Lusitanica Plantation Research Articles

Effects of exotic plantation expansion and management intervention on woody plant species diversity, regeneration and soil seed bank in Tarmaber district, Ethiopia

This study was carried out to determine the effect of plantation forest with management intervention on woody plant species diversity in Tarmaber district north shewa zone Ethiopia, regeneration and soil seed bank species composition in five different forest types. A total of 75 circular sample plots of 314 m2 were established along a transect lines. Soil seed bank analysis was done from soil samples collected in each of the plots (225 samples). Different diversity index and ANOVA was used in SPSS software for analysis. The result showed that a total of 51 woody plant species was recorded in adjacent natural forest (41), managed C. lusitanica (27), not managed C. lusitanica (9), managed E. globules (22) and not managed E. globules (13) species. Regeneration of seedlings were 3538, 5567, 707, 1462 and 2524 mean stems ha-1 for natural forest, managed C. lusitanica, not managed C. lusitanica, managed E. globules and not managed E. globules respectively. Unmanaged C. lusitanica plantations had significantly lower densities of mature tree stems ha-1 as compared to managed C. lusitanica, managed E. globules and adjacent natural forest (F=14.03, p<0.05). Similarly in terms of sapling density ha-1 unmanaged C. lusitanica was significantly lower from other forest types (F=7.37, p <0.05). However managed C. lusitanica had significantly higher seedling regeneration (stem density ha-1) than other plantation and adjacent natural forests (F = 16.11, p < 0.05). Generally mean stem densities including tree, sapling and seedling of woody species among different forest types managed C. lusitanica was significantly higher among different forest types (F= 13.01, p<0.05). From the soil seed bank a total of 22 plant species (20 native and 2 exotic) species were recovered. In different forest types the number of species recorded was in adjacent natural forest (19), managed C. lusitanica (11), unmanaged C. lusitanica (4), managed E. globules (7) and unmanaged E. globules (5). Generally, with appropriate management intervention, undergrowth vegetation and soil seed bank status in plantation forest had good species composition and diversity.

Incidence of Pests and Diseases in Tree Nurseries and Plantations in Kimondi Forest, Nandi County, Kenya

Increasing demand for wood is putting pressure on forest resources that are equally under threat from insect pests and diseases. Reported average annual forest loss stands at 0.2% globally, 0.8% in Africa, and 1.6% in Kenya. To meet the increasing demand for forest products in Kenya, the government and private sector have established plantations of non-native tree species dominated by Eucalyptus species, Cupressus lusitanica, and Pinus patula. To ensure successful forest plantation establishment and management schemes, there is a need for sufficient knowledge and understanding of tree growth conditions and threats including pests and diseases. This study aimed at determining the incidence of plantation and tree nurseries in Kimondi Forest, Kenya. Tree plantations were mapped into 2.5 Ha rectangular portion transects parallel to the forest roads. In randomly selected portions, observations were carried out for disease and pest signs and symptoms on various tree parts (leaves, stem, roots, fruits, and twigs). In the tree nurseries, 3 m × 1 m rectangular quadrants were placed on seedling beds and similar observations were made. Collected data indicated a high incidence of nursery seedling pests (5.3 % leaves and 5.1% stems) on Eucalyptus species and least on P. patula (2.4% leaves and 3% stems). Higher incidence of plantation pests (35.0% leaves of Eucalyptus sps.) and least on P. patula stems (1.2%) were recorded. On the other hand, twelve (12.0%) of C. lusitanica and (1.8%) Eucalyptus species plantation twigs were infested by pests. A high incidence of nursery seedling disease (9.8%) was observed on C. lusitanica leaves and least on P. patula stems (3.6%). Higher incidence of plantation diseases (32 %) on leaves of Eucalyptus sps. and least on C. lusitanica stem (1.4%) was recorded. In both tree nurseries and plantations, roots and fruits remained free from pests and disease. Major tree pests and diseases identified in Kimondi forests include (Human, wildlife, livestock, Cinara cupressi, Gonipterus scutellatus, Pinus pini, and Leptocybe invasa) and (damping-off, Fusarium wilt, Botryosphaeria canker, cypress canker, and Mycosphaerella spp.) respectively. These results suggest a need for regular monitoring and intervention measures to control pest and disease infestation in the Kimondi forest.

