石梓幼林生长与立地因子的关系

试验和调查研究表明:北纬23°30′以南为石梓适生地区,其年平均气温20.5—24.5℃,极端最低温>-1.5℃,年降水量1200—2200mm。适宜的生境为地形开阔、阳光充足的静风环境(旬平均风速<<2m/s)。要求土壤疏松、表层有机质>2％,全氮>0.1％,速效磷>0.25mg/100 g土,pH值4.5—6.9,土壤含水率10—24％。不同植被类型和不同坡位上的石梓幼林生长差异达显著水平。经相关分析,在一定范围内,石梓的生长与土壤pH值、水分、养分(N、P)的关系分别成显著和极显著的直线、幂函数、指数函数和S型曲线正相关。其中与速效磷的关系更密切。     

石梓生长规律的研究

研究证明:石梓天然林树高和直径生长有两个速生期,第一个在第10年左右,第二个在第40—50年。材积生长量则一直在上升,其生长旺盛期可延长50—60年;人工播种的苗木高、径生长在播种后第3个月出现高峰,随即下降。苗高生长峰期在第2—5(6)个月,其生长量占苗高总生长量的79—90％。苗径生长峰期有两个,主峰期在第2—4(5)个月,次峰期在第6(7)个月,两次峰期的生长量占苗径总生长量的72—80％,11年生人工幼林,树高生长高峰在第2年,胸径生长高峰在第4年,材积生长高峰在第7年。但树高在第8年后生长缓慢,胸径和材积正处在生长旺盛期。     

单叶省藤与石梓间种的经济效益分析

评价了13a经营期内5种采收方式下单叶省藤人工林的经济效益,分析了间种对上层林木生长收获的影响以及对林地经济收益贡献水平。研究结果表明:不同的初采年龄和采收间隔期对13a单叶省藤人工林经济效益具有重要的影响,其中单叶省藤以9a初采和4a间隔期的采收方式获得最高经济效益,净现值、内部收益率和收益成本比分别为20255元·hm-2、20 08%、1 38;单叶省藤种植后对上层林木石梓的生长与收获量产生不利影响,进而导致20年生石梓林分的纯收益和净现值比未间种时分别减少4000、1500元·hm-2。通过综合分析,5种采收方式对整个林地经济收益仍有较大贡献,林藤间种产生的林地增益水平和净现值增量分别为12 49%～91 10%、706～5145元·hm-2。     

云南石梓育苗技术研究

通过持续多年对云南石梓进行育苗试验,结果表明,云南石梓种子宜随采随播,不同种子催芽处理发芽率差异极显著,浸晒法＞温水浸种法＞浸沤法＞对照;育苗时间选择4月最佳,幼苗分床以具有1～2对幼叶移植为宜;苗木的生长可分为种子萌发期、扎根蹲苗期、苗木速生期和苗木慢生期,苗高速生期在7～10月,生长量占1年生苗木总生长量的86.8％,地径速生期在8～11月,生长量占1年生苗木总生长量的83.3％,依据各时期苗木生长特点采取相应的管理措施;全苗鲜重最能代表苗木的质量, D＞2.5 cm 、 H＞150 cm为Ⅰ级苗, D＝2.5～1.5 cm 、 H＝150～100 cm为Ⅱ级苗, D＜1.5 cm、 H＜100 cm为Ⅲ级苗。     

造林密度对云南石梓幼林生长的影响

通过对云南石梓不同造林密度4 a的生长影响效应进行分析,结果表明:5种不同造林密度(4 444,2 500,1 600,1 111,816株/hm2)对4年生云南石梓冠幅影响差异显著,对胸径、树高和枝下高的影响差异未达显著水平。胸径、冠幅生长量和径阶结构分化率(≥6 cm株数百分比率)随着密度降低而增大,枝下高随着密度降低而减小,树高生长量不随密度的变化而产生有规律的变化。培育云南石梓大径材,初植密度采用816~1 111株/hm2较为有利。     

Soil microbial biomass and population in response to seasonal variation and age in Gmelina arborea plantations in south-western Nigeria

We investigated the Effects of plantation development, seasons, and soil depth on soil microbial indices in Gmelina arborea plantations in south-western Nigeria. Soil samples were obtained from the soil depths of 0-15 and 15-30 cm from plantations of six different ages during the rainy season, dry seasons, and their transitions. We used plate count and fumigation-extraction methods to determine microbe population and microbial biomass carbon (MB-C) and nitrogen (MB-N), respectively. Plantation age did not affect microbial indices, implying a non-significant effect of plantation development on microbial communities. It could also imply that soil microbial indices had already stabilized in the sampled plantations. Seasonal variation and soil depth had significant effects on microbial indices. At 0-15 cm soil depth, mean MB-C increased from 50.74 μg g-1 during the peak of the dry season (i.e. March) to 99.58 μg g-1 during the peak of the rainy season (i.e. September), while it increased from 36.22 μg g-1 to 75.31 μg g-1 at 15-30 cm soil depth between the same seasonal periods. Bacteria populations and MB-N showed similar increasing trends. Correlations between MB-C, MB-N, microbe populations, and rainfall were positive and linear. Significantly higher microbial activities took place in the plantations during the rainy season, increased with soil wetness, and decreased at greater soil depth.     

