Effects of active pasture,teak (Tectona grandis) and mixed native plantations on soil chemistry in Costa Rica

In this study soil samples were taken from the O/A and B horizons of undisturbed forest, active pasture, and 8- to 12-year-old teak and mixed native plantations. Samples were analyzed for K, Ca, Mg, soil organic carbon, pH, exchangeable acidity, bulk density, and compared with a fertility equation. Bulk density was significantly lower in the undisturbed forest than other land uses, suggesting that after approximately 10 years of growth neither plantation lowered bulk density significantly from that of the active pasture. Teak plantations had significantly higher Mg and K (B horizon) and Ca (O/A horizon) concentrations than the undisturbed forest. This trend suggests that exchangeable base concentrations increase when land use changes from undisturbed forest to pasture, then pasture to plantation, with the most pronounced effect of this in teak plantations exhibiting more high fertility plots than other land uses. Soil organic carbon concentration was similar for all land uses except for a significantly lower concentration in teak plantations than in active pasture (O/A horizons). These results suggest that teak plantations may be advantageous for increasing soil fertility but, with respect to restoration of undisturbed forest conditions, present significant deviations in soil chemistry. Options for improved plantations soil management are discussed.     

Growth and mineral nutrient analysis of teak (<Emphasis Type="Italic">Tectona grandis</Emphasis>) grown on acidic soils in south China

Teak (Tectona grandis L.f.) is widely planted in the world due to its high market demand, economic, ecological and social value. Its plantations have mostly been established and expanded into sites that are acidic to severely acidic in southern China. But, there are no available and specific evidence-based nutrient management techniques. To better recognize and understand the relationship between teak tree growth and nutrient content in the foliage and soil and establish nutrient norms are critical to optimally manage these young plantations. We studied the foliar nutrient and soil chemistry in 19 representative teak plantations aged 5–8 years. Regression analysis indicated that the mean annual increment of teak volume was linearly and positively correlated with foliar N, Ca, Fe and B concentrations, with soil base saturation percentage, available P and Zn concentrations, and negatively correlated with soil Al concentration. Only if the Ca and Mg contents in soil were enhanced, could the increase in soil base saturation percentage benefit teak growth. A revised classification of low-and high-yielding stands was established by using a sorting method of principal components over 6 foliar macro and 8 micro elements in a Diagnosis and Recommendation Integrated System (DRIS). Specific DRIS norms for teak plantations in acid soils were derived. The nutrient balance of N, P, K Ca, Mg, Zn, B with Fe or Al, Ca with Mg, and Fe with Al provided a key to promote the growth of teak in acid soils. Meanwhile, soil Zn was also found as a primary trace element that affected teak growth in this study.     

京北山区人工刺槐水源涵养林主要养分元素含量特征分析

北京北部山区刺槐水源涵养林生态系统的总生物量(包括乔木层、灌木层、草本层和枯落物层)为26 301kg/hm2。刺槐林不同器官中各养分元素的含量差异较大,在叶和枝中各养分元素的含量顺序相同,均是Ca>N>K>Mg>P;在干中的含量顺序是N>Ca>Mg>K>P;根系中的养分元素除Ca随着根系直径的增加呈升高的趋势外,其余的养分元素的含量随着根系直径的增加而降低。刺槐林生态系统5种养分元素的贮存量为514.90 kg/hm2,其中,乔木层中的养分贮存量占总贮存量的85.5%。若以各养分元素在生态系统生物层中的贮存量来计,则Ca的贮存量最大,P的最小,不同养分元素贮存量的顺序为Ca>N>K>Mg>P。     