ESTIMATION OF CARBON STOCKS IN COFFEE BASED AGROFORESTRY AND ADJACENT CUPRESSUS LUSITANICA PLANTATION AT WONDO GENET COLLEGE, SOUTHEAST ETHIOPIA

The purpose of this study was to estimate biomass and soil organic carbon (SOC) stock in coffee based Agroforestry and Cupressus lusitanica plantation. A total of 20 plots of 10 m x 10 m were established systematically in coffee based Agroforestry and Cupressus lusitanica plantation to sample soil and vegetation data. The biomass of shade tree, coffee shrubs and Cupressus lusitanica was estimated by previous allometric equations.Variation in biomass carbon and SOC between the two land use types were tested using analysis of variance. The average amount of biomass carbon stored in coffee based Agroforestry was 109.96 Mg C ha-1. The proportion of total aboveground biomass carbon to the total biomass carbon stock was averaged 61.67% for coffee based Agroforestry.The average total biomass carbon was 74.24 Mg C ha-1 in Cupressus lusitanica plantation. Coffee based Agroforestry had accounted more SOC than Cupressus lusitanica plantation in 0-40 cm soil depth. Our study concluded that coffee based Agroforestry, compared with Cupressus lusitanica plantation, had generally higher biomass carbon and SOC stocks.

Demography of the land snail Tikoconus (Tikoconus) costarricanus (Stylommatophora: Euconulidae) in tropical low montane and premontane forests, Costa Rica

Abstract. Introduction: Ecology and natural history of neotropical land snails is almost unknown. Objetive: In this paper I analyse the population dynamics of Tikoconus (Tikoconus) costarricanus Barrientos, in prep., an understory endemic euconulid. Methods: I compared T. costarricanus’ demography patterns in tropical montane forests in central Costa Rica in three habitats with different restoration techniques: a mature forest, a secondary forest and a Cuppressus lusitanica plantation. I collected data in three month periods during a year. I analysed population size in relation with habitat, sampling date, leaf litter humidity, depth and quantity; and specimen size in relation with habitat and sampling date. I also kept some specimens in terraria and described part of their natural history. Results: The species is more abundant in mature forest (Ø = 0.174 ind/m2). The number of specimens in each habitat was constant throughout the year (Kruskall-Wallis = 2.0118, p = 0.57, NS) and hatching occurs in the middle and last months of the rainy season (Kruskall-Wallis = 17.3061, p = 0.00061, **). Number of specimens is related with leaf litter humidity (Spearman correlation, r = 0.3524, n = 232, p = 0.000, **), amount (Spearman correlation, r = 0.3922, n = 232, p = 0.000, **) and depth (Spearman correlation, r = 0.2543, n = 232, p = 0.000, **). This relationship is explained by the high and stable humid environment provided by leaf litter. During the drier months some specimens migrate from the foliage to the leaf litter. Eggs (Ø = 1mm) are laid on moss or soil and the young spend the first 2 or 3 weeks of their life on moss. Egg masses are small (Ø = 4 eggs), and shells look bubbly. Egg development time (20 days) was longer than in other tropical species. Adult pigmentation appears around two months after hatch. In the only case observed egg laying began 5 months after hatching and the specimen lived 9 months. Conclusions: Although no conclusive, these data point to a fragile species susceptible to habitat and climate change. Restorations techniques should consider leaf litter features in order to protect endemic neotropical humid dependent diversity.

Can afforestation with Cupressus lusitanica restore soil C and N stocks depleted by crop cultivation to levels observed under native systems?

This study quantified changes in soil organic carbon (SOC) and total nitrogen (STN) stocks from the conversion of natural forest to crop field followed by afforestation of these fields. Soil (0–100cm), leaf and fine roots were collected in the natural forest, the adjacent to 50-year-old crop fields converted from the natural forest, and 5, 8, and 17-year-old Cupressus lusitanica plantation sites (hereafter P5, P8 and P17, respectively) established on the converted crop fields in Southern Ethiopia. Soil and leaf pH, soil texture, bulk density, fine root mass, and SOC and STN contents and stocks were determined. The results showed that soil pH was lower and clay fraction was higher in P17 site than natural forest. Leaf pH of Cupressus lusitanica in plantation sites was lower than those of trees in natural forest. Fine root mass was greater in the plantation sites than the crop field. Soil bulk density (0–40cm) was higher in the crop fields than the natural forest but there was no significant difference between crop field and plantation sites. SOC and STN stocks (0–100cm) were higher in the natural forest than the crop field and all plantation sites and there was no significant difference between the crop field and all plantation sites. Overall, SOC and STN stocks decreased by 22.9% and 40.3%, respectively, in conversion of natural forest to crop field. However, after 17 years of afforestation, the crop field showed no change of stocks. The results suggest that afforestation in agricultural lands may not guarantee, or take a long period, to restore SOC and STN to the original natural forest level.

