垂柳截头提高园林观赏效果试验初报

１９９１年调查，济南市市区柳树蛀干害虫危害株率为７８．２％至８５．２％，平均８０．３５％，部分重灾区高达９０％至１００％，虫口密度为２８．５头／株至３３头／株，平均３０．８头／株，使树势极度衰弱，并伴随发生枯枝病危害，每年树冠枯枝率达２０％，要花费大...     

二齿茎长蠹生物学特性研究

二齿茎长蠹1年1代，以成虫在虫道内越冬。3月下旬至4月中旬是成虫危害期，主要危害栾树和国槐的幼树主干及大树枝条，危害直径0．4－2．0cm，危害株率达80％以上，株虫口密度37头／株，成虫平均爬行能力为每公钟87．8cm，平均每头成虫日排出木屑量0.0618g。     

松毛虫在林分中分布差异检验

经测定，林中松毛虫平均虫口Xi^-＝2．7头／株，林缘松毛虫平均虫口Zi^-=20．7头／株，计算得随机变量txz≈—8．272，因此，|txz|＞t0.05。故林分中，林中、林缘的马尾松毛虫分布平均数具有的差异性，可信度95％。     

大袋蛾生物防治技术综合应用研究

大袋蛾是林业的一大害虫。在1998-1999年试验的基础上，2000-2002年在刺槐小片林和林网内对综合生物防治技术进行科技攻关和实践应用研究。试验结果表明，Bt制剂的防治效果达到80％以上；寄生蝇的寄生率在片林中达到25％，在林网中达21％；而大山雀的招引率也很高，平均达70％。3种生物防治方法综合使用后，刺槐片林大袋蛾老熟幼虫平均虫口密度由防治前的47.4头／株下降到防治后的0．39头／株，林网内由46．9头／株下降到0．78头／株，而相似的对照区大袋蛾平均虫口密度刺槐片林为34．8头／株，林网37．6头／株。     

萧氏松茎象幼虫食性、危害及防治技术

萧氏松茎象幼虫在南岳衡山主要危害华山松，在寄主树干基部皮层和裸露的根皮层蛀食，造成大量流脂，导致生长衰弱，引起松墨天牛暴发；同时取食新鲜松脂，越冬后的幼虫仅靠取食新鲜松脂就能正常发育。幼虫只危害健康松树，不危害衰弱木、枯立木，说明其蛀食危害与松树能否分泌松脂有关。在被害松林内，单株幼虫数在0～6头之间。幼虫在有虫株之问分布较均匀，1头／株的占82．5％，平均为1．38头／株，且单株虫口密度与树干基部直径呈明显正相关。混交林和非松树林分能阻止该虫扩散。5—10月间在幼虫危害期和蛹期，采用人工清除幼虫和蛹的方法可有效控制该虫危害，而采用化学药剂防治该幼虫，效果不明显。     

5％Nomolt胶悬剂飞机低容量喷雾防治油松毛虫

１９９２年４月中下旬分别在北京市平谷县和辽宁省建平县以５％Ｎｏｍｏｌｔ胶悬剂和２５％灭幼脲Ⅲ号胶悬剂飞机低容量喷雾防治油松毛虫ＤｅｎｄｒｏｌｉｍｕｓｔａｂｕｌａｅｆｏｒｍｉｓＴｓａｉ共２１３．３３公顷，经防治，两地当年的虫口减退率分别为９９．４％和９９．１％。此后北京市平谷县又于１９９２、１９９３年分别做了越冬前虫口调查，虫株率分别为２０．０％和２７．５％，虫口密度为０．４头／株和０．６／株，有效地控制了油松毛虫的危害。     

瓯海茶山镇松褐天牛羽化历期及其危害与分布规律的调查研究

松褐天牛在瓯海区茶山镇羽化始期于5月上旬，盛期5月中旬至6月上旬，末期7月上旬。室内比野外羽化时间滞后，尤其是盛末期更为明显，推迟12～15d。松褐天牛在瓯海茶山镇分布普遍，且危害严重，有虫株率6．3％，致死率达4．6％，平均虫口密度1．93％。松褐天牛幼虫在松树上的垂直分布自上而下呈递减趋势，且70％以上分布在中上部树冠层。     

