Below‐Canopy distribution of photosynthetically active radiation and its relation to seedling growth in a boreal Pinus sylvestris stand

A simulation model was used to predict the spatial distribution of direct and diffuse photosynthetically active radiation below a heterogenous canopy of a Pinus sylvestris stand in eastern Finland. Seedling growth was related to both measured and predicted radiation. The model predicted rather well the overall pattern of radiation distribution beneath the canopy. All the growth parameters of Pinus sylvestris seedlings (height, current height increment and mean height increment) correlated positively with the amount of both measured and predicted radiation. The correlation between seedling growth and irradiance was better for predicted diffuse radiation than for total radiation. This was probably because diffuse radiation, being symmetrically distributed around trees, correlates more strongly than direct radiation with other factors affecting seedling growth.     

Trends of tree growth in Swedish forests 1953–1992: An analysis based on sample trees from the national forest inventory

Average tree height and basal area growth for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) in Sweden were studied as functions of species, age, stand density, location and year of inventory in the period 1953–1992, on the basis of sample tree data from the National Forest Inventory. A highly significant annual increase of both height and basal area growth was found, of the magnitude 0.5–0.8%, during the 40 yr period. Possible reasons for the trend are discussed. The altered way of cutting in the early 1950s, from selective cutting to clear felling and thinning from below, has had a large impact. Also, improved regeneration methods, nitrogen fertilization and ditching have increased growth. The increasing atmospheric deposition of nitrogen is another possible factor.     

湖南马尾松遗传改良现状与策略

在叙述湖南马尾松20多年来于马尾松群体遗传改良、马尾松优良家系定向选择、马尾松基因资源收集与种子园营建等方面所取得成绩的基础上，探讨了目前马尾松遗传改良所存在的问题，提出了今后一段时期湖南马尾松遗传改良策略。     

不同土层中氮磷钾养分对红松针叶磷素的影响

本文以红松1~2年生叶片和其林下生长的土壤为对象,研究红松叶片中磷含量、磷贮量及其林下土壤中0~20、20~40和40~60 cm土层的氮磷钾矿质养分含量。揭示叶片质量、磷素水平与各层土壤速效氮、速效钾和速效磷的相互关系。结果表明：叶片质量与土壤中速效养分含量无关,土壤中速效氮含量与针叶磷含量无关,0~20 cm土层的速效钾含量与2年生针叶磷含量显著相关。不同年生针叶的磷含量与各土层的速效磷含量都有显著的回归关系。针叶中磷贮量与土壤中速效养分无明显相关性。     

四川马尾松疱锈病病原菌及转主寄主的初步研究

马尾松疱锈病是我省马尾松中幼林分的毁灭性枝干病害。经系列实验证明马尾松疱锈病菌的转主寄主为芍药科的山芍药（ Ｐａｅｏｎｉａ ｏｂｏｖａｔａ Ｈａｘｉｍ ），病原菌为松芍柱锈菌（ Ｃｒｏｎａｒｔｉｕｍ ｆｌａｃｃｉｄｕｍ （ Ａｌｂ． ｅｔ Ｓｃｈｗ ．） Ｗ ｉｎｔｅｒ）。     

油松优树子代测定及遗传增益的初步研究

通过对５３０株油松优树子代林内８２９个家系（次）生长疸的测定，初步选出了较为优良的油松家系，并对不同来源的优树家系和单株的树高及地径的遗传率进行了估算。     

The Preliminary Study on Juvenile-Mature Correlation of Pinus Koraiensis

IntroductionWoodisveryimportantfinaIproductinforestman-agement,andimprovingwoodproductandquaIityarecommongoaIinmostbreedingsystems.EarlyselectionfortreegrowthnotonIyprovideexceIIentnurserystorematerialforplantinghighyieIdforest,butaIsopossibIyimproveselec…     

The preliminary study on juvenile-mature correlation ofPinus koraiensis

Through studying seven analytic trees from two stands ofPinus koraiensis artificial forests, the results show that the individual variation coefficient of tree heigh, dbh and volume decreases with age increasing after age of 25. Age of 25 is the age that difference of individual growth is from acute difference to comparatively stability. The optimum selection age is 25a forPinus koraiensis’s artificial forests according to the analysis of juvenile-mature correlation, and early selection efficiency. (Responsible Editor: Zhu Hong)     

The carbon budget of an adult <Emphasis Type="Italic">Pinus cembra</Emphasis> tree at the alpine timberline in the Central Austrian Alps

We investigated carbon (C) uptake and respiratory losses of an adult Pinus cembra tree at the alpine timberline throughout an entire year by means of an automated, multiplexing gas exchange system. These chamber measurements were then combined with biomass data for scaling up the C budget to the tree level. Integrated over an entire year, the cumulative C gain of the tree under study was 23.5 kg of C in 2002. The daily C balance was negative for 5 months and the estimated total wintertime respiratory losses were 9% of the amount of C fixed during the growing season. The total annual C loss of the tree consumed 55% of the annual net C gain and the remaining surplus was stored in new tissues (36%) and used for fine root growth (9%). Thus, the overall C budget of P. cembra at the upper timberline is balanced fairly well, although the C sink strength in fine roots is strongly limited owing to low root zone temperatures when compared to conifers at lower elevation sites.     

滇西北高山针叶林区主要林型下外生菌根真菌的分布

1985年和1986年,我们在云南西北部高山针叶林内,采用标准地调查和路线踏查相结合的方法,在杜鹃-冷杉林等7个主要林型中进行了外生菌根真菌调查。经对采集标本的鉴定,计有33个属约140余种外生菌根真菌。它们在各种林型下的分布有着一定的规律。其种类组成和分布的多度与林木的组成、土壤和地形条件,如海拔高度、坡向、坡度等有密切的关系。