寒温带兴安落叶松林生态系统养分特征

森林生态系统营养元素的积累和循环是维护森林生态系统健康稳定的关键因素之一,对森林生态系统的存在和发育具有重要的意义。文章对寒温带兴安落叶松林生态系统的养分输入、贮藏和输出特征进行了初步的研究。结果表明:林冠对Ca、Mg、Fe总体呈现吸附趋势,其中对Ca元素的吸收最为显著;P、K元素则是经林冠后含量增加;微量元素Mn的输入主要来自降雨,林冠对其的利用很少;各元素在植物和土壤中贮存的比例存在较大的差异,其中Ca、Mg、Mn主要贮存于植物体中,其贮存量约占86.06%、84.25%和94.18%;植物体中P、K的贮存量约占总贮量的44.62%和58.82%;Fe主要贮存于土壤当中,植物体中Fe的贮存量仅占总贮存量的9.16%;在兴安落叶松林生态系统中径流输出是养分元素主要的输出途径,其中P、K、Mn元素的年输入量大于输出量,生态系统中养分含量呈累积增加趋势,而Ca、Mg、Fe元素的输出量大于输入量,表现为养分流失,其中Ca的损失量最大。     

Nutrient content of standing crop and biological cycling in Pinus patula ecosystem

Nutrient contents were estimated in different components of Pinus patula trees growing in six stands ranging from 8 to 34 years of age in the Darjeeling hills, India. The highest concentrations of most nutrients were found in the leaves but the maximum nutrient pool was contained in the bole which accounted for about 58 to 85% of the total aerial contents of different elements. Among the nutrients, N concentration (2.2%) was the highest, followed by Ca Mg K P Na. Nutrient contents in the standing crop increased with stand age and were nearly 2102 kg Ca, 1911 kg N, 875 kg Mg, 478 kg K, 285 kg P and 82 kg Na per ha in above-ground biomass of the 34-year-old stand. The annual uptake of N is highest but its accumulation in the standing stock is lower than that of Ca in the 34-year-old stand. The uptake and storage of Mg closely resembled those of K. Nutrient return and release were also determined to establish biological cycling in the 34-year-old P. patula ecosystem. Litter is resistent to decay and the forest floor retained a very rich nutrient store over the mineral soil. Turnover rates and times for nutrient fluxes showed the higher efficiency of the return pathway and the greater stability of the soil pool.     

泡桐人工林生态系统养分循环的研究

桐粮间作生态系统在黄淮海平原地区具有广泛的代表性。研究比较泡桐的养分循环律,对挖掘其生产潜力,保证高产高效益,维持系统的稳定和平衡具有重要意义。一、试验地概况试验地位于河南省扶沟县江村乡泡桐试验场,东经114°32′,北纬32°0′,属暖温带季风气候,年均日照2361h,年均太阳辐射59.48kcal/cm~2,年均温度14.4℃,年均降水量678.5mm。≥0℃积温5272.8℃,≥10℃积温4692.6℃,年无霜期215d。该区属黄河冲积平原,土壤为沙壤土,pH为7.5,土层深厚,地势平坦,土壤肥沃,距地面1m左右有一粘土间层,厚30cm,保肥保水,对深根性的泡桐生长十分有利。     

Allometry, biomass, and chemical content of Novel African Tulip Tree (Spathodea campanulata) Forests in Puerto Rico

The African tulip tree, Spathodea campanulata, the most common tree in Puerto Rico, forms novel forest types with mixtures of native and other introduced tree species. Novel forests increase in area in response to human activity and there is no information about their biomass accumulation and nutrient cycling. We established allometric relationships and chemically analyzed plant parts of African tulip trees to determine the concentration and standing stock of chemical elements (C, N, P, K, Ca, Mg, S, Mn, Al, Fe, Na), and ash. Trees ranged in diameter at breast height from 8 to 85 cm and in height from 8.8 to 28 m. The concentrations of N, P, K, and Ca in leaves of the African tulip tree were similar to those of the native pioneer Cecropia schreberiana and higher than those of mature forest tree species in Puerto Rico. The over bark wood volume of African tulip trees in nine forest stands where it was dominant ranged from 163 to 849 m³/ha. Aboveground biomass ranged from 60 to 296 Mg/ha, and N and P stocks ranged from 190 to 988 and 32 to 137 kg/ha, respectively. Novel forests on abandoned agricultural lands can store more biomass and elements than native and plantation forest stands of similar age.     