双条杉天牛生物学特性观察与无公害防治

双条杉天牛在济南1年发生1代，以成虫在被害树木蛀道内越冬，翌春3月上旬成虫开始出蛰，3月中、下旬进入出蛰盛期，3月底为末期；4月中、下旬幼虫大量孵化蛀入树干危害；8月下旬陆续化蛹，9月上旬为化蛹盛期；9月下旬成虫开始羽化．10月中旬为成虫羽化盛期，10月下旬为末期。成虫羽化期树干喷布200倍1％的绿色威雷Ⅱ号杀灭成虫，虫株率、虫口密度和受害死亡率较对照分别降低18．5％、2．5头，株和7．4％；林间设饵木引诱成虫产卵效果良好，受害率可降低3．4％；幼虫危害期林间释放管式肿腿蜂，寄生率较空白对照高47．3％以上；及时进行卫生伐，砍除受害树木，消灭虫源，对控制其危害起到较大作用，受害率可降低2．4％。     

松毛虫平均虫口与为害面积关系探讨

通过试验地连续多年观察记录，将松毛虫平均虫口与为害面积绘制成曲线图，从曲线图中可得知平均虫口在5条／株以下时，危害面积占试验地面积15％以下，采用生物防治方法可以控制成灾，平均虫口10株以上的，必须采用化防措施。本研究成果实践效果明显。     

绍兴市开展日本松干蚧工程治理的实践与思考

绍兴市通过3a的工程治理，有效遏止了日本松干蚧的危害。平均虫株率从综防前1年的26％降到工程结束后的14．0％以下；平均虫口密度从0．063头／cm^2。降到0．0027头／cm^2。开展日本松干蚧工程治理，各级领导的重视是保障，完善测报网络，搞好虫情监测是前提，突出营林措施．提高森林的自控能力是基础，科学规划，分类施策是重点，综防措施的协调应用是关键。     

Photosynthetic utilization efficiency of absorbed photosynthetically active radiation by Scots pine and birch forest stands in the southern Taiga

Absorption and utilization of photosynthetically active radiation (PAR) were investigated in Scots pine (Pinus sylvestris L.) and birch (Betula pendula Roth.) stands that were 41 years old at the end of the experimental period. Canopy depth of the Scots pine stand was about half that of the birch stand (6.5 versus 11.0 m), but absorption of PAR was similar in the two stands. The Scots pine forest canopy, with a leaf area index of 8.9, absorbed 90% of the incoming PAR (APAR), whereas the birch forest canopy, with a leaf area index of 5.9, absorbed 92% of APAR. During maximum foliage development, the upper Scots pine canopy absorbed more PAR than the upper birch canopy (75 versus 66%). The upper, middle and lower layers of the Scots pine canopy contained 37, 48 and 15% of the total needle surface area, respectively. The corresponding distribution of foliage surface area in the three layers of the birch canopy was 50, 30 and 20%, respectively. Measurements of photosynthetic rate were combined with estimates of leaf area index and stand phytomass to determine rates of primary production on a sunny day, a cloudy day, and on an annual basis. The energy equivalents of short- and long-term carbon gain were used with determinations of APAR to calculate photosynthetic utilization efficiency. Throughout the growing season, photosynthetic utilization efficiency of APAR in the upper canopy layer of the Scots pine forest was almost twice that in the lower canopy layer. In the birch forest, photosynthetic utilization efficiency was greater in the lower canopy layer than in the upper canopy layer. In all cases, utilization efficiency was higher in the birch stand than in the Scots pine stand (52 versus 29 J kJ(-1)). Taking account of respiration of the non-photosynthetic parts of each stand (night respiration of needles or leaves; respiration of branches, trunk and roots), estimated utilization efficiency of APAR for net primary production was 11 J kJ(-1) for Scots pine and 19 J kJ(-1) for birch. Solar conversion ratios, expressed as whole-plant net primary productivity per unit of APAR for the growing season, were 0.81 g MJ(-1) for Scots pine and 0.93 g MJ(-1) for birch.     

Comparison of water-use efficiency of seedlings from two sympatric oak species: genotype x environment interactions

