Japan

Compositions and spatial distribution patterns of buried viable seeds, and demographic transition from buried viable seeds to seedlings after clear-cutting were examined in a 75-year-old conifer plantation in southwest Japan. A part of the plantation was cleared in December 1997 and study plots were set up on a cleared site and a preserved site. Soil samples (a total of 105 l for the preserved plot and 90 l for the cleared plot) were collected from surface soils in spring 1998 and were incubated in a greenhouse for 120 days. There were an estimated 1064 buried viable seeds per square meter from 67 species in the preserved plot and 1754 seeds/m² from 53 species in the cleared plot. The soil seed bank was from mostly low density species with some high density species, and contained many pioneer species that were absent in the floor vegetation. Buried viable seeds were clumped together, especially in gravity-dispersal species. Although plenty of buried viable seeds were pooled in the soil, few seedlings emerged on the forest floor. In contrast, a number of seedlings, including many pioneer species, emerged in the cleared plots, showing a positive correlation between seed weight and germination rate. It is assumed that dominance of the seedlings established after clear-cutting depends on germination rates and/or growth rates of the seedlings rather than the initial density of buried viable seeds. These results suggest strong contribution of the soil seed bank to the establishment of the secondary vegetation after disturbance in a mature conifer plantation.     

半野生麋鹿秋、冬季粪堆频率分布的研究

通过对江苏大丰麋鹿保护区Ⅰ、Ⅱ放养区内麋鹿粪堆频率分布的系统抽样调查,发现半野生麋鹿在秋、冬季粪堆呈聚集型分布,分布型服从负二项分布、奈曼A型分布和Thomas分布,其中以负二项分布拟合程度最好。造成粪堆聚集分布的主要原因是环境因素的影响,与麋鹿的习性关系不大。在放养区主要生境类型草地和林地中,粪堆均服从负二项分布。粪堆密度林地大于草地,但粪堆聚集指数草地却高于林地。粪堆的聚集强度与鹿群在该生境中的活动类型有关,当麋鹿粪堆在单一生境内服从负二项分布时,粪堆聚集指数与鹿群对该生境的休息利用率之间存在着明显的相关关系(r=0.988,P<0.05)。粪堆频数调查显示,秋、冬季大丰麋鹿对林地的利用率高于草地。     

Models for prediction of mortality in even‐aged forest

Models for predicting mortality in even‐aged stands were developed. The models rely on data from the Norwegian National Forest Inventory, and were designed for use in large‐scale forestry scenario models. A two‐step modelling strategy was applied: (1) logistic regression models predicting the probability of complete survival occurring,” and (2) multiplicative regression models for stem number reduction and diameter calibration. A joint model for all species predicting the probability of survival occurring on a plot was developed. Separate models for forests dominated by spruce, pine and broadleaved trees were developed for stem number reduction, while no appropriate models for diameter calibration were found. The phenomenon mortality is a stochastic, rare and irregular event, and this was reflected as low R ² in the models. However, the model performance appeared logical and the results of validations based on independent data were reasonably good, i.e. the presented models may be applied to large‐scale forestry scenario analyses. With new rotations of permanent sample plot measurements, the models should be evaluated and, if necessary, revised.     

Determination of number of stems in coniferous forest stands by means of aerial photo‐interpretation

Two models for determination of the number of stems per hectare in forest stands (N) from attributes derived by aerial photo‐interpretation were developed. The models relied on the assumption that N could be determined by dividing the total stand volume per hectare with the volume of the “average tree”; defined by stand mean height and the diameter corresponding to mean basal area of a stand. Input variables of the models were stand mean height, crown closure and site quality. Additionally, model II required input of average stand volume per hectare and average mean diameter derived from stratified field sample plot inventories. Material for 143 coniferous stands was used for the testing of the models. The stands were recorded by intensive field measurements. Aerial photographs at the approximate scale of 1:15 000 were used for photo‐interpretation. The N value was underestimated in model I by 5.4–47.0%. The standard deviation for the differences was 15.2–26.2% for mature stands and 41.4–44.2% for young thinning phase stands. For model II, the mean difference between the predicted and observed N value was in the range ‐16.1% to 12.2%.     