Ectomycorrhizal trees intermingled within Cupressus lusitanica plantations sustain the diversity and availability of edible mushrooms

Edible mushrooms are important resources with higher economic value than other non-timber forest products (NTFPs). In this study, we assessed quantitatively how the permanence of native ectomycorrhizal trees within Cupressus lusitanica plantations affects the availability of edible wild mushrooms. We conducted our study in an area composed of native ectomycorrhizal oak-pine forest and no ectomycorrhizal plantations of C. lusitanica. Availability of saprobic and ectomycorrhizal edible mushrooms was evaluated as a multifactorial variable including density, fresh biomass weight, potential monetary value, species richness, dominance and temporal availability of edible wild mushrooms. These variables were compared between plantations and native oak-pine forest through statistical and multi-criteria analyses. No significant differences in temperature and relative humidity at the ground level or in the physical and chemical properties of the soil between the two forest types were detected. We found greater biomass and temporal availability of edible wild mushrooms in the oak-pine forest. Nonetheless, in plantations we found 62.5% of ectomycorrhizal fungi including one species not found in the oak-pine forest (Strobilomyces floccopus), which indicates that native trees in the plantations maintain high diversity of wild mushrooms as well as the availability of some culinary important edible mushrooms.

Sistema reproductivo, comportamiento de apareamiento y ecología básica de un caracol tropical extremadamente raro: Drymaeus tripictus (Stylommatophora: Bulimulidae)

Very little is known about the ecology and biology of Drymaeus tripictus, an extremely rare and endemic land snail species from Costa Rican highlands. I studied the ecology and reproductive biology of D. tripictus from April 2009 through June 2010 in an old forest, a young forest and a Cupressus lusitanica plantation in central Costa Rica. Every three months I visited each habitat and collected specimens in 20 random sampling plots (3x3 m2 each). I observed the snail’s activity and microhabitat preference in the field, and in the laboratory I recorded high definition videos of its mating behavior and analyzed reproductive morphology with light microscopy. The snail is more abundant in the old forest (0.017 ind./m(2)) and prefers leaves with little epiphyllous cover (0-25 % cover, chi-square test, p <0.0001). During the dry season the snails become active between 20:00 pm and 8:00 am (chi-square = 22.65, df=3, p < 0.0001); they are inactive mainly during the afternoon (11:00 am to 16:59 pm). I found active individuals mostly on the upper side of leaves, where they feed (Chi-square =6.76, df=1, p = 0.0093). Mating is unilateral, by shell mounting, with cryptic phallus intromission and without role switching or multiple mating. Its reproductive system is morphologically similar to that of Drymaeus costaricensis. Mating behavior is as expected for snails with high-spired shells, except for the lack of role switching. The density of D. tripictus is low even when compared with other endangered bulimulids.

AVALIAÇÃO DA RESTAURAÇÃO PASSIVA DE UMA ÁREA DE MATA ATLÂNTICA APÓS O CORTE RASO DE UMA PLANTAÇÃO DE &lt;i&gt;Cupressus lusitanica &lt;/i&gt;MILL

Cupressus lusitanica Mill. possui um potencial relativamente baixo para promover a regeneração de espécies nativas sob o dossel da floresta. Entretanto, após o corte raso de uma plantação de Cupressus lusitanica na Floresta Estadual de Avaré (FEA), sudeste do Brasil, uma vigorosa regeneração de espécies arbustivoarbóreas da floresta Atlântica foi observada. Avaliou-se a restauração passiva desse sítio comparando sua vegetação com a vegetação estabelecida em clareiras artificiais abertas em floresta secundária no Parque Estadual da Cantareira (PEC), sudeste do Brasil. A distribuição de frequência de síndromes de dispersão para espécies e a taxa de redução da abundância das espécies pioneiras em um gráfico de rol de abundância não diferiram entre as duas áreas. As curvas de rarefação para riqueza de espécies e diversidade do PEC ficaram abaixo das curvas correspondentes da FEA. As proporções de espécies não pioneiras e de indivíduos de espécies não pioneiras foram maiores na FEA. A distribuição de frequência de síndromes de dispersão para indivíduos diferiu entre as duas áreas devido a uma predominância mais acentuada de zoocoria na FEA. A taxa de redução da abundância das espécies não pioneiras em um gráfico de rol de abundância foi menor na FEA. Concluiu-se que a restauração passiva pode recuperar atributos da vegetação nativa após o corte raso de plantações florestais desprovidas de conspícua regeneração de espécies nativas no sub-bosque. No entanto, esse fenômeno pode ser influenciado por propriedades particulares da espécie florestal, práticas de exploração e integridade da dispersão de sementes pela fauna.

