Preparation and Properties of HBS Lignin from Masson Pine

In order to establish a new method for making cellulose and lignin from Masson pine, a high boiling solvent(HBS) pulping process with an aqueous solvent of 1,4-butanediol was investigated. Masson pine chips were pulped with a 70%—90% aqueous solution of 1,4-butanediol containing a small amount of a catalyst at 200—220 ℃ for 60—180 min. HBS Masson pine cellulose is suitable for making paper. Water-insoluble HBS lignin was separated from the liquor reaction mixture by water precipitation. The recovered high boiling solvent(RHBS) is able to be recycled as a pulping solvent, indicating that the HBS method is a pulping process of Masson pine which is energy saving, resources saving and pollution free. HBS lignin has a better chemical reactivity and a lower ash content than lignin sulfonate.

Water status of bare-root seedlings of Chinese fir and Masson pine

Water relation parameters of bare-root seedlings of Chinese fir (Cunninghamia lanceolata Hook.) and Masson pine (Pinus massoniana Lamb.) were measured and changes of root growth potential as well as field survival rate of both species were studied after the bare-root seedlings were exposed in a sunny field condition. The results showed that Masson pine had a lower osmotic potential (-2.07Mpa) at turgor loss point and at full turgor (-1.29Mpa), compared with Chinese fir (-1.80Mpa and -1.08Mpa respectively). The parameter Vp/V0 (63.27%) of Masson pine was higher than that of Chinese fir (58.03%). This means that Masson pine has a stronger ability to tolerate desiccation, compared to Chinese fir according to analysis of above water relation parameters. Root growth potential and field survival rate decreased with prolonging duration of exposure. The field survival rate of both species was reduced to less than 40% after the seedling being exposed only two hours. Water poten-tials of 1.60 Mpa and -1.70 Mpa were suggested to be critical values for Chinese fir and Masson pine respectively in successful reforestation.

A preliminary study on the characteristics of fogwater in the masson pine forest in Chongqing, China

The masson pine (Pinns massoniana Lamb.) forest of 2000 ha situated on Nanshan, the south bank of the Yangtze River near Chongqing, China. From 1982, some trees began to die. Since then, half of the trees have died and the whole forest is in danger. Prom November 1986 to January 1987, a study dealt with the characteristics of fogwater in that area was carried out, in order to explain the relationship between acid fog and masson pine decline. The results of our study showed that the acid fog might be responsible in part for the decline of the masson pine forest.

Studies on Electrolyte Conductivity and Activity of Dehydrogenase of Chinese Fir and Masson Pine Bare-Root Seedling under Water and Cold Stress

The electrolyte conductivity and activity of dehydrogenase of bare-root seedlings of both Chinese fir (Cunningha-mia lanceolata (Lamb.) Hook.) and Masson pine (Pinus massoniana Lamb.) under freezing and desiccation treatments were studied. The results showed that needle electrolyte conductivity of both species increase significantly after freezing treatment and there are no significant differences in needle electrolyte conductivity between the two species. The dehydrogenase activity (ARD) of fine roots of both Chinese fir and Masson pine was negatively correlated with increasing freezing and desiccation. The results suggest that both electrolyte conductivity and dehydrogenase activity could be used as quick indicators of Chinese fir and Masson pine bare-root seedling quality.

Microfibril angle variability in Masson Pine (Pinus massoniana Lamb.) using X-ray diffraction

The microfibril angle of fiber walls is an ultra-mieroscopic feature affecting the performance of wood products. It is therefore essential to get more definitive information to improve selection and utilization. X-ray diffraction is a rapid method for measuring microfibril angles. In this paper, the variability of microfibril angle in plantation-grown Masson pine was investigated by peak-fitting method. This method was compared with the traditional hand-drawn method, 40% peak height method and half peak height method. X-ray diffraction measurements indicated that the microfibril angle changed as a function of the position in the tree. The mean microfibril angle decreased more gradually as the distance increased from the pith and reached the same level in mature wood. The microfibril angle also seemed to decrease clearly from the base upward. Differences of angle-intensity curves between heartwood and sapwood were also examined.

Simulation of the biomass dynamics of Masson pine forest under different management

TREE submodel affiliated with TREEDYN was used to simulate biomass dynamics of Masson pine （Pinus massoniana） forest under different managements （including thinning, clear cutting, combining thinning with clear cutting）. The purpose was to represent biomass dynamics involved in its development, which can provide scientific arguments for management of Masson pine forest. The results showed the scenario that 10% or 20% of biomass of the previous year was thinned every five years from 15 to 40 years made total biomass of pine forest increase slowly and it took more time to reach a mature community; If clear cutting and thinning were combined, the case C （clear cutting at 20 years of forest age, thinning 50% of remaining biomass at 30 years of forest age, and thinning 50% of remaining biomass again at 40 years of forest age） was the best scenario which can accelerate speed of development of Masson pine forest and gained better economic values.

