日本落叶松人工林重茬林地土壤养分含量变化及其对林木生长的影响

日本落叶松人工林重茬林地土壤养分含量变化及其对林木生长的影响＊孙翠玲郭玉文郭泉水关键词日本落叶松人工林重茬地力衰退日本落叶松（Ｌａｒｉｘｋａｅｍｐｆｅｒｉ（Ｌａｍｂ．）Ｃａｒ．）生长快，适应性强，是北方重要的速生造林树种。我国落叶松人工林栽培面积已达...     

马尾松种子园及其附近人工林的亲子代群体遗传结构分析

利用同工酶标记对广西覃塘林场马尾松无性系种子园及其附近一人工林的亲子代群体遗传结构进行研究。研究结果表明，不论是种子园还是附近人工林均表现为：亲代群体处于遗传平衡状态，杂合体相对过量，但子代已偏离遗传平衡，杂合体相对不足，亲子代的基因频率变化不大。种子园亲代群体的遗传多样性略高于子代，而附近人工林的亲代群体遗传多样性略低于子代。本文研究的种子园具有较宽的遗传基础，该种子园附近人工林的遗传多样性与种子园接近，但不论是人工林本身还是它的子代其多样性平均水平都较种子园的亲代和子代略低。     

Modeling radiation transfer within the canopy of a Chinese fir plantation

Calculation of radiation transfer within the canopy of a plantation on sloped sites is described. The canopy was assumed to consist of evenly cone-shaped crowns. Within-tree shading by object tree and between-tree shading by tree crowns around the object tree were differentiated. The two-dimensional needle area density (NAD) was introduced in the calculation of radiation transfer and interception. The model was validated with measurements of both daily photosynthetic photo flux density (PPFD) and daily photosynthetic radiation at tens of points within the crown of a 17-year-old Chinese fir (Cunninghamia lanceolata) plantation growing on a sloped site. Simulation showed that modeled data closely matched measurements. Simulation errors likely result from the uneven size of tree crowns, irregular crown shape, grouping of needles to shoots and twigs, etc. Scattering radiation amounted to below 10%, in most cases, of daily radiation, and its uncertainty was relatively small.     

垦复对毛竹林鞭系生长影响的研究

垦复是毛竹林抚育的主要技术措施，合理垦复改善土壤的理化性能，促进地下鞭系的生长，致使鞭段数量、竹鞭长度、鞭芽数量、鞭的节间长度均有较大幅度增加，对鞭层深度、鞭龄组成也有影响。     

思茅松人工幼林“3414”施肥试验

2007年8月,在景谷县具有代表性、长势相当的思茅松人工幼林中,采用"3414"试验设计,对氮、磷、钾3种肥料的不同配比组合进行了施肥试验。结果表明:立地条件对思茅松人工幼林的生长影响较大,思茅松人工幼林施肥应区别不同立地条件采用不同的施肥配比组合,地位指数级为12的立地条件较佳组合为50 g氮肥+150 g磷肥+80 g钾肥,地位指数级为14的较佳组合为100 g氮肥+75 g磷肥+80 g钾肥,地位指数级18的较佳组合为100 g氮肥+150 g磷肥+80 g钾肥。     

竹镂舟蛾无公害防治技术研究

为了探索竹镂舟蛾的无公害防治方法和措施,使用森得保粉剂、苦参.烟碱烟剂和高渗苯氧威烟雾剂进行防治试验,防治效果均可达80%以上,可在竹镂舟蛾危害时应用。     

太子山马尾松种子园营建技术研究

本文从建园材料选择和收集、嫁接技术、建植方式及定植密度、种子园营建和激素对促进球花形成的研究等方面总结了太子山马尾松种子园建设的技术及经验。太子山种子园的建成不但加速了我省马尾松良种化的进程 ,而且为今后我省马尾松种子园营建和育种提供了理论依据和材料。     

人工林可持续经营认证标准与指标问题

阐述了森林认证对于人工林可持续经营的必要性。依据黑龙江森工林区人工林经营实践和森林认证在该地区的发展情况，讨论了FSC原则和标准框架下本区域森林可持续经营认证的人工林标准与指标问题。认为标准与指标应该针对本区域天然林破碎严重，人工林树种单一、稳定性差、生长量低、生态效益不好等一系列问题，提出了人工林标准与指标的基本内容。     

Growth and structure development of semi-natural larch-spruce-fir (Larix olgensis–Picea jezoensis–Abies nephrolepis) forests in northeast China: 12-year results after thinning

Analyzing and understanding the structure and growth dynamics of semi-natural plantations is useful for their management. Since 1987, 16 plots with 4 treatments (CT: control; LT: light thinning; MT: medium thinning; and HT: heavy thinning) by 0, 20, 30 and 40% of basal area removal, respectively, and four replications were established in semi-natural larch-spruce-fir forests in northeast China. The structure and growth dynamics of semi-natural larch-spruce-fir stands and the effects of thinning on the growth, structure and diversity were examined. A mixed model repeated measures analysis of variance (RMANOVA) was used to test the effects of treatment and time.

Results showed that differences in periodic annual increment (PAI) of stand basal area and volume and the individual diameter and volume among treatments changed over time in a complex statistical interaction. Thinning, however, had a significant effect on growth at tree and stand levels 12 years after thinning while the PAI of the diameter, basal area and volume was positively correlated with thinning intensity. No significant differences were found in the total stand yield among treatments. Composition of tree species group (larch, other conifers and deciduous trees) during monitoring years did not change significantly. Moreover, no significant differences were observed in tree species and size diversity among treatments in the years following thinning. Both thinning and control plots had similar understory plant diversity after the 12 year period. Univariate point pattern analysis revealed that clumped and random distributions were dominant for tree species groups in this study. The current species composition and regeneration dynamics within these semi-natural plantations suggested a development towards mixed coniferous and broad-leaved forests. Management implications for the transformation from larch plantations towards mixed broad-leaved Korean forests with a more diverse structure, the climax vegetation in this region, were discussed.     

Leaf-water potential and soil-water depletion of walnut mulched with polyethylene and intercropped with alfalfa in Central Italy

In Italy, new agroforestry cultural models could play an important role in the diffusion of plantation forestry timber species. We studied the stem growth rates and leaf water potentials () of common walnut (Juglans regia L.), and gravimetric soil moisture (_DW) depletion during the third and fourth growing seasons in an agroforestry trial in central Italy. Since the establishment of experimental plots in 1992, walnut was intercropped with alfalfa (Medicago sativa L.), with or without polyethylene (PE) mulching along tree rows. By the end of the study period, the unmulched-intercropped walnut was almost 68% smaller in stem diameter and height than the sole-unmulched control, demonstrating walnuts sensitivity to alfalfa competition. The competitive effect of alfalfa on walnut stem growth was effectively controlled/reduced by PE mulching. Stem growth rates of mulched-intercropped walnut were always lower than the control, but much higher (ca. 235% in stem diameter and height) than those of unmulched-intercropped walnut. The higher field performance of mulched-intercropped walnut compared to the un- mulched-intercropped treatment was associated with higher soil moisture and predawn and midday values during the summers driest periods. The presence of PE mulching was also associated with lower levels of soil moisture during the early and late growing season, but this did not negatively affect walnut and growth rates. These results suggest that in the climatic conditions of central Italy, competition for soil moisture between young common walnut trees and alfalfa can be substantially lowered, but not completely eliminated, by PE mulching.This revised version was published online in November 2005 with corrections to the Cover Date.