海南木莲人工林生物量及养分分配

本文测定并分析了海南尖峰岭地区３０年生的热带乡土树种海南木莲人工林生物量及其估算模型，论述了生物量及其养分分配规律。指出：海南木莲各器官及整株生物量模型以幂函数模型Ｗ＝ａ（Ｄ２Ｈ）ｂ比较理想；全林分的总生物量为１４４．０６６ｔ／ｈｍ２，其中地上部分生物量８９．９３５ｔ／ｈｍ２。乔木层生物量占７８．８１％，林下植物层占２１．１９％；在乔木层中，树干、树叶、树枝、树皮和树根所占的比例分别是５４．１２７％、２．３５４％、７．７６２％、９．３７０％和２６．３８８％；乔木层中，各器官的养分含量，除Ｃａ外，都是叶比其它器官（枝、皮、干、根）的养分含量高许多，Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ５个常量养分元素在海南木莲人工林生物体中的总贮量分别为５５７．７５４，２４．３３０，５９９．９０８，２７５．５５７，６４．１０３ｋｇ／ｈｍ２，各养分贮量在各器官中分布，除Ｐ外，从小到大为树叶、树枝、树皮、树干、树根     

Managing forests for wood yield and carbon storage: a theoretical study

Which forest management regimes best achieve the dual objectives of high sustained timber yield and high carbon storage, including the carbon stored in soil and wood products? A mechanistic forest ecosystem simulator, which couples carbon, nitrogen and water (Edinburgh Forest Model), was calibrated to mimic the growth of a pine plantation in a Scottish climate. The model was then run to equilibrium (1) as an undisturbed forest, (2) removing 2.5, 10, 20 or 40% of the woody biomass each year (3) removing 50% of the woody biomass every 20 years, and (4) clear-felling and replanting every 60 years as in conventional plantations in this climate. More carbon was stored in the undisturbed forest (35.2 kg C m(-2)) than in any regime in which wood was harvested. Plantation management gave moderate carbon storage (14.3 kg C m(-2)) and timber yield (15.6 m(3) ha(-1) year(-1)). Notably, annual removal of 10 or 20% of woody biomass per year gave both a high timber yield (25 m(3) ha(-1) year(-1)) and high carbon storage (20 to 24 kg C m(-2)). The efficiency of the latter regimes could be attributed (in the model) to high light interception and net primary productivity, but less evapotranspiration and summer water stress than in the undisturbed forest, high litter input to the soil giving high soil carbon and N(2) fixation, low maintenance respiration and low N leaching owing to soil mineral pool depletion. We conclude that there is no simple inverse relationship between the amount of timber harvested from a forest and the amount of carbon stored. Management regimes that maintain a continuous canopy cover and mimic, to some extent, regular natural forest disturbance are likely to achieve the best combination of high wood yield and carbon storage.     

林下植被对杉木林地力影响的研究*

本文研究了林下植被对杉木林地力的影响,结果表明在正常的经营水平下,林下植被生长迅速。0.7的林分郁闭度,4～5年后生物量积累达4～5 t/ha;营养元素达80～100kg/ha。丰富的林下植被能促进养分的有效化,并且在一定程度上能起到改善土壤肥力的作用,因此对防止杉木林地力衰退具有一定的意义。     

Distribution patterns of tree,understorey, and detritus biomass in coniferous and broad-leaved forests of Western Himalaya,India

Forest biomass pools are the major reservoirs of atmospheric carbon in both coniferous and broad-leaved forest ecosystems and thus play an important role in regulating the regional and global carbon cycle. In this study, we measured the biomass of trees, understorey, and detritus in temperate (coniferous and broad-leaved) forests of Kashmir Himalaya. Total ecosystem dry biomass averaged 234.2 t/ha (ranging from 99.5 to 305.2 t/ha) across all the forest stands, of which 223 t/ha (91.9–283.2 t/ha) were stored in above- and below-ground biomass of trees, 1.3 t/ha (0.18–3.3 t/ha) in understorey vegetation (shrubs and herbaceous), and 9.9 t/ha (4.8–20.9 t/ha) in detritus (including standing and fallen dead trees, and forest floor litter). Among all the forests, the highest tree, understorey, and detritus biomass were observed in mid-altitude Abies pindrow and Pinus wallichiana coniferous forests, whereas the lowest were observed in high-altitude Betula utilis broad-leaved forests. Basal area has showed significant positive relationship with biomass (R² = 0.84–0.97, P < 0.001) and density (R² = 0.49–0.87). The present study will improve our understanding of distribution of biomass (trees, understorey, and detritus) in coniferous and broad-leaved forests and can be used in forest management activities to enhance C sequestration.     