Seedlings of two sympatric oak species, Quercus robur L. and Quercus petraea (Matt.) Liebl., were grown in common garden conditions to test for potential interspecific differences in intrinsic water-use efficiency (WUE). Intrinsic water-use efficiency was estimated based on carbon isotope composition of shoots (delta13C) and on gas exchange measurements (ratio of net CO2 assimilation rate to stomatal conductance (A/g(sw))). In addition, genotype x environment interactions were tested by subjecting the seedlings to four irradiance treatments (8, 18, 48 and 100% of incident solar irradiance) imposed by neutral shading nets, and, in the 100% irradiance treatment, two watering regimes. In all treatments, initial growth of Q. robur was faster than that of Q. petraea. In both species, there was a tight correlation between delta13C and A/g(sw). Intrinsic water-use efficiency increased with increasing irradiance (almost doubling from 8 to 100% irradiance), and this effect paralleled the increase in A with increasing irradiance. In full sun, WUE of Q. petraea seedlings was 10-15% higher than in Q. robur seedlings, with the difference attributable to a difference between the species in g(sw). The interspecific difference in WUE was maintained during drought, despite the appreciable increase in WUE and decrease in growth imposed by drought. No interspecific differences in WUE were observed at low irradiances, suggesting a strong genotype x environment interaction for WUE. These findings confirm the existence of interspecific genetic differences in WUE, but also show that there is large intraspecific variability and plasticity in WUE. The initially greater height and biomass increments in Q. robur seedlings illustrate the ability of this species to out-compete Q. petraea in the early stages of forest regeneration. For adult trees growing in closed canopies, the high WUE of Q. petraea may contribute significantly to its survival during dry years, whereas the low WUE of Q. robur may account for the frequently observed declines in adult trees of this species following drought.     

A basal area increment model for individual trees growing in even- and uneven-aged forest stands in Austria

Because of the gradual shift from pure even-aged forest management in central Europe, existing yield tables are becoming increasingly unreliable for forest management decisions. Individual tree-based stand growth modeling can make accurate stand growth predictions for the full range of conditions between pure even-aged and mixed-species uneven-aged stands. The central model in such a simulator is basal area increment for individual trees. Spatial information is not needed, and age and site index are intentionally not used to gain generality for all possible stand conditions. A basal area increment model is developed for all the main forest species in Austria: spruce (Picea abies), fir (Abies alba), larch (Larix decidua), Scots pine (Pinus sylvestris), black pine (Pinus nigra), stone pine (Pinus cembra), beech (Fagus silvatica), oak (Quercus robur, Quercus petraea and Quercus cerris), and for all other broadleaf species combined. The Austrian National Forest Inventory provided 5-year basal area increment from 44 761 remeasured trees growing on 5416 forested plots in the 1980s. This large sample is representative of forest conditions and forest management practices throughout Austria and therefore provides an excellent data base for the development of an increment model. The resulting increment model explained from 20 to 63% of the variation for all nine species and from 33 to 63% of the variation if the minor species Pinus cembra is excluded. These results compared quite closely with those of Wykoff for mixed conifer stands in the Northern Rocky Mountains. In the Austrian model, size variables (breast height diameter and crown length) accounted for 14–47% of the variation in basal area increment, depending on tree species. The best competition measure was the basal area of larger trees, which provides a tree-specific measure of competition without requiring spatial information; crown competition factor provided only minor improvement. Competition variables accounted for 9% of the variation on average, and up to 15% for some species. Topographic factors (elevation, slope, aspect) explained up to 3% of the variation, as did soil factors. Remaining site factors; such as vegetation type and growth district accounted for a maximum of 3% of the variation in increment. In total, site factors explained from 2 to 6% of the variation. Even though site factors account for a small percentage of the variation, they are not only significant, but serve to localize a particular prediction. These species-specific interrelationships between basal area increment and the various size, competition, and site varibles correspond quite well with ecological expectations and silvicultural understanding of these species in Austria. Because the sample base is so strong, the resulting growth models can be recommended not only for all of Austria but for surrounding regions with similar growth conditions.     

杉木,柳杉混交林营造技术及效益的研究

本文对杉木、柳杉混交林的营造技术及效益研究结果表明:杉木、柳杉混交林能够形成稳定协调的林分结构,能改善林分小气候;16年生的杉木、柳杉混交林单位面积上的蓄积量比杉木纯林高27.5～50.4％,比柳杉纯林高15.5～36.3％;杉木、柳杉混交可以改造杉木低产林,扩大杉木的栽植范围,具有比纯林高的经济效益和生态效益。     

Stem Diameter Estimation from Aerial Photographs

Remote sensing techniques have proven successful for producing stem maps of forests in leaf-on condition from high-resolution imagery. This paper demonstrates how a mathematical model for the surface of a stem can be used to estimate the breast-height diameter of individual trees from aerial photographs to give information on basal area. The diameters are estimated by likelihood estimation from images of a forest in leaf-off condition where the stems and their shadows are visible. Applied to a homogeneous and monospecific oak ( Quercus robur L.) stand under standard silvicultural treatment in Denmark, the estimation was successful for 56 out of 60 trees. The root mean squared error on the diameter was 4.2 and 3.2 cm using three and five images, respectively. The key conclusion is that it is feasible to infer fairly accurate information about the diameters and three-dimensional positions of stems from aerial photographs.     

