Selection, propagation and cultivation of Pinus massoniana clones for pulp use

Based on the growth, wood property of the ortets, and rooting abilities of cuttings, 32 Pinus massoniana clones for pulp use were selected from forests of superior provenance, mixed families, and progeny test of seed orchard by two-step selection. The average height and DBH growth of three-year-old clones were 28.6% and 16.7%, respectively, higher than those from seedlings, and average gain of wood density reached 8.7%. Rooting rate of all these clones was over 80%, 28% higher than the clones selected by a single step. A cutting orchard of 0.33 hm² on the hillside was constructed to intensively produce cuttings according to the tests on construction methods, pruning, and fertilization. A total of 50,000 grade I, 37,500 grade II, and 62,500 grade III cuttings were collected per hectare of this cutting orchard each time, and were cut three times each year. With all the above techniques, 48 hm² of clonal forests for pulp use of those clones had been planted in five places in Fujian Province. Container stecklings are more likely to increase the planting survival rate. __________ Translated from Scientia Silvae Sinicae, 2004, 40(1): 64–69 [译自: 林业科学]     

Land tenure and farm management efficiency: The case of smallholder rubber production in customary land areas of Sumatra

This study assesses the impact of land tenure institutions on the efficiency of farm management based on a case study of rubber production in customary land areas of Sumatra, Indonesia. Using the modes of land acquisition as measures of land tenure institutions, we estimated tree planting, revenue, income, and short-run profit functions, and internal rates of return to tree planting on smallholder rubber fields. We find generally insignificant differences in the incidence of tree planting and management efficiency (defined as residual profits) of rubber production between newly emerging private ownership and customary ownership. This is consistent with our hypothesis that tree planting confers stronger individual rights, if land rights are initially weak (as in the case of family land under customary land tenure systems). On the other hand, short-term profits are higher on land that is rented through share tenancy. This result indicates that rubber trees are over-exploited under renting arrangements due partly to the short-run nature of the land tenancy contracts and partly to the difficulty landowners face in supervising tapping activities of tenants in spatially dispersed rubber fields. This revised version was published online in June 2006 with corrections to the Cover Date.     

Plantation Forests for Sustainable Wood Supply and Development in China

With the implementation of Natural Forests Protection Program, wood resource base in China is shifting from naturally grown forests to plantation forests. This paper reviews: 1) The evolution of Chinese decade-long reforestation program and its contribution to sustainable wood supply and development, and 2) impacts of "China's Natural Forest Protection Program and " Fast-Growing and High-Yield Plantation Program in China " on China's wood supply and sustainability. In addition, this paper highlights Chinese national researches on the integrated intensive management and utilization of the plantation resource.     

元谋干热河谷人工林的土壤养分效应及其评价

研究了元谋干热河谷地区人工林对土壤养分的效应,并选择了土壤有机质、全N、速效N、速效P、速效K作为人工林重建对土壤养分效应的指标,运用灰色关联度进行综合评价.结果表明:(1)12年生的桉树、苏门答腊金合欢、新银合欢类人工林土壤表层有机质、全N量其增幅高于10年生、6年生的人工林;除念珠相思林以外,人工林表层土壤有机质含量均高于所在试验点的对照地.混交林对增加土壤表层有机质含量的作用非常明显,其改良能力优于纯林;人工林土壤表层全N含量均低于1.0 g·kg-1;(2)速效N的变化规律与全N含量基本一致,速效P含量波动较大,土壤速效K含量比较丰富,pH值的范围在4.44～6.42之间;(3)灰色关联度分析的结果为赤桉 苏门答腊金合欢混交林对土壤养分的影响相对较大,其关联系数为0.651,影响最小的为念珠相思纯林,关联度系数为0.343.     

山桂花人工林3年生幼林期的施肥效应研究

在云南省孟连县进行了山桂花人工林3年生幼林期施用N、P、K、NP、NPK、NK、KP肥及不施肥(CK)的试验,以观测其施肥效应。通过对各施肥处理的山桂花3年生幼林期林木的胸径、树高、材积、树冠生长的观测、分析,表明在山桂花3年生的幼林期间,对其幼林生长的促进作用。以施用N肥的效果最好;其次是施用NP肥;再次是施用NPK混合肥;第4是施用NK肥;另4种施肥处理(含CK),对山桂花幼树生长的促进作用不大。试验结果还表明,在山桂花3年生的幼林期内,2.5年生基本是其幼林径、高生长的高峰期;而年生长节律显现的是6~10月雨季山桂花林木的生长量比11月~次年5月旱季大得多。     

粉煤灰复田立地欧美杨营养诊断研究

（１）叶片营养诊断表明，粉煤灰复田立地上欧美杨处于Ｎ素和Ｐ素亏缺状态，而Ｋ素较为充足，但施Ｋ有利于林木对Ｐ素的吸收，效应仍很显著。（２）相关分析表明，叶片Ｎ、Ｋ素浓度与生长呈正相关关系，而Ｐ则呈负相关关系，说明叶片Ｐ素含量与生长的关系实质上是一种“稀释效应”。     