Nail Holding Performance of Self-Tapping Screws on Masson Pine and Chinese Fir Dimension Lumbers

Screw connection is a type most commonly applied to timber structures.As important commercial tree species in China,Masson pine and Chinese fir have the potential to prepare wood structures.In this study,the effects of the diameter of the self-tapping screw and the guiding bores on the nail holding performance on different sections of Masson pine and Chinese fir dimension lumbers were mainly explored.The results showed that:(1)The nail holding strength of the tangential section was the maximum,followed by that of the radial section,and that of the cross section was the minimum.(2)The nail holding strength of Masson pine was higher than that of Chinese fir.(3)The nail holding strength grew with the increase in the diameter of self-tapping screws,but a large diameter would lead to plastic cracking of the timber,thus further affecting the nail holding strength.Masson pine and Chinese fir reached the maximum nail holding strength when the diameter of self-tapping screws was 3.5 mm.(4)Under a large diameter of screws,prefabricated guiding bores could mitigate timber cracking and improve its nail holding strength.(5)Prefabricated guiding bores were more necessary for the screw connection of Masson pine.The results obtained could provide a scientific basis for the screw connection design of Masson pine and Chinese fir timber structures.

In Situ Generation of Copper Nanoparticles in Heat-Treated Copper-Containing Masson’s Pine as a Preservative Process for Sawn Timber

Heat-treated wood has good dimensional stability,durability,and color,but its susceptibility to fungal growth affects its commercial value.In this study,lumber harvested from mature Masson’s pine(Pinus massoniana Lamb.)was vacuum impregnated with a basic copper salt solution(copper hydroxide,diethanolamine,and polyethylene glycol 200)prior to heat-treatment at 220℃ for 3 h.Antifungal properties,surface chemistry,crystal structure and sugar contents were tested,compared with heat treatment alone.The results showed that the samples treated by heating without copper salt treatment showed poor suppression of fungal growth,the copperimpregnated heat-treated wood suppressed(100%)the growth of Botryodiplodia theobromae Pat.,Aspergillus niger V.Tiegh.,Penicillium citrinum Thom,and Trichoderma viride Pers.The combined results of X-ray photoelectron spectroscopy,X-ray diffraction and sugars analysis suggested that fungal inhibition by the heat-treated copper-bearing Masson’s pine was mainly due to the reduction of the metal salt by PEG200 at high temperature to generate copper nanoparticles.In addition,the reduced sugar content of the treated timber,and hence the nutrient substrate for spoilage microbes,reduced in the presence of the metal salts at high-temperature.This study has demonstrated an effective method of increasing low-grade wood’s utility and commercial value.

投加石灰石和菱镁矿对酸化土壤上马尾松(Pinus massoniana)林的影响

为了确定酸化森林生态系统的修复效果,在重庆铁山坪的马尾松林内设立了6个10m×10m的样地,其中2个作为对照样地,另外4个分别在土壤表面施撒石灰石和菱镁矿粉末,各有2个重复。在处理前和处理1a后的生长季末各进行了一次植被观测,协方差分析和多重比较的结果显示投加修复剂对马尾松生长的影响已经初步显现,马尾松的胸径增量和针叶平均长度都有显著的增加,而针叶中Ca、Mg元素含量也表现出显著的差别。另外,立木更新的变化、细根生物量的增加和物种多度的变化也较明显,总体来说生态系统有恢复的趋势。土壤上层细根的增加较快,这与在土壤表面施撒修复剂,上层土壤的化学变化较显著是一致的。而两种修复剂对生态系统的影响也表现出明显的差异,相对而言,施撒菱镁矿的效果可能会更好。由于土壤修复的效果是长期的,其影响观测还将继续下去。

Physiological responses of needles of Pinus massoniana elite families to phosphorus stress in acid soil

