长白山林区天然次生林胡桃楸的适宜生长空间

利用次生林主林层胡桃楸34株平均木(胸径为11.0～39.1 cm)的树干解析数据,结合反映植物生长空间的冠幅,进行5,10和15年抚育间隔期的单株材积定期生长量、林分蓄积增长量与生长空间关系的研究,建立不同抚育间隔期胡桃楸胸径与适宜生长空间关系的模型;利用林冠下层27株胡桃楸平均木(胸径为4.6～14.3 cm)的树干解析数据,评价适宜生长空间模型应用于被压状态胡桃楸时的生长促进效果.结果表明:1)3参数S型曲线模型和二项式模型分别能够很好反映胡桃楸前5,10和15年间单株材积定期生长量、林分蓄积增长量与冠幅的关系;2)不同抚育间隔期胡桃楸胸径与适宜生长空间关系的模型为幂函数模型(y=a×x~b);3)对数函数模型(y=a×ln(x)+b)能显著反映适宜生长空间下胸径与材积定期生长量的关系;4)适宜生长空间下胡桃楸5,10和15年材积定期生长量至少比生长空间受限条件下的林木提高97.8%,114.4%和128.5%.采用5,10,15年抚育间隔期时,不同胸径胡桃楸的适宜生长空间分别是相应胸径的0.256 6～0.368 7,0.344 1～0.447 1和0.449 1～0.504 6倍.     

肉桂人工林土壤速效养分与酶活性的季节变化

研究了广西高峰林场林龄为3年和6年的肉桂人工林土壤速效养分(水解N、速效P、速效K)和土壤酶活性(过氧化氢酶、脲酶、酸性磷酸酶)的季节变化规律及其相互关系。结果表明：两种林地土壤速效养分含量和土壤酶话性均表现出明显的季节动态．：E壤速效N、P、K含量和L壤脲酶活性均以肉桂生长初期(3月中旬)最高．其次是第一个生长高峰期(6月中旬)或第二个生长高峰期(9月中旬)，最低是生长未期(12月中旬)；而土壤过氧化氢酶和酸性磷酸酶活性以第一个生长高峰期或第二个生长高峰期最高．其次是生长初期,最低是生长末期；士壤速效养分与土壤酶活性的季节变化密切相关。因此，生长初期至第一个生长高峰期是肉桂林地施用N、P、K肥的适当时期。     

7年生平欧杂种榛果实生长发育规律的研究

以‘82-11’、‘84-237’和‘84-402’等3个杂种榛优良品系为试材,采用动态监测的方法,研究7年生平欧杂种榛果实生长发育规律。结果表明,3个榛子品系果实重量生长曲线为“慢-快-慢”的“单S”型曲线,其生长过程可分为初始缓慢生长期、快速生长期、第二次缓慢生长期3个阶段。3个榛子品系果仁重量生长曲线为“单S”型曲线,随着果仁的发育,果仁鲜重逐渐增加,果仁重量的增加在果仁发育前期较快,后期较慢。果实发育前期,果实重量的增长主要来自细胞的分裂与膨大,果实发育后期,果实重量的增长主要由果仁的生长引起。     

Acclimation of shoot and needle morphology and photosynthesis of two Picea species to differences in soil nutrient availability