Litter production and nutrient cycling in two plantations and a Podocarpus falcatus dominated natural forest ecosystems in south-eastern highlands of Ethiopia

The production of litter plays a fundamental role in the biogeochemical cycle of organic matter and mineral nutrients in forest ecosystems. The amount of litter produced and nutrients returned, and their accumulation in the organic layers of Eucalyptus globulus and Cupressus lusitanica plantations, and an adjacent Podocarpus falcatus dominated natural forest were monitored over a one year period in Ethiopia. The objective of the study was to asses the general trends of nutrient cycling by litter fall under the two plantations relative to the natural forest. The results showed that annual litter production was significantly highest in the natural forest (4.4 t ha-1year-1) and least in Cupressus plantation (2.2 t ha-1year-1). Litter fall in the natural forest was of high quality and richer in most nutrients than the two plantations which behaved similarly. The annual fluxes of N, S, P, Ca, Mg and K were 1.3 to 2.3 times as much in the natural forest as in Eucalyptus and Cupressus. The organic layer under Cupressus had poor quality litter compared to Eucalyptus and natural forest which behaved similarly mainly due to the influence of the understorey vegetation on Eucalyptus organic layer. Although statistically not significant, dry mass accumulation in the organic layer of Cupressus was higher than in Eucalyptus and lower than in the natural forest, but the approximate residence time was in the order: Cupressus >natural forest>Eucalyptus. The organic layer in the natural forest had always the maximum quantity of nutrients compared to the two plantations. Except for Ca in which Cupressus far better, the other elements were accumulated in larger quantity in the Eucalyptus organic layer than in Cupressus. Overall, the results show that the Cupressus plantation is poor self fertilizing owing to the low quality homogenous materials which could result in a gradual impoverishment of the soil. Key words: Cupressus, Ethiopia, Eucalyptus, litter fall, nutrient cycling, organic layer.

Models for estimation of carbon sequestered by Cupressus lusitanica plantation stands at Wondo Genet, Ethiopia

This study compared models for estimating carbon sequestered aboveground in Cupressus lusitanica plantation stands at Wondo Genet College of Forestry and Natural Resources, Ethiopia. Relationships of carbon storage with tree component and stand age were also investigated. Thirty trees of three different ages (5, 12 and 24 years), comprising 10 trees from each stand, were sampled in order to generate dry biomass and carbon data from tree components. Five linear and non-linear biomass and carbon models were compared and evaluated for estimation of overall aboveground carbon, carbon by age groups, and carbon by diameter at breast height (DBH) classes using performance indicator statistics. Among the models compared, a carbon model described by Y = b 0 D 2 H + ϵ (p-value < 0.001), where D = DBH (in cm), H = total height of the tree (in m), ϵ = error, and b 0 is a parameter, was found to be the best model for estimation of carbon sequestered aboveground in C. lusitanica plantation stands of the study area. The study also indicated the overall superiority of carbon models over biomass models in estimation of aboveground carbon of C. lusitanica. It was concluded that, for the range of DBH utilised in the current study, the carbon model described can be a useful tool in estimation of carbon storage of C. lusitanica plantations in the study area and other related sites.