丽水市莲都区生态公益林资源结构动态变化研究

根据1999年和2008年公益林区两期的森林资源调查数据,采用对比分析和数理统计方法,从时间尺度上对公益林区的森林资源格局动态变化情况进行了研究,掌握了莲都区公益林在林龄、郁闭度、疏密度、森林类型等方面的变化情况。通过1999年到2008年的十年建设,幼、中龄林与近、成、过熟林面积比例由78:22演变到40:60,蓄积比由54:46演变到23:77;低郁闭度(郁闭度小于0.7)林分由76.57%下降到25.14%,高郁闭度林分则从23.43%上升到74.86%;阔叶林面积占比从11.43%增加到11.57%,针阔混交林面积从26.86%增加到40.29%;单位面积平均蓄积从25.65 m3·hm-2增长到37.95 m3·hm-2,年均净增率4.30%。     

Harvest index in northern temperate cultivated conifers

Harvest index is defined and its relationship with primary production, biomass partitioning and yield components in forest trees examined. As stand density has been found to have a major effect on harvest index, it is concluded that further development of the harvest index concept in forest trees will need to take account of density-yield relationships.     

马尾松林火灾后生态效益损失动态评估

依据林分生长规律和经营模式,建立生态效益损失动态评估模型;对广州从化30年生马尾松林分森林火灾后,经过人工更新的林分45年内所产生的生态效益进行模拟,认为该林分若未遭受森林火灾,封山育林模式的生态效益最大;灾后更新林分需要30年才能恢复相当于灾前林分的生态效益;其间生态效益的损失量为传统静态定量估算的25.92倍.如果林分采取30年轮伐的经营模式,在第19年左右时轮伐林分和灾后更新林分所产生的生态效益平衡;此后人工更新林分的生态效益渐高,而受灾林分经人工更新后第17年时的生态效益近似于轮伐林分的稳定值.轮伐型所带来的总效益在前6年大于封育型的总效益,但第7年以后其总效益开始小于封育型经营模式的生态效益.     

桉树焦枯病防治技术研究

在采用室内药效测定的基础上,结合林间防治试验,对桉树焦枯病(Eucalyptus dieback)防治技术进行研究。室内测定结果表明,供试的8种药剂室内毒力强弱顺序为达科宁>甲霜灵锰锌>百菌清>代森锌>加收米>代森锰锌>甲基托布津>多菌灵。4种药剂林间防治试验结果表明,不同药剂中以达科宁的防治效果最佳,甲霜灵锰锌效果其次;不同稀释倍数各药剂均以稀释300倍效果最佳;营林措施中以施肥处理效果最佳,每种措施防治后7 d和21 d防治效果存在极显著差异。该病危害严重时,首选营林措施,以施桉树专用肥+清洁林分措施为佳;其次在经济条件允许的情况下,结合使用达科宁或甲霜灵锰锌化学药剂300倍液每隔10 d左右喷雾2～3次进行防治。对轻度受害林分,采用施肥措施,以降低防治成本。     

马尾松,大头茶针阔混交林森林结构的研究

典型选样调查测定,分析马尾松、大头茶常绿针阔混交林的森林特征、种群结构、林分结构、生物量结构及生态功能。结果表明:1.该混交林是亚热带常绿阔叶林前一阶段的过渡性森林类型,在干扰状态下保持其相对的稳定性。2.复层、异龄现象是该混交林的主要特征。建群种充分利用了林地空间营养面积,发挥了林地的生产潜力。叶面积指数达6.86～8.83,林分木材蓄积量达160～222m~3/ha,林分总生物量达114～163t/ha。其中,乔木层生物量达105～154t/ha。光照充足的林下,草本层生物量可达2.5t/ha,对庇护地表起到了最直接、最明显的作用,而调节林冠密度,可控制或促进草本层生物量的增长。3.此种混交林改善了森林立地的蓄水功能和贮水方式。林地土壤最大贮水量达2645～4100t/ha,降水贮存量达565～1256t/ha,林地枯枝落叶层饱和持水量达4589～8702kg/ha。该类型达到了生态与经济效益兼顾,可在我国南方亚热带山地各类工程造林中推广应用。