Litter production and nutrient cycling in coffee (Coffea arabica) or cacao (Theobroma cacao) plantations with shade trees

The relative importance of N fixation, organic material inputs and nutrient inputs in litterfall, as justifications for including shade trees in plantations of coffee or cacao, is discussed. According to existing data, N fixation by leguminous shade trees does not exceed 60 kg.N/ha/a. However, these trees contribute 5,000–10,000 kg. organic material/ha/a.Comparisons are made between the leguminous shade tree Erythrina poeppigiana and the non-leguminous timber tree Cordia alliodora. The former, when pruned 2 or 3 times/a., can return to the litter layer the same amount of nutrients that are applied to coffee plantations via inorganic fertilizers, even at the highest recommended rates for Costa Rica of 270 kg.N, 60 kg.P, 150 kg.K/ha/a. The annual nutrient return in this litterfall represents 90–100 percent of the nutrient store in above-ground biomass of E. poeppigiana, and hence the consequences of competition with the crop should not be a serious limitation. In the case of C. alliodora, which is not pruned, nutrient storage in the tree stems, especially of K, is a potential limiting factor to both crop and tree productivity.It is concluded that, in fertilized plantations of cacao and coffee, litter productivity is a more important shade tree characteristic than N fixation.An early version of this review was presented at the CATIE-IUFRO meeting Los Arboles de Uso Multiple en Sistemas Agroforestales, June 1985, Turrialba, Costa Rica.     

STUDIES ON BIOMASS AND PRODUCTIVITY FOR DAHUIAN LARCH PLANTATIONS

Dahurianlarch(LarixgmeliniRupr.)isoneofthemostimportanttimberspeciesinthenortheastofChina.Becauseofovercuttingforseveraldecades-naturalfOrestresourceshavebeendeclinedrapidly.Plantationsofdahurianlarchhavebecomeanimportantpartofforestreserveresourcesinthisarea.Butthereisalackofsystematicstudiesonthebiomassandthenetproductivityfordahurianlarchplanta-tions.Inthispaper,wepresentsomeusefuldataofthebiomassandtheproductivityoflburstructuretypes'fordahurianlarchplantations.Itwillprovidesomeinformati…     

Comparative analyses on the litter in Korean pine Mongolian Scots pine and Dahurian Larch plantations

Comparative analyses were conducted on the nutrient element content and returning amount of main fractional compositions of litter in Korean pine (KP), Mongolian Scots pine (MSP) and Dahurian larch (DL) plantations in Laoshan Plantation Experiment Station of Maoershan Experiment Forest Farm of Northeast Forestry University. The results are as follows: (1) The nutrient element content and returning amount in litter varies among different fractional compositions and tree species, the total returning amount of all nutrient elements and the returning amount of K, Ca, Mg, N and P are DL > MSP > KP, the returning amount of Cu is DL > KP > MSP, the returning amount of Fe and Mn are MSP > DL > KP; (2) To KP and DL plantations, the main nutrient element returned is dead needles; dead branches, bark scales and dead cones account for a little proportion; whereas to MSP plantation, besides dead needles, dead branches and bark scales also play an important role in the return of nutrient elements; (3) A little deal of dead leaves can provided a great deal of returning amount of nutrient elements.     

燕山东段森林群落及灌木群落枯落物的研究

燕山东段森林群落枯落物现存量平均为４．３５－２８．６７ｔ／ｈｍ＾２，以山杨混交林、松栎混交林、椴树混交林最高，栎林和油松林次之，侧柏林最低。灌木群落枯落物现存量平均为４．１５－１８．９４ｔ／ｈｍ＾２，低于森林群落。森林枯落物现存量受树种组成、年龄、立地条件及人为干扰的影响。其中，人为干扰影响最大，几乎使枯落物损失殆尽。森林枯落物营养元素总贮量０．１７６－１．５３４ｔ／ｈｍ＾２，最大贮水量３．９－５     

Assessment of tree diversity and above-ground biomass in coffee agroforest dominated tropical landscape of India's Central Western Ghats

The purpose of this study was to quantify the changes in tree diversity and above-ground biomass associated with six land-use types in Kodagu district of India's Western Ghats. We collected data on species richness,composition and above-ground biomass(AGB) of trees,shrubs and herbs from 96 sample plots of 0.1 ha. Totals of83 species from 26 families were recorded across the landuses. Tree species richness, diversity and composition were significantly higher in evergreen forest(EGF) than in other land-uses. Similarly, stem density and basal area were greater in EGF compared to other land-uses. Detrended correspondence analysis(DCA) yielded three distinct groups along the land-use intensities and rainfall gradient on the first and second axes, respectively. The first DCA axis accounted for 45% and second axis for 35% of the total variation in species composition. Together the first two axes accounted for over 2/3 of the variation in species composition across land-use types. Across the land-uses,AGB ranged from 58.6 Mg ha-1 in rubber plantation to327.3 Mg ha-1 in evergreen forest. Our results showed that species diversity and AGB were negatively impacted bythe land-use changes. We found that coffee agroforests resembled natural forest and mixed species plantation in terms of tree diversity and biomass production, suggesting that traditional coffee farms can help to protect tree species, sustain smallholder production and offer opportunities for conservation of biodiversity and climate change mitigation.     