To investigate morphological acclimation to differences in nutrient availability, we compared shoot and needle morphology of Picea glehnii (Friedr. Schmidt) M. T. Mast. and Picea jezoensis (Siebold & Zucc.) Carrière trees growing on nutrient-poor volcanic ash and nutrient-rich, brown forest soil. Trees of both species were shorter and had more open canopies when growing on volcanic ash than when growing on brown forest soil. Nutrient-poor conditions limited height growth less in P. glehnii than in P. jezoensis. In both species, trees growing on volcanic ash had shorter annual increments in the previous year and more needles per shoot length and, hence, a smaller shoot silhouette area (SSA) relative to needle dry mass (NDM) than trees growing on brown forest soil. Soil type had less effect on shoot projected needle area (PNA). Total needle area (TNA) of P. glehnii shoots was similar between soil types, whereas TNA of P. jezoensis was lower in trees growing on volcanic ash than in trees growing on brown forest soil. For both species, low SSA in response to nutrient-poor conditions resulted in low shoot SSA/PNA ratios, indicating high within-shoot self-shading. Shoot SSA/TNA of P. glehnii was lower in trees growing on volcanic ash than in trees growing on brown forest soil, indicating that needles were sun-acclimated. In contrast, shoot SSA/TNA of P. jezoensis was higher in trees growing on volcanic ash than in trees growing on brown forest soil. The contrasting response of TNA to low nutrient availability was associated with species-specific differences in needle morphology. Needles of P. glehnii growing on volcanic ash were slightly shorter, wider, thicker and heavier than those of trees growing on brown forest soil, indicating morphological acclimation to high irradiance. Needles of P. jezoensis growing on volcanic ash were shorter than those of trees growing on brown forest soil, but did not show morphological acclimation to high irradiance in width, thickness or mass. For both species, nutrient-poor conditions decreased maximum photosynthetic rate (Amax) per NDM. However, when expressed per PNA, the decrease in Amax was reduced, and when expressed per SSA, Amax was higher in trees growing on volcanic ash than in trees growing on brown forest soil. On volcanic ash, Amax per NDM was lower for P. glehnii than for P. jezoensis. However, morphological changes at the shoot and needle levels reversed this trend when Amax was expressed per SSA or per PNA. The species-specific differences in morphological response to differences in soil nutrient availability suggest that P. glehnii is more tolerant of nutrient-poor conditions, whereas P. jezoensis is better at exploiting nutrient-rich soils.     

四川盆地丘陵及盆周低山区杉木实生林生长特点及提高产量的途径

四川盆地丘陵及盆周低山区杉木实生林受气候等环境条件的影响,速生期早而短,若立地条件差则很多林木因早熟而达不到培育目标。本研究在调查杉木主要分布区林分生长状况基础上,通过树干解析、生长过程对比分析,弄清了该地区杉木林分速生期持续的年限,并提出了以间作、合理施肥、合理密植为提高产量的主要措施。试验证明,这些措施具有明显的效果,既改良了林地土壤的理化性质、提高了土壤肥力,又延长了林分的速生期,提高林分蓄积并改善了木材的规格质量,其经济效益和社会效益都十分明显。     

美国白松生长特性的研究

以山东乡土针叶树种油松和黑松作对比,研究了从美国引种的１２年生美国白松的物候期及新梢、针叶的生长特性。以Ｌｏｇｉｓｔｉｃ方程拟合３种针叶树新梢和针叶的生长,并用数学分析的方法确定各树种新梢和针叶的速生期和速生点。测定了３个针叶树种的径、高年生长量。结果表明,美国白松在山东能够正常生长发育,生长期比油松和黑松短,但生长迅速,年生长量比较大,是一个值得引进并扩大栽培的速生针叶树种     

Effects of compost additive in sphagnum peat growing medium on Norway spruce container seedlings

Sphagnum peat has been the most commonly used growing medium in containers in tree nurseries worldwide for its good growing properties. As a result of increasing costs and environmental incentives, seedling-growers are seeking more local growing medium components such as composts. Composts are, however, diverse products with varying chemical, physical, and hygienic properties and therefore require thorough testing before real-world use. In this study, a commonly used compost (raw materials: sewage sludge, biowaste, peat, wood chips) was tested for feasibility as a component (0–30 vol.%) of a sphagnum peat container medium for growing Norway spruce (Picea abies (L.) Karst.) container seedlings in a forest-tree nursery. In proportions of up to 30% in peat, the compost additive used was shown to be a feasible material for seedling growing in forest nurseries. On average, the seedlings grew best in pure peat, but the compost additions to peat showed no marked reduction in seedling growth in greenhouses, nor were there any effect on seedling growth in the first summer after outplanting. However, a slightly elevated risk of seed non-germination and of seedling mortality was observed when the growing media contained compost in proportions of 20% or more. The compost additive in peat also changed the bulk density, structure, and chemical properties of the medium during nursery growing. The results suggest that seedling watering and fertilisation should be adjusted for each growing medium mix separately to achieve correct water, oxygen, and nutrient availability in containers during nursery growing.     

