蒸汽爆破预处理对柞木微观结构的影响

对采用0.4MPa压力进行蒸汽爆破预处理及干燥的柞木板材,通过扫描电子显微镜对试件的微观结构进行观察,并对经过爆破处理和未爆破处理的试件的微观结构进行分析比较.试验表明,柞木经爆破处理后管胞纹孔边缘开裂,射线薄壁细胞产生细小的裂隙,导管内的侵填体剥落,这些对木材的力学强度没有太大的影响,但使得木材的渗透性得以提高.     

STUDIES ON STRUCTURE AND FUNCTIONS OF MONGOLIAN OAK FORESTS

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樟子松人工林胸径生长规律的研究

本文以佳木斯市横头山林场樟子松人工林作为研究对象,研究樟子松人工林林木的胸径生长规律,分别用修正指数方程、理查德方程、逻辑斯蒂方程对各等级大小胸径生长数据进行拟合。结果表明,用理查德方程拟合胸径生长较好;胸径连年生长量达到最大的时间在11-14年之间,当时的胸径则差异较大,优势木和劣势木相差将近2cm,范围在5.5-7.5cm之间,年生长最大值的差异较明显,在0.56-0.87cm之间。     

Application of theoretical growth functions for Mongolian oak (Qurcus mongolica)

Four alternative functions are used for fitting tree height and diameter growth models for mongolian oak. (Quercus mongolica Fisch. et Turcz.). The data set includes 1250 random trees and 755 dominant trees coming from 510 temporary plots. The resultsshow that the Richards function is the best model for predicting height. diameter at breast height (DBH) and dominant height from age. The average growth curve of dominant height is used as a guide curve for the construction of a site index table which is partially validated using an independent data set. The Mitscherlich function is the best model for estimating height and dominant height from DBH. (Responsible Editor: Chai Ruihai)     

Application of Theoretical Growth Functions for Mongolian Oak(Qurcus Mongolica)

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金苍林场蒙古栎天然中龄林竞争关系研究

以吉林省汪清林业局金仓林场2块面积为0.25 hm2的蒙古栎天然中龄林固定样地为对象,采用8个竞争指标,研究蒙古栎天然林种内、种间竞争状态。研究结果表明,该林分竞争激烈,蒙古栎与其他各树种存在种间竞争,但其主要竞争压力来自种内,种外竞争压力主要来自黑桦与白桦。其它树种的竞争主要为种间竞争。蒙古栎竞争能力处于中等,白桦与黑桦最强。各竞争指标结果存在差异性,但均能反映蒙古栎天然林竞争状态。蒙古栎竞争强度与胸径存在幂函数关系,竞争强度随个体大小的增大而减小。     

Effects of site conditions and methods of cultivation on growth of sawtooth oak plantations

The effects of site conditions and cultivation on the growth of sawtooth oak (Quercus acutissima Carr.) plantations were evaluated at the Hongyashan forest farm, in Chuzhou City, Anhui Province, China. The results indicate that the position on the slope, the amount of gravel and the thickness of the soil were important factors in the growth of the sawtooth oak. Lower slope positions with small amounts of gravel and a thick soil were better for the growth of this species than middle slope positions with more gravel and a thin soil. Given the site conditions of the hilly and mountainous areas in Chuzhou City, the mixed Chinese fir (Cunninghamia lanceolata Hook.) and sawtooth oak forests did not improve forest productivity compared with pure sawtooth oak forests. Both urea and compound fertilizers promoted the growth of sawtooth oak, as did site preparation and intercropping. Two years after planting, the height growth of ordinary seedlings with a starting height of 0.6 m was higher than that of supper seedlings with a starting height of 1.0 m. Compared with planting, the early growth of the coppices was faster, but the later growth of the coppices was slower. __________ Translated from Journal of Fujian College of Forestry, 2008, 28(2): 130–135 [译自: 福建林学院学报]     

Species composition and dynamics in two hardwood stands in Vermont: a disturbance history

Stand composition and structure utilizing stem analysis was studied in two hardwood stands in Vermont. In a mixed hardwood stand with some white pine and hemlock, a major entry of new trees in the main canopy seems associated with harvesting coincident with land exchange. More recent partial cuttings have promoted establishment of new seedlings or development of suppressed advanced-growth shade-tolerant beech, (Fagus grandifolia, Ehrh.), hophornbeam (Ostrya virginiana, (Mill) K. Koch), and striped maple (Acer pensylvanicum, L.). Very few sugar maple and red oak seedlings and saplings are present.

In a northern hardwood stand some red spruce (Picea rubens, Sarg.), that were 240 to 306 years old, became established before any known harvest, and exhibited release following harvests of the mid-1800s. This major harvest, coupled with the differential growth between spruce and hardwoods, and seed/seedling availability, resulted in a major change in stand composition. Trees now in the main canopy of sampled stands appear to have either been released or newly established following various harvests. Harvests have been of such frequency that natural disturbances seem insignificant. Many of the competitive understory species have become abundant following harvests of the 1960s and 1980s and may have been present as advanced growth and responded to the release. Following the harvest of 1981–1982, abundant yellow birch became established on skid trails. Elsewhere in the stand, yellow birch seedlings and saplings are only in great abundance in areas that were possibly sizable gaps following earlier harvesting.