COMPARATIVE ANALYSES ON THE LITTER IN KOREAN PINE MONGOLIAN SCOTS PINE AND DAHURIAN LARCH PLANTATIONS(Ⅱ)CONTENT AND RETURNING AMOUNT OF NUTRIENT ELEMENTS

Seethefirstpartofthisstudy[']forthepurposeandsignificanceofthestudies,thegeneralsituationofexperimentplotsandresearchmethod,thispartmainlydiscussthenutrientelementcontentandreturningamountofmainfractionalcompositionsoflitterinKoreanpine(KP),MongolianScotspine(MSP)andDahurianlarch(DL)plantationsinLaoshanPlantationExperi-mentStationofMaoershanExperimentForestFarmofNortheastForestryUni-versity-CHEMICALANALYSISMETHODSoFNUTRixNTELEMENTSINLITTERTheovendriedsamplesofdeadneed…     

MANCHURIAN ASH SEED BANK AND SEEDLING RECRUITMENT

To understand the natural regeneration of manchurian ash and the seed banks undervarious secondary stands,we have investigated the seed quantity and vitality of major trees in theground floor of the stands.in natural secondary stands and dahurian larch plantations with seedsourcc of manchurian ash around them,the vital seed numbers of valuable trees(mono maple,manchurian ash,amur linden,manchurian linden,manchurian walnut)are 20933/ha and18000/ha respectively.The numbers of manchurian ash seeds are 110OO/ha and 12133/harespectively.It has been found that litter affects the seedling recruitment of manchurian ash.Whenthe seeds were sown on the litter and under the litter respectively,the final seeding recruitment rateswere 17.9 and 28.9％ respectively.The peak of seedling recruitment in the former case occurred oneyear later.     

Responses of decomposition rate, nutrient return, and composition of leaf litter to thinning intensities in a Pinus tabulaeformis plantation

It is important to study the effect of tree density on the substrate quality and decomposition rate of leaf litter in plantations. In 2002, an experiment of the effects of thinning intensities at four different levels (i.e., 0 (I), 35.7% (II), 49.2% (III), and 64.2% (IV)) on undergrowth were carried out in an 18-year-old Pinus tabulaeformis plantation at an initial density of 3130 trees/hm² in the middle of the hills of Yingpan, Yanqing County, Beijing. Three years later, the rates of decomposition, the amount of nutrients returned, and the characteristics of leaf litter were compared by a litter bag method. The results show that the annual loss of dry matter of leaf litter in plots I, II, III, and IV was 25.81%, 26.25%, 27.68%, and 25.96%, respectively. The turnover of leaf litter was 10.04, 9.84, 9.24, and 9.97 years, respectively. Therefore, it is feasible and convenient to evaluate the effect of thinning on the rate of decomposition. In the first two months, the N, P, K, and Mg nutrients were released quickly. During the entire observation period of 14 months, the return of both N and Mg nutrients in the four plots exhibited a release-accumulation type of cycle. The return of P and K indicated a trend of release-accumulation and a relative balance. However, the return of Ca was far different from that of the other nutrients in the four plots. The total nutrient return of the four elements N, P, K, and Mg in the plots was 10.806, 31.016, 31.798, and 39.365 g/kg, respectively. Specifically, the quality of leaf litter in plot I was the worst in that N and Ca accumulated only 2.567 and 0.767 g/kg, respectively. Thinning did decrease the ratios of lignin to N and C to N and accelerated the rate of decomposition of leaf litter. The content of crude ash in leaf litter was enhanced by thinning, which prevented acid material, such as tannins and resins, from returning to the soil. The effect of thinning intensity was evaluated by the ratio of lignin to N, the ratio of C to N, and the ash content in leaf litter.     

Carbon reservoir and biomass in Canadian prairie shelterbelts

Greenhouse gases in the atmosphere, mainly carbon dioxide (CO₂), can be mitigated by the planting of trees and shrubs. Appropriate agroforestry practices in Saskatchewan include field and farmyard shelterbelts, wildlife plantations, poplar plantations and managed woodlots. A study was conducted to determine the amount of carbon held in prairie shelterbelts. The effect of the soil type and tree species on biomass and carbon content was measured in shelterbelts in the brown, dark brown and black soil zones of Saskatchewan. For some of the main shelterbelt species, the mean aboveground carbon content was 79 kg/tree (32 t/km) for green ash, 263 kg/tree (105 t/km) for poplar, 144 kg/tree (41 t/km) for white spruce and 26 t/km for caragana. In the brown and the dark brown soils, which are more arid than the black soil zone, trees had 60.6% and 65.5%, respectively, of the biomass and carbon content of trees and shrubs in the black soil zone. Improved, fast-growing poplar clones had the greatest biomass at maturity and fixed the greatest amount of carbon. Simple equations were developed to calculate the carbon contents of prairie shelterbelts, based on easily measured tree or shrub parameters. This paper will discuss the results of this particular study and the broader implications of this work. This revised version was published online in June 2006 with corrections to the Cover Date.     

利用线性混合模型和哑变量模型方法建立贵州省通用性生物量方程

以贵州省人工杉木和马尾松地上生物量数据为例,通过利用线性混合模型和哑变量模型方法,建立了适合不同树种和区域(中心区和一般区)的通用性立木生物量方程,为简化生物量建模工作提供了有效途径。结果表明,相同直径林木的地上生物量估计值随树种、区域的不同存在一定程度的差异,带随机参数的线性混合模型和带特定参数的哑变量模型比总体平均模型的精度高;线性混合模型和哑变量模型方法均同等有效,可推广应用于其它通用性模型(如材积方程)的建立。