落叶松人工林短期轮伐可行性分析

落叶松人工林短期轮伐可行性分析赵亚民，刘春延（围场县塞罕坝机械林场０６８４５６）关键词落叶松人工林，短期轮伐塞罕坝林场建于１９６２年，总经营面积９．４ｈｍ￣２，有林地面积５．３万公顷。其中落叶松人工林３．１万公顷，占有林地面积的５８％，活立木蓄积３２...     

叶用银杏园银杏树整形修剪技术研究

连续３年对１￣４年生叶用银杏进行了整形修剪研究，发现１￣２年生实生银杏侧芽发育瘦弱，顶端优势明显；生长季节内除顶芽萌发抽枝外，侧芽难以萌发抽枝；３￣４年以后侧芽发育较为饱满，抽生侧枝数量逐渐增加。休眠期内破坏１￣２年生银杏顶芽，能有效地刺激其侧芽萌发，增加枝梢数量和叶片产量；３￣４年生时休眠期内破除顶芽或轻度短截，再加上生长季节摘心，能明显增加分枝数量，控制株高过度生长，增加群体叶片产量，便于各项     

森草净防除果园杂草应用技术研究

两年田间小区试验表明：在粘壤土条件下，森草净有效成份１ｇ／６６７ｍ＾２土壤处理可在一个月内有效地控制果园草害，防效达９０％￣１００％，森草净有效成份１．５、３．０、６．０ｇ／６６７ｍ＾２土壤处理可在７０ｄ内控制杂草，防效在７５％￣１００％。上述处理对鸭趾草和多年生双子叶杂草防效较差，只有２０％￣７０％。当果园杂草２０￣２５ｃｍ，森草净有效成份４．０和６．０ｇ／６６７ｍ＾２茎叶处理可有效地控制杂草生     

大熊猫主食竹人工栽培技术试验研究：Ⅲ.正交试验设计造林成效分析

选用Ｌ１８（２＾１×３＾７）正交表，将一个因素二水平、七因素三水平按设计方案进行试验，结果表明：（１）王朗林区箭竹造林方案条件的优化组合为成竹实生苗＋带状（或块状）整地＋９月（或５月）造林＋实生苗全留枝叶＋丛植７株以上＋１￣２年刀抚，２￣４年锄抚＋１５００￣２０００丛／ｈｍ＾２＋云杉。（２）箭竹造林方案条件组合，其５年总生物量可达１０５０￣１２００ｇ／丛，即５年总生物量可达１６５０ｋｇ／ｈｍ＾２左     

2000年中国原木进口量

根据国家海关总署的统计数字，２０００年中国进口各种原木１３６１．２万立方米。总价值１６．６亿美元，与１９９９年相比原木进口量增加了２５％。在所有进口原木中，阔叶材的量略高于针叶材，阔叶材为７２１．１万立方米，占总木材进口量的５３％。但从货值上看，进口阔叶材总货值１２．８亿美元，占进口原木总货值的７７％，２０００年进口的针叶材６４０．１万立方米。进口针叶材总货值３．７８８６亿美元。专家分析指出，阔叶材在进口原木总量内占主导地位的原因，主要是国内胶合板，室内装修和家具工业对阔叶材的需求一直居高不下。…     

楸树优良无性系选择初报

通过楸树１０个无性系及金丝楸（对照）测试林５年对比试验，选出速生型优良无性系８６１５。５年生胸径达９．４ｃｍ，年均１．８８ｃｍ；树高５．２ｍ，年均１．０４ｍ；立木材积０．０１７１４ｍ￣３，年均０．００３４３ｍ￣３。与金丝楸相比，胸径、树高、立木材积分别增力０２７．０％、６．１％及１０２．８％。与全林均值相比，胸径、树高、立木材积分别增加２５．３％、１０．６％及９２．２％。胸径重复力为５４．７１％，遗传增益１３．８６％；树高重复力３５．０５％，遗传增益３．７３％；立木材积重复力６１．３７％，遗传增益５６．５５％。     

台湾杉木幼树侧枝扦插试验初报

从５年生台湾杉木幼林中选择优良单株，利用树冠中上部枝条进行扦插试验。结果表明：台湾杉木扦插生根与愈伤组织的形成关系不大，属皮部生根型；用不具顶芽的１年生二级侧枝作插穗，穗长８ｃｍ，去除插穗下部２／３的针叶，用１００×１０￣（－６）ＡＢＴ＿１生根粉处理４小时，插于粘性黄心土上效果最好。     