Plasticity of shoot and needle morphology and photosynthesis of two Picea species with different site preferences in northern Japan

We compared shoot and needle morphology and photosynthesis in Picea glehnii (Friedr. Schmidt) M.T. Mast. and Picea jezoensis (Sieb. et Zucc.) Carr. trees planted on immature volcanic ash and well-developed brown forest soils to investigate whether species differences in morphological and physiological plasticity affected tree growth on different soil types. Height growth of P. glehnii was reduced by about 10% on volcanic ash compared with forest soil, whereas that of P. jezoensis was reduced by more than 60%. Needle morphology of P. glehnii was unaffected by soil type. In contrast, needles of P. jezoensis trees growing on volcanic ash were shorter, narrower and thicker, with less dry mass and area, than those of trees growing on forest soil, and specific needle area was lower, indicating lower foliar light-interception efficiency. In both species, changes in needle morphology with increasing irradiance were similar in trees growing on both soil types, indicating that plasticity of needle morphology was unaffected by soil type. In both species, shoot mass and shoot silhouette area were lower and needle mass per unit shoot mass was higher in trees growing on volcanic ash than in trees growing on forest soil. Trees of both species had more needles per unit shoot length, lower shoot silhouette to projected needle area ratios and lower shoot silhouette areas per unit shoot mass (SAM) on volcanic ash than on forest soil, indicating lower shoot-level light-interception efficiency. For P. glehnii, the response of shoot morphology to increasing irradiance was similar on both soil types, with the exception of SAM, which showed lower plasticity in trees growing on volcanic ash. In contrast, shoot-level morphological plasticity of P. jezoensis was reduced in trees growing on volcanic ash. Light-saturated maximum photosynthetic rate (P(max)) of P. glehnii was unaffected by soil type, whereas mass-based P(max) of P. jezoensis was lower in trees growing on volcanic ash than in trees growing on forest soil. In P. jezoensis trees growing on forest soil, area-based P(max) increased with increasing irradiance, but this response was not observed in trees growing on volcanic ash. As a result, area-based P(max) at the top of the canopy was 39 to 54% lower in trees growing on volcanic ash than in trees growing on forest soil. Our results indicate that constraints on morphological acclimation to high irradiances may contribute to reduced height growth of P. jezoensis on volcanic ash.     

Height development of Betula pubescens following precommercial thinning by breaking or cutting the treetops in different seasons

Topping, i.e. cutting or breaking the treetops of secondary stems, may be an attractive alternative to traditional precommercial thinning. The survival and height development of downy birch (Betula pubescens Ehrh.) after topping were examined over three growing seasons in two dense, naturally regenerated stands, 3.1–3.5 m high, in northern Sweden. The topping was performed in experiments with a two-factor randomized complete block design, as follows. Three treatments were applied to individual secondary stems (top-breaking at half the sample tree mean height, top-cutting at half the sample tree mean height, and traditional cutting just above ground) at each of three times: winter, spring and summer (in frozen, dormant and growing conditions, respectively). A control (no treatment) was also included. The survival rate was lowest for traditionally cut stems and for stems cut in growing conditions. Height development after three growing seasons was significantly affected by time of treatment, the height growth being lowest after treatment in growing conditions, but not by treatment. Height growth of control stems was not significantly different from height growth in any combination of treatment and time of treatment, after three growing seasons. However, control stems had the greatest leading shoot length in the third growing season.     