Biomass production,nutrient cycling and distribution in age-sequence Chinese fir(Cunninghamia lanceolate) plantations in subtropical China

Biomass production and nutrient(N, P, K, Ca and Mg) accumulation, distribution and cycling were quantified in young, mature and over-mature(10-, 22-, and34-year old) Chinese fir [Cunninghamia lanceolate(Lamb.) Hook] plantations in southern China. Total stand biomass of young, mature and over-mature stands was 38,104 and 138 t ha-1respectively. Biomass production increased significantly with age. Stem wood represented the highest percentage of stand biomass, accounting for 41,55 and 63 % in the young, mature and over-mature plantations respectively. Nutrients concentration was highest in live needles and branches, and lowest in stem wood. The plantations accumulated more N, followed by K, Ca, Mg,and P. Nutrient return amount, nutrient utilization efficiency, nutrient turnover time, the ratio of nutrient returnand uptake increased with stand age, which implies that young Chinese fir deplete soil nutrients to maintain growth,and efficiently utilize nutrients to decrease dependence on soil nutrients as they age. Harvesting young Chinese fir plantations would therefore lead to high nutrient loss, but prolonging the rotation length could improve soil recovery,and help sustain productivity in the long-term. Improved nutrient return through litterfall as stands get older may also be beneficial to nutrient pool recovery.     

滇中高原华山松人工林生物量及营养元素分配格局

对云南玉溪磨盘山华山松人工林（16年中龄林、26年近成熟林、43年成熟林）生物量及N、 P、 K、 Ca和Mg等5种营养元素的分配格局和积累规律进行了研究。结果显示,3种林龄华山松人工林的生物量分别为181.515 t/hm2、284.679 t/hm2、295.311 t/hm2,乔木层生物量分别占林分的91.594％、94.760％、93.838％,乔木层的净生产力分别为10.391 t/（ hm2· a）、10.375 t/（ hm2· a）和6.444 t/（ hm2· a）;3种林龄群落各层生物量均为乔木层＞枯落物层＞灌木层＞草本层;乔木各营养器官营养元素含量大小是树叶＞树枝＞树根＞树皮（或树皮＞树根）＞树干;3种林龄华山松各器官营养元素含量均以N含量最高,其他元素含量依次为K＞Mg＞Ca＞P,其中树叶中的N含量最高,达到16.733 g/kg～21.368 g/kg;3种林龄群落营养物质总积累量分别为1497.993 kg/hm2、2257.161 kg/hm2和2810.246 kg/hm2,乔木层营养物质年积累量分别为77.532 kg/（ hm2· a ）、76.679 kg/（ hm2· a）、58.759 kg/（ hm2· a）。     

Heartwood, sapwood and bark content of teak trees grown in Karnataka, India

We evaluated heartwood, sapwood and bark content in teak trees. A total of 27 sample plots were laid out in teak plantations raised by State Forest Department in Karnataka covering different age groups...     