The dynamics of tree entry and growth in gaps of small or large size probably occur in a similar way in many other stands of the region. Though the sampling of this study is limited, there is no suggestion of continuous tree establishment at any particular location, the new age classes seem associated with either a gap or stand replacing disturbance attributed to harvesting.     

糙花少穗竹发笋及幼竹高生长规律的研究

对糙花少穗竹发笋期及幼竹高生长的研究表明 :糙花少穗竹发笋期在 2月中旬至 5月上旬 ,发笋初期在 2月中旬至 3月上旬 ,出笋株数占整个生长期出笋总数的 1 7.6 % ,笋重占 1 4 .5 % ;发笋盛期在 3月中旬至 4月下旬 ,出笋株数占整个生长期出笋的总数 72 .1 % ,笋重占 78.1 % ;发笋末期在 5月 ,发笋株数占整个生长期出笋的总数 1 0 .3% ,重量占 7.4 % ;发笋初期平均单株笋重0 .378kg,盛期平均单株重笋 0 .4 97kg,末期平均单株笋重 0 .32 9kg,表现为 :盛期笋 >初期笋 >末期笋 ;糙花少穗竹幼竹高生长高峰在笋出土后第 3～ 33d,高生长初期平均生长量 7.93cm· d-1 ,后期平均生长 4 .4 4cm· d-1 ,最大日生长量为 2 4 cm,整个生长期平均日生长量 1 5 .1 3cm。     

北美橡树嫁接育苗试验

采集适合湘南地区栽培的北方红栎、猩红栎、娜塔栎、沼生栗栎和柳栎等北美橡树品种的枝条作为接穗,以麻栎实生苗为砧木,开展北美橡树嫁接育苗试验。试验结果为:就嫁接成活率而言,北方红栎的最高,为99.34%;其次是猩红栎的,为98.14%;沼生栗栎和柳栎的分别为94.15%和92.86%;娜塔栎的最低,为76.09%;各品种嫁接成活率排序为北方红栎>猩红栎>沼生栗栎>柳栎>娜塔栎。就保存率而言,北方红栎的最高,为89.40%;其次是柳栎的,为71.79%;沼生栗栎和猩红栎的分别为39.13%和32.28%;娜塔栎的最低,为29.29%;各品种嫁接苗保存率排序为北方红栎>柳栎>沼生栗栎>猩红栎>娜塔栎。不同北美橡树品种间苗高、地径均存在显著差异。就苗高而言,猩红栎及娜塔栎的较高,猩红栎的为149.08cm,娜塔栎的为140.88cm,两者间无显著性差异;北方红栎、沼生栗栎、柳栎的较低,北方红栎的为106.44cm,沼生栗栎的为95.20cm,柳栎的为110.00cm,且三者苗高生长均显著劣于猩红栎及娜塔莉。就地径而言,北方红栎的最大,为16.36mm,且显著优于其他品种;猩红栎与娜塔栎间无显著差异,其地径分别为13.28mm和11.87mm;沼生栗栎与柳栎间无显著差异,其地径分别为9.17mm和8.77mm,且两者均显著劣于其他品种。     

兴凯赤松与樟子松苗期生长性状对比分析

在优异种质选择基础上,引进3个兴凯赤松、5个樟子松天然群体的种子,经有性繁殖获得植株,以此开展种质资源异地保存林营建技术的研究。结果表明:兴凯赤松苗期高生长节律与樟子松相近,且适应性较强,定植成活率较高;樟子松群体内生长性状变异较大,变异幅度30.11%~46.72%(苗高)、23.33%~35.98%(地径);群体内及群体间兴凯赤松生长性状变异较小,变异幅度在30.27%~31.47%(苗高)、24.81%~25.05%(地径)之间,并且,兴凯赤松苗高和地径生长量较樟子松分别提高30.23%、29.40%。     

水分胁迫对栓皮栎幼苗生理特性及生长的影响

通过盆栽实验，研究了在不同的水分条件下栓皮栎幼苗生理特性的变化和苗木生长量的变化。研究表明，在水分胁迫初期，随土壤含水量的降低，栓皮栎叶片的净光合速率、蒸腾速率下降，而水分利用效率提高。在水分胁迫末期，由于长期的干旱胁迫，水分条件最差的一组苗木已干枯死亡，土壤含水量从38．123％下降到20．323％时，净光合速率和蒸腾速率均下降，水分利用效率也下降。随着土壤含水量的降低，苗高、地径和生物量均有下降的趋势，其中生物量下降的幅度最大。     

