红松人工林结实规律及影响结实量因素分析

通过对红松人工林结实规律及影响结实量因素进行分析可知:红松人工林结实量与林龄关系密切,红松人工林9 a左右开始结实,随林龄增长其结实株率和结实量逐渐增加,35 a后结实量达到高峰且种子质量优良,结实的周期变化为每间隔2~3 a丰收1次。林分密度对红松结实量影响较大,适宜的林分密度能提高红松人工林的结实量。     

攀西地区干旱河谷花椒丰产栽培试验

通过对攀西地区干旱河谷花椒品种,整地规格,造林密度,施肥量４因素正交试验,结果表明：在海拔１８００￣２４００ｍ河谷地带栽培大红袍５年生单株结实量比正路椒,青椒分别高２０．４％和３２．６％;整地规格,株行距对结实量影响达１％显著水平;施肥量对结实量影响不显著。文章阐明了攀西地区干旱河谷建立花椒丰产园的栽培技术方案;为该区域推广和经营花椒经济林提供优化模式。     

不同密度的樟子松母树林结实情况调查

探讨樟子松母树林结实多少的原因,找出影响母树结实的主导因子,为合理经营利用母树林提供科学依据。现将连续两年(1986—1987年)对不同密度的母树林结实量调查结果报告如下。     

滇西云南松母树林结实性能的研究

１０余年来在腾冲县古永林场对滇西地区云南松母树林的结实性能进行了试验研究。经观测和统计分析，结果表明：云南松优良林分经疏伐营建的母树林能够促进林木的生长发育，提高母树的结实量和种子品质。１９９３～１９９５年试验林的平均单株结实量和单位面积结实量分别是对照的３９倍和１３５倍，１９９４年种子的发芽率和发芽势分别比对照高６３７％和２０２％；母树的结实性状较为稳定，个体间具一定程度的偏雌和偏雄现象，其单株结实量的频率分布呈对数正态分布〔ＬＮ（μ、σ２）〕，在母树林分中结实少的个体较多，而结实多的个体较少；一般隔２～３年出现一次大年，大小年间结实量差异极大，大年是小年的３６２倍；滇西地区产的云南松球果和种子相对较小，千粒重为１３６４０ｇ，有效产量为结实量的７０％左右；现行良种价格已阻碍了良种的生产，据估算，较合理的价格为１８０元／ｋｇ左右，需尽快进行价格调整，以利于良种的推广和应用。     

红松果材兼用林适宜密度控制技术研究

利用近50年的系统定位观测资料,分析红松果材兼用林不同林分密度与直径、树高、冠幅等主要测树因子的关系.结果表明:在中等立地条件下(14地位指数),最佳的林分密度经验式为N=21 182×D-1.1827.通过对现实林分的最佳密度调控,可改善林分质量,与对照比提高林木直径连年生长量15%～20%;提高树高连年生长量约5%左右,可大大缩短大径材的培育年限.通过对不同林分密度条件下的植被多项因子,土壤物理、化学性质测定与分析得出:林下植物物种多样性以及生物产量,随林分密度的增大而降低;土壤主要营养成分及土壤物理性状则有随林分密度降低而改善的趋势.历经20余年对红松果材兼用林和人工红松大径材培育的试验结果分析表明:林分结实量与林分密度、林龄有直接关系.在适宜的林分密度下,在丰年后的冬季对具备截干条件的林木截去3～4枝以上主干,可人为促使林木形成多头(叉干),达到增加林木结实部位的目的,可明显提高林木结实量,改善林木质量,与对照比39年生林分一个丰年可提高结实量39 kg·hm-2,净增产值约780元·hm-2.     

杉木母树林遗传型疏伐和提高种子产量技术研究

为提高杉木种子产量和提供经过初步改良的优质种子,应在优良种源区选择１０～２０年生Ｉ类林分,通过疏伐建立采种基地示范林。疏伐强度随林分密度,林龄,郁闭度和立地条件而定,建立母树林要注意确定位置,隔离和母树选择。二次疏伐,间隔５年左右,强度为６０％～７０％,最终郁闭度为０．５,保留株数每公顷为３９０～４２０株左右为宜。研究结果表明,母树生长量,结实量有显著的增加。     

沙地樟子松人工林结实影响因素研究

为了对沙地樟子松人工林的结实及良种生产提供帮助。本研究分别设置不同林龄、立地条件、林分密度、施肥量等试验处理,通过观察其结实率、球果数量、种子及球果质量等指标,分析不同试验处理下樟子松人工林的结实情况。结果表明,随着樟子松林龄的增大,结实株数和球果数量不断增加,球果及种子质量也不断提高;当林分密度为667株·hm^-2,樟子松人工林结实最好;合理施肥会促进樟子松人工林结实,且樟子松人工林在丘间地的立地条件下结实最好。     