建设速丰林,推进漳州林业跨越式发展

提出以发展桉树、相思树为主的速生丰产工业用材林基地,是实现漳州林业跨越式发展的突破口;分析了漳州发展速丰林具备的自然优势、技术条件;指出发展速丰林是实现其整体效益的最佳途径,并提出建设速丰林的对策建议。     

Climate impacts on lodgepole pine (Pinus contorta) radial growth in a provenance experiment

A potentially confounding radial-growth interaction exists at the intersection of two well-known principles, one in the field of dendrochronology and the other in quantitative genetics. From a dendrochronology perspective, tree populations growing in climatically marginal environments are expected to be more sensitive to seasonal and annual climate than those growing in optimal climate zones. From a genetics perspective, marginal populations may be adapted to grow a small amount each year and then shut down to prevent climate-induced mortality, or they may be adapted to respond to favourable climate conditions when available. We examined the relative strength of these forces using data from 12 populations of 34-year-old lodgepole pine (Pinus contorta) trees growing in 16 provenance-trial sites in western Canada. Growth generally correlated positively with annual temperature and negatively with summer aridity. The sensitivity of radial-growth to interannual climate fluctuations was both site and provenance-related, with the highest sensitivities occurring among populations from warm, central provenances growing at cold, marginal sites, and among populations from cold, marginal provenances growing at warm, central sites. The correlations between climate and growth varied regionally; notably, populations from warm provenances growing at warm sites responded more strongly to summer aridity, while populations from cold provenances growing at warm sites responded more to annual temperature. Our finding that sensitivity varied among populations growing under similar climate conditions indicates that sensitivity is influenced by genetics as well as by site climate, but the regional specificity of the growth responses did not support a single hypothesis for the influence of genetics on growth among populations from marginal vs. central locations. Implications of our study for forest productivity under climate change are more positive for trees growing in cool locations, where overall warmer temperatures will lead to increased growth, than in warm locations, where the negative effects of arid summers may counteract the positive effects of warmer annual temperatures.     

喜树纯林与混交林生长过程比较分析

本文以湖北省崇阳县桂花林场喜树人工纯林和大悟县仙居顶林场喜树人工混交林为研究对象,通过标准地设置与调查,获得了喜树胸径、树高、材积生长量和生长率数据,在此基础上研究了喜树胸径、树高、材积的生长过程,并比较分析了纯林与混交林喜树生长过程差异。结果表明:喜树胸径、树高生长速生期出现在早期,混交林与纯林中的喜树表现相同;混交林中喜树的胸径、树高、材积生长量和生长率均优于人工纯林;从喜树材积生长过程看,喜树数量成熟年龄30a。     

ECONOMIC ASPECTS OF POPLAR GROWING FOR MATCHWOOD PRODUCTION

Some economic aspects of poplar growing in South Africa are discussed. A volume yield table for Populus deltoides Bartram ex Marshall is presented and the average costs of poplar growing are reproduced. Various types of rotations are calculated and the profitability of poplar growing in South Africa is analysed.     

Light,soil, and seedling characteristics associated with varying levels of competition in a red pine plantation

Red pine (Pinus resinosa Ait.) seedlings growing under differing levels of competition were evaluated during the fifth growing season following planting, and placed into low, moderate, or high tree classes, as a function of levels of competing vegetation. Tree growth, moisture status, and nutrition were monitored over the growing season. Additionally, site characteristics such as soil temperature and moisture, inorganic nitrogen concentration, mineralized soil nitrogen, and light were measured. Red pine seedlings growing under low competition had an absolute volume growth increase of 795% over the seedlings growing under the heaviest competition. The associated relative volume growth increase during the fifth growing season was 44%. Discriminant analysis was used to describe three classes of trees representing low, moderate, and high levels of competition. Trees growing under low competition had longer and heavier needles, but generally lower nutrient concentrations. Pre-dawn plant moisture status did not vary among competition levels. Soil variables indicated that, in general, the trees growing under low competition occupied warmer, drier, and less fertile microsites, as inorganic soil N and mean monthly mineralized NO₃-N and NH₄>-N tended to be lower on these microsites. The suite of independent variables was effective in classifying the model data into three tree competition classes, with percent correct classifications of 92, 75, and 100 for low (tree class one), moderate (tree class two), and heavy (tree class three) competition, respectively.     