Forest Management Influence on the Carbon Flux of Cupressus lusitanica Plantation in the Munessa Forest, Ethiopia

The effect of plantation forests on the global carbon balance is controversially discussed in recent times. As soil respiration is a decisive component in the carbon exchange between terrestrial ecosystems and atmosphere, effects of forest management measures (e.g. thinning) in the context of driving parameters of soil CO2 efflux is a key issue in optimizing carbon friendly land management. In the present study, we report the effects of thinning, soil temperature and soil moisture, and biotic parameters on soil CO2 efflux rate. Soil CO2 efflux was measured by using an Infrared Gas Analyzer. We selected thinned and un-thinned stands within six years old Cupressus lusitanica plantation forest. Soil respiration rate ranged from 1.47 to 6.92 µmol m-2s-1 (thinned) and 1.31 to 5.20 µmol m-2s-1 (control stand). Generally higher soil respiration rates were measured during wet than in dry season. Seasonal variability of soil CO2 efflux was significantly (p<0.05) correlated with soil moisture, but poorly correlated with soil temperature. Soil respiration increased with increasing soil moisture and reached maximum at 31% but after this threshold it start to decline. In general, soil CO2 efflux rate in the first and second year after thinning was 24% and 14% higher in the thinned stand. Increased soil temperature at the thinned stand contributed minor to the larger soil CO2 efflux, the more important reason appeared to be the trees’ direct response. Higher fine root production together with larger microbial concentrations representing different groups infers a higher autotrophic respiration by roots and associated mycorrhizal fungi as well as by heterotrophic respiration. Despite the higher CO2 losses with soil respiration, the organic C and total N concentrations in soil rather tended to increase, indicating higher organic matter input to soil at the thinned stand.

Dynamics of leaf litter humidity, depth and quantity: two restoration strategies failed to mimic ground microhabitat conditions of a low montane and premontane forest in Costa Rica.

Little is known about how restoration strategies affect aspects like leaf litter's quantity, depth and humidity. I analyzed leaf litter's quantity, depth and humidity yearly patterns in a primary tropical lower montane wet forest and two restored areas: a 15 year old secondary forest (unassisted restoration) and a 40 year old Cupressus lusitanica plantation (natural understory). The three habitats are located in the Rio Macho Forest Reserve, Costa Rica. Twenty litter samples were taken every three months (April 2009-April 2010) in each habitat; humidity was measured in 439g samples (average), depth and quantity were measured in five points inside 50x50cm plots. None of the restoration strategies reproduced the primary forest leaf litter humidity, depth and quantity yearly patterns. Primary forest leaf litter humidity was higher and more stable (mean=73.2), followed by secondary forest (mean=63.3) and cypress plantation (mean=52.9) (Kruskall-Wallis=77.93, n=232, p=0.00). In the primary (Kruskal-Wallis=31.63, n=78, p<0.001) and secondary (Kruskal-Wallis=11.79, n=75, p=0.008) forest litter accumulation was higher during April due to strong winds. In the primary forest (Kruskal-wallis=21.83, n=78, p<0.001) and the cypress plantation (Kruskal-wallis=39.99, n=80, p<0.001) leaf litter depth was shallow in October because heavy rains compacted it. Depth patterns were different from quantity patterns and described the leaf litter's structure in different ecosystems though the year. September 01.

Status of Native Woody Species Diversity and Soil Characteristics in an Exclosure and in Plantations ofEucalyptus globulusandCupressus lusitanicain Northern Ethiopia

Exclusion of grazing animals and tree plantations are 2 methods that have been used for restoration of degraded lands in tropical semiarid areas. These 2 options can foster secondary forest succession by improving soil conditions, attracting seed-dispersal agents, and modifying microclimate for understory growth. We compared native woody plant diversity and soil chemical and physical attributes under exclosure and on Eucalyptus globulus (EGP) and Cupressus lusitanica (CLP) plantations. Vegetation data were collected by an inventory of stands with circular plots of 5.64 m radius, and soil samples were collected from the 4 corners and center of 20 3 20 m plots. As a result, 15 native woody plant species belonging to 13 families were recorded. Importance value index (IVI), Shannon-Wiener, Simpson’s diversity, and species richness were higher in the exclosure, followed by EGP and CLP. Contents of soil organic carbon and total nitrogen showed significance difference and were highest in the exclosure, followed by CLP, EGP, and grazing land. Although the difference was not significant, an increasing trend was observed for cation exchange capacity and K + . Bulk density was highest on the grazing land, followed by EGP, CLP, and exclosure. Our results suggest that degraded land reclamation can be achieved with plantation of rapidly growing tree species as well as exclosure. However, native woody species diversity and improved soil attributes are better achieved with exclosure. Exclosures can be established interspersed strategically with single- or mixed-species plantations to facilitate restoration of native vegetation. However, it is important to conduct further research on the comparative advantage of enrichment planting of exclosures with preferred tree species or exclosures interspersed within blocks of plantation.