杉木母树林遗传型疏伐和提高种子产量技术研究

为提高杉木种子产量和提供经过初步改良的优质种子,应在优良种源区选择１０～２０年生Ⅰ类林分,通过疏伐建立采种基地示范林。疏伐强度随林分密度、林龄、郁闭度和立地条件而定。建立母树林要注意确定位置、隔离和母树选择。二次疏伐,间隔５年左右,强度为６０％～７０％,最终郁闭度为０５,保留株数每公顷以３９０～４２０株左右为宜。研究结果表明,母树生长量、结实量有显著的增加。     

湿地松种子园疏伐试验及效果分析

根据子代测定结果和当代表现等因子对湿地松种子国进行疏伐,使种子园的结实量成倍增加,强度伐的结实株百分率为62％;中度伐的为39％,轻度代的为28％,不疏伐的为22％,单株产种量的比例为:不疏伐100％:轻度伐120％:中度伐200％:强度代400％;每公顷产种子量的比例为:不疏伐100％:轻度代119％:中度伐208％:强度伐411％。当种子园进入结实盛期时,每公顷保留120—150株是合理的,如果无性系的营养生长和生殖生长能力特别强,每公顷保留90—120株即可。当具有结实能力的母树直径达30cm以上,冠幅达8—10米时,每株年产种子0.5—1.5公斤,每公顷年产种子60—150公斤是完全可以达到的。     

樟子松母树林不同疏伐强度对结实量的影响

樟子松是辽西北地区防沙治沙优选树种,生产上存在良种缺乏的问题。为了提高樟子松母树林结实量,以付家林场30～35年生樟子松母树林为研究对象,探讨疏伐强度对母树林结实量的影响,结果表明:当樟子松母树林处于中龄林时,对初植密度4 m×5 m的母树林采取重度疏伐,保留密度为8 m×8 m,即每公顷保留150株,樟子松母树林球果数量和质量达到最佳。该研究结果为辽西北地区樟子松母树林管理提供技术支持。     

湿地松林分间伐对材种结构的影响研究

根据间伐8年后的湿地松林分生长和主伐造材调查结果，建立了胸径和断面积等与林分保留密度及本底断面积的回归关系，分析比较了不同间伐强度对林木径阶分布和造材材种结构的影响效果。研究结果表明，间伐后林分保留密度对林木胸径和断面积生长以及材种结构等均产生显著影响；尾径20cm及以上规格的材种出材率随间伐强度增大而增大，而14cm及以下规格的材种出材率则随间伐强度的增大而减小。不同伐对照总的出材量虽比间伐的大，但增加的部分主要为较小规格的材种。     

落叶松人工林威布尔分布参数与林分因子模型的研究

以落叶松人工林２５８块标准地为材料，求解了各标准地威布尔分布概率密度函数参数。多数普遍随上层高、直径的增大而增大，随密度增大而降低，据此构建林分因子与参数、参数间拓广Ｒｉｃｈａｒｄｓ模型。通过精度、显著性、适用性、断面积平均直径等检验，参数模型与密度、上层高、直径模型结合最佳。模型可动态预测林分株数分布，为森林抚育间伐设计各生长阶段间伐方法、强度，预测林分蓄积等提供依据。     

树种各疏密度条件下密度与直径的关系

本文以杉木人工林和落叶松天然林标准地数据为材料,应用D=aN~bP~cS~dH~e数学模型进行计算分析,并从理论上证明,当同一树种的树高一定时,疏密度和株数相同,各地位指数(级)林分平均直径一致。为森林的抚育间伐,林分直径生长的预测、预报,确定林分工艺成熟龄及森林调查设计等提供了理论依据和重要参数。     

思茅松人工林林分密度控制图的编制与应用

在思茅松人工林集中分布的西双版纳、思茅地区的 10个县 (市 ) ,按照立地条件、年龄、郁闭度、生长状况等的不同 ,设置 16 6块标准地 ,用以编制林分密度控制图 ,包括等树高线、等直径线、最大密度 (饱和密度 )线、等疏密度线、等自然稀疏线等 5条曲线 ,根据密度控制图可以求算林分蓄积量、疏密度、优势高 ;可以求算林分间伐量、间隔期进行间伐设计 ;可以预测各生长阶段的平均胸径、生长量等。经检验等树高线精度为 96 1% ,等直径线精度为 97 8%。     

不同间伐强度对云南松人工林生长影响的研究

在云南省石屏牛达林场小白得林区,对造林密度为4 464株/hm2的14年生云南松人工林,设置了伐除林分中林木株数15%、25%、35%、50%的4个间伐强度试验,以研究不同间伐强度对云南松人工林生长的影响。通过对不同间伐强度间伐3年后林木的胸径、树高生长量和林分单株材积以及单位面积活立木蓄积生长量的测试分析,提出该云南松人工林幼林期最佳的间伐强度为35%。     

Natural thinning and structural patterns of intermediate cutting intensity in a Cunninghamia lanceolata stand