小径柞木真空干燥应力的试验研究

在真空干燥条件下,分析小径级柞木板材的应力与含水率、时间的关系,结果表明:在低温条件下,由于真空负压作用,水分蒸发速度得到了加快,干燥应力由于干燥前板材内的初始应力的差异,导致干燥过程中应力的发生、发展有所差异。根据应力表现的差异应当在干燥不同阶段及时进行调湿处理,预防板材开裂产生。     

木荷防火林生长特性的初步研究

不同立地、不同年龄、不同起源、不同产区木荷防火林林分生长特性研究结果表明 :立地条件、年龄、林分起源对木荷生长存在显著影响 ,通过不同产区木荷生长比较分析认为闽西北适宜木荷生长 ,可营造木荷防火与用材两用林     

Lifting and storing bareroot blue oak (Quercus douglasii) seedlings

In California today, several species of native oaks are not regenerating adequately. Artificial regeneration is a means of ensuring sufficient recruitment to replace trees that die or are harvested, and restoring areas where trees have been cleared. Until recently, however, no bareroot oak seedlings were being produced in the state and there was little information to guide nursery operators. This study evaluated the potential of bareroot blue oak seedlings to survive and grow after outplanting. Results indicated that 1-0 nursery stock performed well in the field as long as seedlings were planted early enough in the season to take advantage of a favorable growing environment. Late lifting and long storage resulted in planting at a time when soils were already becoming dry and temperatures were hot. As a result, seedlings grew slowly or even died. Seedlings lifted early in the season (December) grew best. Either one or two months of storage had little effect on seedlings lifted at this time of year. However, seedlings lifted in January, February, and even early March performed adequately as long as they were in the ground by early March. In this study, root growth capacity was not a good predictor of subsequent field performance.     

林分生长模型研究的进展*

本文叙述了林分生长模型的发展及目前研究方向；评价模型的分类方法和各种模型的关系及应用范围，强调模型系的相容性及完备性原则，指出近代模型往往是一个森林系统，大都含有多个被预测的变量和说明变量，必须注意因子间的关系，用高次，多项式方程决不是好方法。因子间的“相互预报”是模型中的大问题，方程组之间的“循环估计”往往产生有偏估计。     

美国红橡木在粤北引种早期生长调查分析

为了探明南方红橡木(Quercus falcata)、北方红橡木(Q.rubra)和杂种橡(Q.hybrid)3个美国栎属树种在广东省的适应性,开展了苗期生长调查,并在广东省乳源天井山林场进行了引种试验。结果表明,3个树种间的苗高与地径差异显著,平均苗高为9.6～24.4 cm,变异系数为21.83%～36.89%,平均地径为0.31～0.41 cm,变异系数为20.08%～25.33%。引种1 a时的成活率超过71%,补植后的成活率超过90%。3个树种平均树高为32.6～34.1 cm,变异系数为37.94%～45.65%,平均地径为0.38～0.45 cm,变异系数为35.37%～45.85%,树种间的地径存在极显著差异。表明3个树种均能适应粤北山地气候与环境条件,但个体的分化较大。     

太行山阳坡樟子松的生长表现及发展前景

对太行山石灰岩区干旱阳坡引种了11a的樟子松的生长、开花结实及其对土壤的改良效果、水保效益进行了分析,结果表明,引种的樟子松比相同立地条件下同龄油松的树高平均提高了28.60%,地径平均提高了8.20%,林地持水量提高了23.9%。实践证明,樟子松是适宜在太行山阳坡生长的优良水土保持树种。     

Potential long-term growth gains from early clump thinning of coppice-regenerated oak stands

A study was established in the Missouri Ozarks to evaluate coppice regeneration of oak. Five years after a 32-year-old stand was clearcut and regenerated naturally through stump sprouts, the dominant sprout on each stump was identified based upon height. Treated plots were thinned to the single dominant sprout on each stump whereas control plots were not thinned. Twenty-five years later the largest 247, 371, 494, and 618 stems per ha were examined and height of the dominant sprout at age 5 was found to be strongly related to dbh at age 30 in both thinned and unthinned plots. However, in the thinned plots, the largest 494 stems per ha were on average 11%, 28%, and 58% greater, respectively, in height, dbh, and volume compared to similar dominant sprouts in unthinned plots. Logistic regression analysis was used to develop curves for the evaluation of potential gains from clump thinning. In this analysis, the average height of a stand at age 5 was used to estimate thinning gains at age 30.     

蒙古族传统家具的游牧特征

蒙古族传统家具是蒙古族日常生活的必需品之一。在广袤的蒙古高原上,辽阔的天然牧场及原始森林赋予蒙古族人民游牧为主的经济生活,草原上逐水草而建的蒙古包成为蒙古族的主要居所。以上条件形成了传统蒙古族家具的特有种类及其游牧特征。蒙古族传统家具的种类以箱型结构为常见,蒙古族传统家具的游牧特征体现在以下几个方面:就地取材;为适用于蒙古包而形体矮小;因需在不同的营地放牧,家具需在运输过程中可拆装与折叠;也由于频繁的运输,蒙古族传统家具部件粗大;彩绘与雕花的家具丰富了单一的生活色调。