Pinus massoniana Lamb. is a major timber species widely planted in the South China, where the soil is acidic and deficient in phosphorus （P） due to fixation by aluminum and iron. Understanding the physiological responses to rhizospheric insoluble P is essential for enhancing plantation productivity. Thus, a sand culture experiment was conducted with four levels of P treatment （0, 5, 20 g insoluble P and 10 g soluble P）, and 11 P. massoniana elite families. Physiological responses were measured after two months of stress. Compared to the normal soluble P treatment, the insoluble P treatment significantly reduced the proline content and the APase activity in the needles, while it significantly increased the catalase activity by 1.3-fold and malondialdehyde content by 1.2-fold. Soluble protein content was unaffected by the treatments, but chlorophyll content was significantly lower in P-deprived treatment compared with soluble and insoluble P treatments. These physiological responses also exhibited highly significant variation among families （p 〈 0.01）. The findings suggest that increased catalase activities in the presence of insoluble P might be involved in the activation of an anti-oxidation defense mechanism that scavenges the reactive oxygen species elicited by the stress. And this response has a strong genetic control that can be exploited to identify desirable genotypes.

Microwave vacuum drying characteristics of Pinus massoniana wood

Microwave-vacuum （MV） drying characteristics of plantation Masson pine （Pinus massoniana） were studied experimentally for various levels of microwave radiation time, initial moisture content 0VIC）, vacuum level and wood thickness. The results show that the process of MV drying for wood can be significantly divided into a short accelerating rate drying period, a long constant rate drying period and falling rate drying period, and the second drying period can extend to levels of mean MC below the fiber saturation point. With the increase of initial MC and microwave radiation time, the drying rate of wood increases significantly. The vacuum level affects the drying rate in a slightly positive way. Within the range of 2 to 6 cm, the effects of sample thickness on the drying rate can be negligible.

Patterns of biomass,carbon,and nitrogen storage distribution dynamics after the invasion of pine forests by Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) in the three Gorges Reservoir Region

Masson pine stands infected by Pine wilt disease(PWD) in the Three Gorges Reservoir Region of central China were surveyed to quantify the immediate responses and subsequent trajectories of biomass,carbon(C),and nitrogen(N) in stand-level major ecosystem compartments.The biomasses of above-and belowground tree components,as well as of the understory,forest floor,and mineral soil(0–40 cm),were determined within each stand.C and N storage were also estimated for each ecosystem compartment.Overstory biomass decreased steadily with the extent of PWD infection.Understory biomass ranged from1.97 to 4.16 Mg ha,and the observed value for forest floor biomass was 12.89–22.59 Mg ha.The highest mean C and N concentrations were found in the stem bark and needles of Masson pine,respectively,while the lowest were found in the semi-to fully decomposed layer of the forest floor and stem wood of Masson pine,respectively.The C and N storage of aboveground trees,tree roots,and the aboveground ecosystem decreased with the extent ofPWD infection.However,the C and N contents of the understory,forest floor,and total mineral soil initially declined after PWD infection before recovering over the following several years.Those result concluded that the biomass,C,and N storage of different forest ecosystem compartments have experienced certain variations following the PWD epidemic.This is vital to understand the shifts in stand-level C and N allocation in PWD-damaged forest stands,as well as for predicting the responses of regional and global C and N cycling.

Early Monitoring of Pine Wilt Disease in Pinus massioniana based on Hyperspectral Data

We selected healthy Pinus massioniana for pine wood nematode inoculation experiments to get the spectral reflectance of healthy and infected Pinus mas- sioniana in different infection stages via a ground spectrometer （ wavelength in 350 - 2 500 nm）, and analyzed the changes in chlorophyll content at various periods. The original spectral reflectance of healthy and infected P. massoniana was significantly different in the middle and late infection stages, and the reflection peak and absorption valley in visible light region and near infrared region gradually weakened and even disappeared to a straight line. There was significant correlation rela- tionship between chlorophyll content of infected plants and spectral reflectance at the wavelength of 1 405 nm, and the quantitative inversion model of chlorophyll content was correspondingly established as follows： Car = - 1.74（X1~ ）2 ＋ 4. 72X1,~ - 0. 76. Through first-order derivative spectra at the wavelength of 593 nm, combined with quantitative inversion of the corresponding chlorophyll content, we can discriminate whether P. massoniana is infected by pine lt disease or not, especially in the early stages before disease features are visible to the naked eyes it has a good quantitative monitoring effect.

