Crystallinity of wood and the size of cellulose crystallites in Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis>)

X-ray diffraction was used to study variations in the crystallinity of wood and the average thickness and length of the crystallites of cellulose as a function of the number of the year ring in Norway spruce [Picea abies (L.) Karst.]. The crystallinity increased from ring 4 to ring 10 from the pith and was constant after ring 10. The crystallinity of mature wood was about 30% ± 5%. The average thickness and average length of the crystallites were 3.2 ± 0.1nm and 28 ± 2nm, respectively; and no systematic variation of these values with the number of the year ring was observed. The mean microfibril angle decreased near the pith but was constant in the mature wood.     

Thinning intensity effects on carbon and nitrogen stores and fluxes in a Norway spruce (Picea abies (L.) Karst.) stand after 33 years

The present paper deals with C and N storage in soil and vegetation, litter fall and CO₂ efflux from the soil 32–33 years after early thinning in a Norway spruce (Picea abies (L.) Karst.) stand in order to evaluate the effect of thinning regime on C sequestration. At 22 years old, the stand was reduced from 3190 to 2070, 1100 and 820 trees per hectare in four replicates. The N2070 treatment represents the recommended start density in practical forestry, while the other represent a moderate to large reduction in tree number at the present stand age. Aboveground biomass was estimated from single tree measurements of diameter and height based on allometric functions. Litter fall was collected during one and a half years and soil respiration was measured on five occasions during one summer. Ground vegetation was mapped and sampled for biomass, C and N determination. A significant decrease in aboveground tree (including stump-root system) C storage of 27% and 22% due to thinning was found in the N820 and N1100 treatments, respectively, compared to the N2070 treatment. Ground vegetation C storage was little affected by treatment, while litter fall C showed a non-significant decrease in the N820 and N1100 treatments compared to the N2070 treatment. Soil respiration was significantly lower in parts of the summer in the N2070 treatment compared to the N820 treatment. The reason for this is still unexplained since no differences in soil temperature, soil moisture or litter fall chemistry was found between the treatments. No significant treatment effects on humus and mineral soil C storage could be detected. With the present soil variability, the time period of 32 years is probably too short to detect soil C differences due to thinning. The N storage followed the same pattern as for C.     

Effects of <Emphasis Type="Italic">Ips typographus</Emphasis> (L.) damage on litter quality and decomposition rates of Oriental Spruce [<Emphasis Type="Italic">Picea Orientalis</Emphasis> (L.) Link.] in Hatila Valley National Park,Turkey

This study investigated the effects of Ips typographus (L.) damage on initial litter quality parameters and subsequent decomposition rates of oriental spruce tree species [Picea orientalis (L.) Link]. The needle litter was collected from highly damaged, moderately damaged and control stands on two aspects (north and south) and two slope position (top and bottom) on each aspect. The litter was analyzed for initial total carbon, lignin and nutrient (nitrogen, phosphorus, potassium, calcium, magnesium and manganese) concentrations. The variability in nitrogen and calcium concentrations and ratios of C:N, lignin:N and lignin:Ca was significantly affected by the insect damaged levels. While nitrogen concentrations in needle litter increased with increasing insect damage (and consequently the ratios of C:N and lignin:N decreased), calcium concentrations decreased (and consequently the ratio of lignin:Ca increased). Aspect and slope positions explained most of the variability in carbon, lignin, phosphorus, potassium, magnesium and manganese concentrations and lignin:P ratio between all studied stands. Litter decomposition was studied in the field using the litterbag technique. The litter from highly damaged stands showed highest decomposition rates followed by moderately damaged and control stands. The mass loss rates were significantly positively correlated with initial nitrogen concentration and negatively with C:N and lignin:N ratios. The effects of microclimate resulting from canopy damage on litter decomposition was also examined at the same time using standard litter with the same litter quality parameters, but they showed no significant differences among the insect damage levels indicating that alteration of the litter quality parameters produced by I. typographus damage played a more important role than altered microclimate in controlling needle litter decomposition rates. However, changes in microclimate factors due to topography influenced decomposition rates.     

