日本松干蚧在山东省日照市生活历的测定

日本松干蚧于20世纪90年代初期传入日照市，对松林造成严重危害，赤松濒临灭绝。为更好开展科学防治，从2000年开始对该虫进行系统虫情调查，通过设立固定标准地，对日本松干蚧越冬代和越夏代各虫态进行系统观测，确定了其在日照地区的生活历，填补了日本松干蚧发生发展规律在该地域的空白，对指导该地区开展科学防治具有重要意义。     

舟山海岛松材线虫病疫区迹地晚稻杨梅更新技术

在定海区岑港镇烟墩椗次何家山松材线虫病为害迹地上,试用晚稻杨梅进行树种更替,5年生幼林株高普遍在2m以上,冠幅2m×2m左右,最大植株树高达3m,冠幅2.7m×2.7m,幼林生长正常,试验初见成效.     

广东南岭保护区的基本特点和有效管理的展望

广东省南岭保护区是广东省面积最大的保护区,它由分散的分别属于3个县市管辖的5个部分组成,总面积58 368.4 ha;南岭保护区生物多样性和文化多样性丰富多彩。文章就如何开展有效管理提出以下建议:1)健全和完善保护区的建制;2)重视科研监测工作的建设;3)加强宣传教育和培训工作;4)充分发挥资源优势,发动社区共同建立新的生物多样性产业;5)注意生态旅游的发展。     

巨尾桉生长率对伐区设计精度的影响分析

通过对巨尾桉 5个标准地连续观测资料的分析 ,结果表明 :随着伐区调查设计与实际采伐间隔时间的延长 ,巨尾桉生长率对伐区调查设计精度的影响日趋显著 ,并提出克服林木自身生长对伐区调查设计精度产生影响的方法     

人工落叶松采伐迹地更新针叶树种试验

在人工落叶松采伐迹地上更新长白落叶松、樟子松，红松、云杉，与荒山荒地造林相比，长白落叶松增长4．2％，樟子松，红松、云杉增产幅度在35．3％至38．5％之间。     

A family of segmented polynomial functions for modelling the border effect on the diameter growth of Ayous (Triplochiton scleroxylon K. Schum)

This paper introduces a family of four segmented (or grafted) polynomial functions for modelling the decrease in the diameter of Ayous (Triplochiton scleroxylon K. Schum) with distance from the border of the plantation. The functions, each comprising two segments of second degree or less, were fitted to data collected in the Cameroon rain forest. A comparative assessment of the fit was carried out using criteria such as mean deviation, root mean squared deviation, and fit index.

The border effect extended to 10 m inside the plantation where a 50% decrease in diameter occurred. Beyond that distance, the diameter appeared to be stable except for random variation. The estimated functions performed equally well as they all provided a good fit to the data, with a small bias. Most importantly, they proved to be flexible and thus adaptable to a wide variety of situations.

Recommendations are made concerning setting up a guard area and ways of improving the silviculture of Ayous. Also, the possibilities for an agrisilvipastoral system are explored.     

在韩国片断化林区内道路对小型啮齿类种群的影响

The road effect on small rodent population is investigated at 8 fragmented forest areas in the Baekdudaegan moun-tain range, South Korea in September 2001, We especially focused on the distribution and body condition of small rodents near the roads, Korean field mouse (Apodemus peninsulae) seems to be more sensitive to the existence of a road than striped field mouse (Apodemus agradus), Korean field mouse prefers interior forest area to around road. Striped field mouse is a habitat generalist and has wide distributional range around road, but Korean field mouse is forest-inhabiting species and their distribu-tion is limited in forest area. These results suggest the effect of road is different on each small rodent species and their habitat preferences.     

石竹叶面积指数的测定

通过对石竹叶面积指数测定表明 ,叶面积随胸径的增大而趋于增大 ,当林分密度为 30 0 0 0～ 375 0 0株·hm-2 ,平均直径 2～ 3cm时 ,叶面积指数趋于合理 ,这时产量也最高     

Defining competition vectors in a temperate alley cropping system in the midwestern USA: 2. Competition for water

A study was carried out in an alley cropping system in the Eastern Maize Belt of the United States with the objective of quantifying the competition for water between trees (black walnut (Juglans nigra L.) and red oak (Quercus rubra L.) and maize (Zea mays L.). Spatial and temporal variation in soil moisture, tree and maize rooting patterns, tree and maize water uptake, and maize leaf area expansion were determined in three treatments; barrier (polyethylene root barriers separating maize and tree roots), trench (trenching without a polyethylene barrier), and no barrier (control). Significant temporal variation in soil moisture was observed in both black walnut and red oak alley cropping systems. The barrier and trench treatments resulted in higher soil moisture in the maize alley and lower soil moisture in the tree row than the no barrier treatment. Uptake of water by maize was higher in the barrier than the no barrier treatment. However, tree water uptake was higher in the no barrier treatment than in the barrier treatment because tree roots utilized water from the maize alley. Maize leaf area was negatively impacted by water stress in the no barrier treatment. Quantification of rooting patterns revealed that maize and tree roots were concentrated in the top 30 cm soil layer where water fluctuations were greatest. The barrier and trench treatments successfully eliminated the belowground root competition between trees and maize and resulted in greater leaf area and higher grain yields than the no barrier treatment. Thus, competition for water rather than competition for light seems to be critical in defining the productivity and sustainability of this alley cropping system.This revised version was published online in November 2005 with corrections to the Cover Date.