半野生麋鹿秋、冬季粪堆频率分布的研究*

通过对江苏大丰麋鹿保护区Ⅰ、Ⅱ放养区内麋鹿粪堆频率分布的系统抽样调查,发现半野生麋鹿在秋、冬季粪堆呈聚集型分布,分布型服从负二项分布、奈曼A型分布和Thomas分布,其中以负二项分布拟合程度最好。造成粪堆聚集分布的主要原因是环境因素的影响,与麋鹿的习性关系不大。在放养区主要生境类型草地和林地中,粪堆均服从负二项分布。粪堆密度林地大于草地,但粪堆聚集指数草地却高于林地。粪堆的聚集强度与鹿群在该生境中的活动类型有关,当麋鹿粪堆在单一生境内服从负二项分布时,粪堆聚集指数与鹿群对该生境的休息利用率之间存在着明显的相关关系(r=0.988,P<0.05)。粪堆频数调查显示,秋、冬季大丰麋鹿对林地的利用率高于草地。     

Impacts of fructification on biomass production and correlated genetic effects in Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> [L.] Karst.)

For the period 2003–2006, fructification of Norway spruce (Picea abies [L.] Karst.) was recorded at the Kranzberg forest site in Southern Germany by employing a crane with access to the canopy of more than 266 trees. For each tree, stem diameter and growth parameters were assessed annually as well as biomass of cones and seeds, number of seeds per cone, and proportions of empty seeds for a total of 371 trees with cone crop. Genotypes at 19 enzyme coding gene loci of 110 trees were included in the study of correlations between morphological and genetic traits. Re-scaling the observed values for a virtual pure Norway spruce stand of 1 ha, cone biomass including winged seeds (oven-dried at 38°C) varied between 706.8 kg/ha in 2006 (average value per tree was 3.6 kg) and values close to zero in 2005. Corresponding values for vegetative biomass increment of the coning trees in 2006 were 9,273.0 kg/ha and 10.8 kg/tree. A significant higher biomass investment was determined for dominant trees in terms of absolute cone mass as well as in terms of cone mass relative to vegetative biomass and fructification frequency. No trade-off effects in decreased vegetative biomass growth were found in the fructification year, compared to trees that did not grow cones. Although the dominant trees invested proportionally considerable biomass in cones, they showed no significant reduction in vegetative biomass growth. In the following year no decrease in vegetative growth was detected. Based on logistic regressions and homogeneity tests, respectively, significant genetic effect became evident with respect to the gene loci AAP-B and AAT-C concerning fructification probability in the year with maximum generative biomass investment. These and closely related loci also have been found to be indicative for growth and viability, respectively, in other species.     

杉木无性系生长与材性测定的适宜无性系株数与小区株数

对 1块 7年生杉木无性系试验林在不同无性系株数、小区株数抽样下 ,进行树高、胸径、材积及木材密度的无性系排序、遗传参数估算 ,并作效果比较 ,结果如下 :对于生长量测定 ,适宜无性系株数应在 2 0株以上 ,以 30株测定效果较佳 ;适宜小区株数在不同无性系株数下 ,结果不太一致 ,普遍表现为参试无性系株数少 ,宜采用少株小区 ;参试无性系株数多 ,则宜采用多株小区。试验株数为 6、12、2 4株时 ,分别采用 2、4、3或 4株小区的效果较好。对于测定木材密度的适宜无性系采样株数宜在 6株以上 ,而适宜小区采样株数为 1株 ,且为所在小区最优株     