酚醛树脂对人工林杉木木材的浸注性及其改善的研究

研究了低分子量酚醛树脂对杉木木材的浸注性及树脂在木材内的分布状态，并对苯醇抽提前处理法、常压浸渍和真空浸注的效果进行了评价。无论抽提处理与否，常压浸渍的树脂水溶液充填率为理论最大浸注量的10％左右，而真空浸注可达到90％以上，真空浸注效果明显；无论是常压浸渍还是真空浸注，抽提处理后树脂的浸注性有很大改善，但常压浸渍的效果不是非常明显。软X射线解析样品纵向树脂分布状态结果表明：无论是否经过抽提处理，在常压浸渍的情况下，树脂主要分布在样品的端部，而经过真空浸注处理，树脂注入的深度增加，尤其经过抽提处理后树脂可达到样品中心。由此可见，抽提处理和真空浸注并用，使树脂的分布状态有很大改善。另外，抽提处理后样品之间树脂分布的差异也趋于减小，即树脂在样品间的分布状态也有改善。用实体显微镜观察树脂在木材细胞腔内的充填状况结果表明：沿着样品纵向从端部到中心树脂充填率呈下降趋势，而且抽提处理的充填率比未抽提处理的高。     

蓝桉幼林施肥效应研究

在云南省保山市石灰岩红壤地区进行了历时4年的蓝桉幼林N、P、K不同配比的10种处理施肥试验。结果表明，施肥能明显促进蓝桉（Eucalyptusglobulus）幼林的生长；其中处理6、9、10增产效果极显著，树高增加16．31％～20．40％，胸径分别增加18．78％～19．21％，材积增加65．04％～70．19％。有机肥对蓝桉生长有促进作用，施过有机肥的处理10生长始终保持优势；磷肥是蓝桉增产的主要因素，每株施430g钙镁磷肥做底肥能使树高、胸径分别增加14．67％、15．87％，每株施215g钙镁磷肥则树高、胸径分别增加11．44％、7．83％；氮肥各水平间无差异，增产效果不明显；钾肥1、2水平间无差异，3水平可能过量，阻碍了肥效发挥。施肥能提高蓝桉生产的经济效益，较好的几个处理依次为6、9、2、10、3产出投入比值均大于对照。综合以上几个因素，N2P3K2为蓝桉幼林的最佳施肥方案。     

Microbial biomass in subtropical forest soils： effect of conversion of natural secondary broad-leaved forest to Cunninghamia lanceolata plantation

Conversion of natural secondary broad-leaved forest to Cunninghamia lanceolata plantation is a common management practice in subtropical China. In this study, we compared soil physico-chemical properties, microbial biomass in one natural secondary broad-leaved forest and two C. lanceolata plantation sites to estimate the effects of forest conversion on soil microbial biomass at the Huitong Experimental Station of Forestry Ecology, Chinese Academy of Sciences. Concentrations of soil organic carbon, total nitrogen, NH4^＋-N and microbial biomass carbon and nitrogen were much lower under C. lanceolata plantations as compared to natural secondary broad-leaved forest. Soil microbial biomass C in the first and second rotation of C. lanceolata plantations was only 53%, 46% of that in natural secondary broad-leaved forest, and microbial biomass N was 97% and 79%, respectively. The contribution of microbial biomass C to soil organic C was also lower in the plantation sites. However, the contribution of microbial N to total nitrogen and NH4^＋-N was greater in the C. lanceolata plantation sites. Therefore, conversion of natural secondary broad-leaved forest to C. lanceolata plantation and continuous planting of C. lanceolata led to the decline in soil microbial biomass and the degradation of forest soil in subtropical China.     

速生人工林桉树木材材色处理初步研究

试验用漂白剂、酸性染料和其他化学药剂,采用单纯漂白、单纯染色、先漂白再染色和化学着色等4种不同的方案对人工林桉树木材进行材色改良处理研究.结果发现:单纯漂白可获得一定的材色改良效果;硫化物类、过硫酸铵类的药剂配方漂白效果不明显;硼氢化钠类的药剂配方可得到一定的漂白效果;双氧水类、次氯酸钠类的药剂配方可得到很好的漂白效果.单纯染色比较难获得好的材色处理效果.采用先漂白后染色的方法,获得的材色过于鲜艳.采用化学着色的方法,可获得较理想的材色改良效果;草酸类药剂配方着色效果明显,可消除材色缺陷,根据不同的配方和处理工艺可获得从浅粉红色到红棕色的色调;用双氧水做活性剂,引入带发色团的化学药剂,材色改良效果明显,通过调整配方药品的浓度和处理工艺可获得从浅黄色到橙黄色的不同色调和较佳的材质.