Modeling diameter distributions of Gmelina arborea plantation in Omo Forest Reserve,Nigeria with Johnson’s SB

Diameter distribution modeling is an essential tool for obtaining reliable information on the structure, growth, and yield of forests. However, this tool has not been duly utilized in many forest plantations, especially in Nigeria. Thus, this article presents the effectiveness of using the Johnson S_B function for modeling diameter distributions of a Gmelina arborea plantation in Omo Forest Reserve, Nigeria. Fifty plots of 0.04 ha were randomly selected across three age series. All trees with DBH ≥ 5.0 cm in the selected plots were measured. Three fitting methods for the S_B distribution were compared: conditional maximum likelihood (CML), moments (MOM), and Knoebel and Burkhart (KB) methods. The parameter recovery model (PRM) was used to recover the parameters of the distribution. The assessment was based on Kolmogorov-Smirnov (K-S), mean square error (MSE), mean absolute error (MAE), and bias. The results showed that the underlying diameter distribution of the Gmelina arborea followed the Johnson’s S_B distribution fitted with MOM. The number of rejections by the K-S test was zero for MOM and CML. The mean K-S value for MOM was statistically different from CML and KB methods. The results obtained after recovering the parameters of the S_B distribution were comparable with the real distributions of the Gmelina arborea stand.     

Secondary forest regeneration under fast-growing forest plantations on degraded Imperata cylindrica grasslands

Natural regeneration of native tree species in the understoreys of fast-growing plantation tree species (Acacia mangium, Gmelina arborea and Paraserianthes falcataria) and in adjacent natural riverine forest and non-cultivated grassland areas were studied on Imperata cylindrica grassland sites in Riam Kiwa plantation area, South Kalimantan, Indonesia. Seedling and sapling densities as well as species composition and richness were assessed in a total of 35 ha by a systematic line plot survey.Floristic composition was similar in A. mangium and P. falcataria stands which differed distinctly from G. arborea stands and Imperata grassland area. Riverine forest was characterized by later successional species. In A. mangium and P. falcataria stands, a total of 63 species from 24 families were recorded. Seedling stock consisted merely of pioneer and secondary species, but also several fairly commonly occurring primary forest species. Euphorbiaceae was the most common family representing 42% of sapling and 29% of seedling densities. The most abundant regeneration occurred in A. mangium stands (4,706 seedling/sapling ha^-1), followed by P. falcataria (2,242 ha^-1) and G. arborea (554 ha^-1). Seedling recruitment was significantly lower in plots dominated by grass vegetation than those dominated by no vegetation or shrub vegetation. Breast height diameter and basal area of canopy trees as well as coverage and height of ground vegetation did not explain seedling/sapling density. Results show that plantation establishment with suitable fast-growing tree species facilitates recruitment of a variety of native tree species. This provides potential for rapid restoration of forest ecosystem and for further development of the mixed stands of fast-growing exotics and naturally regenerated native species.     

海南石梓在闽南山地的引种表现

介绍海南石梓在闽南山地的引种表现,通过对其开展相关试验,分析了它们的生物学特性、生态适应性以及山地造林生长情况,总结出其相应的栽培技术,为海南石梓作为珍贵用材树种在闽南山地推广应用提供科学依据。     

DRIS evaluation of teak (Tectona grandis L.f.) mineral nutrition and effects of nutrition and site quality on teak growth in West Africa

The objective of the investigation was to study the site variables controlling teak yield (Tectona grandis Linn.fil.) and to establish guidelines for the selection of high productivity sites in Benin, Côte d'Ivoire, Liberia, Nigeria and Togo. Depending on stand age, soil and region, between 70 and 90% of the variation in tree growth (site index, SI) could be explained by the supply of nitrogen, the root-available soil depth and precipitation. Diagnostic foliar analysis for a broad range of elements was carried out in all plantations with the exception of Nigeria. This showed that in 20% of the stands, various deficiency symptoms occur, and in an additional 40%, hidden demand of at least one nutrient is apparent. According to the Diagnosis and Recommendation Integrated System (DRIS), the most deficient nutrients besides N are Ca and P, while in 45% of all stands there is a relative Al excess. Recommendations for the evaluation and classification of site quality and the number of trees sampled for foliar analysis are given.     