饲放山羊对杉木幼林的影响试验

试验研究表明：１－３年生杉木幼林地禁止饲放山羊，因山羊取食３年生杉木 林技叶次数占总次数的７５．７５％，特别是取食杉木顶梢后，对杉木幼林的高生长，成材有极大影响。山羊取食杉木幼林侧枝叶，对杉木幼林的高径生长及成材影响差异性不显著。４年生以后的杉木幼林地内及林缘可饲放山羊。     

马尾松林昆虫及蜘蛛群落的研究报告

１９９２－１９９４年，在浙江马尾松林里进行昆虫及蜘蛛群落，松毛虫天敌和种群动态的分析。结果表明：（１）１５年生马尾松针叶立体分布，确认砍枝取薪以留７轮为好，不低于留４轮；（２）马尾松林昆虫群落分属１８目１１８科，其中直翅目，鞘翅目，同翅目，膜翅目，半翅目占优势，经测定，龙游县落结构复杂，分布均匀，群落与层次，坡向，郁闭度，灌层盖度关系密切；（３）蜘蛛群落分属１９科４６种，其中萧蛸科，猫蛛科和蟹蛛科     

水杉人工林生物生产力及纸浆材工艺成熟研究

本文研究了水杉的生长进程，各测树因子与地上部分生物量的关系及水杉纸浆性能。研究结果表明：１）密度对胸径、材积的连年生长量影响显著；２）水杉地上部分生物总量、树干重、枝叶重与胸径（Ｄ）、树高（Ｈ）的关系密切，相关系数均在０．９５以上；３）水杉纤维素含量在４１．６％￣４８．９％之间，平均纤维长度在３．０￣５．２毫米，并随年龄的增加纤维素含量增加、纤维长度加大；４）水杉纸浆材工艺成熟龄在８￣１０年。     

Seasonal differences in freezing stress resistance of needles of Pinus nigra and Pinus resinosa: evaluation of the electrolyte leakage method

Seasonal changes in freezing stress resistance of needles of red pine (Pinus resinosa Ait.) and Austrian pine (Pinus nigra Arnold) trees were measured by an electrolyte leakage method and by visual observation. During most of the year, freezing stress resistance determined by the two methods gave similar results. The electrolyte leakage method provided a good estimate of seasonal changes in freezing stress resistance except for red pine needles in their most winter-hardy state. To obtain a reliable estimate of freezing stress resistance in winter-hardy red pine needles it was necessary to combine the electrolyte leakage method with visual observations. When red pine needles survived exposure to -80 degrees C or lower, electrolyte leakage was never more than 30% even when the needles were exposed to a slow freeze-thaw stress of -196 degrees C. However, rapid freezing of red pine needles to -196 degrees C resulted in electrolyte leakage of over 80%. Red pine needles attained a much higher freezing stress resistance during the winter than Austrian pine. Red pine needles also acclimated and deacclimated faster than Austrian pine needles. An index of injury was developed based on the electrolyte leakage method ((R(2) + R(1))/2, where R(1) is the minimum % electrolyte leakage from noninjured tissue and R(2) is the maximum % electrolyte leakage at the highest injury) that reliably predicted freezing stress resistance of pine needles for most of the year. Important aspects for developing a successful index of injury for pine needles are: use of cut needles, vacuum infiltration and shaking during incubation in water.We conclude that: (1) during cold acclimation the cell wall properties of the pine needles changed and these changes, which appeared to differ in the two species, might explain the very low leakage of electrolytes from winter-hardy needles of red pine; (2) pine needles survive winter by developing the ability to tolerate extracellular ice formation, because after rapid freezing the needles were severely injured; and (3) red pine is adapted to a shorter growing season and colder winters than Austrian pine.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.     

樟子松人工林下针阔叶凋落物分解动态

实验在位于张广才岭西坡的东北林业大学帽儿山实验林场老山人工林实验站进行。结果如下，樟子松枯叶在凋落后第１年和第３年的失重率分别３４．６７％和６３．７５％，樟子松枯落球果、树皮和树枝在凋落后第１年的失重率仅为枯叶的３６．６９％、３３．６６％和３０．１２％；红松、柞树、榆树和水曲柳枯叶在凋落后第１年和第３年的干物质失重率分别为樟子松枯叶的５８．７０％和８４．７１％、８１．６％和８０．５５％、１３４．９４％和１５６．５５％及１２４．２６％和１４７．７１％。凋落后第１年的干物质失重量达总凋落量的２６．６１％，其中占总凋落量的１１．８５％阔叶树枯叶的失重量达总失重量的２０．５１％；占总凋落量４３．６４％的樟子松枯叶的失重易达总失重量的５８．２９％；而占总凋落量２４．２８％、１３．１０％和６．８９％的樟子松柏树皮、枯树皮和枯球果分别仅提供１０．９２％、５．２８％和３．３７％的失重量、不同枯落物的营养元素净释放率和释放量的实验分析结果表明，凋叶树枯叶在林地地力维持中起重大作用。     