云杉梢斑螟生物学特性与防治

云杉梢斑螟以幼虫危害青海云杉新梢嫩叶，在甘肃省寿鹿山林区一年发生1代，以1龄幼虫在当年新梢基部和针叶中越冬，翌年5月中旬开始活动并危害新梢，6月中旬化蛹，6月底始见成虫，7月上旬末，中旬初达羽化高峰。7月中旬为产卵盛期，7月下旬幼虫孵化，幼虫轻微危害后于9月中，下旬进入越冬状态，6月中旬，用2.5%敌杀死乳油5000倍液或2.5%功夫乳油3000倍液喷雾，防治效果均在95%以上，用25%灭幼脲Ⅲ号悬浮液3000倍液喷雾，防治效果90%左右；羽化期可利用黑光灯诱杀成虫。     

红皮云杉嫩枝扦插繁殖技术的研究

本文描述了红皮云杉嫩枝扦插繁殖技术。通过试验筛选出１种适合于红皮云杉嫩枝扦插的基质（插壤），２种使生根率达９８％且根系发育良好的生根剂。同时，提出了把握扦播时机，合理运用生根剂浓度及处理时间的方法和技术措施。     

青海云杉种实害虫危害情况及综合治理调查分析

青海云杉的种实害虫有十几种，危害严重的有三种，即云杉球果小卷蛾、云杉蛀果斑螟和云杉梢斑螟，主要发生在甘肃祁连山林区。本文经过调查，根据青海云杉和种实害虫的生物学特性，提出加强青海云杉林的经营管理，尽量减少广谱性化学药剂的大面积使用；尽可能多的应用营林技术为主的、不杀伤天敌的防治措施，以达到青海云杉种实害虫综合治理的良性循环；并提出青海云杉种实害虫综合治理的策略、原则以及评价青海云杉种实害虫综合治理的步骤和方法。     

挪威云杉幼树韧皮部挥发性物质的测定

通过GC-MS测定挪威云杉幼树主干上部与下部韧皮主要挥发性物质的化学成分与含量，结果表明挪威云杉幼树的韧皮部挥发性物质的主要成分为α-蒎烯、茨烯、β-蒎烯、月桂烯、3-蒈烯、柠檬烯、β-水芹烯7种单萜化合物。α-蒎烯、β-蒎烯、月桂烯、3-蒈烯、β-水芹烯的含量在上部韧皮与下部韧皮有明显差异，其中上部韧皮部α-蒎烯、β-蒎烯和β-水芹烯的含量明显高于下部主干韧皮部,这为解释松树皮象的取食习性，打下了基础。     

金沟岭云冷杉针阔混交林林分结构研究

以吉林汪清金沟岭林场1 hm2云冷杉针阔混交林数据为研究基础,对样地内树种组成、直径结构以及树种的空间分布结构进行分析。结果表明:1)优势物种云杉Abies nephrole-pis、冷杉Picea koraiensis、枫桦Betula costata大径阶的单木占多数,云冷杉的峰度值小于0,直径分布较为分散,枫桦峰度值大于0,直径分布比较集中。在物种的胸径分布格局解释上,负指数模型的解释程度要优于Weibull模型。2)该群落树种的平均角尺度为0.545,空间分布格局呈聚集分布,3种优势树种的平均角尺度为0.475～0.517,呈现随机分布特征。3)云杉、枫桦的平均混交度较高,而冷杉的平均混交度相对较低。4)样地所有物种的平均大小比数为0.496,3种主要树种的平均大小比数排序为云杉<冷杉<枫桦,表明云杉竞争力最大,冷杉次之,而枫桦的竞争力最小。该林分结构较为复杂,群落内树种以聚集分布为主,所以应调整林分林木分布格局,促进林木向随机分布格局发展,同时伐除上层的"霸王树"以及病腐木、弯曲树等处于竞争劣势的林木,将混交度维持在中度混交,从而尽可能保留维持群落的物种多样性。     

Crown development in young Picea abies stands

A dynamic model of branch length and weight growth was developed for two contrasting sites, both with young stands of spruce. At one site sample trees were obtained from both unfertilised plots and from plots with increased growth rate maintained by annual fertilisation. At the second site unfertilised trees and trees subject to single applications of fertiliser were modelled. A model of the same structure was developed for each site and tested by application at the alternate site. In view of the close agreement between sites, model parameters were calculated based on all data combined. The model is driven by height increment and branch age. The sample trees were mostly open grown so that only a tentative estimate of the effects of between tree competition is given. The limitations of the model are stressed.     

Induction of tumours by various strains of Agrobacterium tumefaciens on Abies nordmanniana and Picea abies

Abies nordmanniana and Picea abies seedlings were inoculated with a wild‐type (C 58) or an attenuated strain (rooter or shooter mutants) of Agrobacterium tumefaciens. Large tumours were formed on A. nordmanniana in response to the wild‐type and rooter strains, 60–65 % of the seedlings being susceptible. Smaller tumours were formed on Picea abies in response to the wild‐type strain, at least 12% of the seedlings being susceptible. Tumours from both species induced by the wild‐type strain grew in vitro on medium without added phytohormones.