抚育间伐对栓皮栎人工林直径和树高分布的影响

【目的】以河南登封林场栓皮栎人工林为研究对象,研究抚育间伐对林分不同生长阶段林木株数、林木直径分布和树高分布的影响,为制定科学合理的抚育经营措施奠定理论和技术基础。【方法】在株数强度为31.55%的间伐林分和条件基本一致的未间伐林分内,分别设置1个1 hm2样地,间伐作业2 a后获取每木检尺数据,分别利用Normal分布、Gamma分布、Lognormal分布、Weibull分布、Logistic分布函数对间伐样地和对照样地栓皮栎人工林林木个体直径分布、树高分布进行拟合,并应用Kolmogorov-Smirnov(KS)拟合优度检验,选择拟合效果最好的分布模型。【结果】1)间伐和对照样地幼树、小树和大树林木株数比例分别是9:642:582和229:978:585。相比对照样地,间伐样地林木小树和大树生长阶段株数比重较高。2)间伐样地林木直径分布范围主要集中在8~18 cm,高于对照样地的4~16 cm。KS拟合优度检验结果表明,间伐样地林木直径分布采用Weibull分布拟合效果最好,Normal和Logistic分布次之;对照样地林木直径分布采用Weibull分布拟合效果最好,Normal和Gamma分布次之。3)间伐样地和对照样地林木树高级分别为8~16 m和4~14 m,但KS拟合优度检验结果表明,5种分布函数对间伐样地和对照样地树高分布拟合优度排序一致,说明抚育间伐对林分树高分布的影响不明显。【结论】抚育间伐调整了栓皮栎人工林林分的直径结构,林分直径分布向较大径阶方向偏移,使林分直径分布结构更趋于对称分布,但对树高分布影响不明显。     

Long-lasting effects of unplanned logging on the seed rain of mixed conifer-hardwood forests in southern South America

Understanding the effects of disturbance on seed rain is critical to predict changes in forest species composition and diversity.Logging effects on seed rain in a mixed conifer-hardwood forest complex in southern Brazil were evaluated.One year of seed rain data were collected from a large-scale observational experiment in logged and protected forests and quantity and average seed size weighted by species abundance(CWM) were compared between old-growth and logged stands 55 years after logging activities.Using these data,variations in frequency of functional groups of species in the seed rain were examined to see if they could be attributed to logging.Results show that the number of seeds per trap was highly right-skewed,ranging from 13 to 12,788 seeds per trap in one year.Seed rain was affected by logging history,with seed traps in old-growth plots receiving significantly less seeds than traps in logged plots.All species included mean seed size weighted by species abundance were significantly smaller in logged than in old-growth forests.This difference persisted after the exclusion of Arawcaria a large-seeded pioneer which was intensively logged,although the difference of seed size between the two forest classes was greatly reduced.Species abundance in the seed rain differed significantly from the established tree community,between logged and oldgrowth stands.The composition of the seed rain was much more variable than the composition of the established tree community and its points more scattered over the ordination space than the points corresponding to the protected forests.The number of collected seeds across different functional groups of species significantly differed between logged and old-growth plots.The seed rain of logged forests reflects their arrested succes sion as indicated by reduced abundance of functional groups such as pioneers,large seeded pioneers and A raucaria,as well as reduced functional diversity.S eed rain differences between logged and old-growth stands reflect the intensive logging of A.angustifolia.     

基于固定样地的林分乔木层年净生产力参数结构化估算

为更准确估算林分乔木层年净生产力,解析林分乔木层生产力的构成,本研究提出了基于固定样地数据的林分乔木层年净生产力参数结构化估算方法。利用天台县2009-2014,2014-2016,2016-2017年3个阶段固定样地数据,同时考虑森林类别、树种组、龄组等因子,结构化估算4组参数,第1组是保留木生物量年均生长率,第2组是生物量年均保留率,第3组是进界木生物量年均生长率,第4组是单位面积年均进界株数。第1组参数结果表明,各树种组保留木生物量年生长率随着龄组增大而减小;商品林保留木生物量年均生长率普遍比公益林高。第2组参数结果表明,公益林内所有树种组的生物量年保留率都低于其在商品林内的保留率。第3组参数结果表明,除硬阔Ⅰ类外,公益林中其他树种进界木生物量年均生长率都高于商品林。第4组参数结果表明,随着龄组的增大,单位面积年进界木株数减少;任一龄组下,公益林中的单位面积年进界木株数均高于商品林。研究结果表明,本方法能够解析乔木层生产力的构成情况,是一种结构化估算方法,其计算结果与其他相关研究相比更具优点。     