吸湿解吸循环过程中木材水分吸附特性

【目的】探究吸湿解吸循环过程中木材水分吸附特性,阐释湿度循环对木材细胞壁及其吸着水分子的影响机制,为木材的实际使用和合理开发提供理论依据和数据参考。【方法】以杉木和马尾松木材为试验材料,采用动态水分吸附分析仪在3或5次吸湿解吸循环(0%→95%→0%)过程中实时测定木材水分吸附数据,绘制水分吸着-解吸等温线,借助H-H模型对其吸湿平衡含水率进行非线性拟合分析。【结果】1)吸湿解吸循环前后,木材平衡含水率最大值呈降低趋势,其差值范围为0.21%~1.76%;初次循环过程木材吸湿平衡含水率低于后续循环过程,相对湿度40%~95%时尤为明显;2)随着吸湿解吸循环次数增加,木材单次循环所需时间减少,且降低幅度也明显变小;与块状试样相比,粉末状试样单次循环所需时间较少;3)初次循环过程木材吸湿滞后现象相比后续循环过程更明显,随着循环次数增加,吸湿滞后最大值减小,吸湿滞后率均值增大;4)H-H模型可用于分析吸湿解吸循环过程中木材水分等温吸附,其拟合度(R2)均高于0.996;随着循环次数增加,代表含有单位摩尔吸附位点的绝干木材质量(W)参数呈降低趋势,木材单分子层吸附水最大质量分数呈增大趋势,多分子层吸附水最大质量分数和吸附水总质量分数最大值均呈降低趋势。【结论】随着吸湿解吸循环次数增加,湿度循环对木材细胞壁的影响减弱:木材吸湿性能降低,其平衡含水率最大值呈降低趋势;单次循环所需时间减少;吸湿滞后现象减弱。

马尾松人工林碳储量密度控制图研建及应用研究

[目的]马尾松是我国重要的人工林树种,不但发挥着重要的经济效益,而且在固碳释氧,应对气候变化等生态服务方面发挥着重要的作用。开展抚育间伐,调控林分密度是人工林经营过程中的重要手段,而当前马尾松人工林抚育间伐存在“定性”不“定量”的问题,制约着经营目标的实现。本研究拟构建马尾松人工林碳储量密度控制图,实现马尾松人工林抚育间伐过程中的精准化。[方法]首先,以湖南省马尾松人工纯林为研究对象,基于森林资源连续清查(一类清查)数据,以Reineke自然稀疏模型为基础,构建湖南省马尾松基本密度控制图。其次,将碳储量等高线加入到基本密度控制图上,构建了碳储量密度控制图,增加了以碳储量调控为目标的密度调控功能。再次,基于所构建的密度控制图,以湖南慈利县为例,对马尾松人工林的林分密度合理性进行诊断,生成密度诊断图,并提出相关经营建议。[结果]湖南省慈利县(1)绝大部分马尾松人工林的密度高于合理密度区间,林木对有限的光照、温度、水分等自然资源产生强烈竞争,甚至有些林分会产生严重的自然枯死现象,亟待开展抚育间伐,降低林分密度;(2)少部分林分位于合理密度区间范围内,此时的林分能够充分利用自然资源,林木个体之间处于互相促进的状态;(3)少部分林分密度低于最优密度下限,此时的林地空间没有得到充分的利用,造成林地资源的浪费,亟待开展林下补植作业。[结论]本研究所构建的马尾松林分密度控制图,能够精准指导森林抚育,此外还能够对森林经营单位的林分密度合理性进行诊断,形成林分密度诊断图,进而为合理经营措施的制定提供依据。

林木自然纤维增强建筑工程混凝土综合性能研究

传统的建筑工程混凝土增强纤维以剑麻、黄麻或竹纤维为主,对林木自然纤维的应用案例较少。以马尾松林木资源为例,对马尾松松针纤维制备增强建筑工程混凝土的方法进行阐述,以试验形式对该马尾松松针纤维增强混凝土的综合性能进行分析。结果表明:经过质量分数2%NaOH预处理后的马尾松林木自然纤维增强混凝土能够显著提高混凝土的短期、长期力学性能,马尾松林木自然纤维掺量超过1.5%后,混凝土力学性能的提升不再显著。

Assessment of tree-ring mercury radial translocation and age effect in Masson pine:Implications for historical atmospheric mercury reconstruction

The tree ring has been regarded as an emerging archive to reconstruct historical atmospheric mercury(Hg)trends,but with the large knowledge gaps in the reliability.In this study,we comprehensively evaluated the Hg source,radial translocation and age effect of Masson pine(Pinus massoniana)tree ring at Mt.Jinyun in Chongqing,to assess the suitability of such tree ring as the archive of atmospheric Hg.Results showed that distinct variabilities among Masson pine tree-ring Hg concentration profiles.The Hg concentration significantly increased along with stem height(P<0.05),indicating the Hg in tree rings mainly derived from foliage uptake atmospheric Hg.We found a distinct age effect that the tree ring of young trees had the higher Hg concentration.Besides,we used the advection-diffusion model to demonstrate how Hg concentration shifted by the advection or/and diffusion in tree rings.The modeling results showed that the advection induced radial translocation during the young growth period of tree was a plausible mechanism to result in the tree-ring Hg record largely different from the trend of anthropogenic Hg emissions in Chongqing.We finally suggest that in further Hg dendrochemistry,better discarding the tree-ring Hg profile of the young growth period to reduce impacts of the radial translocation and age effect.