黄土丘陵区坡面林-草边界土壤养分特征

应用定位、连续观测的方法,对黄土丘陵区刺槐林-草地复合系统景观边界不同季节时期土壤养分因子进行测定和分析的结果表明,林-草边界土壤有机质、有效P、有效K含量在生长季末期含量最高,而土壤有效N含量在生长季前期含量最高。应用主成分分析的方法,对3个时期的边界土壤养分综合影响边缘效应的位置与宽度进行了判定,结果表明：林-草边界土壤养分综合因子具有较明显的边缘效应位置与宽度,生长季、生长季末期土壤养分综合影响边缘效应的位置都为从林内8m到林外4m、宽度12m,生长季前期土壤养分综合影响边缘效应的位置为从林内4m到林外8m、宽度12m。     

新疆杨、速生杨（中林-46）树种光合特性研究

通过对新疆杨、速生杨沙地造林树种光合特性比较研究发现：（1）新疆杨、速生杨是高光能利用效率树种：新疆杨净光合速率平均值高于速生杨（中林-46）;（2）新疆杨树种蒸腾速率受气温、空气相对湿度及水汽压的直接影响而变化的幅度大于速生杨（中林-46）;（3）新疆杨水分利用效率高于速生杨（中林-46）;（4）新疆杨和速生杨树种的光能利用效率,与水分竞争能力之间具有互补性,反映出这2种杨树对干旱环境的适应策略较强;（5）速生杨气孔导度均值大于新疆杨气孔导度,但是,新疆杨气孔导度值变化幅度较大。     

栽培条件下华中五味子茎生物学特性研究

研究发现,华中五味子茎按生长习性分为地走性和缠绕性两种;从萌生部位分有发育地下部、根颈部、主茎基部和成年枝条腋芽等四种,各具不同的生长习性;从抽发时间及生长季节分为春梢、夏梢和秋梢。茎的生长属阶段性生长类型,春梢、夏梢生长规律符合三次曲线,秋梢符合二次曲线,各生长期重叠,生长高峰错开。据此提出了生产建议。     

火炬松和湿地松幼苗蔗糖含量与生长潜势关系的研究初报

火炬松(Pinux taeda L.)和湿地松(Pinus elliottii Engelm)是我国南方重要的外引用材树种,经过多年的试验研究,已选出一批较好的种源、家系和单株,并建立了种子园。当前早期鉴定和早期选择已成为必不可少的一项研究内容,近几年来越来越多的研究者指出,林木幼龄期的某些性状或生理生化指标与成熟期性状之间存在一定的相关性,认为树木生长的早期选择是可能的,尤其从生理生化方面来探索林木早期预测的研究已引起人们的高度重视。但     

Identifying important biophysical and social determinants of on-farm tree growing in subsistence-based traditional agroforestry systems

Many expert-designed agroforestry projects enunciated in 1970s around the world, particularly in the developing countries, had uneven success due to inadequate adoption or abandonment after adoption. There are many empirical studies on factors affecting on-farm tree cultivation mainly where expert-designed agroforestry programmes were introduced but lacking in case of traditional agroforestry. Moreover, the concern to identify key factors influencing on-farm tree growing is gaining importance. The present study identifies key factors in on-farm tree growing based on investigation of traditional agroforestry using logistic regression approach. The study is based on household survey of 401 households located in Indian Western Himalaya. The factors affecting on-farm tree growing were grouped into: biophysical (included land use and infrastructural aspects) and social. Models predicting on-farm tree growing for each category were developed and key factors affecting on-farm tree growing in the respective category were identified. A composite model was also developed by combining biophysical and social factors. In the present study, farm size, agroclimatic zone, soil fertility, mobility and importance of tree for future generations respectively were the key factors which influenced tree growing. In contrast to many previous studies which considered either biophysical or social factors, the composite model in the present study reveals that both biophysical and social factors are simultaneously important in motivating the farmers to grow trees on their farms in traditional agroforestry. Moreover, the present study open vistas for using farmers’ experience and knowledge of adoption of agroforestry to stimulate on-farm tree growing. The wider implication of the study is that biophysical as well as social variables should be considered together in designing suitable agroforestry systems in various parts of the world.