Photosynthetic utilization efficiency of absorbed photosynthetically active radiation by Scots pine and birch forest stands in the southern Taiga

Absorption and utilization of photosynthetically active radiation (PAR) were investigated in Scots pine (Pinus sylvestris L.) and birch (Betula pendula Roth.) stands that were 41 years old at the end of the experimental period. Canopy depth of the Scots pine stand was about half that of the birch stand (6.5 versus 11.0 m), but absorption of PAR was similar in the two stands. The Scots pine forest canopy, with a leaf area index of 8.9, absorbed 90% of the incoming PAR (APAR), whereas the birch forest canopy, with a leaf area index of 5.9, absorbed 92% of APAR. During maximum foliage development, the upper Scots pine canopy absorbed more PAR than the upper birch canopy (75 versus 66%). The upper, middle and lower layers of the Scots pine canopy contained 37, 48 and 15% of the total needle surface area, respectively. The corresponding distribution of foliage surface area in the three layers of the birch canopy was 50, 30 and 20%, respectively. Measurements of photosynthetic rate were combined with estimates of leaf area index and stand phytomass to determine rates of primary production on a sunny day, a cloudy day, and on an annual basis. The energy equivalents of short- and long-term carbon gain were used with determinations of APAR to calculate photosynthetic utilization efficiency. Throughout the growing season, photosynthetic utilization efficiency of APAR in the upper canopy layer of the Scots pine forest was almost twice that in the lower canopy layer. In the birch forest, photosynthetic utilization efficiency was greater in the lower canopy layer than in the upper canopy layer. In all cases, utilization efficiency was higher in the birch stand than in the Scots pine stand (52 versus 29 J kJ(-1)). Taking account of respiration of the non-photosynthetic parts of each stand (night respiration of needles or leaves; respiration of branches, trunk and roots), estimated utilization efficiency of APAR for net primary production was 11 J kJ(-1) for Scots pine and 19 J kJ(-1) for birch. Solar conversion ratios, expressed as whole-plant net primary productivity per unit of APAR for the growing season, were 0.81 g MJ(-1) for Scots pine and 0.93 g MJ(-1) for birch.     

The effects of ultraviolet-B radiation on photosynthesis of different aged needles in field-grown loblolly pine

We examined the effect of supplemental UV-B radiation (290-320 nm) on photosynthetic characteristics of different aged needles of 3-year-old, field-grown loblolly pine (Pinus taeda L.). Needles in four age classes were examined: I, most recently fully expanded, year 3; II, first flush, year 3; III, final flush, year 2; and IV, oldest needles still present, year 2. Enhanced UV-B radiation caused a statistically significant decrease (6%) in the ratio of variable to maximum fluorescence (F(v)/F(m)) following dark adaptation only in needles from the youngest age class, suggesting transient damage to photosynthesis. However, no effects of enhanced UV-B radiation on other instantaneous measures of photosynthesis, including maximum photosynthesis, apparent quantum yield and dark respiration, were seen for needles of any age. Foliar nitrogen concentration was unaffected by UV-B treatment. However, the (13)C/(12)C carbon isotope ratios (delta(13)C-a time integrated measure of photosynthetic function) of needles in age classes II and IV were 3% (P < 0.01) and 2% (P < 0.05) more negative, respectively, in treated plants than in control plants. Exposure to enhanced UV-B radiation caused a 20% decrease in total biomass and a 4% (P < 0.05), 25% (P < 0.01), and 9% (P < 0.01) decrease in needle length of needles in age classes I, II, and IV, respectively. The observed decreases in delta(13)C, and F(v)/F(m) of the needles in the youngest needle age class suggest subtle damage to photosynthesis, although overall growth reductions were probably a result of decreased total leaf surface rather than decreased photosynthetic capacity. Needles of age class IV had lower light- and CO(2)-saturated maximum photosynthetic rates (39%), lower dark respiration (34%), lower light saturation points (37%), lower foliar nitrogen concentration (28%), and lower delta(13)C (14%) values than needles of age class I. Apparent quantum yield and F(v)/F(m) did not change with needle age. The observed changes in photosynthesis and foliage chemical composition with needle age are consistent with previous studies of coniferous trees and may represent adaptations of older needles to shaded conditions within the canopy.     