贵州省建造石头梯田对限制水土流失的效益和风险分析

在贵州全境建造石头梯田来减少水土流失的现象十分普遍。但此项技术本身却有其固有的风险性。石头梯田通常比土质的梯田高,填在石头挡墙中的土壤的量更大,更易导致梯田的垮塌,也会减少梯田上部的土壤,降低土壤的养分和水分含量。石头的挡墙会威胁土地的长期生产力,因为一旦石头挡墙垮塌,所有的碎石就会堆积在下部的梯田中,使耕作十分困难。这种垮塌现象会通过增加地表径流而形成冲沟,使向下的沉积物运输增加。尤其是梯田之间的人工排水道使这种风险加剧。因为这种排水道使降水很难渗人土壤中,使土壤的保水和蓄水能力下降,从而造成作物的受旱。水流通过排水道输送的速度加快,很容易造成水流的汇集,增加洪水泛滥的可能性。由于建造了排水道,即使一般的暴雨,也会因为输送速度的加快而导致洪峰升高而成灾。因此,对水土流失的工程治理方式不应该取代、而应该与好的土地管理策略相结合。尽管土地利用方式有所改变,但通过采用新技术和坚持可持续发展的原则,在此类的土地上仍可获得最高的产量。图7表1参14。     

海南尖峰岭地区三种热带复合农林业体系效益研究

对海南岛尖峰岭地区热带珍贵树种母生、海南石梓人工林下种植经济作物益智、咖啡的复合农林业系统的生态和经济效益研究表明：复合系统能显著促进主林层乔木的生长,胸径生长速度比对照地高出４３％～１３４％,材积生长高出１８％～８１％,生物量高出５％～８６％;生物量净积累量９．５３～１５．２３ｔ·ｈｍ－２·ａ－１,为对照地的１．６～５．１倍;系统的光能利用率为０．７８％～１．２６％,为对照样地的１．９４～５．０４倍;同时系统具有较高的经济效益,林下种植益智后的产值可达１．８～３万元·ｈｍ－２·ａ－１,为对照地的５．２６～９．８２倍,投入产出比为１∶２．９３～１∶４．１７。     

热带松树种、种源引种试验初报

地处南亚热带的福建省长泰岩溪国有林场引种 5种热带松树的 7a栽培试验表明 :湿地松×加勒比松F1、F2 代生长均优于马尾松、湿地松 ;台库努曼松、马克西姆松与湿地松持平 ,各种源间初显差异。卵果松生长虽好 ,但抗逆能力差 ;墨西哥松基本不能适应新的环境     

石梓栽培技术的研究

本文报道了石梓栽培技术研究结果：23°N以南为石梓适生地区,其年均温20．5－24．5℃,极端低温＞－1．5℃,年降雨量1200－2000mm,年平均风速＜2．5m/s。适宜立地为地形开阔,阳光充足,土壤疏松,表土层含有机质＞2％,全氮＞0．1％,速效磷＞0．025mg/100g土,PH4．5－6．9,土壤含水率10％－24％,种子贮存以干燥器最好,贮存一芽率87．4％,催芽用浸晒和浸沤处理,比不处理提前10天发芽,发芽率提高9％－12％,不同子叶类型的芽苗分别移植,较混合移植的苗木合格率提高20．6％;评定了种子主要质量指标和效果良好的育苗,造林方法。技术综合指标;材积年均生长量＞12m^3/ha。     

Incorporation of slow-release fertilisers into nursery media

Field application of fertilisers is frequently ineffective in supplying limiting nutrients during establishment of plantation trees in highly weathered soils in the humid tropics. An alternative strategy for more effective delivery of nutrients to establishing trees was investigated in a field experiment on Kolombangara in the Solomon Islands. Under routine operational nursery conditions, cuttings of Gmelina arborea and seeds of Acacia mangium were planted into a coir (composted coconut husks) potting medium to which a range of rates of slow-release fertilisers had been applied. The growth performance of this nursery stock was then measured during the first 14 months following planting in the field. Incorporation of slow release fertilisers into the nursery medium significantly improved the growth of both species in the field, with more than 100% increases in volume index associated with the highest rates of slow release fertiliser application. This strong nutrient response during tree establishment was in sharp contrast to the absence of any effect from much higher rates of surface applied fertilisers that had been observed in previous field experiments on this same soil type. The placement of the slow release fertilisers within the immediate proximity of roots of the establishing trees, and the subsequent effects of this in increasing their abilities to compete with regrowth vegetation for site nutrient resources probably accounted for the high effectiveness of this fertiliser strategy in enhancing tree growth.     

林木叶片营养诊断研究进展

评述了林木叶片营养诊断中对分析结果解释方面的研究进展。指出了依靠养分浓度评价的局限性,介绍了以养分平衡理论为基础的 DRIS 法,及考虑叶重、叶中养分浓度及含量的诊断方法在林木叶片营养诊断中的应用。