Export of Nutrients in Plant Biomass Following Harvest of Eucalypt Plantations in Kerala,India

Abstract

Pools of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) were examined in the soil and above-ground plant biomass at the end of a 7 year rotation at two E. tereticornis lowland sites and two E. grandis highland sites in Kerala, India. Potential export rates of these nutrients were also examined for different biomass removal scenarios from the plantations. Pools of nutrients were measured in the above-ground components of the tree crop, forest floor and understorey, and in soil down to 1 m depth. At harvest, large quantities of biomass and nutrients are removed from eucalypt plantation sites, with the quantities of nutrients exported unlikely to be replaced through natural atmospheric and weathering inputs. Between 24 Mg ha^-1 and 115 Mg ha^-1 of biomass was exported in stem wood across the sites, and this increased to 40-145 Mg ha^-1 in scenarios where all of the branches, bark and understorey were also exported. Stem wood had the lowest concentration of nutrients and had a relatively low export of nutrient per kg of biomass. On average, 54 kg, 12 kg and 65 kg of N, P and K were removed per hectare in stem wood only, equivalent to 0.46%, 0.17%, and 6.7%, respectively, of above- and below-ground (to 1 m depth) site pools. Export increased to 194 kg, 30 kg, and 220 kg of N, P and K per hectare if the branches, bark and understorey were also removed (equivalent to 1.6%, 0.5% and 24.7% of above- and below-ground site pools down to 1 m depth). Export of Ca and Mg was also high, with an average of 88 kg and 11 kg of Ca and Mg removed per hectare if only the stem wood was taken (3.12% and 1.34% of total above-ground and exchangeable below-ground to 1 m depth), increasing to 501 kg ha^-1 and 66 kg ha^-1 if the branches, bark and understorey were also removed (21.7% and 11.3% of total above-ground and available below-ground to 1 m depth). Removals of this magnitude represent a significant proportion of site nutrient pools and have the potential to reduce future plantation productivity unless steps are taken to promote retention of biomass and nutrients on site and/or replacement of nutrients through fertilizer application.     

Productivity and nutrient cycling of a Javanese homegarden

In a 0.13 ha homegarden in West Java, Indonesia, a 16-week study of production, nutrient in- and outputs as well as internal circulation was carried out in 1989. Total annual agricultural production was 11.4 t ha^–1, of which 6.8 t ha^–1 were timber and firewood. Two thirds of the production was sold, the rest consumed by the owners. The productivity is more than twice the productivity of ricefields in the area, but can be raised further. Nutrient inputs in rainfall, streamwater and via N-fixation were estimated to a total of: 33 kg N, 7 kg P, 115 kg K, 79 kg Ca and 55 kg Mg ha^–1 yr^–1. Outputs in streamwater, harvest sold and erosion were estimated at: 42 kg N, 11 kg P, 151 kg K, 278 kg Ca and 83 kg Mg. Litterfall and pruning returned 10.0 and 7.5 t dry matter, respectively, per hectare to the soil annually. Throughfall was on average 92% of incident rainfall. Total amounts of nutrients circulated internally in the homegarden each year were estimated at: 223 kg N, 38 kg P, 373 kg K, 135 kg Ca and 50 kg Mg per hectare. This corresponded to 22, 44, 50, 20 and 30% of nutrients stored in the plant biomass, respectively. The balance is negative for all elements, the magnitude depending on whether the part of harvest consumed by the family itself is regarded as internal circulation or as an output. Compared to available soil reserves the system is likely to be sustainable for many years ahead, but may be vulnerable because of the high fraction of plant nutrient storage cycled annually.     

Biomass,decomposition and nutrient release of Vaccinium myrtillus leaf litter in four forest stands

Biomass and nutrient transfer (N, P, K, Ca, Mg) of bilberry (Vaccinium myrtillus L.) leaf litter fall, as well as decomposition and nutrient release, were studied in four mature forest stands situated in Central and South Sweden. Bilberry leaf litter fall amounted to between 33 and 55 kg ha^‐1 yr^‐1 in the four stands. Only minor differences between sites were noted for litter concentrations of N, P and Ca, whereas K and Mg showed somewhat larger variability. Relative amounts of the five nutrient elements in the litter fall were generally in the order N > Ca > K > Mg > P. The amounts of nutrients returned to the forest floor by the annual leaf litter fall in the stands ranged from 0.4 to 0.8 kg ha^‐1 for N, 0.4 to 0.6 kg ha^‐1 for Ca, 0.2 to 0.7 kg ha^‐1 for K, 0.1 to 0.2 kg ha^‐1 for Mg and 0.04 to 0.08 kg ha^‐1 for P.