In the intermediate cutting intensity experiment of a Cunninghamia lanceolata plantation for 20 years, the changing pattern of natural thinning in these stands, with different intermediate cutting intensities, was studied. The relationship between the number of trees removed by natural thinning and stand density and site conditions was explained. The mathematical equation M = K ₁·K ₂ of natural thinning lines of C. lanceolata stand density management maps was tested and the relationship of diameter, height and canopy structure of stands with different intermediate cutting intensities are proposed. Our study of natural thinning in these stands indicates that the starting and peak periods of natural thinning in the check and slightly thinned plots were both early. The amount of thinned wood was large and the course of thinning proceeded continuously. The three levels of thinning: the slight thinning period, the intensive thinning period and the continued thinning period could be divided on the basis of the amount of thinned wood. Natural thinning would be a very long process without artificial interference. The starting and peak periods of thinning in the middle and strong intermediate felling are both late and present intermittence. Their thinning stages were not clearly evident. Through our studies, we also discovered that stand density and site conditions had important effects on the number of dead and dying trees, but that density was more important than site conditions. By way of tests, the relative error of the mathematical equation of natural thinning lines of C. lanceolata stand density management maps was 3.91% and the precision was relatively high. The practical test results of the stands, given different intermediate cutting intensities and different site indices, show that the relative error of the check plots was 5.23%, while the relative errors of the other tested items were all < 5%, well within the allowable experimental error. The mathematical equation was comparatively practical. The study demonstrated the distribution laws of diameter and height classes of the stand at different intermediate cutting intensities. From this study we also obtained the growth differences and changing dynamics of the height to the first branch, canopy length and relative canopy height of the stand at different intermediate cutting intensities and various related patterns with an increase of stand age and proposed a mathematical model relating stand age and the single-tree periodic volume increment. __________ Translated from Scientia Silvae Sinicae, 2006, 42(1): 55–62 [[译自: 林业科学]     

湿加松F2代采穗圃修剪促萌试验

对湿加松F2代母株进行修剪促萌试验,结果表明,最好的修剪方式是截顶,主茎留高约10cm,从基部剪除生长细弱且过密的侧枝;对比较粗壮的侧枝,采取截顸,侧枝剪口与主茎的剪口保持在同一水平面,控制分枝级数到3～4级,形成主茎短、侧枝长的平台状植株。以此种方式修剪的母株,保存率高且萌穗数量多,保存率达到96．7％,3个月后平均每株产萌稳95．8条。     

拯救伐与封育油松林的研究

对低质油松中龄林进行拯救伐而后封山育林5a的试验结果表明:对确无培育前途,但具有天然更新能力的油松中龄林,进行拯救伐而后严加封禁,能达到以封代造、恢复森林植被的目的,并且,比人工造林投资小。     

核磁共振法测定光皮树优树果实含油量的研究

采用核磁共振仪分析21株光皮树优树样品,平均果皮含油量为54.84％,标准差变幅为0.21％ ～0.92％,变异系数变幅为0.40％ ～ 1.52％;种子含油量为10.9％,标准差变幅为0.06％ ～0.22％,变异系数变幅为0.63％ ～ 2.18％,采用核磁共振法测定光皮树果实中的含油量精度较好.与索氏提取法相比,...     

Quantitative stand structure of woody components of homestead forests and its implications on silvicultural management: a case study in Sylhet Sadar, Bangladesh

This study determined existing quantitative stand structure and its implication on silvicultural management of homestead forestry. The results showed that fruit and timber species have importance values of 57% and 43%, respectively, in the study area, which is in contrast to the commonly held view of absolute domination of fruit species. The fruit species were only moderately dominant over timber species in relation to the quantitative stand structure of homestead forests. Two fruit species, Mangifera indica and Artocarpus heterophyllus, contribute about one third of the stand structure, while amongst the timber species Samanea saman and Albizia spp. are the most important species. A simulated evaluation of soil expectation value of homestead forest showed that the existing stand structure would not maximize the financial gain perpetually, in contrast, the quantitative stand structure could be effectively regulated to maximize grower benefit without compromising the existing biodiversity. Optimization of the quantitative stand structure of homestead forests could be achieved by changing the species composition, specifically by increasing the percentage of commercially valuable species like Michelia champaca, Tectona grandis, Artocarpus chapalasha, Gmelina arborea, Litchi chinensis, Citrus grandis, Psidium guajava, Lagerstroemia speciosa, Swietenia mahogany, etc., reducing the percentage of species like Mangifera indica, Artocarpus heterophyllus, Cocos nucifera, Samanea saman, Spondias pinnata, Phoenix sylvestris, etc., and eradicating species like Lannea coromandelica and Ficus benghalensis. It was estimated that the optimal relative density of fruit and timber species that would generate optimal financial benefit would be 40.4% and 59.6%, respectively.