Fine root biomass and production in Scots pine stands in relation to stand age

We determined fine root biomass and production of 15-, 35- and 100-year-old Scots pine (Pinus sylvestris L.) stands during three growing seasons. Fine roots were sampled by the soil core method. Mean (+/- SE) annual fine root biomass of Scots pine in the 15-, 35- and 100-year-old stands was 220 +/- 25, 357 +/- 21 and 259 +/- 26 g m(-2), respectively. Fine root biomass of the understory vegetation was 159 +/- 54 g m(-2), 244 +/- 30 and 408 +/- 81 g m(-2), and fine root necromass was 500 +/- 112, 1,047 +/- 452 and 1,895 +/- 607 g m(-2) in the sapling, pole stage and mature stands, respectively. Both understory and Scots pine fine root production increased with stand age. Mean annual Scots pine fine root production was 165 +/- 131, 775 +/- 339 and 860 +/- 348 g m(-2) year(-1) in the sapling, pole stage and mature stand, respectively. The respective mean annual production of all fine roots (Scots pine and understory) was 181 +/- 129, 1,039 +/- 497 and 1,360 +/- 869 g m(-2) year(-1). The Scots pine and understory fine root biomass, necromass and production varied in relation to stand age, although the variation was not statistically significant.     

油松对赤松毛虫的诱导化学防御及滞后诱导抗性

对当年受赤松毛虫危害和未受危害的油松新长出的一年生针叶化学成分以及用其饲养的赤松毛虫的发育情况进行了测定分析，结果发现受害油松新长出的一年生针叶化学成分仍有较大幅度的变化，主要表现在氨基酸总量及多数游离氨基酸含量下降；水溶性总糖，粗脂肪，生物碱含量及总糖／投案基酸比例上升；脂肪酸、单宁、酚类化合物均有较大幅度的减少，用其饲不养的赤松毛虫幼虫体三 ，死亡率比对照高１９．２％，油松对赤松毛虫的滞后诱导     

Effects of needle age, long-term temperature and CO(2) treatments on the photosynthesis of Scots pine

Naturally regenerated 20-25-year-old Scots pine (Pinus sylvestris L.) trees were grown in open-top chambers in the presence of an elevated temperature or CO(2) concentration, or both. The elevated temperature treatment was administered year-round for 3 years. The CO(2) treatment was applied between April 15 and September 15 for 2 years. The photosynthetic responses of 1- and 2-year-old needles to varying photon flux densities (0-1500 micro mol m(-2) s(-1)) and CO(2) concentrations (350, 700 and 1400 micro mol mol(-1)) during measurement were determined. The CO(2) treatment alone increased maximum photosynthetic rate and light-use efficiency, but decreased dark respiration rate, light compensation and light saturation regardless of needle age. In contrast, the temperature treatment decreased maximum photosynthetic rate and photosynthetic efficiency, but increased dark respiration rate, light compensation and light saturation. The aging of needles affected the photosynthetic performance of the shoots; values of all parameters except photosynthetic efficiency were less in 2- than in 1-year-old needles. The CO(2) treatment decreased and the temperature treatment enhanced the reduction in maximum photosynthesis due to needle aging.     

Characterization of glutathione S-transferase from dwarf pine needles (Pinus mugo Turra)

Glutathione S-transferase activity conjugating xenobiotics with glutathione (GSH) was found in extracts from needles of dwarf pine (Pinus mugo Turra). In vivo incubation of needle segments with the herbicide fluorodifen at 25 degrees C resulted in conversion of the xenobiotic to water-soluble products at initial rates of 0.7 nmol h(-1) g(fw) (-1). At 15 degrees C, the initial rate of product formation was decreased to 0.1 nmol h(-1) g(fw) (-1). In vitro conjugation studies with chloro-2,4-dinitrobenzene (CDNB) and 1,2-dichloro-4-nitrobenzene (DCNB) as model substrates gave apparent K(m) values of 0.5 mM GSH and 1.14 mM CDNB in the GSH/CDNB system and 0.3 mM GSH and 0.44 mM DCNB in the GSH/DCNB system. The pH optimum was between 7.7 and 7.9 for both the GSH/CDNB and the GSH/DCNB systems. The temperature optimum for these model substrates was between 30 and 35 degrees C, and only minute amounts of enzyme activity were detected at 15 degrees C. The activation energy in the temperature range of 15 to 30 degrees C was 46 kJ mol(-1). Dwarf pine glutathione S-transferase exhibited an approximate molecular weight of 52 kD.