皱绿柄天牛幼虫空间分布型初步研究

应用聚集度指标测定法、线形回归方程检验法和空间频次分布检验研究皱绿柄天牛幼虫的空间分布型.结果表明,皱绿柄天牛幼虫的空间分布型属聚集型的负二项分布.在此基础上,利用Iwao的M*-m回归方程分别计算出了0.05、0.1及0.2允许误差水平下皱绿柄天牛幼虫的最适抽样数.     

3种肥料不同用量对金花茶生长的影响

试验设7个处理、1个对照,结果表明：不同施肥用量对金花茶的生长均有显著差异,其中每株施芭田顺水复肥250g 的单株平均新梢抽梢数为72．33枝、平均新梢长为16．57cm ,比对照高分别为73．58％、31．20％;每株施天脊复合肥250 g的单株平均新梢抽梢数为55．33枝、平均新梢长为14．50cm ,比对照高分别为32．78％、14．80％;每株施芭田顺水复肥150g＋天脊复合肥150g的单株平均新梢抽梢数为56．67枝、平均新梢长为14．70cm ,比对照高分别为36．00％、16．39％;每株施芭田顺水复肥150g ＋湖兴尿素50g 的单株平均新梢抽梢数为67．00枝、平均抽梢长为15.73cm ,比对照高分别为60．79％、24．54％。施肥植株的叶绿素平均值为0．620～0．707mg／g ,而对照组的平均值为0．587mg／g ,施肥的植株叶片浓绿,枝叶繁茂,叶绿素的平均值明显高于对照,其平均值高于对照的5．62％～20．44％。     

火炬松人工林直径分布收获模型的研究

搜集福建省火炬松人工林各30株林分平均木和优势木的树干解析数据，运用正态分布、对数正态分布、Weibull分布、B分布、Γ分布函数来拟合福建省火炬松人工林的直径分布规律。结果表明：Weibull分布的拟合效果好，标准地接受率为80％，用参数回收技术建立火炬松人工林直径分布收获模型，经检验，每公顷材积平均相对误差8．37％，每公顷胸高断面积平均相对误差6．72％。因此该模型可以用来估测福建省火炬松人工林的林分结构和产量。     

Fitting diameter distributions with a hand‐held,programmable calculator

Simple techniques are described and illustrated for fitting four common diameter distribution models: Beta, Gamma, Lognormal, and Weibull. A visual goodness of fit test is illustrated using typical plot data. Programs by the authors are available which allow all necessary computations to be easily performed on a hand‐held, programmable calculator.     

灭幼脲对杨干象作用机制和防治的研究

采用灭幼脲油剂，油胶悬剂等，用点涂的方法对杨干象幼虫和成虫进行了适时防治，结果表明：灭幼脲油剂可抑制表皮几丁质的合成达１５％以上；灭幼脲油胶悬剂抑制杨干象成虫精巢和卵巢的发育，可使成虫产卵间降低４０－７０％，使卵的孵化率降为零。这为杨干象的防治找到一条高效，安全，经济，易全文的新途径。     

九寨沟华西箭竹（Fargesia nitida）开花种群特征

2009年4月、7月对九寨沟自然保护区内各样地进行调查,只在鹰爪洞沟3 000 m以上的山坡中上部发现开花的华西箭竹种群分布。调查发现：开花竹种群为典型的下降型年龄结构,表现出明显的衰退种群的特点,约22%～29%的箭竹正在开花。平均花穗密度约为296朵.m-2,平均种子密度约为3 923粒.m-2。华西箭竹的花为顶生的总状花序,花穗颜色以绿色为主,黄色、黄绿色花也较多,偶见绿紫色花。单株花穗数约在10朵～19朵之间,单株种子数在约130粒～250粒之间。平均每朵花穗的种子数约为13粒。