Tree taper models for Cupressus lusitanica plantations in Ethiopia

To provide a taper model for planning and management of Cupressus lusitanica plantations in Ethiopia, seven taper models were compared. Four performance indicator statistics were used for comparing the models in their ability to estimate tree diameter, and total and merchantable volumes. For the selected species, Kozak (1988) was found to be the best, followed by modified Lee et al. (2003) and Kozak (2004) as second and third best taper models, respectively. Both the Kozak (Kozak, 1988, 2004) and the modified Lee et al. (2003) models were very flexible in capturing the different shapes of trees. In particular, Kozak (2004) proved to be best of all models in diameter estimation even though it was found to be inferior to the Kozak (1988) and modified Lee et al. (2003) models for total and merchantable volume estimation. To understand the influence of the inflection point p in the Kozak (1988) model, Monte Carlo simulation was used to examine sensitivity of the model performance against inflection point p. In this effort, slightly lower standard errors were observed for p between 0.1 and 0.3. Mixed effects modeling was also used to further study the inflection point p as a random effect. The empirical Bayes estimates of the random effects were found to vary from tree to tree and also appear to depend on tree size. The results from both the Monte Carlo and mixed effects modeling study seem to indicate the need to estimate p from the data.

Site index functions for Cupressus lusitanica at Munesa Shashemene, Ethiopia

In 25 permanent sample plots in Cupressus lusitanica plantations of the Munesa Shashemene Wood Industry Enterprise, in the Oromia Federal Regional State, Ethiopia, the dominant height growth was observed and site index functions fitted. The plots had been continuously observed from ages 7 (10) to 21 (18) in the Gambo–Shashemene and the Munesa growth districts, respectively. Measurements in each plot were taken 5–8 times, altogether a total of 163 observations were available. Parameterising the general Chapman–Richards function, showed that (i) no point of inflection within the range of the data was found, (ii) the growth rate parameter, k, of the model did not depend on site index, and (iii) the growth rate parameter, k, and thus the shape of the height growth curves differed significantly between the Gambo–Shashemene and Munesa growth districts. Previous site index curves for the same region fitted well for the Gambo–Shashemene district but not so for Munesa. Therefore, it is concluded that when developing and using site index functions, growth districts as a possible reason for different shapes have to be taken into account.

Photosynthetically active radiation transmittance of forest plantation canopies in the Ethiopian highlands

Hemispherical photographs and a quantum sensor were used to study the canopy photosynthetic photon flux density (PPFD) transmittance of five forest plantation species in Ethiopia. Red/far-red (R/FR) ratios and temperatures beneath the forest plantations were also measured. The species studied were: Eucalyptus globulus, Pinus patula, Cupressus lusitanica, Grevillea robusta, and Juniperus procera. The canopies of E. globulus, P. patula and G. robusta transmitted about three times as much PPFD as J. procera or C. lusitanica plantations. Furthermore, plantations of G. robusta and E. globulus had the highest, while J. procera had the lowest R/FR ratio. In contrast to J. procera and C. lusitanica, E. globulus and G. robusta had relatively open crowns, higher crown-bases and lower leaf area indices, and as a result, their canopies had higher PPFD transmittance percentages as well as higher below-canopy R/FR ratios and temperatures. From the perspective of understory light regime, plantations of E. globulus and G. robusta are best suited for promoting the natural regeneration of native species. In general, opening of gaps in plantations of heavy-shading tree species may increase the herbaceous layer ground cover, enhance the colonisation and growth of native woody species and consequently may also increase the floristic diversity of mono-specific plantations.

The effect of abandoned plantations of Pinus patula and Cupressus lusitanica on soilsand regeneration of a tropical montane rain forest in Colombia

Species richness and diversity and soil physical and chemical properties were compared between a mature lower montane rain forest (LMRF) and abandoned 21-year-old plantations of introduced Pinus patula and Cupressus lusitanica in the central Andes of Colombia (2000m). In 0.1ha plots, species richness (number of species) and diversity (Shannon and Simpson indexes) were higher in the LMRF, followed by P. patula and C. lusitanica plantations. There were 56species and 30families of higher plants in the LMRF, 26species and 15families in the P. patula plantation, and 18species and 10families in the C. lusitanica plantation. There were no statistically significant differences (p<0.05) in soil physical or chemical properties between P. patula, C. lusitanica and native LMRF. Nevertheless, soil carbon, the C/N ratio and total bases tended to be higher in the native forest than in the plantations. Available P tended to be higher in the P. patula plantation. These results show that, although abandoned plantations can support some native species, particularly in the understorey, species richness is far from that of the native forest.