武夷山马尾松生长季净碳交换及其昼夜环境影响因子分析

马尾松作为中国东南部最大的有机碳库,在调节CO_(2)、维持生物圈碳氧平衡过程中发挥着重要作用。该文基于涡度相关观测数据,从生态系统尺度分析了武夷山国家公园马尾松2019年生长季的碳源汇变化特征与影响因子,并对不同条件下的光合参数进行了拟合推算。结果表明:(1)马尾松净生态系统碳交换量(NEE)的生长季总量为-593.06 g CO_(2)/m^(2);日尺度上,马尾松NEE的日变化特征均为“U”型,在12:00-14:00时碳汇能力最强;月总量上,马尾松9月碳汇能力最强(-94.55 g CO_(2)/m^(2)),而5-7月较弱。(2)光合有效辐射是日间碳交换的主导因子,两者呈显著负相关关系;土壤温度是夜间碳交换的主导因子,两者呈显著的二次函数关系。(3)光响应曲线表明,3月和7月马尾松生态系统的最大光合速率(Pmax)较高,而5月植被初始光能利用率(α)高;饱和水汽压差在1~2.5 k Pa时Pmax和α均较大,最适合马尾松进行碳吸收;土壤含水量的上升会引起生态系统呼吸(Rd)、α和Pmax上升,当土壤含水量过饱和时,Rd的增量与Pmax相近,植被净固碳量保持稳定。研究结果有助于提高对马尾松生态系统碳汇功能的全面认识。

北亚热带马尾松净生产力对气候变化的响应

掌握马尾松生产力与气候变化的关系,特别是在马尾松自然分布的北界研究生产力对气候变化的响应具有重要意义,以马尾松自然分布北界的河南鸡公山国家级自然保护区内的老龄马尾松林作为研究对象,根据河南信阳的马尾松生物量与树高胸径的关系,利用样地调查和年轮宽度推算出过去的30a中的生物量和生产力动态,并用当地的温度、湿度、降水、光照以及帕尔默干旱度指数5项气候因子与生产力做相关分析,在此基础上用多元逐步回归得到了气候因子与生产力的回归方程。结果显示:鸡公山马尾松林生物量从1980年的59.00 t/hm2逐步增加到2009年的254.75 t/hm2,30a中平均年净生产力为6.64 t/hm2;气候分析表明年净生产力与气候因子关系较为密切:上年8月降水、当年2月温度、3月湿度以及10月的光照和温度与生产力正相关,当年5月光照、10月的降水和湿度与生产力负相关,当年2月到9月的PDSI都与生产力正相关,并且在6月的相关系数最高。研究表明,北亚热带的马尾松生产力的年际变化主要是气候因素引起的,受当年生长季的长短和生长季的土壤水分可用性限制,在未来该地区升温增湿的条件下马尾松林的生产力可能会升高。

24年生马尾松生长、形质和木材基本密度的种源变异与种源区划

利用设置在浙江省淳安县姥山林场的24年生49个产地的马尾松种源试验,以研究和揭示已达主伐年龄时马尾松生长、形质和木材基本密度的种源差异和地理变异模式,通过聚类进行种源区划并选择优良种源。结果表明:马尾松生长、形质和木材基本密度皆存在显著的种源差异,种源胸径、树高和材积生长及树干通直度呈典型的纬向倾群变异模式,这种变异主要是由其产地水热资源条件差异引起的。较之于北部种源,南部的种源生产力水平高且树干通直。种源木材基本密度虽与产地经纬度相关性较小,但却与产地年均温、1月均温、无霜期和≥10℃积温呈显著的负相关。性状遗传相关分析结果显示,选择生产力高的速生种源可同时改良树干通直度,但会明显降低其木材基本密度。根据种源聚类结果,可将马尾松划分为南部、中部和北部3个种源区,并分别纸浆材和锯材筛选出19个和6个优良种源,这些优良种源主要来自马尾松的南部种源区,部分来自中部种源区。