The decomposition of the local bilberry leaf litter was followed by means of litterbags during three years. At all sites there was an extremely rapid mass loss from the litter (between 45% and 54%) during the first four to five months of decomposition. After this initial phase, the decomposition rates decreased markedly and after three years the accumulated mass losses of the litters varied between 64% and 78% at the studied sites. After two and three years of decomposition, three of the sites exhibited almost similar litter mass losses whereas at the fourth site the litter was decomposed to a significantly lower degree. The pattern of nutrient release from the decomposing bilberry leaf litter differed somewhat from site to site. Minor differences were, however, noted for P, Ca and Mg while N and K were more strongly retained in the litter at one of the sites.     

Site index for teak in Colombia

Determination of site quality is a basic tool for proper selection of locations and species, in management of forest plantations.Throughout the Caribbean studies of site quality are few and are hampered by statistical limitations, inappropriate growth models, and limited data. We fitted growth curves for dominant height to evaluate and classify site quality of teak (Tectona grandis) plantations by using data from 44 permanent sample plots established since 1990 in 3 22 years old teak plantations in the Colombian Caribbean region. We used Korf’s and von Bertalanffy’s models to fit curves as nonlinear effects models. Both models, with a single random parameter, were considered as adequate for dominant height growth modelling, but Korf’s model was superior. There sulting curves were anamorphic and closely reflected high variability insite quality. Five site classes were clarified: at a base age of 12 years old,teak reached a mean dominant height of 24.8 m on the best sites, 9.8 m inthe worst sites, and in the averages sites, 15.8-18.8 m. Using this model,we identified the best and the worst sites for teak plantations in the Caribbean region. This model proved a useful tool, not only for site quality evaluation, but also for improved teak plantation planning and management.     

国有北岭山林场生态公益林碳储量和碳密度研究

研究以小班为基本研究单元,按起源分林龄对广东省肇庆市国有北岭山林场生态公益林碳储 量进行了研究。国有北岭山林场乔木林总碳储量为 278.0×106kg,其中生态公益林碳储量为 244.9×106kg。生态公益林中天然林在不同林龄间的林分间平均碳密度不存在显著差异,范围（25.24±1.02）~ （28.01±1.69）×103 kg/hm2;而人工林则存在显著的差异,以 20~40 a 林龄的林分最大,为（34.22±2.77） ×103 kg/hm2,其次为大于 40 a 林龄的林分,为（23.34±0.72×103kg/hm2。在 20~40 a 林龄的生态公益林中,人工林平均碳密度显著大于天然林,但在大于 40 a 林龄的林分中,则显著小于天然林。     

Carbon stocks in a 50‑year‑old Eucalyptus camaldulensis stand in Sicily,Italy

Eucalyptus stands in semi?arid areas may contribute to enhance carbon (C) stocks in both biomass and soil. However, the limited information available is mainly focused on short?rotation plantations. In this study, the above? and below?ground C pools in five 50?year?old Eucalyptus camaldulensis Dehnh. stands planted on Miocenic evaporitic deposits in Sicily, Italy, with a xeric and thermic pedoclimate, were measured. Above?ground biomass was determined by partitioning and weighing branches, stem and leaves. Below?ground C pools included the determination of litter, root biomass, and soil organic and inorganic C. In terms of the above?ground biomass, the E. camaldulensis stand accumulated on average 116?Mg ha?1 corresponding to 55?Mg C ha?1. Below?ground biomass consisted mainly of larger roots, followed by fine and medium roots (33?Mg ha?1 corresponding to 14?Mg C ha?1). Litter accumulation on the soil surface accounted for 13?Mg ha?1 corresponding to 5?Mg C ha?1. The amount of C stored in soil was 554?Mg C ha?1, of which 75% was in organic form. Although E. camaldulensis is planted extensively throughout the Southern Hemisphere and tropics where it is managed over short rotations (c. 2–4 years), the results obtained from this study make this species important in terms of future afforestation planning for longer rotations due to its potential to sequester C, particularly in the below?ground components.