Comparisons of Understorey Vegetation and Soil Fertility in Plantations and Adjacent Natural Forests in the Ethiopian Highlands

Eighty-three plantations and adjacent natural forest stands in highland Ethiopia were analysed for herbaceous plant cover and biomass, species richness, and soil physical and chemical characteristics, in order to reveal the impact of plantation establishment. Climatic (temperature and rainfall) and altitudinal control over the distribution of herbaceous plant species in the forests was exposed by canonical correspondence analysis, and the areas of sampling were segregated on the basis of the gradients this revealed. Sites at higher altitudes were characterized by tall trees with large basal area, and by soil with a high organic matter, high N content and low pH. In contrast to the frequent view of eucalypts as harmful for understorey plants, the richness and biomass of herbaceous plant species in plantations of Eucalyptus spp., and also of Pinus patula, was as high as that of natural forests. However, most of the herbs in the plantations were widespread species, mainly weeds or species invading from montane or wooded grassland. The herbaceous vegetation in Cupressus lusitanica plantations older than 9 years was distinct in composition, less diverse, and much reduced in terms of cover and biomass compared with similarly aged plantations of Eucalyptus globulus, E. grandis, E. saligna, Pinus patula and with natural forests. Cupressus lusitanica should therefore not be planted because of the risk of soil erosion. The overall soil characteristics of the natural forests differed from those of the five most common plantation tree species, as revealed by redundancy analysis. Natural forest soil had a higher content of total N, available P and exchangeable Ca (in the case of P as much as 4-25 times higher), possibly owing to a combination of loss of organic matter during conversion of natural forest to plantations, increased leaching in young plantations, and low nutrient demand by natural forest trees as compared with fast-growing exotics.

Exotic tree plantations and the regeneration of natural forests in Kibale National Park, Uganda

Exotic tree plantations have been considered as a management strategy for the rehabilitation of indigenous tree communities in situations that require human intervention to assure forest ecosystem rehabilitation. This study evaluated the value of pine Pinus caribaea and Pinus patula and cypress Cupressus lusitanica plantations as a means of permitting indigenous trees to become established on derelict land in the Kibale National Park (766 km 2) of western Uganda. We present data on the size and density of indigenous trees >2 m tall growing in 80 (10 m × 10 m) quadrats in plantation areas before and after plantation harvest. Species richness for indigenous trees was high in the plantation areas; 47 species of indigenous trees were found in the 0·8 ha sampled, as compared to 78 species in a 5·4 ha area of intact forest. The number of indigenous trees in the quadrats varied from five to 38. There was no significant difference in species richness or density between areas of logged and unlogged P. patula. However, damage resulting from the logging operation was evident and may affect longer term regeneration patterns. Recommendations and cautionary remarks are made with respect to using plantations as a management scheme to rehabilitate indigenous tree communities in derelict areas.

Effect of thinning on biophysical soil properties of Cupressus lusitanica stand in Munessa forest, Ethiopia

Forest management practices such as thinning can dramatically change the microenvironment and thereby affect the physicochemical and soil microbiological properties. The aim of this research was to determine the effect of thinning on soil physicochemical properties and microbial biomass under Cupressus lusitanica plantation at Munessa forest. The experiment was carried out in a fenced stand treated differently (thinned and unthinned plots) with a completely randomized design. In each plot, 20 sampling spots were randomly selected for soil sample collection from 0 to 10 cm and 10 to 25 cm depth. Independent t-test was used to compare effects of thinning on biophysical properties of the soil. Results showed that soil organic carbon (SOC) and total nitrogen varied significantly between treatments. SOC concentration was generally lower at the soil depth of 0-10 to 10-25 cm. The concentrations of microbial biomarker used as a proxy for microbial biomass assessment were 22% larger in thinned stands. Soils under the thinned stand contained larger concentration of arbuscular mycorrhizal fungi biomarker. The two forest stands were established at the same time with the same stocking and hence differences in soil quality could be possibly resulted from management intervention. These findings showed that Cupressus thinning could enhance biomass accumulation and organic C input to the soil.