向云南同行请教:云南有否天然分布的海南粗榧?

看了《云南林业》1987年第2期刊登的《宁蒗县发现三尖杉》一文后,不禁引起我的一些联想。约在10年前,我曾受领导的委托,调查三尖杉属一些树种的地理分布而到云南了解情况。当时,在云南省林业科学研究所、中国科学院昆明植物研究所和云南林学院的专家老师的帮助下,我查阅了许多三尖杉属植物标本,初步的结论是:海南粗榧可能是海南岛的特产,云南并无天然分布。然而,过去的资料一直记载,云南省的富宁和麻栗坡也有海南粗榧分布,连1982年出版、由中国林科院等单     

两种三尖杉属植物的遗传多样性研究

以种子的胚乳为材料,采用等位酶凝胶电泳技术,分析了高山三尖杉和粗榧两种三尖杉属植物的遗传多样性特征。结果表明,高山三尖杉和粗榧的遗传多样性水平较低,其多态位点比率均为0.273,平均每个位点的等位基因数分别为1.364和1.455,平均期望杂合度分别为0.092和0.101,观察杂合度分别为0.074和0.093;内繁育系数分别为0.194和0.086,均存在一定的内繁育现象。结合已报道的三尖杉属其他植物的遗传多样性研究结果,认为:三尖杉属植物低水平的遗传多样性是它们极度濒危现状的反映。建议将三尖杉属的全体植物列为国家重点保护野生植物,以利进一步加强对三尖杉属植物保护的力度和宽度。同时指出,三尖杉属植物的内繁育系数与其自然分布范围大小呈正相关,自然分布范围小的物种比分布范围大的物种具有更为严重的内繁育现象。     

濒危植物篦子三尖杉的群落特征

研究了云南、贵州和江西自然分布的8个篦子三尖杉群落。群落共有微管属植物108科,235属,336种。篦子三尖杉在群落中是主要层的共优种或伴生种,但随着生境条件不一致,这些篦子三尖杉生长地的植物群落类型也各不相同。群落组成上以樟科和蔷薇科等为主要优势科,山胡椒属和荚蒾属等属为主要优势属,伊桐、灯台树、木姜子、八角枫、短梗大参、大叶方竹、毛竹等是主要优势种;群落外貌特征同亚热带常绿阔叶林近似,生活型组成以高位芽植物为主, 高位芽植物(Ph.)、地上芽植物(Ch.)、地面芽植物(H.)、隐芽植物(Cr.)和一年生植物(Th.)分别占62.78%、12.67%、9.73%、12.29%和2.53%。叶级以微型叶为主(68.49%),无大型叶和巨型叶。叶质以纸质叶所占比例最大(55.89%),膜质叶最小(4.93%)。叶型以单叶为主(76.99%),全缘叶和非全缘叶近相等;从群落结构上看,8个群落的乔灌木个体在水平空间均呈集群分布状态,而群落以高于3.5 m以上的层次在群落中占优势, 平均盖度为68.71%。从目前的静态生命表看,道真县、江口县、台江县、镇远县的篦子三尖杉种群属于增长型种群,而芦溪县、凯里市、屏边县和新平县的种群属于稳定型种群;此外,不同群落之间具有物种多样性水平明显不同,群落之间的共有种少,相似程度较低等特点。     

云南拟单性木兰的地理分布与气候因子的关系

在广泛收集云南拟单性木兰的地理分布资料及其分布地气候资料的基础上,利用温暖指数WI、寒冷指数CI、湿度指数HI及其他气候指标,分析了该树种的地理分布与气候因子的关系,结果表明:云南拟单性木兰是一种喜欢温暖而具有一定的耐寒性,喜欢湿润而不耐旱,喜欢年均日照时数少而偏中的亚高温植物;气候指标对其地理分布作用的次序是热量因子>水分因子>日照因子。     

滇藏杜英适生环境及果实应用前景初探

滇藏杜英系杜英科杜英属植物,果实又名克地老、野桃子,为多年生常绿乔木。云南主要分布在保山、德宏、思茅、临沧、西双版纳等地、州;是杜英属在云南分布较广的一种植物。除我国云南、西藏有分布外,印度、缅甸、泰国等也有分布。滇藏杜英一般生长在海拔800—2400米的沟谷、山坡常绿阔叶林中年降雨量1500毫米左右,年均温在14—20℃的地区。在阳光充足、土层深厚、土壤疏松的酸性土壤上生长良好。其生长范围极广,阴坡、阳坡、土壤贫瘠的地方均可生长。     

广东仁化篦子三尖杉种群及其生境特征研究

用HOBO温湿度记录仪,于2013年对广东仁化长江的篦子三尖杉(Cephalotaxus oliveri)种群生境进行了为期1年的监测,同时测定土壤的理化特性、光照强度、植物叶片生理生态特性和种群结构。结果表明:生境年均气温13.854℃,年均相对湿度96.317%;土壤pH 5.49,有效钾含量(742.50 mg/kg)较高;林内叶面光照强度不足旷地的15%;叶片SPAD值约60,净光合速率为2.85~3.53μmol/(m2·s)(以CO2计),蒸腾速率0.36~1.43 mmol/(m2·s)(以H2O计),其中7月测定的净光合速率和蒸腾速率显著低于同属植物三尖杉(C.fortunei);篦子三尖杉种群的径级、高度和年龄结构均表明,种群目前虽处于增长阶段,但因缺乏4年内的幼苗,而这可能与2008年南岭地区的冰灾影响关系密切,推测40年后将趋于衰退,为此应加强该种群的就地、迁地保护。     

中国竹亚科植物空间分布及多样性研究

以竹亚科植物为研究对象,以相关文献为资料来源,从县级尺度上揭示了中国竹亚科植物分布范围和多样性中心。中国竹亚科植物广泛分布于秦岭以南的大部分地区,此亚科中的33个属的分布范围及多样性中心有差异,其中刚竹属是中国分布最广的属,贡山竹属是中国分布最狭窄的属,玉山竹属等13个属的多样性中心在云南,另有15个属可分布到云南,云南可能是中国竹亚科植物的起源中心。     

组分多度的相似相异百分率

根据组分组度比较分析的概念，建立了组分多度相似相异是分率的计算公式和两个详细不同的相似相异等级标准。根据对三尖杉属（Ｃｏｐｈａｌｏｔａｘｕｓ）在云南的分布格局间的样和性分析，表明发多度比较分析具有分析严密、计算简单和结果直观等优点。     

抗癌植物三尖杉

三尖杉属三尖杉科三尖杉属常绿乔木，叶形似杉，但柔软不刺手，枝端冬芽呈三个排列，春来小枝分三叉生长，故名三尖杉。三尖杉常自然散生于海拔500～1100米的山涧潮湿地带，属古老孑遗植物。该树种木材坚实，纹理直，结构细密，为高级家具、室内装饰良材。种子可榨油，出油率高，供工业用，还是润肺、止咳、消积的良药。因三尖杉的根、茎、皮、叶内含多种生物碱，对治疗血癌（白血病）和淋巴肉瘤有特殊的疗效，故近年来名噪医学界。     

贡山三尖杉

在云南省贡山县独龙江流域的马库、石灰窑一带,生长着一种云南独有的抗癌珍稀树种——贡山三尖杉。贡山三尖杉(Ceplzalotaxccs lanceolata)三尖杉科三尖杉属,本科仅有三尖杉一属,在拉丁学名中:Ceplzalotaxccs为聚成头状,种附加词lanceolata为披针形,指贡山三尖杉的叶为披针形,雄球花聚成头状的意思。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.