Dynamics of some mineral nutrients and heavy metals in decomposing forest litter

The dynamics of three major mineral nutrients (K, Ca, Mg) and six heavy metals (Fe, Mn, Zn, Cu, Pb and Cd) were studied in decomposing natural, unpolluted litter in two forest types: Scots pine needle litter in a pure Scots pine forest and oak‐hornbeam leaf litter in a mixed oak‐hornbeam stand. Of the mineral nutrients, only K in the oak‐hornbeam system showed a significant decrease in concentration during the course of litter decomposition. For Ca and Mg in both systems and for K in the Scots pine system no clear relation between concentration and accumulated litter‐mass loss was observed. On the other hand, for Fe, Zn, Pb and Cd at both sites, as well as for Mn in the oak‐hornbeam stand and Cu in the Scots pine stand highly significant positive relations were found between heavy metal concentrations and accumulated mass loss. A decrease in concentration was noted only in the case of Mn in the Scots pine system. No clear pattern was found for Cu in the oak‐hornbeam stand. Concentrations of heavy metals in the decomposing litter reached levels at or above those reported to retard decomposition in other studies. At the oak‐hornbeam stand increased also the absolute amounts of Fe, Zn, Pb and Cd.     

菌根化柞苗补植柞蚕场效果调查与分析

针对辽宁部分柞蚕场退化、沙化以及缺株少墩等现状，基于建设生态型柞蚕场的需要，我们自2002年起在辽宁省凤城市、东港市、庄河市、宽甸县和岫岩县生态型柞蚕场示范建设过程中推广使用菌根化柞苗补植蚕场。通过连续11年跟踪调查，结果表明：菌根化柞苗的成活率显著高于对照；苗高、地径、茎叶重等指标也高于对照。     

Green gluing of oak wood (Quercus conferta L.) with a one-component polyurethane adhesive

Abstract

This research work presents a study on the properties of finger jointing green oak wood (Quercus conferta L.) using a one-component polyurethane adhesive. The effect of finger-joint orientation (vertical or horizontal fingers) was also examined. In general, the results from the measurements of modulus of rupture and modulus of elasticity of green-glued finger-jointed specimens indicated that the green gluing of a high-density species such as oak wood is feasible.     

以乌兰格木为母本的中蒙沙棘杂种F1表型性状分离规律研究

基于远缘杂交技术路线,以引进的蒙古大果沙棘乌兰格木实生子代优株为母本,中国沙棘优良种源丰宁的优良单株为父本,开展了蒙古沙棘与中国沙棘两个亚种间杂交育种工作,对杂种F1表型性状分离规律进行了研究。发现杂种F1代性状分化严重,棘刺数、生长量、叶片、果实等性状的变异程度依次降低,以蒙古大果沙棘为母本的中蒙沙棘杂交能使F1代在...     

Influences of woody encroachment and restoration thinning on overstory savanna oak tree growth rates

Midwestern savannas historically covered >10 M ha in central North America, but are now rare due to agricultural conversion and anthropogenic modifications to disturbance regimes - particularly fire suppression. Throughout this range, Midwestern savannas are characterized by scattered overstory trees; however, with fire suppression, these systems are invaded by non-savanna trees. Restoration of encroached savannas involves removal of invading trees, yet little is known about the impacts of encroachment or encroachment removal on the relict savanna overstory trees, which define these systems. Here, we use tree ring analysis to investigate savanna tree growth rates in encroached, non-encroached, and experimentally restored Midwestern oak savannas in central Iowa. We found that woody encroachment led to pronounced declines in growth rate (ring width) of relict overstory white oak (Quercus alba), relative to Q. alba trees in competition-free, open-grown conditions, or in an encroachment-free remnant woodland. To further understand effects of encroachment removal on relict Q. alba savanna trees, we conducted a large-scale restoration experiment, where encroaching trees were mechanically removed from four encroached savannas, with an additional four savannas retained as encroached controls. Restoration led to elevated tree growth rates, with these changes generally persistent through 7 years post-restoration (2003-2009). Over the course of this post-restoration study period, ring width, basal area increment, and relative basal area increased by 49%, 59%, and 55%, respectively, in trees from restored sites, relative to trees from encroached, control sites. These results suggest that woody encroachment has strong influence on overstory savanna trees, through increased competitive dynamics; however, woody encroachment removal may help to restore relict savanna tree growth rates, even after prolonged periods of encroachment (>40 years). To restore the oak savannas at our sites, and perhaps elsewhere, we advocate a three step process: (1) mechanical woody encroachment removal, (2) maintenance of the encroachment-free state through prescribed fire, and (3) promotion of a diverse understory layer, characteristic of oak savanna in our region. While promoting oak regeneration will be important for the long-term maintenance of these sites as oak savanna, relict savanna trees appear responsive to restoration and should maintain overstory conditions through the near-term.     

Morphology and molecular phylogeny of Erysiphe japonica var. japonica found on Quercus aliena in Korea

In October 2022, Erysiphe powdery mildew from the section Typhulochaeta was found on Quercus aliena for the first time in Korea. Based on morphological characteristics and molecular-phylogenetic analysis of the internal transcribed spacer region (ITS) and large subunit (LSU) gene sequences of the rDNA, the fungus was identified as Erysiphe japonica var. japonica. This is the first report of E. japonica var. japonica in Korea and the third report of this mildew on Q. aliena, with this current fungus-host association spreading to China and Japan. Based on Korean samples, this study provides detailed morphology and molecular phylogeny of E. japonica var. japonica.     

锐齿栎林生态系统对水质影响的研究

对秦岭辛家山锐齿栎林生态系统对水质的影响进行了探讨，结果表明：锐齿栎林生态系统对水质具有净化作用，并以林冠层的净化作用为最强，效应指数达－５２．４％，枯落物层次之，效应指数为－６．６％，以土壤层最弱，效应指数为－１．０６％；对水质的评价表明，该地区大气降水的水质为轻污染（质量指数为０．９０５９），以迳流的形式输出系统时的水质为微污染（质量指数为０．３０４４）。     

柞树木醋液酚类物质的组分分析

采用常规方法测定了柞树木醋液的基本参数，所得木醋液为黑褐色且带有烟焦味，pH值4.06，有机酸含量（以醋酸计）5.20％，密度（20℃）1．0260g／cm^3，木炭粉吸附法精制得率90.7％。采用分配法将柞树木醋液系统地划分为酸性物、酚类物和中性物，并利用GC—MS联用仪对酚类物进行了组分分析。结果表明，酚类物中的主要组分是苯酚3．60％、2-甲基苯酚1．20％、1，2,3-三甲氧基苯12．82％、2,6-二甲氧基苯酚34．41％和4,6-二（1，1-二甲基乙基）-2-甲基-苯酚35．97％。该分析对柞树木醋液产品品质基准的制订具有重要意义。     

栎林及其经营

本文主要论述了河北低山丘陵区自建国以来封育及被反复砍伐利用的栎林结构及其经营情况。仅山海关林场保存了一些30～50a生的栎林,阳坡为麻栎、栓皮栎及柞栎林,阴坡为蒙古栎林。林内幼树更新良好。萌生栎林早期生长迅速,10a后高生长逐渐减缓,50a生林分平均高才10m.1a生萌生栎林,每亩产枝干干重28.5～425kg不等。在土壤为中层-厚层厚度的条件下,栎林矮林作业轮伐期以3～5a为宜。采伐35～40a生栎林,每年每亩平均产值要略高于短轮伐期的栎林。在较好的立地条件下,还可采用选留木法的矮林作业,形成轮伐期不一致的具有2个林层的栎林。